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Title: Thermal and fast neutron detection in chemical vapor deposition single-crystal diamond detectors

Abstract

Recently, a compact solid-state neutron detector capable of simultaneously detecting thermal and fast neutrons was proposed [M. Marinelli et al., Appl. Phys. Lett. 89, 143509 (2006)]. Its design is based on a p-type/intrinsic/metal layered structure obtained by Microwave Plasma Chemical Vapor Deposition (CVD) of homoepitaxial diamond followed by thermal evaporation of an Al contact and a {sup 6}LiF converting layer. Fast neutrons are directly detected in the CVD diamond bulk, since they have enough energy to produce the {sup 12}C(n,{alpha}){sup 9}Be reaction in diamond. Thermal neutrons are instead converted into charged particles in the {sup 6}LiF layer through the {sup 6}Li(n,{alpha})T nuclear reaction. These charged particles are then detected in the diamond layer. The thickness of the {sup 6}LiF converting layer and the CVD diamond sensing layer affect the counting efficiency and energy resolution of the detector both for low- (thermal) and high-energy neutrons. An analysis is carried out on the dynamics of the {sup 6}Li(n,{alpha})T and the {sup 12}C(n,{alpha}){sup 9}Be reactions products, and the distribution of the energy released inside the sensitive layer is calculated. The detector counting efficiency and energy resolution were accordingly derived as a function of the thickness of the {sup 6}LiF and CVD diamond layers,more » both for thermal and fast neutrons, thus allowing us to choose the optimum detector design for any particular application. Comparison with experimental results is also reported.« less

Authors:
; ; ; ; ; ;  [1]; ; ;  [2]; ;  [3]
  1. Dipartimento di Ingegneria Meccanica, Universita di Roma 'Tor Vergata', Via del Politecnico 1, I-00133 Roma (Italy)
  2. Associazione EURATOM-ENEA sulla Fusione, Via E. Fermi 45, I-00044 Frascati (Roma) (Italy)
  3. ENEA-FIS C.R. Frascati, Via E. Fermi 45, I-00044 Frascati (Roma) (Italy)
Publication Date:
OSTI Identifier:
21133977
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 103; Journal Issue: 5; Other Information: DOI: 10.1063/1.2838208; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ALPHA PARTICLES; ALUMINIUM; BERYLLIUM 9; CARBON 12 TARGET; CHEMICAL VAPOR DEPOSITION; DIAMONDS; ENERGY RESOLUTION; EVAPORATION; FAST NEUTRONS; LITHIUM 6 TARGET; LITHIUM FLUORIDES; MONOCRYSTALS; NEUTRON DETECTION; NEUTRON DETECTORS; NEUTRON REACTIONS; SEMICONDUCTOR DETECTORS; SEMICONDUCTOR MATERIALS; THERMAL NEUTRONS

