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  • 51.
    Li, Han
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Jobs, Magnus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Santiago Kern, Rocio
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Goryashko, Vitaliy A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Hermansson, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Bhattacharyya, Anirban
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Lofnes, Tor
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Gajewski, Konrad
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Fransson, Kjell
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Ruber, Roger
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Characterization of a beta=0.5 double spoke cavity with a fixed power coupler2019Ingår i: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 927, s. 63-69Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    ESS, the European Spallation Source, will adopt a single family of double spoke cavities for accelerating the beam from the normal conducting section to the first family of the elliptical superconducting cavities. It will be the first double spoke cavities in the world to be commissioned for a high power proton accelerator. The first double spoke cavity for the ESS project was tested with high power in the HNOSS cryostat at Uppsala University. A pulse-mode test stand based on a self-excited loop was used in this test. The qualification of the cavity package involves a double-spoke superconducting cavity, a fixed fundamental power coupler, tuner, a low-level radiofrequency (LLRF) system and a high-power radiofrequency (RF) station. The test represents an important verification milestone before the module assembly. This cavity had unfortunately a high dynamic loss of 12W @ 9 MV/m, where potential causes for such a high value have been studied and corresponding suggestions are listed. This paper presents the test configuration, RF conditioning history, first high power performance and experience of this cavity package.

  • 52.
    Li, Han
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Maiano, Cecilia
    ESS.
    Conejero, Emilio
    ESS.
    Zeng, Rihua
    ESS.
    An optimal procedure for coupler conditioning for ESS superconducting LINAC2017Ingår i: Proceedings of SRF2017, 2017Konferensbidrag (Övrigt vetenskapligt)
  • 53.
    Li, Han
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Santiago-Kern, Rocio
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Jobs, Magnus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Bhattacharyya, Anirban
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Goryashko, Vitaliy
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Hermansson, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Gajewski, Konrad
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Lofnes, Tor
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Fransson, Kjell
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Ruber, Roger
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    First High Power Test of the ESS Double Spoke Cavity2017Rapport (Övrigt vetenskapligt)
    Abstract [en]

    The first double spoke cavity for ESS project was tested with high power in the HNOSS cryostat at FREIA Laboratory. This cavity is designed for 325.21MHz, a pulse mode with 14 Hz repetition rate, up to peak power of 360 kW. The qualification of the cavity package in a high power test, involved a spoke superconducting cavity, a fundamental power coupler, LLRF system and a RF station, represented an important verification before the module assembly. This report presents the test configuration, RF conditioning history and first high power performance of this cavity package.

  • 54.
    Li, Han
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Santiago-Kern, Rocio
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Jobs, Magnus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Hermansson, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Gajewski, Konrad
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Lofnes, Tor
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Fransson, Kjell
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Ruber, Roger
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    First High Power Test of the ESS High Beta Elliptical Cavity package2018Rapport (Övrigt vetenskapligt)
    Abstract [en]

    The first high-beta elliptical cavity for ESS project was tested with high power in the HNOSS cryostat at FREIA Laboratory.  This cavity is designed for 704.42 MHz, a pulse mode with 14 Hz repetition rate, up to peak power of 1.5 MW. The qualification of the cavity package in a high power test, involved an elliptical superconducting cavity, a fundamental power coupler, cold tuning system, LLRF system and klystron system, represented an important verification before the module assembly. This report presents the test configuration, RF conditioning history and first high power performance of this cavity package.

  • 55.
    Mak, Alan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Salén, Peter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Goryashko, Vitaliy
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Compact undulator line for a high-brilliance soft-X-ray free-electron laser at MAX IV2019Ingår i: Journal of Synchrotron Radiation, ISSN 0909-0495, E-ISSN 1600-5775, Vol. 26, s. 891-898Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The optimal parameter space for an X-ray free-electron laser (FEL) in the self-amplified spontaneous emission (SASE) operation mode is examined. This study focuses on FEL operation with a shorter undulator period and higher undulator strength made available through recent developments in in-vacuum, cryogenic and superconducting undulators. Progress on short-period undulator technologies is surveyed and FEL output characteristics versus undulator parameters are computed. The study is performed on a case of the planned soft-X-ray FEL at the MAX IV Laboratory in Sweden. An extension of the SASE mode into the harmonic lasing self-seeded mode is also analysed.

  • 56.
    Mak, Alan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Salén, Peter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Goryashko, Vitaliy
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Undulator Considerations in the Baseline Design of the MAX IV Soft X-Ray Laser2018Rapport (Övrigt vetenskapligt)
    Abstract [en]

    We examine the optimal parameter space for an x-ray free-electron laser (FEL) in the operation mode of self-amplified spontaneous emission (SASE). The study focuses on FEL operation with a shorter undulator period and higher undulator strength made available through recent developments in in-vacuum, cryogenic and superconducting undulators. We survey the progress on short-period undulator technologies and compute the FEL output characteristics versus the undulator parameters. We perform the study on a case of the planned soft-x-ray FEL at the MAX IV Laboratory in Sweden. An extension of the SASE mode into the harmonic lasing self-seeded mode is also analysed.

  • 57.
    Mak, Alan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Salén, Peter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Goryashko, Vitaliy
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Clarke, Jim
    STFC Daresbury Laboratory, Warrington, United Kingdom.
    Science Requirements and Performance Specification forthe CompactLight X-Ray Free-Electron Laser2019Rapport (Övrigt vetenskapligt)
    Abstract [en]

    CompactLight is a consortium funded by the European Union through the Horizon 2020 Research and Innovation Programme under Grant Agreement No. 777431.  This report summarizes science requirements and performance specification for the CompactLight x-ray free-electron laser. 

