SRF2013 - List of Keywords (background)

Paper	Title	Other Keywords	Page
MOP052	RF Aspects of Quality Control for Industrial XFEL Cavities Fabrication	cavity, controls, SRF, pick-up	237
	A.A. Sulimov, V. Gubarev, S. Yasar DESY, Hamburg, Germany
	Quality control of XFEL serial cavities allows us not only except the using of reject cavities for linac, but also give a feedback to the industry in case of cavity parameters come to their limits. RF control assays not only the electro dynamical characteristics (as frequencies, Q-factors and fields), but also provide the mechanical revise with a very high accuracy. Automation of this quality control in XFEL data base gave us a powerful tool which is required for the big projects as European-XFEL.
	Poster MOP052 [1.178 MB]

TUP035	Neutron Activation Analysis as a Foreign Intrusion Cavity DetectionTool	neutron, detector, radioactivity, cavity	495
	C. Maiano, P. Michelato INFN/LASA, Segrate (MI), Italy M. Clemenza Universita Milano Bicocca, MILANO, Italy C. Pagani Università degli Studi di Milano & INFN, Segrate, Italy
	Neutron Activation Analysis (NAA) is one of the currently available techniques used to determine contaminants in Nb superconducting cavities, allowing a non-destructive determination of foreign materials, provided they have radioactive isotopes with a sufficiently long half-life. We present the NAA technique application with the goal of contaminants determination, identification and localization for the European XFEL 3rd harmonic cavities (3.9 GHz). Irradiation and analysis has been performed in collaboration with the LENA nuclear reactor (Pavia, Italy) and the University of Milano Bicocca. The main difference respect to the measurements performed in the past is the goal to apply of the NNA directly to entire cavities and not to material samples. Currently nine samples were exposed to thermal and fast neutron flux and the resulting activity was measured with HPGe detectors.

TUP055	Electropolishing of the ANL Deflecting Cavity for the APS Upgrade	cavity, niobium, SRF, coupling	544
	Y. Yang, J.D. Fuerst, J.P. Holzbauer, J.A. Kaluzny, A. Nassiri, G. Wu ANL, Argonne, USA A.C. Crawford Fermilab, Batavia, USA P. Dhakal, J.D. Mammosser, H. Wang JLAB, Newport News, Virginia, USA Y. Yang TUB, Beijing, People's Republic of China
	Studies on the application of electropolishing (EP) of the ANL superconducting deflecting cavity have shown promising results. This cavity geometry is a squashed single-cell cavity with Y-end group waveguide as well as on-cell LOM damper. The cavity works at TM110-like deflecting mode, in which the iris between the cavity cell and the Y-end group is the highest magnetic field region. Before EP, the cavity had been chemically etched (BCP) several times. Forty-um EP processing was performed on one Mark II prototype deflecting cavity at Fermilab. No mild baking was performed before the cavity vertical test. The test showed that the low-field Q had improved from 2·10⁹ to 3·10⁹ and the high-field Q-slope had been successfully removed. The quench limit was slightly improved from 10⁶ mT to 113 mT. Fast T-mapping had detected a significant decrease of local temperature rise in the cavity iris. Optical inspection before EP found a lot of grooves around the iris, which might be related to the gas bubbles generated during BCP. This suggests that horizontal EP is a promising processing technique to remove the high-field Q-slope and improve the deflecting cavity performance.

WEIOB01	Status of MgB2 Coating Studies for SRF Applications	cavity, SRF, controls, superconductivity	777
	T. Tajima, L. Civale, D.J. Devlin, G.C. Martinez, R.K. Schulze LANL, Los Alamos, New Mexico, USA
	Funding: DOE Office of Science/Nuclear Physics MgB2 has shown promising results on small samples and its coating development is entering into the stage to coat large samples and elliptical cavities. Several coating techniques that seem to be appropriate for cavity coating and their status will be shown together with some cavity measurement results with either 6 GHz or 1.3 GHz single-cell cavities. Other data such as RF surface resistance at low temperatures and vortex penetration fields with small samples will also be shown.
	Slides WEIOB01 [2.183 MB]

