Pub Date : 2007-06-25DOI: 10.1109/PAC.2007.4440645
M. Venturini, M. Furman, J. Vay, M. Pivi
Use of grooved vacuum chambers have been suggested as a way to limit electron cloud accumulation in the ILC- DR. We report on simulations carried out using an augmented version of POSINST, accounting for e-cloud dynamics in the presence of grooves, and make contact with previous estimates of an effective secondary electron yield for grooved surfaces.
{"title":"Modelling of E-cloud build-up in grooved vacuum chambers using posinst","authors":"M. Venturini, M. Furman, J. Vay, M. Pivi","doi":"10.1109/PAC.2007.4440645","DOIUrl":"https://doi.org/10.1109/PAC.2007.4440645","url":null,"abstract":"Use of grooved vacuum chambers have been suggested as a way to limit electron cloud accumulation in the ILC- DR. We report on simulations carried out using an augmented version of POSINST, accounting for e-cloud dynamics in the presence of grooves, and make contact with previous estimates of an effective secondary electron yield for grooved surfaces.","PeriodicalId":446026,"journal":{"name":"2007 IEEE Particle Accelerator Conference (PAC)","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122929661","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}
Pub Date : 2007-06-25DOI: 10.1109/PAC.2007.4439966
B.Y. Wang, B.G. Sun, J.G. Wang, P. Lu, H.L. Xu, J. Wang
A simple measurement method of beam bunch length in time domain for HLS (Hefei Light Source) has been proposed. The bunch length measurement system is composed of an optical system, a high speed photo- receiver and a wide bandwidth oscilloscope. The photo- receiver which is made by FEMTO has high sensitivity and high bandwidth, which converts the synchrotron radiation light into electronic signal. The oscilloscope which is made by Tektronix is TDS7704B, which has a high bandwidth up to 7GHz and show the bunch length in time domain. The measurement results of the bunch length and its analysis are given. We compare the results with that measured by the conventional method using a streak camera.
{"title":"Bunch length measurement in time domain for HLS","authors":"B.Y. Wang, B.G. Sun, J.G. Wang, P. Lu, H.L. Xu, J. Wang","doi":"10.1109/PAC.2007.4439966","DOIUrl":"https://doi.org/10.1109/PAC.2007.4439966","url":null,"abstract":"A simple measurement method of beam bunch length in time domain for HLS (Hefei Light Source) has been proposed. The bunch length measurement system is composed of an optical system, a high speed photo- receiver and a wide bandwidth oscilloscope. The photo- receiver which is made by FEMTO has high sensitivity and high bandwidth, which converts the synchrotron radiation light into electronic signal. The oscilloscope which is made by Tektronix is TDS7704B, which has a high bandwidth up to 7GHz and show the bunch length in time domain. The measurement results of the bunch length and its analysis are given. We compare the results with that measured by the conventional method using a streak camera.","PeriodicalId":446026,"journal":{"name":"2007 IEEE Particle Accelerator Conference (PAC)","volume":"195 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122521602","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}
Pub Date : 2007-06-25DOI: 10.1109/PAC.2007.4440881
X. Yang, A. Drozhdin, W. Pellico
The maximal capacitance for the Booster to deliver the 8-GeV beam to downstream accelerators is limited by the beam loss. Most of losses happen at injection due to space charge effect being the strongest at the injection energy. Optimizing the RF voltage ramp in the presence of the space charge effect to capture more beam and simultaneously keep small beam emittance has been numerically investigated using 3-D STRUCT [1] code. The results of simulations agree well with the measurements in the machine. Possibilities, such as beam painting and using the third RF harmonic at injection, for further reductions of beam loss in order to reach the maximum beam intensity delivered from Booster have been investigated.
{"title":"Injection parameters optimization for the fermilab booster","authors":"X. Yang, A. Drozhdin, W. Pellico","doi":"10.1109/PAC.2007.4440881","DOIUrl":"https://doi.org/10.1109/PAC.2007.4440881","url":null,"abstract":"The maximal capacitance for the Booster to deliver the 8-GeV beam to downstream accelerators is limited by the beam loss. Most of losses happen at injection due to space charge effect being the strongest at the injection energy. Optimizing the RF voltage ramp in the presence of the space charge effect to capture more beam and simultaneously keep small beam emittance has been numerically investigated using 3-D STRUCT [1] code. The results of simulations agree well with the measurements in the machine. Possibilities, such as beam painting and using the third RF harmonic at injection, for further reductions of beam loss in order to reach the maximum beam intensity delivered from Booster have been investigated.","PeriodicalId":446026,"journal":{"name":"2007 IEEE Particle Accelerator Conference (PAC)","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122569434","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}
Pub Date : 2007-06-25DOI: 10.1109/PAC.2007.4441184
S. An, C. Gao, Y. Cho, B.H. Choi
An elliptical superconducting RF cavity of 700 MHz with betag=0.42 has been designed for the linac of the Proton Engineering Frontier Project (PEFP). A double-ring stiffening structure is used for a low-beta cavity for Lorentz force detuning. The results of the electron multipacting analysis of the cavity are presented. A HOM analysis shows that the HOM coupler's Qext is lower than 3times105, thus reducing the influence of dangerous modes on the beam instabilities and the HOM-induced power.
