Neutron Detection with Cryogenics and Semiconductors
|Zane W. Bell 2, D. A. Carpenter 3, S. S. Cristy 3, V. E. Lamberti 3, Arnold Burger 4, B. F. Woodfield 5, T. Niedermayr 1, I. Dragos Hau 1, S. E. Labov 1, S. Friedrich 1, K. R. Pohl 6, L. van den Berg 6|
1. Lawrence Livermore National Laboratory (LLNL), 7000 East Ave., L-270, Livermore, CA, United States
Advances in materials and methods have enabled the detection of radiation by means today that would have seemed like science fiction a century ago to pioneers in the field. Improvements in technology have resulted, for gamma ray detection, in high-purity germanium operating at 77 K and providing 0.1% energy resolution, more than an order of magnitude improvement over what was (and still is) achievable by scintillators. However, operating below 1 K, cryogengic calorimeters have been used in x-ray astronomy, in the search for dark matter, and more recently in gamma ray spectroscopy, and have achieved 70 eV resolution at 60 keV, an order of magnitude improvement over high-purity germanium. Meanwhile, at the other end of the temperature spectrum, the development of new, wide band-gap semiconductors has sparked research in room temperature gamma detectors and has held out the hope of 1 - 2% resolution and freedom from cryogenics. With such results being reported from the x- and gamma ray world it is natural to examine the possibilities for neutron detection. A cryogenic neutron detection would operate by detecting the heat pulses caused by neutron capture and scattering, while a semiconducting detector would detect the nuclear reaction products from a sensitizer (for example, fission fragments detected in a 235U-coated Si diode) or from some constituent of the semiconductor. In this paper, we will briefly review the common methods of neutron detection, and discuss the application of cryogenics and semiconductors to the problem. Work on LiF-based calorimeters will be discussed, and on the work by the present authors on the search for, and successful demonstration of a boron-based instrument. Turning to semiconductors, we will discuss CZT, HgI2, and other materials with constituents with high neutron interaction cross sections that can be applied to neutron detection. Results obtained by the authors with HgI2 will be shown.
Presentation: invited oral at NATO Advanced Research Workshop, by Zane W. Bell
See On-line Journal of NATO Advanced Research Workshop
Submitted: 2004-08-02 11:03 Revised: 2009-06-08 12:55