SRF2013 - List of Keywords (detector)

Paper	Title	Other Keywords	Page
MOP001	CASCADE: a Cavity Based Dark Matter Experiment	cavity, experiment, photon, shielding	66
	M.K. Kalliokoski, I.R. Bailey, N. Woollett Lancaster University, Lancaster, United Kingdom G. Burt, A.C. Dexter Cockcroft Institute, Lancaster University, Lancaster, United Kingdom S. Chattopadhyay Cockcroft Institute, Warrington, Cheshire, United Kingdom J.B. Dainton The University of Liverpool, Liverpool, United Kingdom P. Goudket, A.J. Moss, S.M. Pattalwar, T.T. Thakker, P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	An experiment is proposed that uses a pair of RF cavities as a source and detector of hidden sector photons (HSP). HSP's are hypothetical low-mass dark matter candidates with coupling to ordinary photons. SRF cavities are favoured in this experiment as they are able to store a high number of photons for a given input power due to the high Q available. When powered, such a cavity will act as a source of HSPs, while an empty cavity will be able to capture any HSP's decaying back into RF photons. Such an experiment (CASCADE) is being developed at the Cockcroft Institute using single cell 1.3 GHz cavities previously utilised for manufacturing and BCP studies. The aims of the CASCADE project are detailed, along with the system specification.

MOP079	Design and Test of a Cryogenic Seal for Rectangular Waveguide Using VATSEAL Technology	vacuum, cryogenics, superconducting-RF, controls	325
	J.D. Fuerst, J.P. Holzbauer, J.A. Kaluzny, C.R. Montiel, Y. Shiroyanagi, B.K. Stillwell ANL, Argonne, USA
	Funding: This work was supported by the U. S. Department of Energy, Office of Science, under contract No. DE-AC02-06CH11357. A commercially available rectangular metal seal from VAT Vacuum Valves AG has been evaluated and cold tested as a possible cryogenic seal for srf cavities. A program of analysis and cryogenic testing was undertaken to evaluate seal parameters and suitability. Seal line loads, bolt torque and resultant flange/seal deformation at low temperature and during thermal cycling were calculated both statically and via time-dependent numerical simulation to confirm the mechanical integrity of the flange/seal system. Cold testing of flange/waveguide assemblies included thermal shocks in liquid nitrogen and realistic cool-downs below the λ point. Acceptable seal performance has been demonstrated under all test conditions although seal joint assembly is sensitive to details including bolt torque, flange flatness, and surface finish.

TUIOA06	Research on Field Emission and Dark Current in ILC Cavities	electron, cavity, simulation, photon	392
	Y.M. Li, K.X. Liu PKU, Beijing, People's Republic of China R.L. Geng, A.D. Palczewski JLAB, Newport News, Virginia, USA
	Funding: Work supported by DOE. Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Field emission and dark current are issues of concern for SRF cavity performance and SRF linac operation. Complete understanding and reliable control of the issue are still needed, especially in full-scale multi-cell cavities. Our work aims at developing a generic procedure for finding an active field emitter in a multi-cell cavity and benchmarking the procedure through cavity vertical test. Our ultimate goal is to provide feedback to cavity preparation and cavity string assembly in order to reduce or eliminate filed emission in SRF cavities. Systematic analysis of behaviors of field emitted electrons is obtained by ACE3P developed by SLAC. Experimental benchmark of the procedure was carried out in a 9-cell cavity vertical test at JLab. The energy spectrum of Bremsstrahlung X-rays is measured using a NaI(Tl) detector. The end-point energy in the X-ray energy spectrum is taken as the highest kinetic electron energy to predict longitudinal position of the active field emitter. Angular location of the field emitter is determined by an array of silicon diodes around irises of the cavity. High-resolution optical inspection was conducted at the predicted field emitter location.
	Slides TUIOA06 [4.565 MB]

TUP035	Neutron Activation Analysis as a Foreign Intrusion Cavity DetectionTool	neutron, radioactivity, cavity, background	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.