  • 58.
    Mak, Alan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Shamuilov, Georgii
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Salén, Peter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA. Stockholm Univ, Stockholm, Sweden.
    Dunning, David
    Cockcroft Inst, Warrington, Cheshire, England;STFC Daresbury Lab, Warrington, Cheshire, England.
    Hebling, Janos
    Univ Pecs, Pecs, Hungary.
    Kida, Yuichiro
    SPring 8 Ctr, RIKEN, Kobe, Hyogo, Japan.
    Kinjo, Ryota
    SPring 8 Ctr, RIKEN, Kobe, Hyogo, Japan.
    McNeil, Brian W. J.
    Cockcroft Inst, Warrington, Cheshire, England;Univ Strathclyde, Dept Phys, SUPA, Glasgow, Lanark, Scotland.
    Tanaka, Takashi
    SPring 8 Ctr, RIKEN, Kobe, Hyogo, Japan.
    Thompson, Neil
    Cockcroft Inst, Warrington, Cheshire, England;STFC Daresbury Lab, Warrington, Cheshire, England.
    Tibai, Zoltan
    Univ Pecs, Pecs, Hungary.
    Toth, Gyorgy
    Univ Pecs, Pecs, Hungary.
    Goryashko, Vitaliy
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Attosecond single-cycle undulator light: a review2019Ingår i: Reports on progress in physics (Print), ISSN 0034-4885, E-ISSN 1361-6633, Vol. 82, nr 2, artikel-id 025901Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Research at modern light sources continues to improve our knowledge of the natural world, from the subtle workings of life to matter under extreme conditions. Free-electron lasers, for instance, have enabled the characterization of biomolecular structures with sub-angstrom spatial resolution, and paved the way to controlling the molecular functions. On the other hand, attosecond temporal resolution is necessary to broaden our scope of the ultrafast world. Here we discuss attosecond pulse generation beyond present capabilities. Furthermore, we review three recently proposed methods of generating attosecond x-ray pulses. These novel methods exploit the coherent radiation of microbunched electrons in undulators and the tailoring of the emitted wavefronts. The computed pulse energy outperforms pre-existing technologies by three orders of magnitude. Specifically, our simulations of the proposed Soft X-ray Laser at MAX IV (Lund, Sweden) show that a pulse duration of 50-100 as and a pulse energy up to 5 mu J is feasible with the novel methods. In addition, the methods feature pulse shape control, enable the incorporation of orbital angular momentum, and can be used in combination with modern compact free-electron laser setups.

  • 59.
    Mangiarotti, Franco
    et al.
    CERN, CH-1211 Geneva, Switzerland.
    Bajas, Hugues
    CERN, CH-1211 Geneva, Switzerland.
    Ambrosio, Giorgio
    FNAL, POB 500, Batavia, IL 60510 USA.
    Bajko, Marta
    CERN, CH-1211 Geneva, Switzerland.
    Bordini, Bernardo
    CERN, CH-1211 Geneva, Switzerland.
    Bourcey, Nicolas
    CERN, CH-1211 Geneva, Switzerland.
    Duda, Michal
    CERN, CH-1211 Geneva, Switzerland;IFJ PAN, PL-31342 Krakow, Poland.
    Desbiolles, Vincent
    CERN, CH-1211 Geneva, Switzerland.
    Feuvrier, Jerome
    CERN, CH-1211 Geneva, Switzerland.
    Fleiter, Jerome
    CERN, CH-1211 Geneva, Switzerland.
    Bermudez, Susana Izquierdo
    CERN, CH-1211 Geneva, Switzerland.
    Chiuchiolo, Antonella
    CERN, CH-1211 Geneva, Switzerland.
    Devred, Arnaud
    CERN, CH-1211 Geneva, Switzerland.
    Ferracin, Paolo
    CERN, CH-1211 Geneva, Switzerland.
    Fiscarelli, Lucio
    CERN, CH-1211 Geneva, Switzerland.
    Mentink, Matthias
    CERN, CH-1211 Geneva, Switzerland.
    Nobrega, Alfred
    FNAL, POB 500, Batavia, IL 60510 USA.
    Pepitone, Kevin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Ravaioli, Emmanuele
    CERN, CH-1211 Geneva, Switzerland.
    Schmalzle, Jesse
    BNL, Upton, NY 11973 USA.
    Todesco, Ezio
    CERN, CH-1211 Geneva, Switzerland.
    Perez, Juan Carlos
    CERN, CH-1211 Geneva, Switzerland.
    Vallone, Giorgio
    LBL, Berkeley, CA 94720 USA.
    Willering, Gerard
    CERN, CH-1211 Geneva, Switzerland.
    Yu, Miao
    FNAL, POB 500, Batavia, IL 60510 USA.
    Test Results of the CERN HL-LHC Low-beta Quadrupole Short Models MQXFS3c and MQXFS42019Ingår i: IEEE transactions on applied superconductivity (Print), ISSN 1051-8223, E-ISSN 1558-2515, Vol. 29, nr 5, artikel-id 4001705Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    For the high luminosity upgrade of the CERN large hadron collider, lower beta* quadrupole magnets based on advanced Nb3Sn conductors will be installed on each side of the ATLAS and compact muon solenoid (CMS) experiment insertion zones. As part of the technological developments needed to achieve the required field gradient of 132.6 T/m within a 150-mm aperture, short length model magnets, named MQXFS, are tested both at the CERN SM18 and Fermilab test facilities. The model magnets rely on two types of Nb3Sn conductors (restack rod process (RRP) and powderin-tube (PIT)) and on an innovative bladders and keys design to provide mechanical support against the Lorentz forces. In 2016 and 2017, the powering tests of the first two models MQXFS3 (RRP) and MQXFS5 (PIT) proved that nominal performance (16.5 kA) could be reached with excellent memory of the quench current after thermal cycle. However both magnets showed a slow training behavior with clear observations of voltage disturbances before the quench. Besides, only MQXFS5 could reach ultimate current (17.9 kA) whereas erratic behavior was observed on MQXFS3 due to conductor local degradation at the head of one of the coils. In 2018, this limiting coil was changed and the applied azimuthal prestress increased. While ultimate current could then be reached, no stable current could be maintained due to identified defect on the outer layer of the new coil. Finally the outcome of the test of the new model MQXFS4, featuring the final RRP conductors that will be used for the series production and variation on the inner layer quench heater designs are here reported in details.

