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Title: Construction and Test of a Novel Superconducting RF Electron gun

The University of Wisconsin-Madison has completed installation of a superconducting electron gun. Its concept was optimized to be the source for a CW free electron laser facility with multiple megahertz repetition rate end stations. This VHF superconducting configuration holds the promise of the highest performance for CW injectors. Initial commissioning efforts show that the cavity can achieve gradients of 35 MV/m at the cathode position. With the cathode inserted CW operation has been achieved at 20 MV/m with good control of microphonics, negligible dark current, and Q0 > 3×109 at 4 K. Bunch charges of ~100 pC have been delivered, and first simple beam measurements made. These preliminary results are very encouraging for production of 100s pC bunches with millimeter-milliradian or smaller normalized emittances. Plans are in place to carry out more definitive studies to establish the full capabilities. However, since the grant was not renewed, the electron gun is currently mothballed, and without supplemental fund the opportunity for further work will be lost.
  1. University of Wisconsin-Madison
Publication Date:
OSTI Identifier:
Report Number(s):
Final Report
DOE Contract Number:
Resource Type:
Technical Report
Research Org:
University of Wisconsin-Madison
Sponsoring Org:
USDOE; USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
43 PARTICLE ACCELERATORS superconducting radio frequency cavities; electron gun; low emittance; free electron laser; microphonics