Hoyong Jeong, Seongtae Park, E. Petrakou, E. Stephenson, E. Won, Y. Semertzidis
The Center for Axion and Precision Physics Research (CAPP) of the Institute for Basic Science (IBS) is attempting to develop prototype polarimeter detector using gas electron multiplier (GEM) technology for the storage ring proton EDM (SR pEDM) experiment. Systematic errors in the polarimeter mainly come from geometric characteristics of the polarimeter and beam dynamics. Such as beam tilt, shift or detector misalignment etc. can be sources of errors. This investigation of systematic errors has been done with GEANT4 simulation package modified by ourselves. The modified GEANT4 can calculate spin-dependent hadron elastic cross-section of proton-carbon scattering, unlike the original one. This research will explain how to realize spin-dependent hadronic elastic scattering in the azimuth angle and demonstrate its application to the geometric error related systematic error study of polarimeter.
{"title":"Realization of Spin-dependent p-C Scattering in GEANT4 and Its Application To Storage Ring Experiment For pEDM","authors":"Hoyong Jeong, Seongtae Park, E. Petrakou, E. Stephenson, E. Won, Y. Semertzidis","doi":"10.22323/1.324.0027","DOIUrl":"https://doi.org/10.22323/1.324.0027","url":null,"abstract":"The Center for Axion and Precision Physics Research (CAPP) of the Institute for Basic Science (IBS) is attempting to develop prototype polarimeter detector using gas electron multiplier (GEM) technology for the storage ring proton EDM (SR pEDM) experiment. Systematic errors in the polarimeter mainly come from geometric characteristics of the polarimeter and beam dynamics. Such as beam tilt, shift or detector misalignment etc. can be sources of errors. This investigation of systematic errors has been done with \u0000GEANT4 simulation package modified by ourselves. The modified GEANT4 \u0000can calculate spin-dependent hadron elastic cross-section of \u0000proton-carbon scattering, unlike the original one. This research will explain how to realize spin-dependent hadronic elastic scattering in the azimuth angle and demonstrate its application to the geometric error related systematic error study of polarimeter.","PeriodicalId":166894,"journal":{"name":"Proceedings of XVII International Workshop on Polarized Sources, Targets & Polarimetry — PoS(PSTP2017)","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125887953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Grames, D. Moser, P. Adderley, J. Hansknecht, R. Kazimi, M. Poelker, M. Stutzman, R. Suleiman, Shukui Zhang
Extending the charge lifetime of today’s spin polarized GaAs photoelectron guns from tens to thousands of Coulombs is a requirement for long-duration operation at milliampere beam current. There are two main approaches frequently considered to achieve this goal. The first is improving photo-gun vacuum, which provides a direct means to minimize the ill effects of ion bombardment and associated QE decay. In this contribution, we demonstrate the second: enhancing the charge lifetime at milliampere beam current by using large laser spots which serves to distribute ion damage over a larger region of the photocathode. The efficacy of this approach was presented at past workshops, but using bulk GaAs and green laser light without RF structure. In this contribution, highly polarized beam was produced from strained-superlattice GaAs/GaAsP photocathodes inside the 130 kV photo-gun at the CEBAF photoinjector, at beam currents from 0.5 to 1.5 mA and with a clear indication of lifetime enhancement using laser beams as large as ~8 mm$^2$. However, when the laser beam size was increased beyond this diameter, further lifetime enhancement was not observed which highlights the importance of proper cathode/anode design to maintain loss-free beam delivery and the preservation of static vacuum conditions. In addition, this contribution presents electron beam polarization measurements at currents to 1 mA.