  • 60.
    Mangiarotti, Franco J.
    et al.
    CERN, CH-1211 Geneva, Switzerland.
    Kirby, Glyn
    CERN, CH-1211 Geneva, Switzerland.
    Duda, Michal
    CERN, CH-1211 Geneva, Switzerland;IFJ PAN, PL-31342 Krakow, Poland.
    Mentink, Matthias
    CERN, CH-1211 Geneva, Switzerland.
    Fiscarelli, Lucio
    CERN, CH-1211 Geneva, Switzerland.
    Bajko, Marta
    CERN, CH-1211 Geneva, Switzerland.
    Coll, Dominic
    M&I Mat, Manchester M32 0ZD, Lancs, England.
    Desbiolles, Vincent
    CERN, CH-1211 Geneva, Switzerland.
    Feuvrier, Jerome
    CERN, CH-1211 Geneva, Switzerland.
    Mazet, Jacky
    CERN, CH-1211 Geneva, Switzerland.
    Van Nugteren, Jeroen
    CERN, CH-1211 Geneva, Switzerland.
    Pepitone, Kevin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Pincot, Francois-Olivier
    CERN, CH-1211 Geneva, Switzerland.
    de Rijk, Gijs
    CERN, CH-1211 Geneva, Switzerland.
    Robertson, Jeff
    M&I Mat, Manchester M32 0ZD, Lancs, England.
    Steckert, Jens
    CERN, CH-1211 Geneva, Switzerland.
    Todesco, Ezio
    CERN, CH-1211 Geneva, Switzerland.
    Willering, Gerard
    CERN, CH-1211 Geneva, Switzerland.
    Test of Short Model and Prototype of the HL-LHC D2 Orbit Corrector Based on CCT Technology2019Ingår i: IEEE transactions on applied superconductivity (Print), ISSN 1051-8223, E-ISSN 1558-2515, Vol. 29, nr 5, artikel-id 4002305Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the frame of the high-luminosity upgrade project for the large hadron collider, new twin aperture beam orbit corrector magnets will be installed near the recombination dipole (D2). These magnets are 2.2 m long canted cosine theta NbTi dipoles, with two independently powered apertures oriented such that their field vectors are perpendicular to each other and to the direction of the beams. A 0.5 m model magnet in single and double aperture configuration and a full-length double aperture prototype were built and tested at CERN. In this paper, the performance of these magnets at 1.9 K in terms of training behavior, quench detection and protection, and other tests is discussed. In addition, the thermal response of the magnet to a hypothetical beam discharge is simulated and analyzed.

  • 61.
    Novotny, O.
    et al.
    Max Planck Inst Nucl Phys, D-69117 Heidelberg, Germany.;Columbia Univ, Columbia Astrophys Lab, 538 W 120th St, New York, NY 10027 USA..
    Buhr, H.
    Max Planck Inst Nucl Phys, D-69117 Heidelberg, Germany.;Weizmann Inst Sci, Fac Phys, IL-76100 Rehovot, Israel..
    Geppert, W.
    Stockholm Univ, Dept Phys, AlbaNova, SE-10691 Stockholm, Sweden..
    Grieser, M.
    Max Planck Inst Nucl Phys, D-69117 Heidelberg, Germany..
    Hamberg, Mathias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA. Stockholm Univ, Dept Phys, AlbaNova, SE-10691 Stockholm, Sweden..
    Krantz, C.
    Max Planck Inst Nucl Phys, D-69117 Heidelberg, Germany..
    Mendes, M. B.
    Max Planck Inst Nucl Phys, D-69117 Heidelberg, Germany..
    Petrignani, A.
    Max Planck Inst Nucl Phys, D-69117 Heidelberg, Germany.;Univ Amsterdam, Sci Pk 904, NL-1098 XH Amsterdam, Netherlands..
    Repnow, R.
    Max Planck Inst Nucl Phys, D-69117 Heidelberg, Germany..
    Savin, D. W.
    Columbia Univ, Columbia Astrophys Lab, 538 W 120th St, New York, NY 10027 USA..
    Schwalm, D.
    Max Planck Inst Nucl Phys, D-69117 Heidelberg, Germany.;Weizmann Inst Sci, Fac Phys, IL-76100 Rehovot, Israel..
    Stutzel, J.
    Max Planck Inst Nucl Phys, D-69117 Heidelberg, Germany..
    Wolf, A.
    Max Planck Inst Nucl Phys, D-69117 Heidelberg, Germany..
    Dissociative Recombination Measurements of Chloronium Ions (D2Cl+) Using an Ion Storage Ring2018Ingår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 862, nr 2, artikel-id 166Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report our plasma rate coefficient and branching ratio measurements for dissociative recombination (DR) of D2Cl+ with electrons. The studies were performed in a merged-beams configuration using the TSR heavy-ion storage ring located at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. Starting with our absolute merged-beams recombination rate coefficient at a collision energy of approximate to 0 eV, we have extracted the cross section and produced a plasma rate coefficient for a translational temperature of approximate to 8 K. Furthermore, extrapolating our cross-section results using the typical low-energy DR behavior, we have generated a plasma rate coefficient for translational temperatures from 5 to 500 K. We find good agreement between our extrapolated results and previous experimental DR studies on D2Cl+. Additionally, we have investigated the three fragmentation channels for DR of D2Cl+. Here we report on the dissociation geometry of the three-body fragmentation channel, the kinetic energy released for each of the three outgoing channels, the molecular internal excitation for the two outgoing channels that produce molecular fragments, and the fragmentation branching ratios for all three channels. Our results, in combination with those of other groups, indicate that any remaining uncertainties in the DR rate coefficient for H2Cl+ appear unlikely to explain the observed discrepancies between the inferred abundances of HCl and H2Cl+ in molecular clouds and predictions from astrochemical models.

  • 62.
    Opanasenko, A. M.
    et al.
    Natl Sci Ctr, Kharkov Inst Phys & Technol, Kharkov, Ukraine.
    Goryashko, Vitaliy
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Multislice Model Of Electron Bunch For Study Of Ballistic Bunching Of Low Emittance Beams2018Ingår i: Problems Of Atomic Science And Technology, ISSN 1562-6016, nr 3, s. 73-80Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    At ballistic bunching of an electron beam the transverse distribution of space-charge field varies along a bunch greatly. It can lead to emittance growth unless to provide its compensation. To study this problem, a multislice model of a bunch of relativistic charged particles that needs no smallness of energy spread between slices are developed. This removes the limit on the value of the RF field that modulates the slices by velocity before their injection into a drift space. The longitudinal dynamics of each slice is determined by its interaction with the field of the entire bunch averaged over the slice. Transverse beam characteristics are found from a differential equation for root-mean-square envelope of a beam.

