TASLImage™ Neutron Dosimetry System
See also our TASLImage™ systems page

NVLAP accredited in the USA and HSE accredited in the UK

• A complete system for measuring fast and thermal neutrons, based on our TASLImage™ microscope-based analysis system.
• Calibrated doses from 0.1 mSv to 600 mSv, showing a linear relationship between exposure and measured dose. Neutrons with energies from 200 keV to 14 MeV are detected using our TASTRAK™ polyallyl diglycol carbonate (PADC) plastic by recording associated the knock-on protons. Doses from thermal- and epithermal neutrons, can be measured with an additional overlying converter.
• Etching of the TASTRAK™ reveals conelike-shaped tracks of knock-on protons which are analysed for dose determination. The size distribution of these etch-tracks is dependent on the detector sensitivity and the subsequent etch conditions, which TASLImage™ takes into account via a self-calibration procedure. This automatically calibrates the plastics, allowing for a variation in sensitivity of between 150 to 750 tracks per mSv.

Fig. 1: Miscellany of recoil proton tracks

Fig. 2: Recoil proton etch-tracks in TASTRAK™

Fig. 1 shows a typical neutron dosemeter element comprising TASTRAK™ plastic overlaid with a 1 mm thick polyethylene radiator. Recoil proton tracks can originate in the radiator itself, or within the body of the TASTRAK™. Tracks are revealed if part of their path length is within the etched volume of the plastic, i.e. the volume between the pre- and post-etch surfaces.

Etch-tracks from recoil protons are typically 3-15 microns in size (Fig. 2). The track sizes overlap with those for alpha-particles at large track sizes, where shape differences are used to discriminate particle species. At the small track sizes, efficient discrimination between noise (primarily dust on the surface) and genuine tracks is achieved with the measurement of 26 track parameters, including a variety of size and shape characterisations. These allow discrimination of tracks against high backgrounds of non-track features per cm² without compromising the measurement accuracy. Even a low energy fast neutron signal (~200 keV), which is almost identical to that of the background, is distinguishable by use of a variety of complex shape-detection algorithms. This enables the system to work in normal laboratory environments, including the presence of a high radon atmosphere.

A complete neutron measurement system comprises:

TASLImage™ fully automated high specification image analysis detector readout system with high throughput and unparalleled accuracy and low background

• Unique modelling software for neutron dosemeter design and response
• Sophisticated autofocus, including live tracking of the plastic surface
• Automatic dosemeter ID reading, standard or customised
• All necessary software. work instructions and operator training

Associated components

• High sensitivity, low background TASTRAK™ (PADC) plastic elements, cut and scribed to customer requirements
• Boron, ¹⁰B loaded radiators for thermal/epithermal neutron dosimetry
• Stainless steel etch/scan holders which transfer between etching and scanning without the need to remount the detectors: standard sizes, 7 x 7 (49) and 7 x 8 (56) detectors (Fig. 4).
• Stainless steel Cradle for six etch holder (Fig. 5)
• Etch tank and processing facility