{"title":"Milliampere Beam Studies using High Polarization Photocathodes at the CEBAF Photoinjector","authors":"J. Grames, D. Moser, P. Adderley, J. Hansknecht, R. Kazimi, M. Poelker, M. Stutzman, R. Suleiman, Shukui Zhang","doi":"10.22323/1.324.0014","DOIUrl":"https://doi.org/10.22323/1.324.0014","url":null,"abstract":"Extending the charge lifetime of today’s spin polarized GaAs photoelectron guns from tens to thousands of Coulombs is a requirement for long-duration operation at milliampere beam current. There are two main approaches frequently considered to achieve this goal. The first is improving photo-gun vacuum, which provides a direct means to minimize the ill effects of ion bombardment and associated QE decay. In this contribution, we demonstrate the second: enhancing the charge lifetime at milliampere beam current by using large laser spots which serves to distribute ion damage over a larger region of the photocathode. The efficacy of this approach was presented at past workshops, but using bulk GaAs and green laser light without RF structure. In this contribution, highly polarized beam was produced from strained-superlattice GaAs/GaAsP photocathodes inside the 130 kV photo-gun at the CEBAF photoinjector, at beam currents from 0.5 to 1.5 mA and with a clear indication of lifetime enhancement using laser beams as large as ~8 mm$^2$. However, when the laser beam size was increased beyond this diameter, further lifetime enhancement was not observed which highlights the importance of proper cathode/anode design to maintain loss-free beam delivery and the preservation of static vacuum conditions. In addition, this contribution presents electron beam polarization measurements at currents to 1 mA.","PeriodicalId":166894,"journal":{"name":"Proceedings of XVII International Workshop on Polarized Sources, Targets & Polarimetry — PoS(PSTP2017)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129513301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. Fimushkin, A. Kovalenko, R. Kuzyakin, M. Kulikov, L. V. Kutuzova, Y. Plis, Yu. V. Prokofichev, V. Shutov, A. Belov, A. V. Turbabin, V. Zubets
The paper describes the JINR polarized ion source operating by means of the atomic beam method. The results of testing of the plasma ionizer with a storage cell and tuning of high frequency transition units are presented. The source was installed in the linac injector hall of the NUCLOTRON in May 2016. The source was commissioned and used in the NUCLOTRON runs in 2016 and February – March 2017. Polarized and unpolarized deuteron beams as well as polarized proton beam were produced to accelerate in the NUCLOTRON. The polarized deuteron beam with pulsed current up to 3.7 mA has been produced. Deuteron beam polarization of 0.6-0.9 of theoretical values for different modes of high frequency transition units has been measured with the NUCLOTRON ring internal polarimeter for the accelerated deuteron and proton beams.
{"title":"Source of polarized ions and polarized beams at the NUCLOTRON","authors":"V. Fimushkin, A. Kovalenko, R. Kuzyakin, M. Kulikov, L. V. Kutuzova, Y. Plis, Yu. V. Prokofichev, V. Shutov, A. Belov, A. V. Turbabin, V. Zubets","doi":"10.22323/1.324.0019","DOIUrl":"https://doi.org/10.22323/1.324.0019","url":null,"abstract":"The paper describes the JINR polarized ion source operating by means of the atomic beam method. The results of testing of the plasma ionizer with a storage cell and tuning of high frequency transition units are presented. The source was installed in the linac injector hall of the NUCLOTRON in May 2016. The source was commissioned and used in the NUCLOTRON runs in 2016 and February – March 2017. Polarized and unpolarized deuteron beams as well as polarized proton beam were produced to accelerate in the NUCLOTRON. The polarized deuteron beam with pulsed current up to 3.7 mA has been produced. Deuteron beam polarization of 0.6-0.9 of theoretical values for different modes of high frequency transition units has been measured with the NUCLOTRON ring internal polarimeter for the accelerated deuteron and proton beams.","PeriodicalId":166894,"journal":{"name":"Proceedings of XVII International Workshop on Polarized Sources, Targets & Polarimetry — PoS(PSTP2017)","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124344550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The sensitivity of Neutron Macromolecular Crystallography to the presence of hydrogen makes it a powerful tool to study protein structure. This technique is currently limited by the relative low neutron flux provided by even the most modern neutron sources. The strong polarization dependence of the neutron scattering cross section of hydrogen will allow Dynamic Nuclear Polarization to dramatically improve the sensitivity of protein structure measurements. This will enable the use of substantially smaller protein crystals, allowing structure measurements which are currently impossible. We present a proof of concept frozen spin target, built at Oak Ridge National Laboratory to polarize single protein crystals on the IMAGINE beamline at the High Flux Isotope Reactor. The results of the first test on the neutron beam will be discussed, as will planned upgrades to the system.
