Graded-Z flash-bremsstrahlung depth-dose spectrometer

A depth-dose spectrometer is described for measuring photon spectra from a single, short, intense burst of photons in the energy range of 30-1000 keV. It consists of 13 layers of three each thermoluminescent dosimeters (TLDs) separated by metallic foils graded in Z and thickness such that depth-dose responses Dsub(j)(I) to photons of energy Esub(j) are step functions with positive initial slope and with an endpoint that increases monotonically with Esub(j), giving a unique measure of energy. These features enhance the stability of the solution phi(J) of the matrix equation D(I)=A(I, J)phi(J) to oscillations. The response vectors Dsub(j)(I) that make up the detector response matrix A(I, J) were calculated and compared with measurements using thin teflon TLDs loaded with a low-Z(LiF) and a medium-Z(CaF2) phosphor. These three sets of data yield phosphor grain-size corrections for CaF2 (manganese activated). A comparison with an independent measurement for a 1 MeV endpoint bremsstrahlung spectrum gives a measure of the confidence interval of the spectrometer. (Auth.)