{"title":"PEFP low-beta SRF cavity design","authors":"S. An, C. Gao, Y. Cho, B.H. Choi","doi":"10.1109/PAC.2007.4441184","DOIUrl":"https://doi.org/10.1109/PAC.2007.4441184","url":null,"abstract":"An elliptical superconducting RF cavity of 700 MHz with betag=0.42 has been designed for the linac of the Proton Engineering Frontier Project (PEFP). A double-ring stiffening structure is used for a low-beta cavity for Lorentz force detuning. The results of the electron multipacting analysis of the cavity are presented. A HOM analysis shows that the HOM coupler's Qext is lower than 3times105, thus reducing the influence of dangerous modes on the beam instabilities and the HOM-induced power.","PeriodicalId":446026,"journal":{"name":"2007 IEEE Particle Accelerator Conference (PAC)","volume":"90 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122578275","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}
Pub Date : 2007-06-25DOI: 10.1109/PAC.2007.4440158
S. Casalbuoni, A. Grau, M. Hagelstein, R. Rossmanith, A. Bernhard, A. Mueller, D. Wollmann, T. Baumbach, B. Kostka, E. Mashkina, E. Steffens, H. Braun, M. Korostelev, Y. Papaphilippou, F. Zimmermann
The CLIC damping ring requires wigglers with both high on-axis fields and short periods. The present design foresees a superconductive wiggler with a period length of 5 cm, a peak on-axis field of 2.5 T and a full aperture of 12 mm. In this paper we explore the performance improvements of the damping ring when these parameters are pushed to 2.7 T at a period length of 2 cm with the expense of a reduced aperture of 5 mm. A design for a prototype for testing the field quality of such a wiggler is presented in this paper and the possibility to test this wiggler with beam in the storage ring ANKA is described.
{"title":"Superconductive damping wigglers for the CLIC project","authors":"S. Casalbuoni, A. Grau, M. Hagelstein, R. Rossmanith, A. Bernhard, A. Mueller, D. Wollmann, T. Baumbach, B. Kostka, E. Mashkina, E. Steffens, H. Braun, M. Korostelev, Y. Papaphilippou, F. Zimmermann","doi":"10.1109/PAC.2007.4440158","DOIUrl":"https://doi.org/10.1109/PAC.2007.4440158","url":null,"abstract":"The CLIC damping ring requires wigglers with both high on-axis fields and short periods. The present design foresees a superconductive wiggler with a period length of 5 cm, a peak on-axis field of 2.5 T and a full aperture of 12 mm. In this paper we explore the performance improvements of the damping ring when these parameters are pushed to 2.7 T at a period length of 2 cm with the expense of a reduced aperture of 5 mm. A design for a prototype for testing the field quality of such a wiggler is presented in this paper and the possibility to test this wiggler with beam in the storage ring ANKA is described.","PeriodicalId":446026,"journal":{"name":"2007 IEEE Particle Accelerator Conference (PAC)","volume":"241 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122630166","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}
Pub Date : 2007-06-25DOI: 10.1109/PAC.2007.4440048
M. Rihaoui, C. Bohn, P. Piot, J. Power
The properties of electron beams produced in a photoinjector are strongly dependent on the initial conditions, i.e. the photocathode drive laser shape and its uniformity. We explore the impact of well-defined transverse laser perturbations on the evolution of the electron beam both in configuration and velocity spaces and especially investigate how certain types of perturbations evolve as the beam propagates in the Argonne Wakefield Accelerator facility. Numerical simulations performed with IMPACT-T are presented. Finally preliminary experimental results aimed at validating our simulations are discussed.
