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It is demonstrated that the supralinearity of the dose response of glow peaks 7, 8 in the glow curve ofLiF:Mg,Ti (TLD-100) are very strongly dependent on photon/electron energy. Previously published data onf(D)max at photon energies of 1.25 MeV, 100 keV and 8.1 keV effective energy coupled with new dataat w 540 keV using 90Sr/90Y beta rays reveals that the maximum supralinearity f(D)max decreases fromvalues ofw200 andw30 at 1.25MeV, through intermediate values at 540 keV and 100 keV, to values ofw30andw3 at 8.1 keV effective energy. The normalized dose response f(D) for all energies is modeled using theUnified Interaction Model and the dependence of f(D)max on energy is interpreted as arising from strongdependence of the relative intensity of localized recombination on particle energy (ionization density).

Three outstanding effects of ionization density on the thermoluminescence (TL) mechanisms giving rise to the glow peaks of LiF:Mg,Ti (TLD-100) are currently under investigation: (i) the dependence of the heavy charged particle (HCP) relative efficiency on ionization density and the effectiveness of its modeling by track structure theory (TST) (ii) the behavior of the TL efficiency, f(D), as a function of photon energy and dose and (iii) the shape of composite peak 5 in the glow curve for various HCP types and energies and following high dose electron irradiation. It is concluded that (i) The predictions of TST are very strongly dependent on the choice of photon energy used in the determination of f(D), (ii) Modified TST employing calculated values of f(D) at 2 keV is in agreement with 5 MeV alpha particle experimental results for composite peak 5 but underestimates the 1.5 MeV proton relative efficiencies. Both the proton and alpha particle relative TL efficiencies of the high temperature TL (HTTL) peaks 7 and 8 are underestimated by an order of magnitude suggesting that the HTTL efficiencies are affected by other factors in addition to radial electron dose. (iii) The dose response supralinearity of peaks 7 and 8 change rapidly with photon energy: this behavior is explained in the framework of the Unified Interaction Model as due to a very strong dependence on photon energy of the relative intensity of localized recombination, (iv) The increased width and decrease in Tmax of composite peak 5 as a function of ionization density is due to the greater relative intensity of peak 5a (a low temperature component of peak 5 arising from two-energy-transfer events which leads to localized recombination).

It is demonstrated that the supralinearity of the dose response of glow peaks 7, 8 in the glow curve ofLiF:Mg,Ti (TLD-100) are very strongly dependent on photon/electron energy. Previously published data onf(D)max at photon energies of 1.25 MeV, 100 keV and 8.1 keV effective energy coupled with new dataat w 540 keV using 90Sr/90Y beta rays reveals that the maximum supralinearity f(D)max decreases fromvalues ofw200 andw30 at 1.25MeV, through intermediate values at 540 keV and 100 keV, to values ofw30andw3 at 8.1 keV effective energy. The normalized dose response f(D) for all energies is modeled using theUnified Interaction Model and the dependence of f(D)max on energy is interpreted as arising from strongdependence of the relative intensity of localized recombination on particle energy (ionization density).

Three outstanding effects of ionization density on the thermoluminescence (TL) mechanisms giving rise to the glow peaks of LiF:Mg,Ti (TLD-100) are currently under investigation: (i) the dependence of the heavy charged particle (HCP) relative efficiency on ionization density and the effectiveness of its modeling by track structure theory (TST) (ii) the behavior of the TL efficiency, f(D), as a function of photon energy and dose and (iii) the shape of composite peak 5 in the glow curve for various HCP types and energies and following high dose electron irradiation. It is concluded that (i) The predictions of TST are very strongly dependent on the choice of photon energy used in the determination of f(D), (ii) Modified TST employing calculated values of f(D) at 2 keV is in agreement with 5 MeV alpha particle experimental results for composite peak 5 but underestimates the 1.5 MeV proton relative efficiencies. Both the proton and alpha particle relative TL efficiencies of the high temperature TL (HTTL) peaks 7 and 8 are underestimated by an order of magnitude suggesting that the HTTL efficiencies are affected by other factors in addition to radial electron dose. (iii) The dose response supralinearity of peaks 7 and 8 change rapidly with photon energy: this behavior is explained in the framework of the Unified Interaction Model as due to a very strong dependence on photon energy of the relative intensity of localized recombination, (iv) The increased width and decrease in Tmax of composite peak 5 as a function of ionization density is due to the greater relative intensity of peak 5a (a low temperature component of peak 5 arising from two-energy-transfer events which leads to localized recombination).