{"title":"Dynamic Nuclear Polarization for Neutron Protein Crystallography","authors":"J. Pierce","doi":"10.22323/1.324.0010","DOIUrl":"https://doi.org/10.22323/1.324.0010","url":null,"abstract":"The sensitivity of Neutron Macromolecular Crystallography to the presence of hydrogen makes it a powerful tool to study protein structure. This technique is currently limited by the relative low neutron flux provided by even the most modern neutron sources. The strong polarization dependence of the neutron scattering cross section of hydrogen will allow Dynamic Nuclear Polarization to dramatically improve the sensitivity of protein structure measurements. This will enable the use of substantially smaller protein crystals, allowing structure measurements which are currently impossible. We present a proof of concept frozen spin target, built at Oak Ridge National Laboratory to polarize single protein crystals on the IMAGINE beamline at the High Flux Isotope Reactor. The results of the first test on the neutron beam will be discussed, as will planned upgrades to the system.","PeriodicalId":166894,"journal":{"name":"Proceedings of XVII International Workshop on Polarized Sources, Targets & Polarimetry — PoS(PSTP2017)","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115569636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The 12 GeV physics program in Hall B at Jefferson Lab will be centered on the newly commissioned, high acceptance spectrometer CLAS12 and will utilize a variety of nuclear targets, including a dynamically polarized solid target for experiments on longitudinally polarized protons, deuterons, and lithium nuclei. The target, under construction in a collaborative effort between the Jefferson Lab Target Group, Christopher Newport University, Old Dominion University, and the University of Virginia, is designed with a number of innovative features. These include multiple target cells for reduced systematic uncertainties, internal superconducting shim coils to adjust the polarizing magnetic field, and a 1 K evaporation refrigerator with an integrated load lock system for the target samples. The current status of the system's design, construction, and various R&D efforts are described.
{"title":"A Dynamically Polarized Solid Target for CLAS12","authors":"C. Keith","doi":"10.22323/1.324.0008","DOIUrl":"https://doi.org/10.22323/1.324.0008","url":null,"abstract":"The 12 GeV physics program in Hall B at Jefferson Lab will be centered on the newly commissioned, high acceptance spectrometer CLAS12 and will utilize a variety of nuclear targets, including a dynamically polarized solid target for experiments on longitudinally polarized protons, deuterons, and lithium nuclei. The target, under construction in a collaborative effort between the Jefferson Lab Target Group, Christopher Newport University, Old Dominion University, and the University of Virginia, is designed with a number of innovative features. These include multiple target cells for reduced systematic uncertainties, internal superconducting shim coils to adjust the polarizing magnetic field, and a 1 K evaporation refrigerator with an integrated load lock system for the target samples. The current status of the system's design, construction, and various R&D efforts are described.","PeriodicalId":166894,"journal":{"name":"Proceedings of XVII International Workshop on Polarized Sources, Targets & Polarimetry — PoS(PSTP2017)","volume":"3 6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120848548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Moriguchi, A. Ozawa, Y. Yamato, S. Suzuki, M. Amano, D. Kamioka, D. Nagae, Y. Abe
The Lamb-shift polarized ion source (PIS) was installed as one of the ion sources for the 12UD Pelletron tandem accelerator at the University of Tsukuba Tandem Accelerator Complex (UTTAC) in 1976. The PIS makes it possible to produce highly polarized negative proton and deuteron beams. However, the Great East Japan Earthquake on 11 March 2011 seriously damaged not only the accelerator but also the PIS. Following the disaster, it was decided that the PIS should be reconstructed and used as the ion source for the newly designed 6 MV tandem accelerator. Main components including the duoplasmatron chamber and spin filter were reused, while other components including the accelerator tubes and some beam ducts were newly produced. After the reconstruction of the PIS, we attempted to generate polarized beams and measure the polarization. Recently, we attempted to produce unstable nuclei with the polarized proton beam for measurements of nuclear moments of unstable nuclei.
