Search

Deuterated ( 2 H -based) organic scintillators, unlike conventional 1 H -based scintillators can generate pulse-shape gated neutron energy spectra 1 to 30 MeV without need for time-of-flight (ToF). They are especially appropriate for measurements at high-intensity, low-energy accelerators where a pulsed beam is not available. Even when the latter is available, the loss in effective beam intensity combined with the need for suitable long-path ToF measurements can be very inefficient. In contrast, as we demonstrate, arrays of d- benzene scintillators (NE230, BC537, EJ315) and recently xylene-d10 (EJ301D) together with related digital signal processing (DSP) can provide highly efficient neutron energy measurements w/o n-ToF. We also report the recent synthesis and initial testing of crystalline d-stilbene as a neutron detector. [ABSTRACT FROM AUTHOR]

In conjunction with Eljen Technology, Inc. (Sweetwater,TX) we have designed, constructed, and evaluated a 3 in. ×3 in. deuterated-xylene organic liquid scintillator (C 8 D 10 ; EJ301D) as a fast neutron detector. Similar to deuterated benzene (C 6 D 6 ; NE230, BC537, and EJ315) this scintillator can provide good pulse-shape discrimination between neutrons and gamma rays, has good timing characteristics, and can provide a light spectrum with peaks corresponding to discrete neutron energy groups up to ca. 20 MeV. Unlike benzene-based detectors, deuterated xylene is less volatile, less toxic, is not known to be carcinogenic, has a higher flashpoint, and hence is much safer for many applications. In addition EJ301D can provide slightly more light output and better PSD than deuterated-benzene scintillators. We show that, as with deuterated-benzene scintillators, the light-response spectra can be unfolded to provide useable neutron energy spectra without need for time-of-flight (ToF). An array of these detectors arranged at many angles close to a reaction target can be much more effective (×10 to ×100 or more) than an array of long-path ToF detectors which must utilize a narrowly-bunched and pulse-selected beam. As we demonstrate using a small Van de Graaff accelerator, measurements can thus be performed when a bunched and pulse-selected beam (as needed for time-of-flight) is not available. [ABSTRACT FROM AUTHOR]

Abstract: A modified version of EBT radiochromic medical imaging film, which is light insensitive and requires no special development or processing, is shown to be useful for imaging low-energy (few MeV) ion beams and radioactive sources. It appears especially well suited for use with low-intensity short-lived (radioactive) secondary beams (RNB). The film can assist in optimizing the collimation needed to minimize unwanted background ions, and to accurately determine the ion-optical alignment of RNB production and transport systems. It allows for effective imaging of beam profiles and relative intensities throughout the beam-transport system and especially at locations not readily accessible to electronic imaging detectors. The special advantages of using the film for RNBs, which often are spatially extended and contaminated with unwanted ions, are demonstrated. [Copyright &y& Elsevier]