It is demonstrated that the supralinearity of the dose response of glow peaks 7, 8 in the glow curve ofLiF:Mg,Ti (TLD-100) are very strongly dependent on photon/electron energy. Previously published data onf(D)max at photon energies of 1.25 MeV, 100 keV and 8.1 keV effective energy coupled with new dataat w 540 keV using 90Sr/90Y beta rays reveals that the maximum supralinearity f(D)max decreases fromvalues ofw200 andw30 at 1.25MeV, through intermediate values at 540 keV and 100 keV, to values ofw30andw3 at 8.1 keV effective energy. The normalized dose response f(D) for all energies is modeled using theUnified Interaction Model and the dependence of f(D)max on energy is interpreted as arising from strongdependence of the relative intensity of localized recombination on particle energy (ionization density).

Three outstanding effects of ionisation density on the thermoluminescence (TL) mechanisms giving rise to the glow peaks of LiF:Mg,Ti (TLD-100) are currently under investigation: (1) the dependence of the heavy charged particle (HCP) relative efficiency with increasing ionisation density and the effectiveness of its modelling by track structure theory (TST), (2) the behaviour of the TL efficiency, f(D), as a function of photon energy and dose. These studies are intended to promote the development of a firm theoretical basis for the evaluation of relative TL efficiencies to assist in their application in mixed radiation fields. And (3) the shape of composite peak 5 in the glow curve for various HCP types and energies and following high-dose electron irradiation, i.e. the ratio of the intensity of peak 5a to peak 5. Peak 5a is a low-temperature satellite of peak 5 arising from electron-hole capture in a spatially correlated trapping centre/luminescent centre (TC/LC) complex that has been suggested to possess a potential as a solid-state nanodosemeter due to the preferential electron/hole population of the TC/LC at high ionisation density. It is concluded that (1) the predictions of TST are very strongly dependent on the choice of photon energy used in the determination of f(D); (2) modified TST employing calculated values of f(D) at 2 keV is in agreement with 5-MeV alpha particle experimental results for composite peak 5 but underestimates the 1.5-MeV proton relative efficiencies. Both the proton and alpha particle relative TL efficiencies of the high-temperature TL (HTTL) peaks 7 and 8 are underestimated by an order of magnitude suggesting that the HTTL efficiencies are affected by other factors in addition to radial electron dose; (3) the dose–response supralinearity of peaks 7 and 8 change rapidly with photon energy: this behaviour is explained in the framework of the unified interaction model as due to a very strong dependence on photon energy of the relative inten

Purpose: Cone beam computed tomography (CBCT) is fast becoming standard on modern linear accelerators. CBCT increases the dose to regions within and outside the treatment field, potentially increasing secondary cancer induction and toxicity. This study quantified megavoltage (MV) CBCT skin dose and compared it to skin dose delivered during standard tangential breast radiotherapy. Method: Dosimetry was performed both in- and out-of-field using thermoluminescent dosimeters (TLDs) and a metal-oxide-semiconductor-field-effect-transistor (MOSFET) detector specifically designed for skin dosimetry; these were placed superficially on a female anthropomorphic phantom. Results: The skin dose from a single treatment fraction ranged from 0.5 to 1.4 Gy on the ipsilateral breast, 0.031–0.18 Gy on the contralateral breast, and 0–0.02 Gy in the head and pelvic region. An 8 MU MV CBCT delivered a skin dose that ranged from 0.02 to 0.05 Gy in the chest region and was less than 0.01 Gy in the head and pelvis regions. One MV CBCT per fraction was found to increase the outof- field skin dose from both the CBCT and the treatment fields by approximately 20%. The imaging dose as a percentage of treatment doses in the ipsilateral breast region was 3% for both dosimeters. Conclusion: Imaging increases the skin dose to regions outside the treatment field particularly regions immediately adjacent the target volume. This small extra dose to the breasts should be considered when developing clinical protocols and assessing dose for clinical trials.

