Products / Neutron Diagnostics / Diamond Thermal-Neutron Monitor
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The Thermal-Neutron Counter
The A7 Diamond Thermal-Neutron Monitor is designed for the measurement of the neutron flux in thermal neutron beams. A highly enriched 6LiF layer is used as thermal neutron converter, where the 6Li(n,α)3H reaction is used for neutron detection. The monitor is optimized for high count rates and allows using cables up to 10 m length between detector and amplifier, to enable the usage in high-radiation environments.
The A7 is available as remotely controlled Thermal-Neutron Monitoring System including ROSY®
with integrated power supply and GUI, for real-time neutron flux measurements.
Detector type:
B6 Thermal-Neutron Diamond Detector
Sensor thickness:
140 μm
Thermal-neutron converter:
Neutron detection efficiency:
0.5% at 25 meV
TCT Broadband Amplifier:
2GHz, 40 dB
The A7 Diamond Thermal-Neutron Monitor can be provided with alternative detector designs:
  • Slim detectors with Ø12 mm for confined spaces.
  • Temperature resistant detectors up to 500 K.
  • UHV vacuum compatible detectors.
The spectrum recorded with the A7 Diamond Thermal-Neutron Monitor is shown in the picture. The spectrum was recorded in the thermal neutron beam at the Institute of Atomic and Subatomic Physics of TU Wien, Vienna/Austria.

The triton peak from 6Li(n,α)t is well separated from the α-particle distribution and not affected by the γ-background from the TRIGA Mark II reactor. The neutron rate is determined using a threshold of 2 MeV and counting the tritons as function of time.
A7 Diamond Thermal-Neutron Monitor

Diamond Detectors in CROCUS
A reactor physics research campaign at the CROCUS reactor at EPFL, Lausanne/Switzerland, has led to the development of our compact design detectors. The A7 Diamond Thermal-Neutron Monitor is used with a compact B6-C detector for in-core measurements at this research reactor. ROSY® provides the spectra of thermal neutrons, γ and fast-neutrons in real-time with the Selective Spectroscopy Application.
Modeling the response of a diamond detector in the zero power reactor CROCUS
C. Kong, et al., Eur. Phys. J. Plus, 137:25, 2022

Selective data analysis for diamond detectors in neutron fields
C. Weiss, et al., EPJ Web of Conferences, 146, 03004, 2017


Pulse-Shape Analysis for Gamma Background Rejection in Thermal Neutron Radiation using CVD Diamond Detectors
P. Kavrigin, et al., NIMA, 795, 88-91, 2015


A CVD Diamond Detector for (n,α) Cross-Section Measurements
C. Weiss, PhD Thesis, Technische Universität Wien, Faculty of Physics, 2014