TUP102	Quench Detection Diagnostics on 3.9 GHz XFEL Cavities	cavity, site, diagnostics, superconductivity	710
	M. Bertucci, A. Bosotti, L. Garolfi, P. Michelato, L. Monaco, D. Sertore INFN/LASA, Segrate (MI), Italy C. Pagani Università degli Studi di Milano & INFN, Segrate, Italy
	This paper presents results of quench localization on 3.9 GHz XFEL prototype cavities tested at LASA vertical test facility. Cavities have been equipped with OST second sound detectors and thermometry sensors. A first guess for quench position has been obtained from modal analysis. Second sound sensors confirmed the quench position resolving also the symmetry degeneracy given by the RF mode pattern analysis. In a subsequent vertical test, second sound and temperature sensors have been installed nearby the suspect quench position. From Thermometry mapping, a sudden increase in cavity temperature within a small region is evident, therefore confirming that a local thermal breakdown due to defect heating occurs in the predicted quench point. The quench region deduced with the mentioned techniques is eventually compared with results of optical inspection.

TUP103	Calibration and Characterization of Capacitive OST Quench Detectors in SRF Cavities at IPN Orsay	SRF, cavity, cryogenics, diagnostics	714
	M. Fouaidy, F. Dubois, J.-M. Dufour, D. Longuevergne, A. Maroni, G. Michel, J.-F. Yaniche IPN, Orsay, France
	Funding: IPNO/IPN2P3/CNRS The maximum RF surface magnetic field (Bs) achieved with SRF bulk Nb cavities is often limited by anomalous losses due to Joule heating of normal-resistive defects embedded onto the RF surface. At high BS (e.g Bs>50 mT), the defect temperature increases strongly with BS, leading to a thermal runaway of the cavity or quench. The unloaded quality factor Q0 of the cavity decreases suddenly and strongly due to superconducting to normal state phase transition of the hot spot area. Quench detectors, called Oscillating Superleak Transducer (OST) and sensing 2nd sound events in He II, have been recently used to study quench of SRF cavities. IPN developed his prototypes of OST quench detectors and a test stand for their calibration and characterization in the temperature range T0=1.6 K-2.2 K. This device allows precise and controlled experimental simulation of SRF cavity quench using pulsed heat sources. Experimental runs were performed to study the dynamic response of OST detectors when the heat source is subjected to a time varying heat flux q(t) as function of several parameters (T0, q(t) time structure and density, heat source size) and first experimental data are presented.

TUP104	Temperature Waves in SRF Research	cavity, SRF, experiment, software	719
	A. Ganshin, R.G. Eichhorn, D.L. Hartill, G.H. Hoffstaetter, E.N. Smith, N.R.A. Valles Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA X. Mi Cornell University, Ithaca, New York, USA
	Funding: This work has been supported by NSF award PHY-0969959 and DOE award DOE/SC00008431 Previously Cornell University developed Oscillating Superleak Transducers (OST) to locate quench spots on superconducting cavities in superfluid helium. This work builds upon this research and presents a technique to automatically visualize quench locations from OST data (1). This system is now fully automated. The current system consists of between 8 and 16 OSTs, a high gain low noise preamplifier, and a data acquisition card that can log up to 16 simultaneously recorded inputs. The developed software allows computing quench locations on various cavity geometries, adjustment of the location of each OST and a choice between several quench finding algorithms. Observed results are in excellent agreement with optical inspection and temperature map data. 1. http://newsline.linearcollider.org/2011/04/21/the-sound-of-accelerator-cavitie

TUP110	An X-Ray Fluorescence Probe for Defect Detection in Superconducting 1.3 GHz Cavities	cavity, niobium, embedded, radiation	736
	P. Michelato, M. Bertucci INFN/LASA, Segrate (MI), Italy A. Navitski, W. Singer, X. Singer DESY, Hamburg, Germany C. Pagani Università degli Studi di Milano & INFN, Segrate, Italy Y. Tamashevich Uni HH, Hamburg, Germany
	The aim of this project is to develop a system for defect detection by means of X-ray fluorescence (XRF) analysis. XRF is a high sensitivity spectroscopy technique allowing the detection of trace element content, such as the few microgram impurities, responsible for low cavity performances if embedded in the equatorial region during cavity manufacturing. The proposed setup is customized on 1.3 GHz TESLA-type niobium cavities: both the detector and the X-ray excitation source are miniaturized so to allow the probe to enter within the 70 mm iris diameter and aside of the HOM couplers. The detection-excitation geometry is focused on cavity cell equator surface located at about 10³ mm from the cavity axis, with an intrinsic spot-size of about 10 mm. The measuring head will be settled on a high angular resolution optical inspection system at DESY, exploiting the experience of OBACHT. Defect position is obtained by means of angular inner cavity surface scanning. A quantitative determination of defect content can also be carried out by means of fundamental parameters technique with a Niobium standard calibration.

