Superconducting High Resolution Fast-Neutron Spectrometers

PDF Version Also Available for Download.

Description

Superconducting high resolution fast-neutron calorimetric spectrometers based on {sup 6}LiF and TiB{sub 2} absorbers have been developed. These novel cryogenic spectrometers measure the temperature rise produced in exothermal (n, {alpha}) reactions with fast neutrons in {sup 6}Li and {sup 10}B-loaded materials with heat capacity C operating at temperatures T close to 0.1 K. Temperature variations on the order of 0.5 mK are measured with a Mo/Cu thin film multilayer operated in the transition region between its superconducting and its normal state. The advantage of calorimetry for high resolution spectroscopy is due to the small phonon excitation energies k{sub B}T on ... continued below

Physical Description

PDF-file: 157 pages; size: 3.6 Mbytes

Creation Information

Hau, I D May 25, 2006.

Context

This thesis or dissertation is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided by UNT Libraries Government Documents Department to Digital Library, a digital repository hosted by the UNT Libraries. More information about this document can be viewed below.

Who

People and organizations associated with either the creation of this thesis or dissertation or its content.

Author

Publisher

Provided By

UNT Libraries Government Documents Department

Serving as both a federal and a state depository library, the UNT Libraries Government Documents Department maintains millions of items in a variety of formats. The department is a member of the FDLP Content Partnerships Program and an Affiliated Archive of the National Archives.

Contact Us

What

Descriptive information to help identify this thesis or dissertation. Follow the links below to find similar items on the Digital Library.

Description

Superconducting high resolution fast-neutron calorimetric spectrometers based on {sup 6}LiF and TiB{sub 2} absorbers have been developed. These novel cryogenic spectrometers measure the temperature rise produced in exothermal (n, {alpha}) reactions with fast neutrons in {sup 6}Li and {sup 10}B-loaded materials with heat capacity C operating at temperatures T close to 0.1 K. Temperature variations on the order of 0.5 mK are measured with a Mo/Cu thin film multilayer operated in the transition region between its superconducting and its normal state. The advantage of calorimetry for high resolution spectroscopy is due to the small phonon excitation energies k{sub B}T on the order of {mu}eV that serve as signal carriers, resulting in an energy resolution {Delta}E {approx} (k{sub B}T{sup 2}C){sup 1/2}, which can be well below 10 keV. An energy resolution of 5.5 keV has been obtained with a Mo/Cu superconducting sensor and a TiB{sub 2} absorber using thermal neutrons from a {sup 252}Cf neutron source. This resolution is sufficient to observe the effect of recoil nuclei broadening in neutron spectra, which has been related to the lifetime of the first excited state in {sup 7}Li. Fast-neutron spectra obtained with a {sup 6}Li-enriched LiF absorber show an energy resolution of 16 keV FWHM, and a response in agreement with the {sup 6}Li(n, {alpha}){sup 3}H reaction cross section and Monte Carlo simulations for energies up to several MeV. The energy resolution of order of a few keV makes this novel instrument applicable to fast-neutron transmission spectroscopy based on the unique elemental signature provided by the neutron absorption and scattering resonances. The optimization of the energy resolution based on analytical and numerical models of the detector response is discussed in the context of these applications.

Physical Description

PDF-file: 157 pages; size: 3.6 Mbytes

Language

Identifier

Unique identifying numbers for this document in the Digital Library or other systems.

  • Report No.: UCRL-TH-221650
  • Grant Number: W-7405-ENG-48
  • Office of Scientific & Technical Information Report Number: 900877
  • Archival Resource Key: ark:/67531/metadc885836

Collections

This document is part of the following collection of related materials.

Office of Scientific & Technical Information Technical Reports

Reports, articles and other documents harvested from the Office of Scientific and Technical Information.

Office of Scientific and Technical Information (OSTI) is the Department of Energy (DOE) office that collects, preserves, and disseminates DOE-sponsored research and development (R&D) results that are the outcomes of R&D projects or other funded activities at DOE labs and facilities nationwide and grantees at universities and other institutions.

What responsibilities do I have when using this thesis or dissertation?

When

Dates and time periods associated with this thesis or dissertation.

Creation Date

  • May 25, 2006

Added to The UNT Digital Library

  • Sept. 22, 2016, 2:13 a.m.

Description Last Updated

  • Dec. 8, 2016, 11:21 p.m.

Usage Statistics

When was this document last used?

Yesterday: 0
Past 30 days: 0
Total Uses: 3

Interact With This Thesis Or Dissertation

Here are some suggestions for what to do next.

Start Reading

PDF Version Also Available for Download.

Citations, Rights, Re-Use

Hau, I D. Superconducting High Resolution Fast-Neutron Spectrometers, thesis or dissertation, May 25, 2006; Livermore, California. (digital.library.unt.edu/ark:/67531/metadc885836/: accessed April 24, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.