  • 63.
    Opanasenko, A.
    et al.
    NSC KIPT, Acad Skay 1, UA-61108 Kharkov, Ukraine.
    Mytrochenko, V.
    NSC KIPT, Acad Skay 1, UA-61108 Kharkov, Ukraine.
    Zhaunerchyk, V.
    Univ Gothenburg, Kemivagen 9, S-41296 Gothenburg, Sweden.
    Goryashko, Vitaliy
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Design study of a low-emittance high-repetition rate thermionic rf gun2017Ingår i: PHYSICAL REVIEW ACCELERATORS AND BEAMS, ISSN 2469-9888, Vol. 20, nr 5, artikel-id 053401Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We propose a novel gridless continuous-wave radiofrequency (rf) thermionic gun capable of generating nC ns electron bunches with a rms normalized slice emittance close to the thermal level of 0.3 mm mrad. In order to gate the electron emission, an externally heated thermionic cathode is installed into a stripline-loop conductor. Two high-voltage pulses propagating towards each other in the stripline-loop overlap in the cathode region and create a quasielectrostatic field gating the electron emission. The repetition rate of pulses is variable and can reach up to one MHz with modern solid-state pulsers. The stripline attached to a rf gun cavity wall has with the wall a common aperture that allows the electrons to be injected into the rf cavity for further acceleration. Thanks to this innovative gridless design, simulations suggest that the bunch emittance is approximately at the thermal level after the bunch injection into the cavity provided that the geometry of the cathode and aperture are properly designed. Specifically, a concave cathode is adopted to imprint an.-shaped distribution onto the beam transverse phase-space to compensate for an S-shaped beam distribution created by the spherical aberration of the aperture-cavity region. In order to compensate for the energy spread caused by rf fields of the rf gun cavity, a 3rd harmonic cavity is used. A detailed study of the electrodynamics of the stripline and rf gun cavity as well as the beam optics and bunch dynamics are presented.

  • 64.
    Persson, Daniel
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Application of GEANT4 toolkit for simulations of high gradient phenomena2018Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    To study electron emissions and dark currents in the accelerating structures in particle colliders, a test facility with a spectrometer has been constructed at CERN. This spectrometer has been simulated in the C++ toolkit GEANT4 and in this project the simulation has been improved to handle new realistic input data of the emitted electrons. The goal was to find relations between where the electrons are emitted inside the accelerating structure and the energy or position of the particles measured by the spectrometer. The result was that there is a linear relation between the initial position of the electrons and the width in the positions of the particles measured by the spectrometer. It also appears to be a relations between energy the emitted electrons get in the accelerating structure, which is related to the position, and the energy they deposit in the spectrometer. Further studies where the simulations are compared with real measurement data are required to determine whether these relations are true or not, find better reliability in the relations and get a better understanding of the phenomena.

  • 65. Quirante, J. L. Navarro
    et al.
    Corsini, R.
    Grudiev, A.
    Lefevre, T.
    Mazzoni, S.
    Pan, R.
    Tecker, F.
    Farabolini, W.
    Peuger, F.
    Gamba, D.
    Yaqub, K.
    Ögren, Jim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi.
    Ruber, Roger
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Vitoratou, N.
    CALIFES: A Multi-Purpose Electron Beam for Accelerator Technology Tests2014Ingår i: Proceedings, 27th Linear Accelerator Conference, LINAC2014: Geneva, Switzerland, August 31-September 5, 2014, 2014Konferensbidrag (Övrigt vetenskapligt)
  • 66.
    Reid, A. H.
    et al.
    SLAC Natl Accelerator Lab, Stanford Inst Mat & Energy Sci, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA.;SLAC Natl Accelerator Lab, Linac Coherent Light Source, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA..
    Shen, X.
    SLAC Natl Accelerator Lab, Accelerator Div, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA..
    Maldonado, Pablo
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Chase, T.
    SLAC Natl Accelerator Lab, Stanford Inst Mat & Energy Sci, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA.;Stanford Univ, Dept Appl Phys, Stanford, CA 94305 USA..
    Jal, E.
    SLAC Natl Accelerator Lab, Stanford Inst Mat & Energy Sci, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA.;Univ Paris 06, UPMC, Sorbonne Univ, CNRS,Lab Chim Phys Matiere & Rayonnement, F-75005 Paris, France..
    Granitzka, P. W.
    SLAC Natl Accelerator Lab, Stanford Inst Mat & Energy Sci, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA.;Univ Amsterdam, Van der Waals Zeeman Inst, NL-1018 XE Amsterdam, Netherlands..
    Carva, K.
    Charles Univ Prague, Dept Condensed Matter Phys, Fac Math & Phys, Ke Karlovu 5, CZ-12116 Prague 2, Czech Republic..
    Li, R. K.
    SLAC Natl Accelerator Lab, Accelerator Div, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA..
    Li, J.
    Brookhaven Natl Lab, Upton, NY 11973 USA..
    Wu, L.
    Brookhaven Natl Lab, Upton, NY 11973 USA..
    Vecchione, T.
    SLAC Natl Accelerator Lab, Accelerator Div, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA..
    Liu, T.
    SLAC Natl Accelerator Lab, Stanford Inst Mat & Energy Sci, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA.;Stanford Univ, Dept Phys, Stanford, CA 94305 USA..
    Chen, Z.
    SLAC Natl Accelerator Lab, Stanford Inst Mat & Energy Sci, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA.;Stanford Univ, Dept Phys, Stanford, CA 94305 USA..
    Higley, D. J.
    SLAC Natl Accelerator Lab, Stanford Inst Mat & Energy Sci, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA.;Stanford Univ, Dept Appl Phys, Stanford, CA 94305 USA..
    Hartmann, N.
    SLAC Natl Accelerator Lab, Linac Coherent Light Source, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA..
    Coffee, R.
    SLAC Natl Accelerator Lab, Linac Coherent Light Source, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA..
    Wu, J.
    SLAC Natl Accelerator Lab, Accelerator Div, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA..
    Dakovski, G. L.
    SLAC Natl Accelerator Lab, Linac Coherent Light Source, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA..
    Schlotter, W. F.
    SLAC Natl Accelerator Lab, Linac Coherent Light Source, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA..
    Ohldag, H.
    SLAC Natl Accelerator Lab, Stanford Synchrotron Radiat Lab, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA..
    Takahashi, Y. K.
    Natl Inst Mat Sci, Magnet Mat Unit, Tsukuba, Ibaraki 3050047, Japan..
    Mehta, V.
    HGST Western Digital Co, San Jose Res Ctr, 3403 Yerba Buena Rd, San Jose, CA 95135 USA.;Thomas J Watson Res Ctr, 1101 Kitchawan Rd, Yorktown Hts, NY 10598 USA..
    Hellwig, O.
    HGST Western Digital Co, San Jose Res Ctr, 3403 Yerba Buena Rd, San Jose, CA 95135 USA.;Tech Univ Chemnitz, Inst Phys, Reichenhainer Str 70, D-09107 Chemnitz, Germany.;Helmholtz Zentrum Dresden Rossendorf, Inst Ion Beam Phys & Mat Res, D-01328 Dresden, Germany..
    Fry, A.
    SLAC Natl Accelerator Lab, Linac Coherent Light Source, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA..
    Zhu, Y.
    Cao, J.
    Florida State Univ, Dept Phys, Tallahassee, FL 32310 USA.;Florida State Univ, Natl High Magnet Field Lab, Tallahassee, FL 32310 USA..
    Fullerton, E. E.
    Univ Calif San Diego, Ctr Memory & Recording Res, 9500 Gilman Dr, La Jolla, CA 92093 USA..
    Stohr, J.
    SLAC Natl Accelerator Lab, Stanford Inst Mat & Energy Sci, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA..
    Oppeneer, Peter M.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Wang, X. J.
    SLAC Natl Accelerator Lab, Accelerator Div, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA..
    Dürr, Hermann A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA. SLAC Natl Accelerator Lab, Stanford Inst Mat & Energy Sci, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA..
    Beyond a phenomenological description of magnetostriction2018Ingår i: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 9, artikel-id 388Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Magnetostriction, the strain induced by a change in magnetization, is a universal effect in magnetic materials. Owing to the difficulty in unraveling its microscopic origin, it has been largely treated phenomenologically. Here, we show how the source of magnetostriction-the underlying magnetoelastic stress-can be separated in the time domain, opening the door for an atomistic understanding. X-ray and electron diffraction are used to separate the subpicosecond spin and lattice responses of FePt nanoparticles. Following excitation with a 50-fs laser pulse, time-resolved X-ray diffraction demonstrates that magnetic order is lost within the nanoparticles with a time constant of 146 fs. Ultrafast electron diffraction reveals that this demagnetization is followed by an anisotropic, three-dimensional lattice motion. Analysis of the size, speed, and symmetry of the lattice motion, together with ab initio calculations accounting for the stresses due to electrons and phonons, allow us to reveal the magnetoelastic stress generated by demagnetization.