Citation Formats

Almaviva, S., Marinelli, M., Milani, E., Prestopino, G., Tucciarone, A., Verona, C., Verona-Rinati, G., Angelone, M., Lattanzi, D., Pillon, M., Montereali, R. M., and Vincenti, M. A.. Thermal and fast neutron detection in chemical vapor deposition single-crystal diamond detectors. United States: N. p., 2008. Web. doi:10.1063/1.2838208.
Almaviva, S., Marinelli, M., Milani, E., Prestopino, G., Tucciarone, A., Verona, C., Verona-Rinati, G., Angelone, M., Lattanzi, D., Pillon, M., Montereali, R. M., & Vincenti, M. A.. Thermal and fast neutron detection in chemical vapor deposition single-crystal diamond detectors. United States. doi:10.1063/1.2838208.
Almaviva, S., Marinelli, M., Milani, E., Prestopino, G., Tucciarone, A., Verona, C., Verona-Rinati, G., Angelone, M., Lattanzi, D., Pillon, M., Montereali, R. M., and Vincenti, M. A.. 2008. "Thermal and fast neutron detection in chemical vapor deposition single-crystal diamond detectors". United States. doi:10.1063/1.2838208.
@article{osti_21133977,
title = {Thermal and fast neutron detection in chemical vapor deposition single-crystal diamond detectors},
author = {Almaviva, S. and Marinelli, M. and Milani, E. and Prestopino, G. and Tucciarone, A. and Verona, C. and Verona-Rinati, G. and Angelone, M. and Lattanzi, D. and Pillon, M. and Montereali, R. M. and Vincenti, M. A.},
abstractNote = {Recently, a compact solid-state neutron detector capable of simultaneously detecting thermal and fast neutrons was proposed [M. Marinelli et al., Appl. Phys. Lett. 89, 143509 (2006)]. Its design is based on a p-type/intrinsic/metal layered structure obtained by Microwave Plasma Chemical Vapor Deposition (CVD) of homoepitaxial diamond followed by thermal evaporation of an Al contact and a {sup 6}LiF converting layer. Fast neutrons are directly detected in the CVD diamond bulk, since they have enough energy to produce the {sup 12}C(n,{alpha}){sup 9}Be reaction in diamond. Thermal neutrons are instead converted into charged particles in the {sup 6}LiF layer through the {sup 6}Li(n,{alpha})T nuclear reaction. These charged particles are then detected in the diamond layer. The thickness of the {sup 6}LiF converting layer and the CVD diamond sensing layer affect the counting efficiency and energy resolution of the detector both for low- (thermal) and high-energy neutrons. An analysis is carried out on the dynamics of the {sup 6}Li(n,{alpha})T and the {sup 12}C(n,{alpha}){sup 9}Be reactions products, and the distribution of the energy released inside the sensitive layer is calculated. The detector counting efficiency and energy resolution were accordingly derived as a function of the thickness of the {sup 6}LiF and CVD diamond layers, both for thermal and fast neutrons, thus allowing us to choose the optimum detector design for any particular application. Comparison with experimental results is also reported.},
doi = {10.1063/1.2838208},
journal = {Journal of Applied Physics},
number = 5,
volume = 103,
place = {United States},
year = 2008,
month = 3
}
  • High performance neutron detectors sensitive to both thermal and fast neutrons are of great interest to monitor the high neutron flux produced, e.g., by fission and fusion reactors. An obvious requirement for such an application is neutron irradiation hardness. This is why diamond based neutron detectors are currently under test in some of these facilities. In this paper the damaging effects induced in chemical vapor deposition (CVD) diamond based detectors by a neutron fluence of approx2x10{sup 16} neutrons/cm{sup 2} have been studied and significant changes in spectroscopic, electrical, and optical properties have been observed. The detectors are fabricated using highmore » quality synthetic CVD single crystal diamond using the p-type/intrinsic/Schottky metal/{sup 6}LiF layered structure recently proposed by Marinelli et al. [Appl. Phys. Lett. 89, 143509 (2006)], which allows simultaneous detection of thermal and fast neutrons. Neutron radiation hardness up to at least 2x10{sup 14} n/cm{sup 2} fast (14 MeV) neutron fluence has been confirmed so far [see Pillon et al., (Fusion Eng. Des. 82, 1174 (2007)]. However, at the much higher neutron fluence of approx2x10{sup 16} neutrons/cm{sup 2} damage is observed. The detector response to 5.5 MeV {sup 241}Am alpha-particles still shows a well resolved alpha-peak, thus confirming the good radiation hardness of the device but a remarkable degradation and a significant instability with time of charge collection efficiency and energy resolution arise. Symmetric, nearly Ohmic I-V (current-voltage) characteristics have been recorded from the metal/intrinsic/p-doped diamond layered structure, which before neutron irradiation acted as a Schottky barrier diode with a strong rectifying behavior. The nature and the distribution of the radiation induced damage have been deeply examined by means of cathodoluminescence spectroscopy. A more heavily damaged area into the intrinsic diamond at the same position and with the same extension of the {sup 6}LiF layer has been found, the increased damage being ascribed to the highly ionizing particles produced in the {sup 6}LiF layer by thermal neutrons through the nuclear reaction {sup 6}Li(n,alpha)T.« less
  • Detectors made from artificial chemical vapor deposition single crystal diamond have shown great potential for fast neutron spectrometry. In this paper, we present the results of measurements made at the Physikalisch-Technische Bundesanstalt accelerator using neutron fields in the energy range from 7 MeV to 16 MeV. This study presents the first results of the characterization of the detector in this energy range.
  • A neutron bang time and burn history monitor in inertial confinement fusion with fast ignition are necessary for plasma diagnostics. In the FIREX project, however, no detector attained those capabilities because high-intensity X-rays accompanied fast electrons used for plasma heating. To solve this problem, single-crystal CVD diamond was grown and fabricated into a radiation detector. The detector, which had excellent charge transportation property, was tested to obtain a response function for intense X-rays. The applicability for neutron bang time and burn history monitor was verified experimentally. Charge collection efficiency of 99.5% ± 0.8% and 97.1% ± 1.4% for holes andmore » electrons were obtained using 5.486 MeV alpha particles. The drift velocity at electric field which saturates charge collection efficiency was 1.1 ± 0.4 × 10{sup 7} cm/s and 1.0 ± 0.3 × 10{sup 7} cm/s for holes and electrons. Fast response of several ns pulse width for intense X-ray was obtained at the GEKKO XII experiment, which is sufficiently fast for ToF measurements to obtain a neutron signal separately from X-rays. Based on these results, we confirmed that the single-crystal CVD diamond detector obtained neutron signal with good S/N under ion temperature 0.5–1 keV and neutron yield of more than 10{sup 9} neutrons/shot.« less
  • We have fabricated high-performance ultraviolet (UV) detectors with high-quality undoped and B-doped homoepitaxial diamond layers which were sequentially grown on a high-pressure/high-temperature-synthesized (HPHT) type-Ib (100) substrate by means of a high-power microwave-plasma chemical vapor deposition method. The detector performance measured had large quantum efficiencies due to an effective built-in current amplification function, fast temporal responses, and high UV/visible sensing ratios although the HPHT substrate used had considerable amounts of various defects inducing visible light absorptions and slow detector responses. The usefulness of the bilayer detector structure employed is discussed.