THP053	Development of Quality Control Procedures for the Processing of ReA3 Copper Plated Fundamental Power Coupler	controls, cavity, SRF, operation	1031
	R. Oweiss, J.L. Crisp, A. Facco, M. Leitner, D. Morris, J. Popielarski FRIB, East Lansing, Michigan, USA A. Facco INFN/LNL, Legnaro (PD), Italy L. Popielarski, J. Wenstrom NSCL, East Lansing, Michigan, USA
	The processing of copper plated fundamental power couplers (FPCs) has posed major risks to the successful performance of superconducting cavities. This paper discusses the lessons learnt throughout the development of quality control procedures for the ReA3 copper plated FPCs. Michigan State University (MSU) Re-Accelerator project (ReA3) utilizes eight copper plated coaxial FPCs to power the 80.5 MHz=0.085 quarter-wave resonators (QWRs) for which baseline quality control procedures are established. The effectiveness of visual inspection process using the microscope & borescope to qualify FPC components is evaluated. The adaptive use of quality control diagnostic devices as the liquid particle counter, surface particle detector & desiccator for the clean processing & assembly is assessed. A summary of the collaborative work to refine and optimize FPC design & processing in correlation to cavity performance and experimental results is presented. *This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE SC0000661.

THP095	Error Analysis for Vertical Test Stand Cavity Measurements at Fermilab	cavity, resonance, simulation, SRF	1148
	O.S. Melnychuk Fermilab, Batavia, USA
	Overview of Vertical Test Stand (VTS) facility at Fermilab is presented. Uncertainty calculations for the measurements of quality factor and accelerating field are described Sources of uncertainties and assumptions on their correlations are reviewed. VTS hardware components with non-negligible instrumental errors are discussed. Relative contributions of individual sources to the total uncertainties are assessed. Stability of VTS test results with respect to potential mismeasurements of calibration coefficients and decay constant are studied.

Paper

Title

Other Keywords

Page

MOP001

CASCADE: a Cavity Based Dark Matter Experiment

cavity, experiment, photon, shielding

66

M.K. Kalliokoski, I.R. Bailey, N. Woollett
Lancaster University, Lancaster, United Kingdom
G. Burt, A.C. Dexter
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
S. Chattopadhyay
Cockcroft Institute, Warrington, Cheshire, United Kingdom
J.B. Dainton
The University of Liverpool, Liverpool, United Kingdom
P. Goudket, A.J. Moss, S.M. Pattalwar, T.T. Thakker, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

An experiment is proposed that uses a pair of RF cavities as a source and detector of hidden sector photons (HSP). HSP's are hypothetical low-mass dark matter candidates with coupling to ordinary photons. SRF cavities are favoured in this experiment as they are able to store a high number of photons for a given input power due to the high Q available. When powered, such a cavity will act as a source of HSPs, while an empty cavity will be able to capture any HSP's decaying back into RF photons. Such an experiment (CASCADE) is being developed at the Cockcroft Institute using single cell 1.3 GHz cavities previously utilised for manufacturing and BCP studies. The aims of the CASCADE project are detailed, along with the system specification.

MOP079

Design and Test of a Cryogenic Seal for Rectangular Waveguide Using VATSEAL Technology

vacuum, cryogenics, superconducting-RF, controls

325

J.D. Fuerst, J.P. Holzbauer, J.A. Kaluzny, C.R. Montiel, Y. Shiroyanagi, B.K. Stillwell
ANL, Argonne, USA

Funding: This work was supported by the U. S. Department of Energy, Office of Science, under contract No. DE-AC02-06CH11357.
A commercially available rectangular metal seal from VAT Vacuum Valves AG has been evaluated and cold tested as a possible cryogenic seal for srf cavities. A program of analysis and cryogenic testing was undertaken to evaluate seal parameters and suitability. Seal line loads, bolt torque and resultant flange/seal deformation at low temperature and during thermal cycling were calculated both statically and via time-dependent numerical simulation to confirm the mechanical integrity of the flange/seal system. Cold testing of flange/waveguide assemblies included thermal shocks in liquid nitrogen and realistic cool-downs below the λ point. Acceptable seal performance has been demonstrated under all test conditions although seal joint assembly is sensitive to details including bolt torque, flange flatness, and surface finish.