  • 67.
    Reid, A. H.
    et al.
    SLAC Natl Accelerator Lab, Stanford Inst Mat & Energy Sci, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA; SLAC Natl Accelerator Lab, Linac Coherent Light Source, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA.
    Shen, X.
    SLAC Natl Accelerator Lab, Accelerator Div, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA.
    Maldonado, Pablo
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Chase, T.
    SLAC Natl Accelerator Lab, Stanford Inst Mat & Energy Sci, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA; Stanford Univ, Dept Appl Phys, Stanford, CA 94305 USA.
    Jal, E.
    SLAC Natl Accelerator Lab, Stanford Inst Mat & Energy Sci, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA; UPMC Univ Paris 06, Sorbonne Univ, Lab Chim Phys Matiere & Rayonnement, CNRS, F-75005 Paris, France.
    Granitzka, P. W.
    SLAC Natl Accelerator Lab, Stanford Inst Mat & Energy Sci, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA; Univ Amsterdam, Van der Waals Zeeman Inst, NL-1018 XE Amsterdam, Netherlands.
    Carva, K.
    Charles Univ Prague, Dept Condensed Matter Phys, Fac Math & Phys, Ke Karlovu 5, CZ-12116 Prague 2, Czech Republic.
    Li, R. K.
    SLAC Natl Accelerator Lab, Accelerator Div, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA.
    Li, J.
    Brookhaven Natl Lab, Upton, NY 11973 USA.
    Wu, L.
    Brookhaven Natl Lab, Upton, NY 11973 USA.
    Vecchione, T.
    SLAC Natl Accelerator Lab, Accelerator Div, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA.
    Liu, T.
    SLAC Natl Accelerator Lab, Stanford Inst Mat & Energy Sci, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA; Stanford Univ, Dept Phys, Stanford, CA 94305 USA.
    Chen, Z.
    SLAC Natl Accelerator Lab, Stanford Inst Mat & Energy Sci, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA; Stanford Univ, Dept Phys, Stanford, CA 94305 USA.
    Higley, D. J.
    SLAC Natl Accelerator Lab, Stanford Inst Mat & Energy Sci, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA; Stanford Univ, Dept Appl Phys, Stanford, CA 94305 USA.
    Hartmann, N.
    SLAC Natl Accelerator Lab, Linac Coherent Light Source, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA.
    Coffee, R.
    SLAC Natl Accelerator Lab, Linac Coherent Light Source, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA.
    Wu, J.
    SLAC Natl Accelerator Lab, Accelerator Div, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA.
    Dakowski, G. L.
    SLAC Natl Accelerator Lab, Linac Coherent Light Source, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA.
    Schlotter, W. F.
    SLAC Natl Accelerator Lab, Linac Coherent Light Source, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA.
    Ohldag, H.
    SLAC Natl Accelerator Lab, Stanford Synchrotron Radiat Lab, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA.
    Takahashi, Y. K.
    Natl Inst Mat Sci, Magnet Mat Unit, Tsukuba, Ibaraki 3050047, Japan.
    Mehta, V.
    HGST, San Jose Res Ctr, 3403 Yerba Buena Rd, San Jose, CA 95135 USA; Thomas J Watson Res Ctr, 1101 Kitchawan Rd, Yorktown Hts, NY 10598 USA.
    Hellwig, O.
    HGST, San Jose Res Ctr, 3403 Yerba Buena Rd, San Jose, CA 95135 USA; Tech Univ Chemnitz, Inst Phys, Reichenhainer Str 70, D-09107 Chemnitz, Germany; Helmholtz Zentrum Dresden Rossendorf, Inst Ion Beam Phys & Mat Res, D-01328 Dresden, Germany.
    Fry, A.
    SLAC Natl Accelerator Lab, Linac Coherent Light Source, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA.
    Zhu, Y.
    Brookhaven Natl Lab, Upton, NY 11973 USA.
    Cao, J.
    Florida State Univ, Dept Phys, Tallahassee, FL 32310 USA; Florida State Univ, Natl High Magnet Field Lab, Tallahassee, FL 32310 USA.
    Fullerton, E. E.
    Univ Calif San Diego, Ctr Memory & Recording Res, 9500 Gilman Dr, La Jolla, CA 92093 USA.
    Stohr, J.
    SLAC Natl Accelerator Lab, Stanford Inst Mat & Energy Sci, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA.
    Oppeneer, Peter M.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Wang, X. J.
    SLAC Natl Accelerator Lab, Accelerator Div, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA.
    Dürr, Hermann A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA. SLAC Natl Accelerator Lab, Stanford Inst Mat & Energy Sci, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA.
    Publisher Correction: Beyond a phenomenological description of magnetostriction2018Ingår i: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 9, artikel-id 1035Artikel i tidskrift (Övrigt vetenskapligt)
  • 68.
    Salén, Peter
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA. Department of Physics, Stockholm University, Stockholm, Sweden.
    Schio, Luca
    Richter, Robert
    Alagia, Michele
    Stranges, Stefano
    Zhaunerchyk, Vitali
    Investigating core-excited states of nitrosyl chloride (ClNO) and their break-up dynamics following Auger decay2018Ingår i: The Journal of Chemical Physics, Vol. 149, nr 16, artikel-id 164305Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The fragmentation of ClNO upon resonant core-electron excitation to the LUMO and LUMO+1 orbitals at the N and O K-edges is investigated. The produced fragment ions were detected in coincidence with a position sensitive ion time-of-flight detector which enables deduction of the angular distribution of the ions. This facilitates a comparison between the two resonances and the two Kedges with respect to fragmentation time, transition dipole moment orientation, fragment yield of single-ion and ion-pair channels, and fragmentation mechanisms. We observe significant correlations between the core-excited site and the location of the bonds that are broken, as well as the dissociation time. Moreover, we observe preferential cleavage of specific bonds upon excitation to the LUMO and LUMO+1 states which can be attributed to their orbital character.

