DC Photoelectron Gun Parameters for Ultrafast Electron Microscopy

被引：9

作者：

Berger, Joel A. ^{[1
]}

Hogan, John T. ^{[1
]}

Greco, Michael J. ^{[1
]}

Schroeder, W. Andreas ^{[1
]}

Nicholls, Alan W. ^{[2
]}

Browning, Nigel D. ^{[3
,4
]}

机构：

[1] Univ Illinois, Dept Phys, Chicago, IL 60607 USA

[2] Univ Illinois, Res Resources Ctr, Chicago, IL 60607 USA

[3] Lawrence Livermore Natl Lab, Livermore, CA 94550 USA

[4] Univ Calif Davis, Dept Chem Engn & Mat Sci, Davis, CA 95616 USA

来源：

MICROSCOPY AND MICROANALYSIS | 2009年 / 15卷 / 04期

关键词：

ultrafast; electron microscopy; photoemission; emittance; X-RAY; FEMTOSECOND; ACCELERATION; DIFFRACTION; EMISSION; DYNAMICS; PURE; TA; MO;

D O I：

10.1017/S1431927609090266

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

We present a characterization of the performance of an ultrashort laser pulse driven DC photoelectron gun based on the thermionic emission gun design of Togawa et al. [Togawa, K., Shintake, T., Inagaki, T., Onoe, K. & Tanaka, T. (2007). Phys Rev Spec Top-AC 10, 020703]. The gun design intrinsically provides adequate optical access and accommodates the generation of similar to 1 mm(2) electron beams while contributing negligible divergent effects at the anode aperture. Both single-photon (with up to 20,000 electrons/pulse) and two-photon photoemission are observed from Ta and Cu(100) photocathodes driven by the harmonics (similar to 4 ps pulses at 261 nm and similar to 200 fs pulses at 532 nm, respectively) of a high-power femtosecond Yb:KGW laser. The results, including the dependence of the photoemission efficiency on the polarization state of the drive laser radiation, are consistent with expectations. The implications of these observations and other physical limitations for the development of a dynamic transmission electron microscope with sub-1 nm . ps space-time resolution are discussed.

引用

页码：298 / 313

页数：16

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[21] Theoretical model of the intrinsic emittance of a photocathode [J].