{"title":"Lamb-shift Polarized Ion Source at UTTAC","authors":"T. Moriguchi, A. Ozawa, Y. Yamato, S. Suzuki, M. Amano, D. Kamioka, D. Nagae, Y. Abe","doi":"10.22323/1.324.0018","DOIUrl":"https://doi.org/10.22323/1.324.0018","url":null,"abstract":"The Lamb-shift polarized ion source (PIS) was installed as one of the ion sources for the 12UD Pelletron tandem accelerator at the University of Tsukuba Tandem Accelerator Complex (UTTAC) in 1976. The PIS makes it possible to produce highly polarized negative proton and deuteron beams. However, the Great East Japan Earthquake on 11 March 2011 seriously damaged not only the accelerator but also the PIS. Following the disaster, it was decided that the PIS should be reconstructed and used as the ion source for the newly designed 6 MV tandem accelerator. Main components including the duoplasmatron chamber and spin filter were reused, while other components including the accelerator tubes and some beam ducts were newly produced. After the reconstruction of the PIS, we attempted to generate polarized beams and measure the polarization. Recently, we attempted to produce unstable nuclei with the polarized proton beam for measurements of nuclear moments of unstable nuclei.","PeriodicalId":166894,"journal":{"name":"Proceedings of XVII International Workshop on Polarized Sources, Targets & Polarimetry — PoS(PSTP2017)","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132508499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Hadjidakis, M. Anselmino, R. Arnaldi, S. Brodsky, V. Chambert, C. Silva, J. Didelez, M. Echevarria, E. Ferreiro, F. Fleuret, Y. Gao, B. Genolini, I. Hrivnácová, D. Kikoła, A. Klein, A. Kurepin, A. Kusina, J. Lansberg, C. Lorcé, F. Lyonnet, G. Mart́ınez, L. Massacrier, A. Nass, C. Pisano, P. Robbe, I. Schienbein, M. Schlegel, E. Scomparin, J. Seixas, H. Shao, A. Signori, E. Steffens, L. Szymanowski, N. Topilskaya, B. Trzeciak, U. Uggerhøj, A. Uras, R. Ulrich, J. Wagner, N. Yamanaka, Z. Yang
By extracting the beam with a bent crystal or by using an internal gas target, the multi-TeV proton and lead LHC beams allow one to perform the most energetic fixed-target experiments (AFTER@LHC) and to study $p$+$p$ and $p$+A collisions at $sqrt{s_{NN}}$=115 GeV and Pb+$p$ and Pb+A collisions at $sqrt{s_{NN}}$=72 GeV. Such studies would address open questions in the domain of the nucleon and nucleus partonic structure at high-$x$, quark-gluon plasma and, by using longitudinally or transversally polarised targets, spin physics. In this paper, we discuss the physics opportunities of a fixed-target experiment at the LHC and we report on the possible technical implementations of a high-luminosity experiment. We finally present feasibility studies for Drell-Yan, open heavy-flavour and quarkonium production, with an emphasis on high-$x$ and spin physics.
{"title":"Physics opportunities with a fixed target experiment at the LHC (AFTER@LHC)","authors":"C. Hadjidakis, M. Anselmino, R. Arnaldi, S. Brodsky, V. Chambert, C. Silva, J. Didelez, M. Echevarria, E. Ferreiro, F. Fleuret, Y. Gao, B. Genolini, I. Hrivnácová, D. Kikoła, A. Klein, A. Kurepin, A. Kusina, J. Lansberg, C. Lorcé, F. Lyonnet, G. Mart́ınez, L. Massacrier, A. Nass, C. Pisano, P. Robbe, I. Schienbein, M. Schlegel, E. Scomparin, J. Seixas, H. Shao, A. Signori, E. Steffens, L. Szymanowski, N. Topilskaya, B. Trzeciak, U. Uggerhøj, A. Uras, R. Ulrich, J. Wagner, N. Yamanaka, Z. Yang","doi":"10.22323/1.324.0035","DOIUrl":"https://doi.org/10.22323/1.324.0035","url":null,"abstract":"By extracting the beam with a bent crystal or by using an internal gas target, the multi-TeV proton and lead LHC beams allow one to perform the most energetic fixed-target experiments (AFTER@LHC) and to study $p$+$p$ and $p$+A collisions at $sqrt{s_{NN}}$=115 GeV and Pb+$p$ and Pb+A collisions at $sqrt{s_{NN}}$=72 GeV. Such studies would address open questions in the domain of the nucleon and nucleus partonic structure at high-$x$, quark-gluon plasma and, by using longitudinally or transversally polarised targets, spin physics. \u0000In this paper, we discuss the physics opportunities of a fixed-target experiment at the LHC and we report on the possible technical implementations of a high-luminosity experiment. We finally present feasibility studies for Drell-Yan, open heavy-flavour and quarkonium production, with an emphasis on high-$x$ and spin physics.","PeriodicalId":166894,"journal":{"name":"Proceedings of XVII International Workshop on Polarized Sources, Targets & Polarimetry — PoS(PSTP2017)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129846194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Poelker, P. Adderley, J. Benesch, B. Bullard, J. Grames, F. Hannon, J. Hansknecht, C. Hernández-García, R. Kazimi, G. Krafft, M. Mamun, R. Suleiman, M. Tiefenback, Yan Wang, S. Wijiethunga, J. Yoskovitz, S. Zhang
