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.
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:
2 GHz, 40 dB
The A7 Diamond Thermal-Neutron Monitor can be provided with alternative detector designs and as self-standing monitoring system:
  • Slim detectors with Ø12 mm for measurements in confined spaces.
  • Temperature resistant detector up to 500 K.
  • Vacuum compatible detector up to UHV.
  • Full Diamond Thermal-Neutron Monitoring System including ROSY® AX106 with integrated Neutron Flux Monitoring Application for real-time neutron beam monitoring.
  • Full Diamond Thermal-Neutron Monitoring System including ROSY® AX106 with Neutron Flux Monitoring Application and integrated HV and LV power supply, as autonomous, turn-key neutron monitoring system.
The A7 Diamond Thermal-Neutron Monitor can be adapted for application where particle discrimination is of interest. With the ROSY® AX106 n-γ Discrimination Application, background photons are rejected in real time with an efficiency of 99%, for a puristic thermal-neutron measurement for count rates up to 3 MHz.

The Figure shows results from a measurement in the thermal neutron beam at the Institute of Atomic and Subatomic Physics of TU Wien, Vienna/Austria. Despite the high photon background from the reactor, the α particles from 6Li(n,α)t could be extracted from the spectrum.
A7 Diamond Thermal-Neutron Monitor

This product information download contains the following CIVIDEC documents :
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.
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