Test study of boron nitride as a new detector material for dosimetry in high-energy photon beams

Phys Med Biol. 2017 Sep 5;62(18):N436-N444. doi: 10.1088/1361-6560/aa81f7.


The aim of this test study is to check whether boron nitride (BN) might be applied as a detector material in high-energy photon-beam dosimetry. Boron nitride exists in various crystalline forms. Hexagonal boron nitride (h-BN) possesses high mobility of the electrons and holes as well as a high volume resistivity, so that ionizing radiation in the clinical range of the dose rate can be expected to produce a measurable electrical current at low background current. Due to the low atomic numbers of its constituents, its density (2.0 g cm-3) similar to silicon and its commercial availability, h-BN appears as possibly suitable for the dosimetry of ionizing radiation. Five h-BN plates were contacted to triaxial cables, and the detector current was measured in a solid-state ionization chamber circuit at an applied voltage of 50 V. Basic dosimetric properties such as formation by pre-irradiation, sensitivity, reproducibility, linearity and temporal resolution were measured with 6 MV photon irradiation. Depth dose curves at quadratic field sizes of 10 cm and 40 cm were measured and compared to ionization chamber measurements. After a pre-irradiation with 6 Gy, the devices show a stable current signal at a given dose rate. The current-voltage characteristic up to 400 V shows an increase in the collection efficiency with the voltage. The time-resolved detector current behavior during beam interrupts is comparable to diamond material, and the background current is negligible. The measured percentage depth dose curves at 10 cm × 10 cm field size agreed with the results of ionization chamber measurements within ±2%. This is a first study of boron nitride as a detector material for high-energy photon radiation. By current measurements on solid ionization chambers made from boron nitride chips we could demonstrate that boron nitride is in principle suitable as a detector material for high-energy photon-beam dosimetry.

MeSH terms

  • Boron Compounds / chemistry*
  • Diamond / chemistry
  • Electrons
  • Materials Testing*
  • Photons / therapeutic use*
  • Radiometry / instrumentation*
  • Radiometry / methods*
  • Radiotherapy, High-Energy / instrumentation*
  • Reproducibility of Results
  • Silicon / chemistry


  • Boron Compounds
  • boron nitride
  • Diamond
  • Silicon