|WEPWA077||Aperture Test for Internal Target Operation in the JLAB High-current ERL||2289|
Funding: Supported by the Commonwealth of Virginia, U.S. DOE Nuclear and High Energy Physics, and by the U.S. DOE Basic Energy Sciences under contract No. DE-AC05-060R23177.
A high current beam transmission test has been successfully completed at the JLAB FEL Facility, culminating in very low-loss transmission of a high current CW beam through a small aperture. The purpose of this test was to determine if an ERL is capable of meeting the stringent requirements imposed by the use of a 1018/cm3 internal gas target proposed for the DarkLight experiment*. Minimal beamline modifications were made to create a machine configuration that is substantially different from those used in routine UV or IR FEL operation. A sustained (8 hour) high power beam run was performed, with clean transmission through a 2 mm transverse aperture of 127 mm length simulating the target configuration. A beam size of 50 um (rms) was measured near the center of the aperture. Experimental data from a week-long test run consistently exhibited beam loss of only a few ppm on the aperture while running 4.5 mA current at 100 MeV – or nearly 0.5 MW beam power. This surpassed the users’ expectation and demonstrated a unique capability of an ERL for this type of experiments. This report presents a summary of the experiment, a brief overview of our activities, and outlines future plans.
* P. Fisher, et al.,“Jlab PR-11-008: A Proposal for the DarkLight Experiment at the Jefferson Laboratory Free Electron Laser.” http://www.jlab.org/expprog/proposals/11prop.html