Improving chiral property of domain-wall fermions by reweighting method (open access)

Improving chiral property of domain-wall fermions by reweighting method

The reweighting method is applied to improve the chiral property of domain-wall fermions. One way to achieve this is to enlarge L{sub s}, the size of fifth dimension, which controls the size of the induced chiral symmetry breaking. While this is a type of reweighting method for shifting the action parameter, it seems non-trivial since this reweighting means change of the five dimensional lattice volume. In this report, we address issues in this direction of reweighting and evaluate its effectiveness.
Date: July 25, 2009
Creator: Ishikawa, T.; Aoki, Y. & Izubuchi, T.
Object Type: Article
System: The UNT Digital Library
Initial Component Testing for a Germanium Array Cryostat (open access)

Initial Component Testing for a Germanium Array Cryostat

This report describes progress on the construction of two ultra-low-background cryostats that are part of the NA-22 funded “Radionuclide Laboratories” (RN Labs) project. Each cryostat will house seven high-purity germanium crystals (HPGe). These cryostats are being built from a limited set of materials that are known to have very low levels of radioactive impurities. The RN Labs instrument is designed to take advantage of low background performance, high detection efficiency, and - coincidence signatures to provide unprecedented gamma spectroscopy sensitivity. The project is focused on improving gamma analysis capabilities for nuclear detonation detection (NDD) applications. The instrument also has the potential for basic nuclear physics research. Section 1 provides the background for the project. Section 2 discusses germanium crystal acceptance testing. Design problems were found after the first delivery of new detectors from the vendor, Canberra Semiconductors. The first four crystals were returned for repair, resulting in a delay in crystal procurement. Section 3 provides an update on copper electroforming. In general, electroforming parts for RN Labs has proceeded smoothly, but there have been recent problems in electroforming three large copper parts necessary for the project. Section 4 describes the first round of testing for the instrument: anti-cosmic scintillator testing, …
Date: July 25, 2009
Creator: Keillor, Martin E.; Aalseth, Craig E.; Day, Anthony R.; Fast, James E.; Hoppe, Eric W.; Hyronimus, Brian J. et al.
Object Type: Report
System: The UNT Digital Library