{"title":"Impact of transverse irregularities at the photocathode on the production of high-charge electron bunches","authors":"M. Rihaoui, C. Bohn, P. Piot, J. Power","doi":"10.1109/PAC.2007.4440048","DOIUrl":"https://doi.org/10.1109/PAC.2007.4440048","url":null,"abstract":"The properties of electron beams produced in a photoinjector are strongly dependent on the initial conditions, i.e. the photocathode drive laser shape and its uniformity. We explore the impact of well-defined transverse laser perturbations on the evolution of the electron beam both in configuration and velocity spaces and especially investigate how certain types of perturbations evolve as the beam propagates in the Argonne Wakefield Accelerator facility. Numerical simulations performed with IMPACT-T are presented. Finally preliminary experimental results aimed at validating our simulations are discussed.","PeriodicalId":446026,"journal":{"name":"2007 IEEE Particle Accelerator Conference (PAC)","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122876422","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}
Pub Date : 2007-06-25DOI: 10.1109/PAC.2007.4440239
S. Kahn, M. Alsharo'a, R.P. Johnson, V. Kashikhin, K. Yonehara, A. Zlobin
A helical cooling channel (HCC) consisting of a pressurized gas absorber imbedded in a magnetic channel that provides superimposed solenoidal, helical dipole, and helical quadrupole fields has shown considerable promise in providing six-dimensional cooling of muon beams. The analysis of this muon cooling technique with both analytic and simulation studies has shown significant reduction of muon phase space emittance. A particular channel that has been simulated is divided into four segments each with progressively smaller apertures and stronger fields to reduce the equilibrium emittance so that more cooling can occur. The fields in the helical channel are sufficiently large that the conductor for segments 1 and 2 can be Nb3Sn and the conductor for segments 3 and 4 may need to be high temperature superconductor. This paper will describe the magnetic specifications for the channel and two conceptual designs on how to implement the magnetic channel.
{"title":"Magnet system for helical muon cooling channels","authors":"S. Kahn, M. Alsharo'a, R.P. Johnson, V. Kashikhin, K. Yonehara, A. Zlobin","doi":"10.1109/PAC.2007.4440239","DOIUrl":"https://doi.org/10.1109/PAC.2007.4440239","url":null,"abstract":"A helical cooling channel (HCC) consisting of a pressurized gas absorber imbedded in a magnetic channel that provides superimposed solenoidal, helical dipole, and helical quadrupole fields has shown considerable promise in providing six-dimensional cooling of muon beams. The analysis of this muon cooling technique with both analytic and simulation studies has shown significant reduction of muon phase space emittance. A particular channel that has been simulated is divided into four segments each with progressively smaller apertures and stronger fields to reduce the equilibrium emittance so that more cooling can occur. The fields in the helical channel are sufficiently large that the conductor for segments 1 and 2 can be Nb3Sn and the conductor for segments 3 and 4 may need to be high temperature superconductor. This paper will describe the magnetic specifications for the channel and two conceptual designs on how to implement the magnetic channel.","PeriodicalId":446026,"journal":{"name":"2007 IEEE Particle Accelerator Conference (PAC)","volume":"3 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114042948","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}
Pub Date : 2007-06-25DOI: 10.1109/PAC.2007.4441062
D. Dowell, E. Jongewaard, C. Limborg-Deprey, J. Schmerge, A. Vlieks
The field emission was measured during the high- power testing of the LCLS photocathode RF gun. A careful study and analysis of the field emission electrons, or dark current is important in assessing the gun's internal surface quality in actual operation, especially those surfaces with high fields. The first indication of a good RF gun design and fabrication is short processing time to the required fields and low electron emission at high- fields. The charge per 2 microsecond long RF pulse (the dark charge) was measured as a function of the peak cathode field for the 1.6 cell, 2.856 GHz LCLS RF gun. Faraday cup data was taken for cathode peak RF fields up to 120 MV/m producing a maximum of 0.6 nC/RF pulse for a diamond-turned polycrystalline copper cathode installed in the gun. Digitized images of the dark charge were taken using a 100 micron thick YAG crystal for a range of solenoid fields to determine the location and angular distribution of the field emitters. The FN plots and emitter image analysis will be described in this paper.
