TY - JOUR
T1 - Near-Threshold Photoemission from Graphene-Coated Cu (110)
AU - Knill, Christopher J.
AU - Yamaguchi, Hisato
AU - Kawahara, Kenji
AU - Wang, Gaoxue
AU - Batista, Enrique
AU - Yang, Ping
AU - Ago, Hiroki
AU - Moody, Nathan
AU - Karkare, Siddharth
N1 - Funding Information:
This work was supported by the U.S. National Science Foundation under Award No. PHY-1549132, by the Center for Bright Beams, Department of Energy under Grant No. DE-SC0021092, and by the U.S. Department of Energy (DOE) Office of Science under the U.S.-Japan Science and Technology Cooperation Program in High Energy Physics and the Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for Scientific Research on Innovative Areas “Science of 2.5 Dimensional Materials: Paradigm Shift of Materials Science Toward Future Social Innovation” (KAKENHI Grants No. JP21H05232 and No. JP21H05233).
Publisher Copyright:
© 2023 American Physical Society.
PY - 2023/1
Y1 - 2023/1
N2 - The brightness of electron beams emitted from photocathode sources plays a critical role in determining the performance of x-ray free-electron lasers and ultrafast electron-diffraction applications. In order to achieve the maximum brightness, the electrons need to be emitted from a photocathode with the lowest-possible mean transverse energy (MTE). Recent investigations have shown that capping a Cu(110) photocathode with a monolayer of graphene can protect the quantum efficiency (QE) from long-term exposure to varying vacuum conditions. However, there have been no studies that investigate the effects that a monolayer of graphene has on the MTE. Here, we report on measurements of a graphene-coated Cu(110) single crystal near the photoemission threshold for room and liquid-nitrogen temperatures. At room temperature, a minimum MTE of 25 meV is measured at 295 nm. At liquid-nitrogen temperatures, a minimum MTE of 9 meV is measured at the photoemission threshold of 290 nm.
AB - The brightness of electron beams emitted from photocathode sources plays a critical role in determining the performance of x-ray free-electron lasers and ultrafast electron-diffraction applications. In order to achieve the maximum brightness, the electrons need to be emitted from a photocathode with the lowest-possible mean transverse energy (MTE). Recent investigations have shown that capping a Cu(110) photocathode with a monolayer of graphene can protect the quantum efficiency (QE) from long-term exposure to varying vacuum conditions. However, there have been no studies that investigate the effects that a monolayer of graphene has on the MTE. Here, we report on measurements of a graphene-coated Cu(110) single crystal near the photoemission threshold for room and liquid-nitrogen temperatures. At room temperature, a minimum MTE of 25 meV is measured at 295 nm. At liquid-nitrogen temperatures, a minimum MTE of 9 meV is measured at the photoemission threshold of 290 nm.
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U2 - 10.1103/PhysRevApplied.19.014015
DO - 10.1103/PhysRevApplied.19.014015
M3 - Article
AN - SCOPUS:85146313076
SN - 2331-7019
VL - 19
JO - Physical Review Applied
JF - Physical Review Applied
IS - 1
M1 - 014015
ER -