A novel fast-neutron detector for space applications

Feldman, W. C.; Auchampaugh, G.F.; Byrd, R.C.

doi:10.1016/0168-9002(91)90342-n

Cited by 48 publications

(22 citation statements)

References 11 publications

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“…In this study, only those events for which the first and second pulses occurred in the same scintillator were treated. The same processing scheme for fast neutrons follows many previous studies with BLP (Feldman et al 1991b and derivative works); however, some adjustment for the phoswiches on GRaND was necessary as described here.…”

Section: Fast Neutron Spectramentioning

confidence: 92%

“…Thermal and epithermal neutrons also produce a unique coincidence signature, corresponding to 93 keV ee of light produced in the plastic in coincidence with 478 keV deposited in the BGO crystal. BLP has been used extensively for neutron spectroscopy in space, including the Army Background Experiment (ABE) (Feldman et al 1991b), Lunar Prospector (Feldman et al 1999(Feldman et al , 2004a; 2001 Mars Odyssey , and MESSENGER (Goldsten et al 2007 Fig. 9).…”

Section: General Descriptionmentioning

confidence: 99%

“…Therefore, light from these interactions sampled the same volume and paths as light made by the 10 B(n, α) reaction. In addition, the 10 B(n, α) peak was assumed to have an equivalent light output of 93 keV ee (Feldman et al 1991a(Feldman et al , 1991b. The edge and reaction peak centroids and their associated energies were fitted to lines, shown in Fig.…”

Section: Fig 21mentioning

confidence: 99%

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Dawn’s Gamma Ray and Neutron Detector

et al. 2011

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The NASA Dawn Mission will determine the surface composition of 4 Vesta and 1 Ceres, providing constraints on their formation and thermal evolution. The payload includes a Gamma Ray and Neutron Detector (GRaND), which will map the surface elemental composition at regional spatial scales. Target elements include the constituents of silicate and oxide minerals, ices, and the products of volcanic exhalation and aqueous alteration. At Vesta, GRaND will map the mixing ratio of end-members of the howardite, diogenite, and eucrite (HED) meteorites, determine relative proportions of plagioclase and mafic minerals, and search for compositions not well sampled by the meteorite collection. The large south polar impact basin may provide an opportunity to determine the composition of Vesta's mantle and lower crust. At Ceres, GRaND will provide chemical information needed to test different models of Ceres' origin and thermal and aqueous evolution. GRaND is also sensitive to hydrogen layering and can determine the equivalent H 2 O/OH content of near-surface hydrous minerals as well as the depth and water abundance of an ice table, which may provide information about the state of water in the interior of Ceres. Here, we document the design and performance of GRaND with sufficient detail to interpret flight data archived in the Planetary Data System, including two new sensor designs: an array of CdZnTe semiconductors for gamma ray spectroscopy, and a loaded-plastic phosphor sandwich for neutron spectroscopy. An overview of operations and a description of data acquired from launch up to Vesta approach is provided, including annealing of the CdZnTe sensors to remove radiation damage accrued during cruise. The instrument is calibrated using data ac-372 T.H. Prettyman et al.quired on the ground and in flight during a close flyby of Mars. Results of Mars flyby show that GRaND has ample sensitivity to meet science objectives at Vesta and Ceres. Strategies for data analysis are described and prospective results for Vesta are presented for different operational scenarios and compositional models.

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Section: Fast Neutron Spectramentioning

confidence: 92%

Section: General Descriptionmentioning

confidence: 99%

Section: Fig 21mentioning

confidence: 99%

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Dawn’s Gamma Ray and Neutron Detector

et al. 2011

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“…2). A similar calculation was made for fast neutrons with the efficiency function estimated for the ACS of the GRS (19,20). Epithermal and fast-neutron counting rates (epi-counts and fastcounts, respectively) can be represented by functions of the form…”

mentioning

confidence: 99%

Fluxes of Fast and Epithermal Neutrons from Lunar Prospector: Evidence for Water Ice at the Lunar Poles

Feldman

Maurice

Binder

et al. 1998

Science

555

373

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Maps of epithermal- and fast-neutron fluxes measured by Lunar Prospector were used to search for deposits enriched in hydrogen at both lunar poles. Depressions in epithermal fluxes were observed close to permanently shaded areas at both poles. The peak depression at the North Pole is 4.6 percent below the average epithermal flux intensity at lower latitudes, and that at the South Pole is 3.0 percent below the low-latitude average. No measurable depression in fast neutrons is seen at either pole. These data are consistent with deposits of hydrogen in the form of water ice that are covered by as much as 40 centimeters of desiccated regolith within permanently shaded craters near both poles.

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“…This shape is the unique signature of the 10 B(n,α) 7 Li * reaction. Here, the low‐energy peak corresponds to the charged‐particle recoils in the plastic, which appears at an equivalent electron energy E eq of 93 keV [ Feldman et al , 1991]. The broad plateau corresponds to the coincident detection of the charged‐particle recoil with the Compton interaction of the gamma ray deexcitation of the first excited state of 7 Li.…”

Section: Experimental Signature Of a Fast Neutron Eventmentioning

confidence: 99%

Fast neutron flux spectrum aboard Mars Odyssey during cruise

et al. 2002

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[1] The energy spectrum of fast neutrons generated by interactions between galactic cosmic rays and the Mars Odyssey spacecraft during quiet interplanetary conditions is determined. It is given byfor energies between 0.7 and 6 MeV. The estimated ratio of this component of spacecraft neutron background to the Martian leakage flux in Mars orbit is expected to amount to between 0.30 and 0.34. This fraction is sufficiently small so that the total background in orbit about Mars is expected to be dominated by Martian leakage neutrons reprocessed by the spacecraft. Nevertheless, the measured asymmetry properties of the Odyssey Neutron Spectrometer response function should allow separation of foreground and background neutron fluxes when in Mars orbit. The fast neutron flux between 0.7 and 6 MeV should only contribute 0.40 Roentgen Equivalent Man (rem) per year to the total radiation dose aboard a Mars Odyssey class spacecraft at solar maximum.

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A novel fast-neutron detector for space applications

Cited by 48 publications

References 11 publications

Dawn’s Gamma Ray and Neutron Detector

Dawn’s Gamma Ray and Neutron Detector

Fluxes of Fast and Epithermal Neutrons from Lunar Prospector: Evidence for Water Ice at the Lunar Poles

Fast neutron flux spectrum aboard Mars Odyssey during cruise

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