TUIOA06

Research on Field Emission and Dark Current in ILC Cavities

electron, cavity, simulation, photon

392

Y.M. Li, K.X. Liu
PKU, Beijing, People's Republic of China
R.L. Geng, A.D. Palczewski
JLAB, Newport News, Virginia, USA

Funding: Work supported by DOE. Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Field emission and dark current are issues of concern for SRF cavity performance and SRF linac operation. Complete understanding and reliable control of the issue are still needed, especially in full-scale multi-cell cavities. Our work aims at developing a generic procedure for finding an active field emitter in a multi-cell cavity and benchmarking the procedure through cavity vertical test. Our ultimate goal is to provide feedback to cavity preparation and cavity string assembly in order to reduce or eliminate filed emission in SRF cavities. Systematic analysis of behaviors of field emitted electrons is obtained by ACE3P developed by SLAC. Experimental benchmark of the procedure was carried out in a 9-cell cavity vertical test at JLab. The energy spectrum of Bremsstrahlung X-rays is measured using a NaI(Tl) detector. The end-point energy in the X-ray energy spectrum is taken as the highest kinetic electron energy to predict longitudinal position of the active field emitter. Angular location of the field emitter is determined by an array of silicon diodes around irises of the cavity. High-resolution optical inspection was conducted at the predicted field emitter location.

Slides TUIOA06 [4.565 MB]

TUP035

Neutron Activation Analysis as a Foreign Intrusion Cavity DetectionTool

neutron, radioactivity, cavity, background

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.

TUP102

Quench Detection Diagnostics on 3.9 GHz XFEL Cavities

cavity, site, diagnostics, superconductivity

710

M. Bertucci, A. Bosotti, L. Garolfi, P. Michelato, L. Monaco, D. Sertore
INFN/LASA, Segrate (MI), Italy
C. Pagani
Università degli Studi di Milano & INFN, Segrate, Italy

This paper presents results of quench localization on 3.9 GHz XFEL prototype cavities tested at LASA vertical test facility. Cavities have been equipped with OST second sound detectors and thermometry sensors. A first guess for quench position has been obtained from modal analysis. Second sound sensors confirmed the quench position resolving also the symmetry degeneracy given by the RF mode pattern analysis. In a subsequent vertical test, second sound and temperature sensors have been installed nearby the suspect quench position. From Thermometry mapping, a sudden increase in cavity temperature within a small region is evident, therefore confirming that a local thermal breakdown due to defect heating occurs in the predicted quench point. The quench region deduced with the mentioned techniques is eventually compared with results of optical inspection.

TUP103

Calibration and Characterization of Capacitive OST Quench Detectors in SRF Cavities at IPN Orsay

SRF, cavity, cryogenics, diagnostics

714

M. Fouaidy, F. Dubois, J.-M. Dufour, D. Longuevergne, A. Maroni, G. Michel, J.-F. Yaniche
IPN, Orsay, France

Funding: IPNO/IPN2P3/CNRS
The maximum RF surface magnetic field (Bs) achieved with SRF bulk Nb cavities is often limited by anomalous losses due to Joule heating of normal-resistive defects embedded onto the RF surface. At high BS (e.g Bs>50 mT), the defect temperature increases strongly with BS, leading to a thermal runaway of the cavity or quench. The unloaded quality factor Q0 of the cavity decreases suddenly and strongly due to superconducting to normal state phase transition of the hot spot area. Quench detectors, called Oscillating Superleak Transducer (OST) and sensing 2nd sound events in He II, have been recently used to study quench of SRF cavities. IPN developed his prototypes of OST quench detectors and a test stand for their calibration and characterization in the temperature range T0=1.6 K-2.2 K. This device allows precise and controlled experimental simulation of SRF cavity quench using pulsed heat sources. Experimental runs were performed to study the dynamic response of OST detectors when the heat source is subjected to a time varying heat flux q(t) as function of several parameters (T0, q(t) time structure and density, heat source size) and first experimental data are presented.

