An imaging neutron spectrometer
We have developed, fabricated and tested a prototype imaging neutron spectrometer designed for real-time neutron source location and identification. Real-time detection and identification is important for locating materials. These materials, specifically uranium and transuranics, emit neutrons via spontaneous or induced fission. Unlike other forms of radiation (e.g. gamma rays), penetrating neutron emission is very uncommon. The instrument detects these neutrons, constructs images of the emission pattern, and reports the neutron spectrum. The device will be useful for security and proliferation deterrence, as well as for nuclear waste characterization and monitoring. The instrument is optimized for imaging and spectroscopy in the 1–20 MeV range. The detection principle is based upon multiple elastic neutron-proton scatters in organic scintillator. Two detector panel layers are utilized. By measuring the recoil proton and scattered neutron locations and energies, the direction and energy spectrum of the incident neutrons can be determined and discrete and extended sources identified. Event reconstruction yields an image of the source and its location. The hardware is low power, low mass, and rugged. Its modular design allows the user to combine multiple units for increased sensitivity. We will report the results of laboratory testing of the instrument, including exposure to a calibrated Cf-252 source. Instrument parameters include energy and angular resolution, gamma rejection, minimum source identification distances and times, and projected effective area for a fully populated instrument.
Calibration of the Fast Neutron Imaging Telescope (FNIT) Prototype Detector
The paper describes a novel detector for neutrons in the 1 to 20-MeV energy range with combined imaging and spectroscopic capabilities. The Fast Neutron Imaging Telescope (FNIT) was designed to detect solar neutrons from spacecraft deployed to the inner heliosphere. However, the potential application of this instrument to Special Nuclear Material (SNM) identification was also examined. In either case, neutron detection relies on double elastic neutron-proton (n-p) scattering in liquid scintillator. We optimized the design of FNIT through a combination of Monte Carlo simulations and lab measurements. We then assembled a scaled-down version of the full detector and assessed its performance by exposing it to a neutron beam and an SNM source. The results from these tests, which were used to characterize the response of the complete FNIT detector to fast neutrons, are presented herein.
“Family” Support for Family Violence: Exploring Community Support Systems for Lesbian and Bisexual Women Who Have Experienced Abuse
ABSTRACT “Family” is a euphemistic term that lesbian, gay, bisexual, and transgender (LGBT) people use among ourselves to designate membership in lesbian, gay, bisexual, and transgender communities. Ironically, this “family” may be the most sought, yet least successful, support for dealing with the intimate partner violence that occurs within LGBT families. This study of 11 lesbian and bisexual women's experiences seeking support revealed several tiers of unmet needs within the LGBT community. They rarely used services in the general community, although these services are often the focus of both criticism and efforts to build support systems for LGBT victim/survivors. A model presents the different stages and potential sources of support.