SRF2011 - List of Authors (Stirbet, M.)

Paper

Title

Page

Fabrication, Tuning, Treatment and Testing of Two 3.5 Cell Photo-Injector Cavities for the ELBE Linac

405

A. Arnold, P. Murcek, J. Teichert, R. Xiang
HZDR, Dresden, Germany
G.V. Eremeev, P. Kneisel, M. Stirbet, L. Turlington
JLAB, Newport News, Virginia, USA

As part of a CRADA (Cooperative Research and Development Agreement) between Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and Thomas Jefferson Lab National Accelerator Facility (TJNAF) we have fabricated and tested two 1.3 GHz 3.5 cell photo-injector cavities from polycrystalline RRR niobium and large grain RRR niobium, respectively. The cavity with the better performance will replace the presently used injector cavity in the ELBE linac*. The cavities have been fabricated and pre-tuned at TJNAF, while the more sophisticated final field tuning, the adjustment of the external couplings and the field profile measurement of transverse electric modes for RF focusing** was done at HZDR. The following standard surface treatment and the vertical test was carried out at TJNAF’s production facilities. A major challenge turned out to be the rinsing of the cathode cell, which has small opening (Ø10mm) to receive the cathode stalk. Another unexpected problem encountered after etching, since large visible defects appeared in the least accessible cathode cell. This contribution reports about our experiences, initial results and the on-going diagnostic work to understand and fix the problems.
* J. Teichert, et al., Proc. FEL 2010, Malmoe, Sweden, p. 453.
** V. Volkov, D. Janssen, Phys. Rev. ST Accel. Beams 11, 061302 (2008).

Poster TUPO019 [1.211 MB]

TUPO061

Preparation and Testing of the SRF Cavities for the CEBAF 12 GeV Upgrade

542

A.V. Reilly, T. Bass, A. Burrill, G.K. Davis, F. Marhauser, C.E. Reece, M. Stirbet
JLAB, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
80 new 7-cell, LL cell-shaped cavities are required for the CEBAF 12 GeV Upgrade project. In addition to ten pre-production units fabricated at JLab, the full set of commercially-produced cavities have been delivered. An efficient processing routine, which includes a controlled 30 micron EP, has been established to transform these cavities into qualified 8-cavity strings. This work began in 2010 and will run through the end of 2011. The realized cavity performance consistently exceeds project requirements and also the maximum useful gradient in CEBAF: 25 MV/m. We will describe the cavity processing and preparation protocols and summarize test results obtained to date.

Poster TUPO061 [1.543 MB]

Paper	Title	Page
TUPO019	Fabrication, Tuning, Treatment and Testing of Two 3.5 Cell Photo-Injector Cavities for the ELBE Linac	405
	A. Arnold, P. Murcek, J. Teichert, R. Xiang HZDR, Dresden, Germany G.V. Eremeev, P. Kneisel, M. Stirbet, L. Turlington JLAB, Newport News, Virginia, USA
	As part of a CRADA (Cooperative Research and Development Agreement) between Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and Thomas Jefferson Lab National Accelerator Facility (TJNAF) we have fabricated and tested two 1.3 GHz 3.5 cell photo-injector cavities from polycrystalline RRR niobium and large grain RRR niobium, respectively. The cavity with the better performance will replace the presently used injector cavity in the ELBE linac. The cavities have been fabricated and pre-tuned at TJNAF, while the more sophisticated final field tuning, the adjustment of the external couplings and the field profile measurement of transverse electric modes for RF focusing* was done at HZDR. The following standard surface treatment and the vertical test was carried out at TJNAF’s production facilities. A major challenge turned out to be the rinsing of the cathode cell, which has small opening (Ø10mm) to receive the cathode stalk. Another unexpected problem encountered after etching, since large visible defects appeared in the least accessible cathode cell. This contribution reports about our experiences, initial results and the on-going diagnostic work to understand and fix the problems. * J. Teichert, et al., Proc. FEL 2010, Malmoe, Sweden, p. 453. ** V. Volkov, D. Janssen, Phys. Rev. ST Accel. Beams 11, 061302 (2008).
	Poster TUPO019 [1.211 MB]

TUPO061	Preparation and Testing of the SRF Cavities for the CEBAF 12 GeV Upgrade	542
	A.V. Reilly, T. Bass, A. Burrill, G.K. Davis, F. Marhauser, C.E. Reece, M. Stirbet JLAB, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. 80 new 7-cell, LL cell-shaped cavities are required for the CEBAF 12 GeV Upgrade project. In addition to ten pre-production units fabricated at JLab, the full set of commercially-produced cavities have been delivered. An efficient processing routine, which includes a controlled 30 micron EP, has been established to transform these cavities into qualified 8-cavity strings. This work began in 2010 and will run through the end of 2011. The realized cavity performance consistently exceeds project requirements and also the maximum useful gradient in CEBAF: 25 MV/m. We will describe the cavity processing and preparation protocols and summarize test results obtained to date.
	Poster TUPO061 [1.543 MB]