TUP104

Temperature Waves in SRF Research

cavity, SRF, experiment, software

719

A. Ganshin, R.G. Eichhorn, D.L. Hartill, G.H. Hoffstaetter, E.N. Smith, N.R.A. Valles
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
X. Mi
Cornell University, Ithaca, New York, USA

Funding: This work has been supported by NSF award PHY-0969959 and DOE award DOE/SC00008431
Previously Cornell University developed Oscillating Superleak Transducers (OST) to locate quench spots on superconducting cavities in superfluid helium. This work builds upon this research and presents a technique to automatically visualize quench locations from OST data (1). This system is now fully automated. The current system consists of between 8 and 16 OSTs, a high gain low noise preamplifier, and a data acquisition card that can log up to 16 simultaneously recorded inputs. The developed software allows computing quench locations on various cavity geometries, adjustment of the location of each OST and a choice between several quench finding algorithms. Observed results are in excellent agreement with optical inspection and temperature map data.
1. http://newsline.linearcollider.org/2011/04/21/the-sound-of-accelerator-cavitie

TUP110

An X-Ray Fluorescence Probe for Defect Detection in Superconducting 1.3 GHz Cavities

cavity, niobium, embedded, radiation

736

P. Michelato, M. Bertucci
INFN/LASA, Segrate (MI), Italy
A. Navitski, W. Singer, X. Singer
DESY, Hamburg, Germany
C. Pagani
Università degli Studi di Milano & INFN, Segrate, Italy
Y. Tamashevich
Uni HH, Hamburg, Germany

The aim of this project is to develop a system for defect detection by means of X-ray fluorescence (XRF) analysis. XRF is a high sensitivity spectroscopy technique allowing the detection of trace element content, such as the few microgram impurities, responsible for low cavity performances if embedded in the equatorial region during cavity manufacturing. The proposed setup is customized on 1.3 GHz TESLA-type niobium cavities: both the detector and the X-ray excitation source are miniaturized so to allow the probe to enter within the 70 mm iris diameter and aside of the HOM couplers. The detection-excitation geometry is focused on cavity cell equator surface located at about 10³ mm from the cavity axis, with an intrinsic spot-size of about 10 mm. The measuring head will be settled on a high angular resolution optical inspection system at DESY, exploiting the experience of OBACHT. Defect position is obtained by means of angular inner cavity surface scanning. A quantitative determination of defect content can also be carried out by means of fundamental parameters technique with a Niobium standard calibration.

THP053

Development of Quality Control Procedures for the Processing of ReA3 Copper Plated Fundamental Power Coupler

controls, cavity, SRF, operation

1031

R. Oweiss, J.L. Crisp, A. Facco, M. Leitner, D. Morris, J. Popielarski
FRIB, East Lansing, Michigan, USA
A. Facco
INFN/LNL, Legnaro (PD), Italy
L. Popielarski, J. Wenstrom
NSCL, East Lansing, Michigan, USA

The processing of copper plated fundamental power couplers (FPCs) has posed major risks to the successful performance of superconducting cavities. This paper discusses the lessons learnt throughout the development of quality control procedures for the ReA3 copper plated FPCs. Michigan State University (MSU) Re-Accelerator project (ReA3) utilizes eight copper plated coaxial FPCs to power the 80.5 MHz=0.085 quarter-wave resonators (QWRs) for which baseline quality control procedures are established. The effectiveness of visual inspection process using the microscope & borescope to qualify FPC components is evaluated. The adaptive use of quality control diagnostic devices as the liquid particle counter, surface particle detector & desiccator for the clean processing & assembly is assessed. A summary of the collaborative work to refine and optimize FPC design & processing in correlation to cavity performance and experimental results is presented.
*This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE SC0000661.

THP095

Error Analysis for Vertical Test Stand Cavity Measurements at Fermilab

cavity, resonance, simulation, SRF

1148

O.S. Melnychuk
Fermilab, Batavia, USA

Overview of Vertical Test Stand (VTS) facility at Fermilab is presented. Uncertainty calculations for the measurements of quality factor and accelerating field are described Sources of uncertainties and assumptions on their correlations are reviewed. VTS hardware components with non-negligible instrumental errors are discussed. Relative contributions of individual sources to the total uncertainties are assessed. Stability of VTS test results with respect to potential mismeasurements of calibration coefficients and decay constant are studied.