title: Evolution of the CaF₂:Tm (TLD-300) glow curve as an indicator of beam quality for low-energy photon beams.
abstract: We study the high- to low- temperature signal ratio (HLTR) of the CaF2:Tm glow curve as a function of beam quality for low-energy photon beams with effective energy between 15.2 and 33.6 keV, generated with W, Mo and Rh anodes. CaF2:Tm dosemeters (TLD-300) were exposed to x-rays and (60)Co gamma-rays. Glow curves were deconvoluted into 7 peaks, using computerized glow curve deconvolution and HLTR was evaluated. Air kerma and dose in water were between 2.1-15.0 mGy and 49.8-373.8 mGy, respectively. All peaks in the glow curve showed a linear response with respect to air kerma and dose in water. HLTR values decreased monotonically between 1.029  ±  0.010 (at 15.2 keV) and 0.821  ±  0.011 (33.6 keV), and no effects due to the use of different anode/filter combinations were observed. The results indicate a relatively high value of HLTR (about 1 for 17 keV effective energy, or 3 keV μm(-1) track-average LET) and a measurable dependence on the photon beam quality. Comparison of these photon data with HLTR for ions shows good quantitative agreement. The reported evolution of the CaF2:Tm glow curve could facilitate the estimation of the effective energy of unknown photon fields by this technique.
authors: Instituto de Física, Universidad Nacional Autónoma de México, 04510 DF, Mexico.
authors: I D
authors: ID
authors: Muñoz
authors: O
authors: O
authors: Avila
authors: I
authors: I
authors: Gamboa-deBuen
authors: M E
authors: ME
authors: Brandan
mesh_terms: D002124:Calcium Fluoride / Q000737:chemistry; D005720:Gamma Rays; D017785:Photons; D011829:Radiation Dosage; D013793:Thallium / Q000737:chemistry; D013819:Thermoluminescent Dosimetry / Q000295:instrumentation / Q000379:methods*; D014965:X-Rays
chemical_list: D013793:Thallium; D002124:Calcium Fluoride