Special MCP-N thermoluminescent detectors (TLD) with better angular dependence

One of the basic parameters in the use of thermoluminescent detectors is the angular characteristics, i.e. receiving different signals depending on the angle of radiation exposure. The TLD detector is typically installed in a slide/badge and here the angular characteristics may have an influence, adding non-uniform coverage of the detectors with filters for the correct determination of the dose as a function of energy, because the energy characteristics are usually not flat.

As part of the work, special MCP-N (LiF:Mg, Cu, P) detectors of various shapes were prepared to improve the angular characteristics. The detectors were round pellets with the same circular shape with a diameter of 4.5 mm, and a modified form inside (large and small drilled holes) or a modified surface (cavity or hemisphere). For comparison, standard MCP-N type detectors were used. Detectors in special boxes were exposed to X-rays with an energy of 80 keV. The radiation beam was formed by a medical X-ray apparatus adapted for experiments at the Warsaw University of Technology in Warsaw. Exposures were made for angles of 0, 30, 45, 50, and 90° for a dose of 1.5 mGy.

Results show that it is possible to improve the angular characteristics for detectors with modified shapes. Better angular characteristics will allow for more accurate measurements, in particular in comparison tests, for accreditation and other calibrations. Especially improved angular dependence detectors could be useful for H*(10) environmental measurements.