1
|
Xiang R, Schaber J. Review of Recent Progress on Advanced Photocathodes for Superconducting RF Guns. MICROMACHINES 2022; 13:mi13081241. [PMID: 36014163 PMCID: PMC9414528 DOI: 10.3390/mi13081241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 07/26/2022] [Accepted: 07/27/2022] [Indexed: 12/04/2022]
Abstract
As is well known, the quality of the photocathodes is essential for the stability and reliability of photoinjector operations. Especially for superconducting radio frequency photoinjectors (SRF guns), the photocathode represents one of the most critical parts. Benefiting from the fast development of photocathode technology in recent years, several SRF guns have been successfully operated or tested for beam generation at the kHz–MHz repetition rate. In this paper, we will review the achievements as well as the open questions in the applications of photocathodes for SRF gun operation. Furthermore, we will discuss the possible improvement of photocathodes for future CW electron sources.
Collapse
Affiliation(s)
- Rong Xiang
- SRF-Gun Group, ELBE Department, Institute of Radiation Physics, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany;
- Correspondence:
| | - Jana Schaber
- SRF-Gun Group, ELBE Department, Institute of Radiation Physics, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany;
- Institute of Physical Chemistry, Technische Universität Dresden, 01062 Dresden, Germany
| |
Collapse
|
3
|
Xie H. Overview of the Semiconductor Photocathode Research in China. MICROMACHINES 2021; 12:mi12111376. [PMID: 34832788 PMCID: PMC8618467 DOI: 10.3390/mi12111376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/30/2021] [Accepted: 09/30/2021] [Indexed: 11/30/2022]
Abstract
With the growing demand from scientific projects such as the X-ray free electron laser (XFEL), ultrafast electron diffraction/microscopy (UED/UEM) and electron ion collider (EIC), the semiconductor photocathode, which is a key technique for a high brightness electron source, has been widely studied in China. Several fabrication systems have been designed and constructed in different institutes and the vacuum of most systems is in the low 10−8 Pa level to grow a high QE and long lifetime photocathode. The QE, dark lifetime/bunch lifetime, spectral response and QE map of photocathodes with different kinds of materials, such as bialkali (K2CsSb, K2NaSb, etc.), Cs2Te and GaAs, have been investigated. These photocathodes will be used to deliver electron beams in a high voltage DC gun, a normal conducting RF gun, and an SRF gun. The emission physics of the semiconductor photocathode and intrinsic emittance reduction are also studied.
Collapse
Affiliation(s)
- Huamu Xie
- State Key Laboratory of Nuclear Physics and Technology, Institute of Heavy Ion Physics, Peking University, Beijing 100871, China
| |
Collapse
|
4
|
Wang E, Litvinenko VN, Pinayev I, Gaowei M, Skaritka J, Belomestnykh S, Ben-Zvi I, Brutus JC, Jing Y, Biswas J, Ma J, Narayan G, Petrushina I, Rahman O, Xin T, Rao T, Severino F, Shih K, Smith K, Wang G, Wu Y. Long lifetime of bialkali photocathodes operating in high gradient superconducting radio frequency gun. Sci Rep 2021; 11:4477. [PMID: 33627743 PMCID: PMC7904862 DOI: 10.1038/s41598-021-83997-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 02/08/2021] [Indexed: 11/09/2022] Open
Abstract
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.
Collapse
Affiliation(s)
- E Wang
- Collider-Accelerator Department, Brookhaven National Laboratory, Upton, NY, 11973, USA.
| | - V N Litvinenko
- Collider-Accelerator Department, Brookhaven National Laboratory, Upton, NY, 11973, USA.,Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, 11794, USA
| | - I Pinayev
- Collider-Accelerator Department, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - M Gaowei
- Collider-Accelerator Department, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - J Skaritka
- Collider-Accelerator Department, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - S Belomestnykh
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, 11794, USA.,Fermi National Accelerator Laboratory, Batavia, IL, 60510, USA
| | - I Ben-Zvi
- Collider-Accelerator Department, Brookhaven National Laboratory, Upton, NY, 11973, USA.,Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, 11794, USA
| | - J C Brutus
- Collider-Accelerator Department, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Y Jing
- Collider-Accelerator Department, Brookhaven National Laboratory, Upton, NY, 11973, USA.,Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, 11794, USA
| | - J Biswas
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, 11794, USA
| | - J Ma
- Collider-Accelerator Department, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - G Narayan
- Collider-Accelerator Department, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - I Petrushina
- Collider-Accelerator Department, Brookhaven National Laboratory, Upton, NY, 11973, USA.,Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, 11794, USA
| | - O Rahman
- Collider-Accelerator Department, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - T Xin
- Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China
| | - T Rao
- Instrumentation Division, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - F Severino
- Collider-Accelerator Department, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - K Shih
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, 11794, USA
| | - K Smith
- Collider-Accelerator Department, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - G Wang
- Collider-Accelerator Department, Brookhaven National Laboratory, Upton, NY, 11973, USA.,Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Y Wu
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, 11794, USA
| |
Collapse
|