Paper

Title

Other Keywords

Page

MOP052

RF Aspects of Quality Control for Industrial XFEL Cavities Fabrication

cavity, controls, SRF, pick-up

237

A.A. Sulimov, V. Gubarev, S. Yasar
DESY, Hamburg, Germany

Quality control of XFEL serial cavities allows us not only except the using of reject cavities for linac, but also give a feedback to the industry in case of cavity parameters come to their limits. RF control assays not only the electro dynamical characteristics (as frequencies, Q-factors and fields), but also provide the mechanical revise with a very high accuracy. Automation of this quality control in XFEL data base gave us a powerful tool which is required for the big projects as European-XFEL.

Poster MOP052 [1.178 MB]

TUP035

Neutron Activation Analysis as a Foreign Intrusion Cavity DetectionTool

neutron, detector, radioactivity, cavity

495

C. Maiano, P. Michelato
INFN/LASA, Segrate (MI), Italy
M. Clemenza
Universita Milano Bicocca, MILANO, Italy
C. Pagani
Università degli Studi di Milano & INFN, Segrate, Italy

Neutron Activation Analysis (NAA) is one of the currently available techniques used to determine contaminants in Nb superconducting cavities, allowing a non-destructive determination of foreign materials, provided they have radioactive isotopes with a sufficiently long half-life. We present the NAA technique application with the goal of contaminants determination, identification and localization for the European XFEL 3rd harmonic cavities (3.9 GHz). Irradiation and analysis has been performed in collaboration with the LENA nuclear reactor (Pavia, Italy) and the University of Milano Bicocca. The main difference respect to the measurements performed in the past is the goal to apply of the NNA directly to entire cavities and not to material samples. Currently nine samples were exposed to thermal and fast neutron flux and the resulting activity was measured with HPGe detectors.

TUP055

Electropolishing of the ANL Deflecting Cavity for the APS Upgrade

cavity, niobium, SRF, coupling

544

Y. Yang, J.D. Fuerst, J.P. Holzbauer, J.A. Kaluzny, A. Nassiri, G. Wu
ANL, Argonne, USA
A.C. Crawford
Fermilab, Batavia, USA
P. Dhakal, J.D. Mammosser, H. Wang
JLAB, Newport News, Virginia, USA
Y. Yang
TUB, Beijing, People's Republic of China

Studies on the application of electropolishing (EP) of the ANL superconducting deflecting cavity have shown promising results. This cavity geometry is a squashed single-cell cavity with Y-end group waveguide as well as on-cell LOM damper. The cavity works at TM110-like deflecting mode, in which the iris between the cavity cell and the Y-end group is the highest magnetic field region. Before EP, the cavity had been chemically etched (BCP) several times. Forty-um EP processing was performed on one Mark II prototype deflecting cavity at Fermilab. No mild baking was performed before the cavity vertical test. The test showed that the low-field Q had improved from 2·10⁹ to 3·10⁹ and the high-field Q-slope had been successfully removed. The quench limit was slightly improved from 10⁶ mT to 113 mT. Fast T-mapping had detected a significant decrease of local temperature rise in the cavity iris. Optical inspection before EP found a lot of grooves around the iris, which might be related to the gas bubbles generated during BCP. This suggests that horizontal EP is a promising processing technique to remove the high-field Q-slope and improve the deflecting cavity performance.

WEIOB01

Status of MgB2 Coating Studies for SRF Applications

cavity, SRF, controls, superconductivity

777

T. Tajima, L. Civale, D.J. Devlin, G.C. Martinez, R.K. Schulze
LANL, Los Alamos, New Mexico, USA

Funding: DOE Office of Science/Nuclear Physics
MgB2 has shown promising results on small samples and its coating development is entering into the stage to coat large samples and elliptical cavities. Several coating techniques that seem to be appropriate for cavity coating and their status will be shown together with some cavity measurement results with either 6 GHz or 1.3 GHz single-cell cavities. Other data such as RF surface resistance at low temperatures and vortex penetration fields with small samples will also be shown.

Slides WEIOB01 [2.183 MB]