Stable operation of a high-voltage high-current dc photoemission gun for the bunched beam electron cooler in RHIC

Gu, X.; Altinbas, Z.; Badea, S.; Bruno, D.; Cannizzo, L.; Costanzo, Michael; Drees, A.; Fedotov, A. V.; Fischer, W.; Gassner, D.; Gaowei, Mengjia; Inacker, Patrick; Jamilkowski, James; Kayran, D.; Kewisch, J.; Liaw, Chong-Jer; Liu, C.; Mapes, M.; Mernick, K.; Mi, C.; Miller, Toby; Minty, M.; Nguyen, Linh; Ptitsyn, V.; Sandberg, J.; Schoefer, V.; Seletskiy, S.; Smart, L.; Sukhanov, A.; Thieberger, P.; Tuozzolo, J.; Wang, E.; Zaltsman, A.; Zhao, He; Zhao, Zhi; Bartnik, Adam; Smolenski, K.

doi:10.1103/physrevaccelbeams.23.013401

Cited by 15 publications

(7 citation statements)

References 47 publications

(54 reference statements)

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“…The entire duration of our cathode growth process is about 2.5 h and is at least a factor of 2–5 times faster than that reported by others 27 – 29 . Our cathodes, produced using this recipe, have demonstrated several weeks lifetime while delivering tens of milliamperes of average current in the DC gun 21 .…”

Section: Methodsmentioning

confidence: 99%

“…Semiconductor and metal photocathodes have been tested in a number of electron guns. Until our SRF gun became operational, the bialkali photocathodes were successfully operated only in the high voltage (HV) DC guns 19 , 20 , generating tens of milliamperes of average current with lifetime of the order of months 21 . However, the performance of alkali cathodes in RF guns were less successful.…”

Section: Introductionmentioning

confidence: 99%

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Long lifetime of bialkali photocathodes operating in high gradient superconducting radio frequency gun

Wang

Litvinenko

Pinayev

et al. 2021

Sci Rep

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High brightness, high charge electron beams are critical for a number of advanced accelerator applications. The initial emittance of the electron beam, which is determined by the mean transverse energy (MTE) and laser spot size, is one of the most important parameters determining the beam quality. The bialkali photocathodes illuminated by a visible laser have the advantages of high quantum efficiency (QE) and low MTE. Furthermore, Superconducting Radio Frequency (SRF) guns can operate in the continuous wave (CW) mode at high accelerating gradients, e.g. with significant reduction of the laser spot size at the photocathode. Combining the bialkali photocathode with the SRF gun enables generation of high charge, high brightness, and possibly high average current electron beams. However, integrating the high QE semiconductor photocathode into the SRF guns has been challenging. In this article, we report on the development of bialkali photocathodes for successful operation in the SRF gun with months-long lifetime while delivering CW beams with nano-coulomb charge per bunch. This achievement opens a new era for high charge, high brightness CW electron beams.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Long lifetime of bialkali photocathodes operating in high gradient superconducting radio frequency gun

Wang

Litvinenko

Pinayev

et al. 2021

Sci Rep

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“…Figure 3 shows the overall conditioning time along with the current, vacuum, and averaged radiation levels in the gun. Our total high voltage conditioning duration is much shorter than other comparable HVDC guns, indicating our new post treatment and clean processing might have played an important role [16,26,27].…”

Section: High Voltage Performancementioning

confidence: 85%

High voltage DC gun for high intensity polarized electron source

Wang,

Rahman,

Skaritka

et al. 2021

Preprint

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The high intensity polarized electron source is a critical component for future nuclear physics facilities. The Electron Ion Collider (EIC) requires a polarized electron gun with higher voltage and higher bunch charge compared to any existing polarized electron source. At Brookhaven National Laboratory, we have built an inverted high voltage direct current (HVDC) photoemission gun with a large cathode size. We report on the performances of GaAs photocathodes in a high gradient with up to a 16 nC bunch charge. The measurements were performed at a stable operating gap voltage of 300 kV -demonstrating outstanding lifetime, and robustness. We observed obvious lifetime enhancement by biasing the anode. The gun also integrated a cathode cooling system for potential application on high current electron sources. The various novel features implemented and demonstrated in this polarized HVDC gun open the door towards future high intensity-high average current electron accelerator facilities.

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“…By September of 2018, we were able to deliver a stable 30 mA beam current to the injection beam dump using a reduced SRF booster voltage. This mode of operation was used to study gun stability and long-term cathode QE lifetime [25]. During several hours of high-current operation, we observed a small recovery of the cathode QE instead of a QE degradation, as shown in Fig.…”

Section: A Gun Tests In Cw Operationmentioning

confidence: 87%

“…The electron beam rms energy spread in the cooling sections is required to be less than 5 × 10 −4 , which corresponds to an absolute energy spread better than 1 keV at the LEReC operation energies of 1.6-2 MeV. At first, special care was taken to make sure that there were no gun high-voltage power supply ripples exceeding 1 kV [25]. To avoid energy spread buildup in the cooling sections due to the longitudinal space-charge effect, the electron bunches are ballistically stretched up to 400 ps in 30 m of the transport line.…”

Section: A Longitudinal Beam Qualitymentioning

confidence: 99%

High-brightness electron beams for linac-based bunched beam electron cooling

Kayran¹,

Altinbas²,

Bruno³

et al. 2020

Phys. Rev. Accel. Beams

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A high-current high-brightness electron accelerator for low-energy RHIC electron cooling (LEReC) was successfully commissioned at Brookhaven National Laboratory. The LEReC accelerator includes a dc photoemission gun, a laser system, a photocathode delivery system, magnets, beam diagnostics, a superconducting rf booster cavity, and a set of normal conducting rf cavities to provide enough flexibility to tune the beam in the longitudinal phase space. Cooling with nonmagnetized rf accelerated electron beams requires longitudinal corrections to obtain a small momentum spread while preserving the transverse emittances. Electron beams with kinetic energies of 1.6 and 2.0 MeV with a beam quality suitable for cooling were successfully propagated through 100 m of beam lines, including dispersion sections, maintained through both cooling sections in RHIC and used for cooling ions in both RHIC rings simultaneously. The beam quality suitable for cooling RHIC beams was achieved in 2018, which led to the first experimental demonstration of bunched beam electron cooling of hadron beams in 2019.

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Stable operation of a high-voltage high-current dc photoemission gun for the bunched beam electron cooler in RHIC

Cited by 15 publications

References 47 publications

Long lifetime of bialkali photocathodes operating in high gradient superconducting radio frequency gun

Long lifetime of bialkali photocathodes operating in high gradient superconducting radio frequency gun

High voltage DC gun for high intensity polarized electron source

High-brightness electron beams for linac-based bunched beam electron cooling

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