{"title":"Measurement and analysis of field emission electrons in the LCLS gun","authors":"D. Dowell, E. Jongewaard, C. Limborg-Deprey, J. Schmerge, A. Vlieks","doi":"10.1109/PAC.2007.4441062","DOIUrl":"https://doi.org/10.1109/PAC.2007.4441062","url":null,"abstract":"The field emission was measured during the high- power testing of the LCLS photocathode RF gun. A careful study and analysis of the field emission electrons, or dark current is important in assessing the gun's internal surface quality in actual operation, especially those surfaces with high fields. The first indication of a good RF gun design and fabrication is short processing time to the required fields and low electron emission at high- fields. The charge per 2 microsecond long RF pulse (the dark charge) was measured as a function of the peak cathode field for the 1.6 cell, 2.856 GHz LCLS RF gun. Faraday cup data was taken for cathode peak RF fields up to 120 MV/m producing a maximum of 0.6 nC/RF pulse for a diamond-turned polycrystalline copper cathode installed in the gun. Digitized images of the dark charge were taken using a 100 micron thick YAG crystal for a range of solenoid fields to determine the location and angular distribution of the field emitters. The FN plots and emitter image analysis will be described in this paper.","PeriodicalId":446026,"journal":{"name":"2007 IEEE Particle Accelerator Conference (PAC)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114399183","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}
Pub Date : 2007-06-25DOI: 10.1109/PAC.2007.4440409
Shengguang Liu, M. Fukuda, S. Araki, N. Terunuma, M. Takano, J. Urakawa, K. Hirano
Laser Undulator Compact X-ray source (LUCX) is a test bench for compact high brightness X-ray generator at KEK in order to demonstrate the possibility on K-edge digital subtraction angiography, based on the Compton Scattering. For this project, one of the challenging problems is to generate and accelerate high brightness multi-bunch electron beams, compensating the energy difference due to beam loading effect. In this paper, we calculate the transient beam loading voltage and energy gain from RF field in standing wave gun cavity and traveling wave accelerating tube for multi-bunch train, considering the process of propagation, buildup of RF field in them and the special RF pulse shape. We generated and accelerated 100 bunch electron beam train with 50 nC, which beam loading effect was compensated effectively by adjusting the laser injection timing. By BPM and OTR system, we measured the electron beam energy bunch by bunch. The average energy of 100 bunch train is 40.5 MeV and maximum energy difference bunch to bunch is 0.26 MeV, the relative energy spread of single bunch is about 0.13%. The transverse emittance can be optimized roughly to 3.6 pimm.mrad.
{"title":"Generation and acceleration of high brightness electron bunch train at ATF of KEK","authors":"Shengguang Liu, M. Fukuda, S. Araki, N. Terunuma, M. Takano, J. Urakawa, K. Hirano","doi":"10.1109/PAC.2007.4440409","DOIUrl":"https://doi.org/10.1109/PAC.2007.4440409","url":null,"abstract":"Laser Undulator Compact X-ray source (LUCX) is a test bench for compact high brightness X-ray generator at KEK in order to demonstrate the possibility on K-edge digital subtraction angiography, based on the Compton Scattering. For this project, one of the challenging problems is to generate and accelerate high brightness multi-bunch electron beams, compensating the energy difference due to beam loading effect. In this paper, we calculate the transient beam loading voltage and energy gain from RF field in standing wave gun cavity and traveling wave accelerating tube for multi-bunch train, considering the process of propagation, buildup of RF field in them and the special RF pulse shape. We generated and accelerated 100 bunch electron beam train with 50 nC, which beam loading effect was compensated effectively by adjusting the laser injection timing. By BPM and OTR system, we measured the electron beam energy bunch by bunch. The average energy of 100 bunch train is 40.5 MeV and maximum energy difference bunch to bunch is 0.26 MeV, the relative energy spread of single bunch is about 0.13%. The transverse emittance can be optimized roughly to 3.6 pimm.mrad.","PeriodicalId":446026,"journal":{"name":"2007 IEEE Particle Accelerator Conference (PAC)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114501718","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}
Pub Date : 2007-06-25DOI: 10.1109/PAC.2007.4440793
H. Akikawa, Z. Igarashi, M. Ikegami, S. Lee, S. Sato, G. Shen, T. Tomisawa, A. Ueno
Beam commissioning of J-PARC linac has been performed since November 2006. We have developed wire scanners in order to measure beam profile and perform transverse matching. Four wire scanners are installed at each matching section. We report the result of measurement of beam profile.
{"title":"Profile measurement and transverse matching in J-PARC linac","authors":"H. Akikawa, Z. Igarashi, M. Ikegami, S. Lee, S. Sato, G. Shen, T. Tomisawa, A. Ueno","doi":"10.1109/PAC.2007.4440793","DOIUrl":"https://doi.org/10.1109/PAC.2007.4440793","url":null,"abstract":"Beam commissioning of J-PARC linac has been performed since November 2006. We have developed wire scanners in order to measure beam profile and perform transverse matching. Four wire scanners are installed at each matching section. We report the result of measurement of beam profile.","PeriodicalId":446026,"journal":{"name":"2007 IEEE Particle Accelerator Conference (PAC)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122047260","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}
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