Structure optimization of diamond personal dosimeters based on Monte Carlo simulations

We have studied the usefulness of diamond personal dosimeters for X-rays and gamma-rays by using a Monte Carlo simulation method. On one hand, the energy responses (ERs) calculated for both diamond and silicon with various thicknesses as a function of incident photon energy indicate that diamond yields much more suitable ERs for personal dosimeters in the energy range from 30 keV to 1.25 MeV than silicon when used in the current measuring mode. This is because the atomic number of diamond is close to the effective atomic number of the human soft tissue. On the other hand, we have found that diamond dosimeters with allowable energy-independent responses in the pulse counting mode can be fabricated for the photon energies ranging from 60 keV to 1.5 MeV by optimizing the layered structures of various materials such as epoxy resin, polyimide, Al and Cu located on the diamond layer sensing the incident photons. The advantage of diamond in terms of dosimeter performance is discussed.

Research Highlights► Diamond is a more suitable material for personal dosimeters than silicon. ► Adding a suitable filter to the diamond detector can improve the energy response. ► We find a suitable structure of diamond personal dosimeter in the pulse mode. ► Light elements, such as epoxy resin or Al, can improve in the high-energy range. ► A Cu film of a few microns in thickness can improve in the low-energy range.