Purpose: Cone beam computed tomography (CBCT) is fast becoming standard on modern linear accelerators. CBCT increases the dose to regions within and outside the treatment field, potentially increasing secondary cancer induction and toxicity. This study quantified megavoltage (MV) CBCT skin dose and compared it to skin dose delivered during standard tangential breast radiotherapy. Method: Dosimetry was performed both in- and out-of-field using thermoluminescent dosimeters (TLDs) and a metal-oxide-semiconductor-field-effect-transistor (MOSFET) detector specifically designed for skin dosimetry; these were placed superficially on a female anthropomorphic phantom. Results: The skin dose from a single treatment fraction ranged from 0.5 to 1.4 Gy on the ipsilateral breast, 0.031–0.18 Gy on the contralateral breast, and 0–0.02 Gy in the head and pelvic region. An 8 MU MV CBCT delivered a skin dose that ranged from 0.02 to 0.05 Gy in the chest region and was less than 0.01 Gy in the head and pelvis regions. One MV CBCT per fraction was found to increase the outof- field skin dose from both the CBCT and the treatment fields by approximately 20%. The imaging dose as a percentage of treatment doses in the ipsilateral breast region was 3% for both dosimeters. Conclusion: Imaging increases the skin dose to regions outside the treatment field particularly regions immediately adjacent the target volume. This small extra dose to the breasts should be considered when developing clinical protocols and assessing dose for clinical trials.

Purpose: Cone beam computed tomography (CBCT) is fast becoming standard on modern linear accelerators. CBCT increases the dose to regions within and outside the treatment field, potentially increasing secondary cancer induction and toxicity. This study quantified megavoltage (MV) CBCT skin dose and compared it to skin dose delivered during standard tangential breast radiotherapy. Method: Dosimetry was performed both in- and out-of-field using thermoluminescent dosimeters (TLDs) and a metal-oxide-semiconductor-field-effect-transistor (MOSFET) detector specifically designed for skin dosimetry; these were placed superficially on a female anthropomorphic phantom. Results: The skin dose from a single treatment fraction ranged from 0.5 to 1.4 Gy on the ipsilateral breast, 0.031–0.18 Gy on the contralateral breast, and 0–0.02 Gy in the head and pelvic region. An 8 MU MV CBCT delivered a skin dose that ranged from 0.02 to 0.05 Gy in the chest region and was less than 0.01 Gy in the head and pelvis regions. One MV CBCT per fraction was found to increase the outof- field skin dose from both the CBCT and the treatment fields by approximately 20%. The imaging dose as a percentage of treatment doses in the ipsilateral breast region was 3% for both dosimeters. Conclusion: Imaging increases the skin dose to regions outside the treatment field particularly regions immediately adjacent the target volume. This small extra dose to the breasts should be considered when developing clinical protocols and assessing dose for clinical trials.

