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Diamond Amplified Photocathodes

Published online by Cambridge University Press:  01 February 2011

John Smedley ,
Ilan Ben-Zvi ,
Jen Bohon ,
Xiangyun Chang ,
Ranjan Grover ,
Abdel Isakovic ,
Triveni Rao  and
Qiong Wu
John Smedley
Affiliation:
smedley@bnl.gov, Brookhaven National Laboratory, Instrumentation, 20 Technology Street, Bldg. 535B, Upton, NY, 11973, United States, 631-344-7865
Ilan Ben-Zvi
Affiliation:
benzvi@bnl.gov, Brookhaven National Laboratory, Upton, NY, 11973, United States
Jen Bohon
Affiliation:
jbohon@bnl.gov, Case Western Reserve University, Clevand, OH, 44106, United States
Xiangyun Chang
Affiliation:
xychang@bnl.gov, Brookhaven National Laboratory, Upton, NY, 11973, United States
Ranjan Grover
Affiliation:
rgover@bnl.gov, Brookhaven National Laboratory, Upton, NY, 11973, United States
Abdel Isakovic
Affiliation:
isakovic@bnl.gov, Brookhaven National Laboratory, Upton, NY, 11973, United States
Triveni Rao
Affiliation:
triveni@bnl.gov, Brookhaven National Laboratory, Upton, NY, 11973, United States
Qiong Wu
Affiliation:
qiowu@bnl.gov, Indiana University, Bloomington, IN, 47405, United States
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Abstract

High-average-current linear electron accelerators require photoinjectors capable of delivering tens to hundreds of mA average current, with peak currents of hundreds of amps. Standard photocathodes face significant challenges in meeting these requirements, and often have short operational lifetimes in an accelerator environment. We report on recent progress toward development of secondary emission amplifiers for photocathodes, which are intended to increase the achievable average current while protecting the cathode from the accelerator.

The amplifier is a thin diamond wafer which converts energetic (few keV) primary electrons into hundreds of electron-hole pairs via secondary electron emission. The electrons drift through the diamond under an external bias and are emitted into vacuum via a hydrogen-terminated surface with negative electron affinity (NEA). Secondary emission gain of over 200 has been achieved. Two methods of patterning diamond, laser ablation and reactive-ion etching (RIE), are being developed to produce the required geometry. A variety of diagnostic techniques, including FTIR, SEM and AFM, have been used to characterize the diamonds.

Keywords

diamondphotoemissioninfrared (IR) spectroscopy
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 1039: Symposium P – Diamond Electronics–Fundamentals to Applications II , 2007 , 1039-P09-02
Copyright
Copyright © Materials Research Society 2008

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