The ion beams of the proposed Jefferson Lab Electron Ion Collider (JLEIC) must be cooled to achieve the required collision luminosity. In general, cooling is accomplished when an electron beam co-propagates with an ion beam moving at the same average velocity, but with different temperature, where the energy of chaotic motion of the ion beam is transferred to the cold electron beam. The cooling rate can be improved by about two orders of magnitude if the process occurs inside a solenoidal magnetic field – so-called magnetized cooling - that forces the electrons to follow small helical trajectories thereby increasing the interaction time with ions and improving the cooling efficiency. However, one of the challenges associated with implementing this cooling technique relates to the fringe field of the cooling solenoid which imparts a large unwanted azimuthal kick onto the electron beam that prevents the electron beam from traveling in the desired tight, well-defined volume within the solenoid. As proposed by Derbenev, the ill-effect of this fringe field can be cancelled if the electron beam is born in a similar field and encountering a fringe field upon exiting the electron gun that produces an azimuthal kick in the opposite direction, such that the two kicks cancel. Besides requiring magnetized beam, the JLEIC re-circulator cooler design requires an electron beam with very high average current and high bunch charge: 140 mA and with nanoCoulomb bunch charge. This contribution describes the latest milestones of a multiyear program to build a magnetized electron beam source based on a 350 kV DC high voltage photogun with inverted insulator geometry.
{"title":"Magnetized electron beam for the JLEIC re-circulator cooler ring","authors":"M. Poelker, P. Adderley, J. Benesch, B. Bullard, J. Grames, F. Hannon, J. Hansknecht, C. Hernández-García, R. Kazimi, G. Krafft, M. Mamun, R. Suleiman, M. Tiefenback, Yan Wang, S. Wijiethunga, J. Yoskovitz, S. Zhang","doi":"10.22323/1.324.0012","DOIUrl":"https://doi.org/10.22323/1.324.0012","url":null,"abstract":"The ion beams of the proposed Jefferson Lab Electron Ion Collider (JLEIC) must be cooled to achieve the required collision luminosity. In general, cooling is accomplished when an electron beam co-propagates with an ion beam moving at the same average velocity, but with different temperature, where the energy of chaotic motion of the ion beam is transferred to the cold electron beam. The cooling rate can be improved by about two orders of magnitude if the process occurs inside a solenoidal magnetic field – so-called magnetized cooling - that forces the electrons to follow small helical trajectories thereby increasing the interaction time with ions and improving the cooling efficiency. However, one of the challenges associated with implementing this cooling technique relates to the fringe field of the cooling solenoid which imparts a large unwanted azimuthal kick onto the electron beam that prevents the electron beam from traveling in the desired tight, well-defined volume within the solenoid. As proposed by Derbenev, the ill-effect of this fringe field can be cancelled if the electron beam is born in a similar field and encountering a fringe field upon exiting the electron gun that produces an azimuthal kick in the opposite direction, such that the two kicks cancel. Besides requiring magnetized beam, the JLEIC re-circulator cooler design requires an electron beam with very high average current and high bunch charge: 140 mA and with nanoCoulomb bunch charge. This contribution describes the latest milestones of a multiyear program to build a magnetized electron beam source based on a 350 kV DC high voltage photogun with inverted insulator geometry.","PeriodicalId":166894,"journal":{"name":"Proceedings of XVII International Workshop on Polarized Sources, Targets & Polarimetry — PoS(PSTP2017)","volume":"44 9","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120974779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Eggert, J. Enders, M. Espig, Y. Fritzsche, N. Kurichiyanil, M. Wagner, S. Weih
GaAs photocathodes can be used for generation of highly polarized electron beams. For high- current applications it is necessary to maximize the charge lifetime of the cathode material to ensure reliable operation. It is expected to increase the local vacuum conditions by cryogenic cooling of the electrode and a local subvolume, due to cryogenic adsorption of reactive residual gas molecules at the surrounding walls. This both protects the sensitive negative-electron-affinity surface of the cathode and allows a higher laser power deposited in the material, resulting in higher possible beam currents. An electrostatic bend is introduced to reduce Ion-backbombardment and further increase the cathode lifetime. To measure the characteristics of such a cryogenic source, a dedicated set-up is being developed at the Photo-CATCH test facility in Darmstadt, Germany.