  • 69.
    Santiago Kern, Rocio
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Bhattacharyya, Anirban
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Gajewski, Konrad
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Goryashko, Vitaliy
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Hermansson, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Jobs, Magnus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Li, Han
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Lofnes, Tor
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Ruber, Roger
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Cryogenic Synopsis from the Testing of the Fully Equipped ESS’ Double Spoke Cavity Romea2017Rapport (Övrigt vetenskapligt)
  • 70.
    Santiago-Kern, Rocio
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Eriksson, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Hermansson, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Jönsson, Åke
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Cryogenic Settings for Testing of the Fully Equipped ESS' High Beta Cavity ESS086-P01 (Part I)2018Rapport (Övrigt vetenskapligt)
  • 71.
    Santiago-Kern, Rocio
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Eriksson, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Hermansson, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Jönsson, Åke
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Cryogenic Settings for Testing of the Fully Equipped ESS' High Beta Cavity ESS086-P01 (Part II)2018Rapport (Övrigt vetenskapligt)
  • 72.
    Santiago-Kern, Rocio
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Eriksson, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Hermansson, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Jönsson, Åke
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Cryogenic Settings for Testing ofthe Fully Equipped ESS’ Double Spoke Cavity Romea2017Rapport (Övrigt vetenskapligt)
  • 73.
    Santiago-Kern, Rocio
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Gajewski, Konrad
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Hermansson, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Jobs, Magnus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Li, Han
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Lofnes, Tor
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Ruber, Roger
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Cryogenic Synopsis from the Testing of the Fully Equipped ESS' High Beta Cavity ESS086-P01 (Part I)2018Rapport (Övrigt vetenskapligt)
  • 74.
    Santiago-Kern, Rocio
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Gajewski, Konrad
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Hermansson, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Jobs, Magnus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Li, Han
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Lofnes, Tor
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Ruber, Roger
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Cryogenic Synopsis from the Testing of the Fully Equipped ESS' High Beta Cavity ESS086-P01 (Part II)2018Rapport (Övrigt vetenskapligt)
  • 75.
    Shamuilov, Georgii
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Mak, Alan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Pepitone, Kevin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Goryashko, Vitaliy
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Child-Langmuir law for photoinjectors2018Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 113, nr 20, artikel-id 204103Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The space-charge field at the cathode limits the current density extracted from particle sources such as photoinjectors. For a long time, the maximum current has been estimated by using the classical Child-Langmuir law, which is derived with an assumption inconsistent with the conditions of modern laser-driven electron guns. Here, we introduce a theoretical model that accurately accounts for space-charge effects in transversely confined particle beams emerging from photocathodes. The model enables us to (i) determine the maximum current density extractable from the photocathode for an arbitrary cathode radius, (ii) reveal its dependence on the transverse profile of the particle beam, and (iii) predict its upper limit for structured beams such as the ones produced by surface-plasmon resonance-enhanced photocathodes.

  • 76.
    Shamuilov, Georgii
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Mak, Alan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Salén, Peter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Goryashko, Vitaliy
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Analytical model of waveform-controlled single-cycle light pulses from an undulator2018Ingår i: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 43, nr 4, s. 819-822Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This Letter builds upon a recent concept [Phys. Rev. Lett. 113, 104801 (2014)] for producing ultrashort optical pulses through the coherent radiation of electrons in an undulator. Each pulse contains only a single oscillation cycle, and has a controlled waveform (and hence a stable carrier-envelope phase). While the concept had been demonstrated numerically, this Letter provides an analytical model for the radiation mechanism, thereby revealing three key observations: (i) the correlation between the waveforms of the optical and undulator fields; (ii) the free-space dispersion of transversely confined light; and (iii) the dependence of the optical pulse shape on the undulator field strength.

  • 77.
    Simion, Patrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Implementation of a solenoidal magnetic field map in FLUKA2017Rapport (Övrigt vetenskapligt)
    Abstract [en]

    This report describes the creation of a solenoidal magnetic field in MATLAB and the process of integrating said field into the physics simulation program FLUKA as a magnetic field map.The implementation of an externally created field map in FLUKA was mainly accomplished through programming of the magfld.f user defined routine which is responsible for reading the map and for conveying the information to the simulation. In order to validate the magnetic field interpretation in FLUKA, charged pions were tracked through a solenoid magnet. The FLUKA simulation was compared with theoretical descriptions of the characteristics shown by a particle travelling inside a solenoid magnet in order to validate that the magnetic field behavedas intended. The method can be further developed to investigate the suitability of alternative pion collectors for producing well collimated, high intensity neutrino beams.

  • 78.
    Simion, Patrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Study of an Alternative Pion Collector Scheme for the ESS Neutrino Super Beam Project2019Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The ESSnuSB will produce a high intensity neutrino super beam based on the 3 ms long proton pulses at 14 Hz from the ESS linac. With the use of a conventional normal-conducting van der Meer horn, to collect pions from the neutrino target, these 3 ms pulses will have to be compressed to of the order of 1 microsecond in order to avoid overheating of the magnet current conductors. Since this pulse compression requires costly extensions to the accelerator complex a prototype design of an alternative normal-conducting hadron collector scheme that could be operated in DC mode has been studied. The magnet has been implemented in the simulation software FLUKA and extensive research has been made to analyse and maximise the flux of charged pions inside and downsteam of the magnet. Further simulations have been made to asses the flux of on-target neutrinos from the alternative collector scheme in comparison to the corresponding flux of a van der Meer horn. Simulation results from the comparison show that the alternative magnet greatly improved the neutrino flux of a bare source but not to the extent necessary to replace the magnetic horn. A conclusion is presented on the future possibilities of an optimized design that can improve the neutrino flux.