Three outstanding effects of ionisation density on the thermoluminescence (TL) mechanisms giving rise to the glow peaks of LiF:Mg,Ti (TLD-100) are currently under investigation: (1) the dependence of the heavy charged particle (HCP) relative efficiency with increasing ionisation density and the effectiveness of its modelling by track structure theory (TST), (2) the behaviour of the TL efficiency, f(D), as a function of photon energy and dose. These studies are intended to promote the development of a firm theoretical basis for the evaluation of relative TL efficiencies to assist in their application in mixed radiation fields. And (3) the shape of composite peak 5 in the glow curve for various HCP types and energies and following high-dose electron irradiation, i.e. the ratio of the intensity of peak 5a to peak 5. Peak 5a is a low-temperature satellite of peak 5 arising from electron-hole capture in a spatially correlated trapping centre/luminescent centre (TC/LC) complex that has been suggested to possess a potential as a solid-state nanodosemeter due to the preferential electron/hole population of the TC/LC at high ionisation density. It is concluded that (1) the predictions of TST are very strongly dependent on the choice of photon energy used in the determination of f(D); (2) modified TST employing calculated values of f(D) at 2 keV is in agreement with 5-MeV alpha particle experimental results for composite peak 5 but underestimates the 1.5-MeV proton relative efficiencies. Both the proton and alpha particle relative TL efficiencies of the high-temperature TL (HTTL) peaks 7 and 8 are underestimated by an order of magnitude suggesting that the HTTL efficiencies are affected by other factors in addition to radial electron dose; (3) the dose–response supralinearity of peaks 7 and 8 change rapidly with photon energy: this behaviour is explained in the framework of the unified interaction model as due to a very strong dependence on photon energy of the relative inten

Three outstanding effects of ionization density on the thermoluminescence (TL) mechanisms giving rise to the glow peaks of LiF:Mg,Ti (TLD-100) are currently under investigation: (i) the dependence of the heavy charged particle (HCP) relative efficiency on ionization density and the effectiveness of its modeling by track structure theory (TST) (ii) the behavior of the TL efficiency, f(D), as a function of photon energy and dose and (iii) the shape of composite peak 5 in the glow curve for various HCP types and energies and following high dose electron irradiation. It is concluded that (i) The predictions of TST are very strongly dependent on the choice of photon energy used in the determination of f(D), (ii) Modified TST employing calculated values of f(D) at 2 keV is in agreement with 5 MeV alpha particle experimental results for composite peak 5 but underestimates the 1.5 MeV proton relative efficiencies. Both the proton and alpha particle relative TL efficiencies of the high temperature TL (HTTL) peaks 7 and 8 are underestimated by an order of magnitude suggesting that the HTTL efficiencies are affected by other factors in addition to radial electron dose. (iii) The dose response supralinearity of peaks 7 and 8 change rapidly with photon energy: this behavior is explained in the framework of the Unified Interaction Model as due to a very strong dependence on photon energy of the relative intensity of localized recombination, (iv) The increased width and decrease in Tmax of composite peak 5 as a function of ionization density is due to the greater relative intensity of peak 5a (a low temperature component of peak 5 arising from two-energy-transfer events which leads to localized recombination).

Three outstanding effects of ionisation density on the thermoluminescence (TL) mechanisms giving rise to the glow peaks of LiF:Mg,Ti (TLD-100) are currently under investigation: (1) the dependence of the heavy charged particle (HCP) relative efficiency with increasing ionisation density and the effectiveness of its modelling by track structure theory (TST), (2) the behaviour of the TL efficiency, f(D), as a function of photon energy and dose. These studies are intended to promote the development of a firm theoretical basis for the evaluation of relative TL efficiencies to assist in their application in mixed radiation fields. And (3) the shape of composite peak 5 in the glow curve for various HCP types and energies and following high-dose electron irradiation, i.e. the ratio of the intensity of peak 5a to peak 5. Peak 5a is a low-temperature satellite of peak 5 arising from electron-hole capture in a spatially correlated trapping centre/luminescent centre (TC/LC) complex that has been suggested to possess a potential as a solid-state nanodosemeter due to the preferential electron/hole population of the TC/LC at high ionisation density. It is concluded that (1) the predictions of TST are very strongly dependent on the choice of photon energy used in the determination of f(D); (2) modified TST employing calculated values of f(D) at 2 keV is in agreement with 5-MeV alpha particle experimental results for composite peak 5 but underestimates the 1.5-MeV proton relative efficiencies. Both the proton and alpha particle relative TL efficiencies of the high-temperature TL (HTTL) peaks 7 and 8 are underestimated by an order of magnitude suggesting that the HTTL efficiencies are affected by other factors in addition to radial electron dose; (3) the dose–response supralinearity of peaks 7 and 8 change rapidly with photon energy: this behaviour is explained in the framework of the unified interaction model as due to a very strong dependence on photon energy of the relative inten