{"title":"First setup for cooled GaAs cathodes with increased charge lifetime","authors":"T. Eggert, J. Enders, M. Espig, Y. Fritzsche, N. Kurichiyanil, M. Wagner, S. Weih","doi":"10.22323/1.324.0017","DOIUrl":"https://doi.org/10.22323/1.324.0017","url":null,"abstract":"GaAs photocathodes can be used for generation of highly polarized electron beams. For high- \u0000current applications it is necessary to maximize the charge lifetime of the cathode material to \u0000ensure reliable operation. It is expected to increase the local vacuum conditions by cryogenic \u0000cooling of the electrode and a local subvolume, due to cryogenic adsorption of reactive residual \u0000gas molecules at the surrounding walls. This both protects the sensitive negative-electron-affinity \u0000surface of the cathode and allows a higher laser power deposited in the material, resulting in higher \u0000possible beam currents. An electrostatic bend is introduced to reduce Ion-backbombardment and \u0000further increase the cathode lifetime. To measure the characteristics of such a cryogenic source, a \u0000dedicated set-up is being developed at the Photo-CATCH test facility in Darmstadt, Germany.","PeriodicalId":166894,"journal":{"name":"Proceedings of XVII International Workshop on Polarized Sources, Targets & Polarimetry — PoS(PSTP2017)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128463835","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. Reicherz, N. Doshita, M. Finger, T. Iwata, Y. Kiselev, J. Koivuniemi, K. Kondo, G. Nukazuka, J. Matoušek, W. Meyer, M. Pešek
The COMPASS collaboration performed a polarized Drell-Yan program to measure TMD (Transverse Momentum Dependent) and PDFs (Parton Distribution Functions) in 2015. We will carry out the program for one more year in 2018 to improve the statistics. In the Drell-Yan program a negative pion beam of 190 GeV/c with an intensity of $10^8$ /s will be scattered on a transversely polarized proton target with a length of 110 cm. We also plan to use a transversely polarized deuteron target for SIDIS (Semi-Inclusive-Deep-Inelastic-Scattering) program with muon beam in 2021 just after a long shut down of the CERN accelerators. We will present the improved COMPASS PT system for the 2018 run and present the future plan of the deuteron target in 2021.
{"title":"Future plannings for the COMPASS polarized target","authors":"G. Reicherz, N. Doshita, M. Finger, T. Iwata, Y. Kiselev, J. Koivuniemi, K. Kondo, G. Nukazuka, J. Matoušek, W. Meyer, M. Pešek","doi":"10.22323/1.324.0004","DOIUrl":"https://doi.org/10.22323/1.324.0004","url":null,"abstract":"The COMPASS collaboration performed a polarized Drell-Yan program to measure TMD (Transverse Momentum Dependent) and PDFs (Parton Distribution Functions) in 2015. We will carry out the program for one more year in 2018 to improve the statistics. In the Drell-Yan program a negative pion beam of 190 GeV/c with an intensity of $10^8$ /s will be scattered on a transversely polarized proton target with a length of 110 cm. We also plan to use a transversely polarized deuteron target for SIDIS (Semi-Inclusive-Deep-Inelastic-Scattering) program with muon beam in 2021 just after a long shut down of the CERN accelerators. \u0000We will present the improved COMPASS PT system for the 2018 run and present the future plan of the deuteron target in 2021.","PeriodicalId":166894,"journal":{"name":"Proceedings of XVII International Workshop on Polarized Sources, Targets & Polarimetry — PoS(PSTP2017)","volume":"03 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127339356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：