  • 79.
    Ström, Petter
    et al.
    KTH Royal Inst Technol, Dept Fus Plasma Phys, Sch Elect Engn, SE-10044 Stockholm, Sweden..
    Petersson, Per
    KTH Royal Inst Technol, Dept Fus Plasma Phys, Sch Elect Engn, SE-10044 Stockholm, Sweden..
    Hamberg, Mathias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Surface oxide and roughness on test samples for the Ultra High Vacuum section of the Laser Heater for the European XFEL2018Ingår i: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 149, s. 83-86Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The European X-ray Free Electron Laser has recently started with operation for users. An approximately 3 m long ultra high vacuum laser heater section is implemented to overcome possible electron bunch instabilities. We describe the process of determining the oxide layer thickness and surface roughness on test samples of the internal surface material in the laser heater vacuum chambers using elastic recoil detection analysis and optical surface profiling. The results are compared to specified values and show that surface roughness on the samples is larger than the requested maximum, with RMS deviations from a mean plane of up to 1.76 mu m for 0.60 x 0.45 square millimeter scans. The maximum oxide layer thickness is 5.5 nm on non-electropolished surfaces assuming cuprous oxide with density 6.0 g per cubic centimeter and 4.0 nm on electropolished surfaces.

  • 80.
    Thomasson, Anna
    et al.
    Lund Univ, Sch Econ & Management, Lund, Sweden..
    Carlile, Colin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Science facilities and stakeholder management: how a pan-European research facility ended up in a small Swedish university town2017Ingår i: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 92, nr 6, artikel-id 062501Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This is the story of how a large research facility of broad European and global interest, the European Spallation Source (ESS), ended up in the small university town of Lund in Sweden. This happened in spite of the fact that a number of influential European countries were at one time or another competitors to host the facility. It is also a story about politics which attempts to illustrate how closely intertwined politics and science are, and how the interplay between those interests affects scientific progress. ESS became an arena for individual ambitions and political manoeuvring. The different stakeholders, in their striving to ensure that their own interests were realised, in various ways and with different degrees of success over the years, have influenced the key decisions that, during the already 30 year history of ESS, have driven the course that this project has taken. What emerges is that the interests of the stakeholders and the interests of the project itself are frequently not in harmony. This imposes challenges on the management of large research facilities as they have to not only navigate in the scientific landscape, which they often are more familiar with, but also in the political landscape. This story is therefore an attempt to shed light on the role of managers of large research facilities and the often delicate balancing act they have to perform when trying to comply with the different and often conflicting stakeholder interests. What is especially worthwhile examining, as we do in this paper, is the role that individuals, and the interaction between individuals, have played in the process. This shows that the focus of stakeholder theory on organisations, rather than the people in the organisations, needs to be redirected on to the individuals representing those organisations and their interrelationships. At the same time it is clear that the developing field of stakeholder management theory has not emerged into the consciousness of science facility managers or their governing bodies and is far down the list of priorities of researchers who use the facilities.

  • 81.
    van Vliet, Philine
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA. University of Amsterdam.
    Simulations of the Electron Current Spectrometer Setup in Geant4: Exploring the Physics Limitations of Compact High Gradient Accelerating Structures2017Rapport (Övrigt vetenskapligt)
    Abstract [en]

    The high field gradient of 100 MV/m that will be applied to the accelerator cavities of the CompactLinear Collider (CLIC), gives rise to the problem of RF breakdowns. The eld collapses and a plasmaof electrons and ions is being formed in the cavity, preventing the RF field from penetrating the cavity. Electrons in the plasma are being accelerated and ejected out, resulting in a breakdown current up to a few Amperes, measured outside the cavities. These breakdowns lead to luminosity loss, so reducing their amount is of great importance. For this, a better understanding of the physics behind RF breakdowns is needed. To study these breakdowns, the XBox 2 test facility has a spectrometer setup installed after the RF cavity that is being conditioned. For this report, a simulation of this spectrometer setup has been made using Geant4. Once a detailed simulation of the RF eld and cavity has been made, it canbe connected to this simulation of the spectrometer setup and used to recreate the data that has been collected at XBox 2, before and after a breakdown has occured. In this way, we hope to be able to look further into the RF breakdowns occuring in high field gradient accelerator structures.

  • 82.
    Volker, Ziemann
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    A Hands-on Course in Sensors using the Arduino and Raspberry Pi2018Bok (Refereegranskat)
  • 83.
    Volker, Ziemann
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Hands-On Accelerator Physics Using MATLAB®2019Bok (Refereegranskat)
  • 84.
    von Ehrenheim, Carl Filip
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Setup for residual magnetic field measurements in cryostats2018Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This thesis covers considerations regarding commercially availble magnetic field sensors and the design work and assembly of a 3-axis magnetic field sensor of Hall technology that is tested for use in a cryostat at the FREIA laboratory, Uppsala university. The assembled sensor needs to withstand cryogenic temperatures and a high vacuum environment. A design for a mechanical structure that will be able to move a matrix of multiple sensors inside the cryostat is also covered. A short section discusses magnetoresistance magnetic field sensors for these purposes. The assembled sensor withstood a cryogenic test and a vacuum test separately, but it did start to show an odd behavior in a specific temperature range towards the last cycles of the cryogenic test. The printed ciruit board didn't show any damage on the board or the solder joints after operation in the vacuum environment.

