RELATIVE NEUTRON SENSITIVITY OF TISSUE-EQUIVALENT IONIZATION CHAMBERSIN AN EPITHERMAL NEUTRON BEAM FOR BORON NEUTRON-CAPTURE THERAPY

In recent years, boron neutron capture therapy has received renewed in terest as new promising boron compounds and epithermal neutron beams h ave become available. For establishment of the different dose componen ts in epithermal neutron beams, various techniques are applied, includ ing the use of tissue-equivalent (TE) ionisation chambers for the dete rmination of the intermediate and fast neutron dose. This paper is dir ected towards the calculation of the relative neutron sensitivity of T E ionisation chambers, k(T), for the free-in-air spectrum at the HB11 epithermal beam facility of the High Flux Reactor in Petten. The k(T) value obtained from the present calculations is 0.87. This value is ab out 10% lower than data currently applied for similar conditions.