SRF2013 - List of Keywords (neutron)

Paper	Title	Other Keywords	Page
TUP035	Neutron Activation Analysis as a Foreign Intrusion Cavity DetectionTool	detector, 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.

TUP061	Update on Study of Welding Porosity in Nb EBW	cavity, SRF, target, superconducting-cavity	567
	Y. Iwashita, Y. Fuwa, H. Tongu Kyoto ICR, Uji, Kyoto, Japan H. Hayano KEK, Ibaraki, Japan
	Voids have been found in the Nb EBW seams. Since the buried defects cannot be observed by the optical inspections, other techniques have to be applied to study their characteristics such as distributions. X-ray or neutron radiography have been tried for the purpose. The recent results will be presented.

TUP095	Field Emission and Consequences as Observed and Simulated for CEBAF Upgrade Cryomodules	cavity, electron, radiation, operation	694
	F. Marhauser, R.P. Johnson, R. Rodriguez Muons, Inc, Illinois, USA P. Degtiarenko, A. Hutton, G. Kharashvili, C.E. Reece, R.A. Rimmer JLAB, Newport News, Virginia, USA
	High gamma and neutron radiation levels were monitored at the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Laboratory (JLab) after installation of new cavity cryomodules and initial test runs in the frame of the ongoing 12 GeV upgrade program. The dose rates scaled exponentially with cavity accelerating fields, but were independent of the presence of an electron beam in the accelerator. Hence, field emission (FE) is the source of origin. This has led to concerns regarding the high field operation (100 MV per cryomodule) in the future 12 GeV era. Utilizing supercomputing, novel FE studies have been performed with electrons tracked through a complete cryomodule. It provides a principal understanding of experimental observations as well as ways to mitigate FE as best as practicable by identification of problematic cavities.

Paper

Title

Other Keywords

Page

TUP035

Neutron Activation Analysis as a Foreign Intrusion Cavity DetectionTool

detector, 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.

TUP061

Update on Study of Welding Porosity in Nb EBW

cavity, SRF, target, superconducting-cavity

567

Y. Iwashita, Y. Fuwa, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
H. Hayano
KEK, Ibaraki, Japan

Voids have been found in the Nb EBW seams. Since the buried defects cannot be observed by the optical inspections, other techniques have to be applied to study their characteristics such as distributions. X-ray or neutron radiography have been tried for the purpose. The recent results will be presented.

TUP095

Field Emission and Consequences as Observed and Simulated for CEBAF Upgrade Cryomodules

cavity, electron, radiation, operation

694

F. Marhauser, R.P. Johnson, R. Rodriguez
Muons, Inc, Illinois, USA
P. Degtiarenko, A. Hutton, G. Kharashvili, C.E. Reece, R.A. Rimmer
JLAB, Newport News, Virginia, USA

High gamma and neutron radiation levels were monitored at the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Laboratory (JLab) after installation of new cavity cryomodules and initial test runs in the frame of the ongoing 12 GeV upgrade program. The dose rates scaled exponentially with cavity accelerating fields, but were independent of the presence of an electron beam in the accelerator. Hence, field emission (FE) is the source of origin. This has led to concerns regarding the high field operation (100 MV per cryomodule) in the future 12 GeV era. Utilizing supercomputing, novel FE studies have been performed with electrons tracked through a complete cryomodule. It provides a principal understanding of experimental observations as well as ways to mitigate FE as best as practicable by identification of problematic cavities.