Performance of bialkali photocathode in DC-SRF photoinjector

Ouyang, Dongming; Zhao, Yungang; Xie, Haoling; Zhang, Xinkai; Zhao, Sheng; Feng, Lixin; Liu, Kexin; Huang, Senlin

doi:10.1016/j.nima.2021.166204

Cited by 5 publications

(4 citation statements)

References 16 publications

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“…To improve the performance of the K-Cs-Sb photocathode, we developed an improved sequential deposition procedure [17], where a faster Cs evaporation rate was adopted, and the cesiation process took less than 10 min. The K-Cs-Sb samples fabricated according to this recipe exhibited a typical QE of 5%-8%, and could be stored without deterioration for more than 2 weeks.…”

Section: Performance Of a Bialkali Photocathode At Cryogenic Temperaturementioning

confidence: 99%

“…We compared different K-Cs-Sb samples, and the results are listed in Table 1. The typical QE drop is about 90%, and the QE could recover to its initial value when we transferred the K-Cs-Sb photocathodes to a room temperature environment after 2 weeks of operation [17].…”

Section: Performance Of a Bialkali Photocathode At Cryogenic Temperaturementioning

confidence: 99%

“…However, the work function values reported by different laboratories usually vary by about 0.1 eV around 1.9 eV [20,44] due to different fabrication processes. Since the work function of the photocathode is a key parameter in the QE formula, it is necessary to use a suitable value to fit the QE behavior of the K-Cs-Sb photocathode fabricated using our fast-cesiation method [17].…”

Section: Temperature Dependence Of Work Functionmentioning

confidence: 99%

“…Among semiconductor photocathodes, K-Cs-Sb is an ideal candidate for electron sources [7,16,17] to obtain low-emittance beams at cryogenic temperature due to its high QE, low thermal emittance, and months-long lifetime in SRF injectors [15]. However, it is necessary to investigate the performance of the K-Cs-Sb photocathode at cryogenic temperature to establish a proper theoretical model for predicting the temperature-dependent behavior of QE.…”

Section: Introductionmentioning

confidence: 99%

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QE evolution of bialkali photocathode at cryogenic temperature

et al. 2023

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Photocathode plays an important role in generating high brightness and low emittance electron beam and K-Cs-Sb photocathode is preferred in SRF injectors for its high quantum efficiency, long lifetime, and low thermal emittance. To predict the QE change of K-Cs-Sb at cryogenic temperature more correctly, we have modified the QE formula of Spicer’s photoemission model considering the temperature dependence of work function and mean free path of photocathode material, which is obtained by fitting experimental data. The calculated QE drop of about 90.1% at 36.4 K fits well with the measured QE change in DC-SRF photoinjector at Peking University. This improved formula could provide a method to evaluate the QE performance of semiconductor photocathodes at cryogenic temperature.

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Section: Performance Of a Bialkali Photocathode At Cryogenic Temperaturementioning

confidence: 99%

Section: Performance Of a Bialkali Photocathode At Cryogenic Temperaturementioning

confidence: 99%

Section: Temperature Dependence Of Work Functionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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QE evolution of bialkali photocathode at cryogenic temperature

et al. 2023

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Thermal emittance measurements of a bi-alkali photocathode based on the high voltage DC photogun beamline

Xu,

Zhao,

Liu

et al. 2024

J. Inst.

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At the SRF Laboratory of Peking University, we utilized the -100 kV high-voltage DC photogun to employ the solenoid scan method for measuring the thermal emittance of CsK2Sb photocathode. Various laser wavelengths were employed at very low currents, leading to a negligible space charge effect. Additionally, we conducted measurements of the CsK2Sb photocathode's thermal emittance at a wavelength of 520 nm under different high voltages, (HV), establishing that the Schottky effect caused by the high voltage essentially unaffected the thermal emittance in the range of 50 kV ∼ 100 kV.

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High-brightness megahertz-rate beam from a direct-current and superconducting radio-frequency combined photocathode gun

Jia,

Li,

Wang

et al. 2024

Phys. Rev. Research

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High-brightness megahertz-rate electron beams are highly desired for cutting-edge applications in many areas of science. Photocathode electron guns capable of generating such beams with low dark current remain to be a challenging field. In this paper, we report breakthroughs with a hybrid gun combining a direct-current gap and a superconducting radio-frequency (SRF) cavity. The gun, employing K2CsSb photocathodes driven by a green laser, delivers a few MeV electron beam at 1 and 81.25 MHz rates with an average current up to 3 mA and a dark current several orders lower than current normal conducting continuous-wave guns. Emittance compensation and multipole field corrections have been applied to achieve a high-quality beam. The achievement will inspire the development of high-brightness SRF guns and promote megahertz-rate beam applications including coherent linac light sources and ultrafast electron diffraction/microscopy. Published by the American Physical Society 2024

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Performance of bialkali photocathode in DC-SRF photoinjector

Cited by 5 publications

References 16 publications

QE evolution of bialkali photocathode at cryogenic temperature

QE evolution of bialkali photocathode at cryogenic temperature

Thermal emittance measurements of a bi-alkali photocathode based on the high voltage DC photogun beamline

High-brightness megahertz-rate beam from a direct-current and superconducting radio-frequency combined photocathode gun

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