Title: Performance of a second generation $X$ -band rf photoinjector

Abstract

rf photoinjectors produce incredibly bright electron beams enabling advanced photon science applications such as the current generation of free electron lasers and high energy x-rays and gammarays via laser-Compton scattering. A second generation 5.59 cell X-band rf gun has been developed, installed, conditioned, commissioned, tuned, and used to produce laser-Compton x-rays and multiple electron bunches. A charge per bunch from a few pC to 500 pC has been measured, consistent with a quantum efficiency of 5 × 10^-5 using a 263 nm 10 Hz photocathode drive laser. The rf gun has operated close to design performance at high gradient, and more reliably at lower gradient achieving a root mean square normalized emittance of 0.3 mm mrad at both 80 pC at 185 MV=m, and 40 pC at 165 MV=m. Thermal emittance is estimated at 0.55 mmmrad=mm. Energy spread of 0.03% has been achieved. These results agree very well with modeling predictions for the operating conditions under which the measurements were made. Unusually disruptive breakdowns were observed with an applied magnetic field of 0.5$$T$$ used for emittance compensation.

Authors:

Marsh, R. A.; Anderson, G. G.; Anderson, S. G.; Gibson, D. J.; Barty, C. P. J.; Hwang, Y.

Publication Date:

Tue Jul 03 00:00:00 EDT 2018

Research Org.:

Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA)

OSTI Identifier:

1458788

Alternate Identifier(s):

OSTI ID: 1523573

Report Number(s):

LLNL-JRNL-740858
Journal ID: ISSN 2469-9888; PRABCJ; 073401

Grant/Contract Number:  

AC52-07NA27344

Resource Type:

Published Article

Journal Name:

Physical Review Accelerators and Beams

Additional Journal Information:

Journal Name: Physical Review Accelerators and Beams Journal Volume: 21 Journal Issue: 7; Journal ID: ISSN 2469-9888

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

43 PARTICLE ACCELERATORS