First operation of a photocathode radio frequency gun injector at high duty factor

Abstract

Tests of the electron beam injector for the Boeing/Los Alamos Average Power Laser Experiment have demonstrated first time operation of a photocathode radio frequency gun accelerator at 25% duty factor, exceeding previous photocathode operating parameters by three orders of magnitude. The macropulse format was 30 Hz and 8.3 ms with a micropulse frequency of 27 MHz. Average beam currents of up to 32 mA have been accelerated to 5 MeV for an average beam power of 160 kW. The macropulse peak current was 128 mA. The 32 mA average beam current exceeds previous cathode performance by a factor of 1000. Emittance measurements demonstrate excellent electron beam quality.

Space charge effects in field emission: One dimensional theory

“…Consequently, both space charge and emittance dominated beams have received intense study, particularly as they relate to thermal and photoemission sources for amplifiers and particle accelerators [1][2][3][4][5][6]. In contrast, field emission relies on quantum mechanical tunneling through barriers thinned through the application of fields on the order of 10 GV/m at the emission site.…”

Formulation of Emission From Relativistic Free Electrons in a Ring Structure for Electro-Optical Applications

“…On this basis, a theoretical study is done and a feasibility evaluation is performed with the FEL technology as reference frame due to similarity of basic physics and practical challenges. Reported advances of FELs in various dimensions [1,[15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] such as higher beam and radiation quality, wider tunable range and bandwidth, better pulse format control, migration towards compact and bench top structures further support the feasibility and significance of such electro-optical couplers.…”

“…These photoinjectors can improve the electron beam brightness by two orders of magnitude. As we discussed for the present scenario (operating in Compton scattering regime), however, the electron beam quality and current requirements introduce less stringent limitations considering the current FEL technology achievements and challenges [19][20][21][22][23][24][25][26][27].…”

“…In the second part; certain operating characteristics particular to this type of scenario such as bandwidth and tunability are described, effect of deviations from assumed or ideal model parameters such as energy spread are discussed, practical challenges and some potential solutions are addressed. These are done by referring to the fundamentally similar FELs operations, reported achievements [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29], and previously published work(s) such as dispersion analysis [8]. It should be noted that we cannot capture all aspects of a practical realization or the associated required assumptions to be included in the formulations.…”

Photoinjected energy recovery linac upgrade for the National Synchrotron Light Source

“…The PERL requires a CW operation of the photoinjector. The device that came closest to this requirement is the Boeing photoinjector [3].…”