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Title: Adaptive electron beam shaping using a photoemission gun and spatial light modulator

The need for precisely defined beam shapes in photoelectron sources has been well established. In this paper, we use a spatial light modulator and simple shaping algorithm to create arbitrary, detailed transverse laser shapes with high fidelity. We transmit this shaped laser to the photocathode of a high voltage dc gun. Using beam currents where space charge is negligible, and using an imaging solenoid and fluorescent viewscreen, we show that the resultant beam shape preserves these detailed features with similar fidelity. Next, instead of transmitting a shaped laser profile, we use an active feedback on the unshaped electron beam image to create equally accurate and detailed shapes. We demonstrate that this electron beam feedback has the added advantage of correcting for electron optical aberrations, yielding shapes without skew. The method may serve to provide precisely defined electron beams for low current target experiments, space-charge dominated beam commissioning, as well as for online adaptive correction of photocathode quantum efficiency degradation.
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1]
  1. Cornell University, Ithaca, NY (United States). Cornell Laboratory for Accelerator-Based Studies and Education.
Publication Date:
Grant/Contract Number:
SC0003965; SC00039650
Type:
Published Article
Journal Name:
Physical Review Special Topics. Accelerators and Beams
Additional Journal Information:
Journal Volume: 18; Journal Issue: 2; Journal ID: ISSN 1098-4402
Publisher:
American Physical Society (APS)
Research Org:
Cornell University, Ithaca, NY (United States). Cornell Laboratory for Accelerator-Based Studies and Education.
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS
OSTI Identifier:
1179916
Alternate Identifier(s):
OSTI ID: 1188409