TY  - JOUR
AU  - Loisch, Gregor
AU  - Chen, Ye Lining
AU  - Koschitzki, Christian
AU  - Qian, Houjun
AU  - Gross, Matthias
AU  - Hannah, Adrian
AU  - Hoffmann, Andreas
AU  - Kalantaryan, Davit
AU  - Krasilnikov, Mikhail
AU  - Lederer, Sven
AU  - Li, Xiangkun
AU  - Lishilin, Osip
AU  - Melkumyan, David
AU  - Monaco, Laura
AU  - Niemczyk, Raffael
AU  - Oppelt, Anne
AU  - Sertore, Daniele
AU  - Stephan, Frank
AU  - Valizadeh, Reza
AU  - Vashchenko, Grygorii
AU  - Weilbach, Tobias
TI  - Direct Measurement of Photocathode Time Response in a High-Brightness Photoinjector
JO  - Applied physics letters
VL  - 120
SN  - 0003-6951
CY  - Melville, NY
PB  - American Inst. of Physics
M1  - PUBDB-2022-01032
SP  - 104102
PY  - 2022
AB  - Electron photoinjectors provide high-brightness electron beams to numerous research applications in physics, chemistry, material, and life sciences. Semiconductor photocathodes are widely used here, as they enable the production of low-emittance beams with variable charge at high repetition rates. One of the key figures of merit of photocathodes is the minimum achievable bunch length. In semiconductor cathodes, this is dominated by scattering effects and varying penetration depths of the extracting photons, which leads to a characteristic electron emission function. We present a method to determine this cathode time response with resolution on the tens of femtoseconds level, breaking the resolution barrier encountered in previous studies. The method is demonstrated with cesium-telluride (Cs<sub>2</sub>Te) and gold cathodes, revealing response times of (184 ± 41) fs up to (253 ± 58) fs for the semiconductor and an upper limit of (93 ± 17) fs for the metal. Monte Carlo simulations of Cs<sub>2</sub>Te emission benchmarked to these results give detailed information about the cathode material. 
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000767648900007
DO  - DOI:10.1063/5.0078927
UR  - https://bib-pubdb1.desy.de/record/474839
ER  -