Detection of fast neutrons with the pixel detector Timepix3

Abstract

We examined the response of the pixel detector Timepix3 with silicon sensor to well-defined fast neutron fields. Part of the pixel detector silicon sensor was additionally equipped with a neutron mask of distinct converter regions. The mask consists of separate thermal and fast neutron regions using 6LiF and hydrogen (plastic) converters, respectively. Measurements were performed with mono-energetic fast neutrons produced at D-D and D-T sources from a Van de Graaff accelerator and a neutron generator, respectively. Data were collected with low background including measurements with moderator material to provide a thermalized neutron component. All the signals produced in the detector were analyzed and decomposed in terms of the spectral-tracking response of the pixel detector. The effect of the fast and thermal components of the neutron converter were determined and compared with direct interactions in the silicon sensor which are significant and can be dominant for fast neutrons. We identify and classify the neutron-induced tracks in terms of the broad-type particle-event track classes. A partial overlap is unavoidable with tracks from direct detection of other radiations in particular protons and low-energy light ions as well as X rays. This will limit the neutron-event discrimination in mixed-radiation fields. The detection response according sensor-mask region was examined and calibrated for the investigated neutron fields. The neutron detection efficiency is selectively derived for the detector particle-event classes. This approach enables to enhance the neutron-discrimination and suppress background and unwanted events. This work enables to extend the response matrix of the detector for broad-type radiations to include neutrons both fast and thermal. The results serve to enhance the sensitivity and determine the neutron component in unknown and mixed-radiation fields such as outer space and particle radiotherapy environments.

Timepix3: Temperature Influence on Radiation Energy Measurement with Si Sensor

“…The TPX3 detector, in combination with a suitable converter, can also be used for neutron detection of both D-D and D-T sources. This has been demonstrated in previous research studies [ 9 , 10 ], which have shown its effectiveness in detecting both fast and thermal neutrons.…”

Quantum-imaging detection of secondary neutrons in proton radiotherapy fields

“…The hybrid semiconductor pixel detector Timepix3 [10] is operated at room temperature and is controlled and readout by the compact radiation camera MiniPIX Timepix [11] -figure 1. The Timepix3 ASIC chip bump-bonded to a 500 μm thick silicon sensor was additionally equipped with a neutron mask of segmented distinct regions of thermal converter ( 6 Li ≈ μm thick) and fast converter (segmented plastic polyethylene (PE) of consecutive thicknesses: 50, 100, 150 μm) [12] figure 1c. Integrated power, control and data readout of the radiation camera are enabled via single USB 2.0 connector to standard PC using the integrated cross-platform (Windows, Linux, MacOS) software tool PIXET [13] which provides imaging visualization of registered particle tracks and online display of the detector response.…”

“…(C) The pixel detector with a segmented mask in contact geometry with distinct regions of thermal ( 6 LiF) and fast (PE) neutron conversion regions [12]. Reproduced from [12]. ©2023 IOP Publishing Ltd and Sissa Medialab.…”

Spectral and directional sensitive composition characterization of mixed-radiation fields with the miniaturized radiation camera MiniPIX Timepix2

“…Another high-LET component (classes d and e, see table 1) of small energy or perpendicular direction (namely protons and light ions -from fast neutron interactions [15]) is shown in figure 5.…”