Our team at Los Alamos National Laboratory has successfully employed Compton spectrometers to measure the X-ray spectra of both continuous and flash radiographic sources. In this method, a collimated beam of X-rays incident on a converter foil ejects Compton electrons. A collimator may be inserted into the entrance of the spectrometer to narrow the angular acceptance of the forward-scattered electrons, which then enter the magnetic field region of the spectrometer. The position of the electrons at the magnet’s focal plane is proportional to the square root of their momentum, allowing the X-ray spectrum to be reconstructed. A new samarium-cobalt spectrometer with an energy range of 50 keV to 4 MeV has been fielded at two facilities. The X-ray generating machines produced intense photon beams (> 4 rad at 1 m) with spectral endpoints below 3 MeV. Recent experimental results will be presented.
A new, accurate, neutron activation detection scheme for measuring pulsed neutrons has been designed and
tested. The detection system is accurate and sensitive to neutrons with energies above 10 MeV;
importantly, it is insensitive to gamma radiation and to lower-energy (e.g., fission and thermal) neutrons. It
is based upon the use of praesodymium, an element that has a single, naturally occurring isotope (Pr-141), a
significant (n,2n) cross section, and decays by positron emission. Neutron fluences are measured by using
the sum-peak method to count gamma-ray coincidences from the annihilation of the positron decay
product. The system was tested using 14 and 2.45 MeV neutron bursts produced by NSTec Dense Plasma
Focus Laboratory fusion sources. Comparisons with lead, copper, beryllium and silver activation detectors
have been performed. The detection method allows measurement of 14 MeV neutrons with a total error of
± 10%.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.