  • 85.
    Yang, Jian-Quan
    et al.
    Chinese Acad Sci, Inst High Energy Phys, Beijing, Peoples R China; Chinese Acad Sci, Univ Chinese Acad Sci, Beijing, Peoples R China.
    Ye, Zou
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Tang, Jing-Yu
    Chinese Acad Sci, Inst High Energy Phys, Beijing, Peoples R China; Chinese Acad Sci, Univ Chinese Acad Sci, Beijing, Peoples R China; Dongguan Neutron Sci Ctr, Dongguan, Peoples R China.
    Collimation method studies for next-generation hadron colliders2019Ingår i: PHYSICAL REVIEW ACCELERATORS AND BEAMS, ISSN 2469-9888, Vol. 22, nr 2, artikel-id 023002Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In order to handle the extremely high stored energy in future proton-proton colliders, an extremely high-efficiency collimation system is required for safe operation. At the LHC, the major limiting locations in terms of particle losses on superconducting (SC) magnets are the dispersion suppressors downstream of the transverse collimation insertion. These losses are due to the protons experiencing single diffractive interactions in the primary collimators. How to solve this problem is very important for future proton-proton colliders, such as the Future Circular Hadron-Hadron Collider and the Super Proton-Proton Collider. In this article, a novel method is proposed, which arranges both the transverse and momentum collimation in the same long straight section. In this way, additional absorbers between the two cleaning hierarchies can clean those particles related to the single diffractive effect, with the downstream momentum collimation system intercepting any further leakage. The effectiveness of the method has been confirmed by multiparticle simulations. In addition, SC quadrupoles with special designs such as an enlarged aperture and good shielding are adopted to enhance the phase advance in the transverse collimation section so that tertiary collimators can be arranged to clean off the tertiary halo which emerges from the secondary collimators and improve the collimation efficiency. With one more collimation stage in the transverse collimation, the beam losses in both the momentum collimation section and the experimental regions can be largely reduced. Multiparticle simulation results with the MERLIN code confirm the effectiveness of the collimation method. At last, we provide a protection scheme of the SC magnets in the collimation section. The FLUKA simulations show that, by adding some special protective collimators in front of the magnets, the maximum power deposition in the SC coils is reduced dramatically, which is proven to be valid for protecting the SC magnets from quenching.

  • 86.
    Ye, Zou
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Challenges and Status of the ESSnuSB Accumulator Design2018Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The 2.0 GeV, 5 MW proton linac for the European Spallation Source, ESS, will have the capacity to accelerate additional pulses, interleaved with the proton pulses for neutron production, and send them to a neutrino target, providing an excellent opportunity to produce an unprecedented high- performance neutrino beam, the ESS neutrino Super Beam (ESSnuSB), to measure, with precision, the CP violating phase at the 2nd oscillation maximum. In order to comply with the acceptance of the target and horn systems that will form the neutrino super beam, the long pulses from the linac must be compressed by about three orders of magnitude with minimal particle loss, something that will be achieved in an accumulator ring. This ring will accommodate about 1015 protons, which means that several design challenges are encountered. Strong space charge forces, low-loss injection, efficient collimation, and e-p instabilities are some of the aspects central to the design work. Different pulse structures and injection painting schemes have been studied, with the goal of mitigating space charge effects and of minimizing the heating of the stripping foil despite the very high beam intensity. This paper presents the status of the accumulator ring design, with multi- particle simulations of the injection procedure.

  • 87.
    Ziemann, Volker
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Beam Optics Primer using Octave or MATLAB2019Rapport (Övrigt vetenskapligt)
    Abstract [en]

    This primer provides a basic introduction to beam optics concepts that arecommonly used to describe charged particle accelerators.

  • 88.
    Ziemann, Volker
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Determining Scattering Source Parameters from Radiation Detector Excitation Patterns2017Rapport (Övrigt vetenskapligt)
    Abstract [en]

    We deduce a simple equation that describes the irradiation pattern of radiationdetectors along the beam pipe due to a localized source from which a beam is scattered.

  • 89.
    Ziemann, Volker
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    GeoScope, a system to finger-print vibrations2017Rapport (Övrigt vetenskapligt)
    Abstract [en]

    We describe a system that interfaces a SM-24 geophone to a NodeMCU micro-controller and allows to display spectrograms on any web browser. The independent sensor nodes can be very exibly placed anywhere because they are battery-powered and connected to the network by WIFI. The presentation software is based on Javascript and can be used in an Internet browser on any computer connected to the same network.

  • 90.
    Ziemann, Volker
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Gyroscope, tracking 3D-motion via WIFI2017Rapport (Övrigt vetenskapligt)
    Abstract [en]

    By connecting a MPU-6050 or MPU-9250 accelerometer with built-in angular velocitymeasurement capabilities to a ESP8266 WIFI dongle it is possible to track motionin three dimensions on any browser connected to a network. This system can be used to visualize for example the motion of rigid bodies in lab courses.

  • 91.
    Ziemann, Volker
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Luminosity Loss due to Kicks and Mismatch from radio-frequency breakdown in a Linear Collider2017Rapport (Övrigt vetenskapligt)
    Abstract [en]

    We calculate the geometric luminosity loss caused by filamentation oftransverse kicks, upright and skew quadrupolar errors due to discharges, so-called RF-breakdown, in the acceleration structures of a Linear Collider.

  • 92.
    Ziemann, Volker
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    PuddlePeeker: a system to monitor the water level at the bottom of the vertical cryostat in FREIA2018Rapport (Övrigt vetenskapligt)
  • 93.
    Ziemann, Volker
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Reflections on RF-breakdown2017Rapport (Övrigt vetenskapligt)
    Abstract [en]

    Collected reflections about breakdown in radio-frequency  accelerationstructures after reading a number of books on related subjects.

  • 94.
    Ziemann, Volker
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Wedberg, Rolf
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Peterson, Tord
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Wirén, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Earth-field Compensation Coils for the Vertical Cryostat in FREIA2018Rapport (Övrigt vetenskapligt)
    Abstract [en]

    We describe the design and construction of coils to compensate the Earth magnetic field in the vertical cryostat in FREIA.

  • 95.
    Ögren, Jim
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi.
    Bhattacharyya, Anirban
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Holz, Michael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Ruber, Roger
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Ziemann, Volker
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi.
    Farabolini, W.
    Beam-based alignment studies at CTF3 using the octupole component of CLIC accelerating structures2017Ingår i: in Proceedings of the 8th International Particle Accelerator Conference (IPAC 2017), Copenhagen, Denmark, May, 2017., 2017Konferensbidrag (Övrigt vetenskapligt)
  • 96.
    Ögren, Jim
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Ziemann, Volker
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Aligning linac accelerating structures using a copropagating octupolar mode2017Ingår i: Physical Review Accelerators and Beams, ISSN 2469-9888, Vol. 20, artikel-id 102801Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We propose a novel method to align accelerating structures such as those used in the Compact Linear Collider (CLIC) by exploiting a mode that copropagates with the normal accelerating mode. This mode has an octupolar dependence in the transverse direction and is caused by radial waveguides intended to damp higher-order modes. The nonlinear dependence of the octupolar mode makes it possible to determine the center of the structure from the nonlinear dependence of the transverse kick, observed on a downstream beam position monitor, while changing the transverse position of the beam with respect to the accelerating structures. We discuss the method, its tolerances and disentangling the individual misalignments of two adjacent accelerating structures that are powered from a single source.

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