The SLAC Polarized Electron Source

Clendenin, J. E.; Brachmann, A.; Galetto, T.; Luh, Dah-An; Maruyama, Takashi; Sodja, J.; Turner, J.

doi:10.1063/1.1607293

Cited by 7 publications

(8 citation statements)

References 3 publications

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“…Operational experiences at several polarized electron beam facilities have shown clear damage pattern corresponding to bombardment from ions [12]. The SLC gun has demonstrated extraction of 10-16 nC bunch charge at µA levels of average current [13]. Jlab group has demonstrated 4 mA average current operation at 1500 MHz rep rate (pC bunch charge) with 85 C of charge lifetime [14].…”

Section: Introductionmentioning

confidence: 99%

Increasing charge lifetime in dc polarized electron guns by offsetting the anode

Rahman

Wang

Ben‐Zvi

et al. 2019

Phys. Rev. Accel. Beams

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Charge lifetime of strained superlattice GaAs photocathodes in DC guns is limited by ion back bombardment. It needs to be improved at least an order of magnitude to meet the requirements for future colliders such as Electron-Ion Collider (EIC). In this work, we propose and present simulation results for an offset anode scheme to increase charge lifetime in DC guns. This scheme eliminates the bombardment of high energy ions on the cathode and enables maximum usage of the available cathode area. Depending on the size of the available cathode area, this method can increase the charge lifetime by an order of magnitude compared to the current best alternative method. An anode assembly capable of in-vacuum movement is required for this method, which has been designed and fabricated at Brookhaven National Laboratory.

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Section: Introductionmentioning

confidence: 99%

Increasing charge lifetime in dc polarized electron guns by offsetting the anode

Rahman

Wang

Ben‐Zvi

et al. 2019

Phys. Rev. Accel. Beams

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“…1. In existing projects of electron-positron colliders, the option of polarized electron and positron beams is considered [1,2]. While one can consider the problem of producing the polarized electron beams with required characteristics as having been solved [3], the existing approaches to polarized positrons generation [4][5][6][7] do not provide required parameters.…”

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confidence: 99%

“…In existing projects of electron-positron colliders, the option of polarized electron and positron beams is considered [1,2]. While one can consider the problem of producing the polarized electron beams with required characteristics as having been solved [3], the existing approaches to polarized positrons generation [4][5][6][7] do not provide required parameters. In quoted papers the schemes were offered, in which by means of various methods a beam of circularly-polarized (CP) photons with energy of ∼ 10 1 MeV is generated to be subsequently used for producing the longitudinally polarized positrons during the process of pair creation in the amorphous converter.…”

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confidence: 99%

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Is It Possible to Obtain Polarized Positrons During Multiple Compton Backscattering Process?

Потылицын

2004

Quantum Aspects of Beam Physics 2003

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1. In existing projects of electron-positron colliders, the option of polarized electron and positron beams is considered [1,2]. While one can consider the problem of producing the polarized electron beams with required characteristics as having been solved [3], the existing approaches to polarized positrons generation [4][5][6][7] do not provide required parameters. In quoted papers the schemes were offered, in which by means of various methods a beam of circularly-polarized (CP) photons with energy of ∼ 10 1 MeV is generated to be subsequently used for producing the longitudinally polarized positrons during the process of pair creation in the amorphous converter.In this paper an alternate approach is discussed -at the first stage the unpolarized positrons are generated by the conventional scheme (interaction of an electron beam with energy of ∼10 1 GeV with an amorphous or crystalline converter), which are accelerated up to energy ∼ 5 ÷ 10 GeV and then interact with intense CP laser radiation.In the scheme of "laser cooling" of an electron beam suggested in the paper [8], electrons with energy of 5 GeV in head-on collisions with laser photons lose their energy practically without scattering. Thus, as a result of a multiple Compton scattering (MCS), the electron beam "is decelerated" resulting in some energy distribution, which variance is determined by the electron energy and laser flash parameters. It is clear that the laser cooling process will accompany also the interaction of positrons with laser photons.If we consider unpolarized positron beam as a sum of two fractions of the identical intensity with opposite signes of 100% longitudinal polarization, its interaction with CP laser radiation results in different Compton effect cross-sections for positrons with opposite helicity. In other words, positrons polarized in opposite directions lose a various part of the initial energy, therefore, by means of momentum selection of the resulting beam, it is possible to get a polarized positron beam with some intensity loss.2. Let us write the Compton effect cross-section of CP photons on relativistic positrons after summing over scattered photon polarization [9] (the system of units being used hereinafter ish = m = c = 1):+ξ 0z ξ z s z s(1 + c 2 − yc 2 ) + c z c 1 1 − y + (1 − y)c 2 = dσ 0 dy + P c ξ 0z dσ 2 dy + P c ξ z dσ 2 dy + ξ 0z ξ z dσ 3 dy .

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“…Plots of charge per bunch vs. laser energy for two photocathodes at SLAG[5]. The lower curve displaying the SCL effect is from a standard strained GaAs with low doping.…”

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confidence: 99%

Summary Report of PESP-2002 Workshop

Farkhondeh¹

2003

AIP Conference Proceedings

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A summary of the presentations for the 2002 Workshop on Polarized Electron Sources and Polarimeters (PESP-2002) will be given. PESP-2002 was held in the vicinity of MIT-Bates Linear Accelerator Center on September 4-6, 2002. It is a satellite workshop for the SPIN2002 symposium supported by the International and Local Organizing Committees of the Spin Physics Symposium, and MIT-Bates. The previous PESP workshop was held in Nagoya, Japan in October 2000. The workshop followed an interdisciplinary approach that included high-energy and low-energy physics, surface and material sciences, and the application of polarized sources in science and industry. In addition, PESP-2002 included contributions on polarized sources for parity-violating experiments that are underway at several medium-and high-energy accelerator centers worldwide. The summary report will include the operational experiences of medium and high-energy labs which are utilizing the latest developments in photocathodes to deliver highly polarized electron beams. Finally, a brief review of polarized sources in non-accelerator applications will be presented.

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The SLAC Polarized Electron Source

Cited by 7 publications

References 3 publications

Increasing charge lifetime in dc polarized electron guns by offsetting the anode

Increasing charge lifetime in dc polarized electron guns by offsetting the anode

Is It Possible to Obtain Polarized Positrons During Multiple Compton Backscattering Process?

Summary Report of PESP-2002 Workshop

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