06 Instrumentation, Controls, Feedback & Operational Aspects
T25 Lasers
Paper Title Page
WEPME001 Virtual Cathode Drive Laser Diagnostics with a Large Dynamic Range for a Continuous Wave SRF Photoinjector 2251
SUSPSNE087   use link to see paper's listing under its alternate paper code  
 
  • E. Panofski, A. Jankowiak, T. Kamps, G. Klemz
    HZB, Berlin, Germany
 
  Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association
In a SRF photoinjector the close relationship between the laser pulse and the generated electron bunch parameters requires continuous monitoring of some of the laser pulse parameters. A laser diagnostic system, called virtual cathode, is a key part of a system that controls the stability of the laser. One of the main challenges for the virtual cathode is to cover the large dynamic range of the photocathode laser between commissioning at 120 Hz and operation at 1.3 GHz repetition rate with constant laser pulse parameters. The design of the virtual cathode as well as first measurements with a photocathode drive laser for the SRF injector test facility GunLab of BERLinPro will be presented.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME001  
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WEPME002 Laser System for SNS Laser Stripping Experiment 2254
 
  • Y. Liu, C. Huang, A. Rakhman
    ORNL, Oak Ridge, Tennessee, USA
 
  Funding: This work is funded by the U.S. DOE under grant number DE-FG02-13ER41967, and by the U.S. DOE under contract number DE-AC05-00OR22725 with UT-Battelle Corporation.
The Spallation Neutron Source (SNS) accelerator complex utilizes charge-exchange injection to stack a high-intensity proton beam in the accumulator ring for short-pulse neutron production. A foil-less charge exchange injection method was researched at SNS by using a laser assisted H beam stripping scheme. Following a proof-of-principle experiment using a Q-switched laser, a new experiment is being prepared to demonstrate laser stripping over a 10-us macropulse. In this talk, we will report the design and measurement results of the laser system for the next stage laser stripping experiment. The laser system adopts a master oscillator power amplifier (MOPA) configuration and contains an actively mode-locked fiber seeder, macropulse generator, multiple-stage Nd:YAG amplifiers, harmonic converters, and control electronics. The laser system generates 50 ps/402.5 MHz pulses (at a macropulse mode) with multiple megawatt peak power at a wavelength of 355 nm. The measurement results of laser pulse width, spectrum, spatial/temporal beam quality and their parameter dependence will be described.

 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME002  
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WEPRI059 Assembly and Installation of the UV Laser Delivery and Diagnostic Platform and the Photocathode Imaging System for the ASTA Front-end 2618
 
  • D.J. Crawford, R. Andrews, T.W. Hamerla, J. Ruan, J.K. Santucci, D. Snee
    Fermilab, Batavia, Illinois, USA
 
  Funding: This work was supported by the Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
The Advanced Superconducting Test Accelerator (ASTA) is in the early stage of commissioning. The Front-End consists of a 1.5 cell normal conducting RF Gun resonating at 1.3 GHz with a gradient of up to 40 MV/m, a cesium telluride cathode for photoelectron production, a pulsed 264 nm ultra-violet (UV) laser delivery system, and a diagnostic area for measuring the characteristics of the photoelectron beam. We report on the design, construction, and early experience of the ultra-violet (UV) Laser Delivery and Diagnostic Platform and the Photocathode Imaging System.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI059  
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