Three outstanding effects of ionisation density on the thermoluminescence (TL) mechanisms giving rise to the glow peaks of LiF:Mg,Ti (TLD-100) are currently under investigation: (1) the dependence of the heavy charged particle (HCP) relative efficiency with increasing ionisation density and the effectiveness of its modelling by track structure theory (TST), (2) the behaviour of the TL efficiency, f(D), as a function of photon energy and dose. These studies are intended to promote the development of a firm theoretical basis for the evaluation of relative TL efficiencies to assist in their application in mixed radiation fields. And (3) the shape of composite peak 5 in the glow curve for various HCP types and energies and following high-dose electron irradiation, i.e. the ratio of the intensity of peak 5a to peak 5. Peak 5a is a low-temperature satellite of peak 5 arising from electron-hole capture in a spatially correlated trapping centre/luminescent centre (TC/LC) complex that has been suggested to possess a potential as a solid-state nanodosemeter due to the preferential electron/hole population of the TC/LC at high ionisation density. It is concluded that (1) the predictions of TST are very strongly dependent on the choice of photon energy used in the determination of f(D); (2) modified TST employing calculated values of f(D) at 2 keV is in agreement with 5-MeV alpha particle experimental results for composite peak 5 but underestimates the 1.5-MeV proton relative efficiencies. Both the proton and alpha particle relative TL efficiencies of the high-temperature TL (HTTL) peaks 7 and 8 are underestimated by an order of magnitude suggesting that the HTTL efficiencies are affected by other factors in addition to radial electron dose; (3) the dose–response supralinearity of peaks 7 and 8 change rapidly with photon energy: this behaviour is explained in the framework of the unified interaction model as due to a very strong dependence on photon energy of the relative inten

It is demonstrated that the supralinearity of the dose response of glow peaks 7, 8 in the glow curve ofLiF:Mg,Ti (TLD-100) are very strongly dependent on photon/electron energy. Previously published data onf(D)max at photon energies of 1.25 MeV, 100 keV and 8.1 keV effective energy coupled with new dataat w 540 keV using 90Sr/90Y beta rays reveals that the maximum supralinearity f(D)max decreases fromvalues ofw200 andw30 at 1.25MeV, through intermediate values at 540 keV and 100 keV, to values ofw30andw3 at 8.1 keV effective energy. The normalized dose response f(D) for all energies is modeled using theUnified Interaction Model and the dependence of f(D)max on energy is interpreted as arising from strongdependence of the relative intensity of localized recombination on particle energy (ionization density).

Three outstanding effects of ionization density on the thermoluminescence (TL) mechanisms giving rise to the glow peaks of LiF:Mg,Ti (TLD-100) are currently under investigation: (i) the dependence of the heavy charged particle (HCP) relative efficiency on ionization density and the effectiveness of its modeling by track structure theory (TST) (ii) the behavior of the TL efficiency, f(D), as a function of photon energy and dose and (iii) the shape of composite peak 5 in the glow curve for various HCP types and energies and following high dose electron irradiation. It is concluded that (i) The predictions of TST are very strongly dependent on the choice of photon energy used in the determination of f(D), (ii) Modified TST employing calculated values of f(D) at 2 keV is in agreement with 5 MeV alpha particle experimental results for composite peak 5 but underestimates the 1.5 MeV proton relative efficiencies. Both the proton and alpha particle relative TL efficiencies of the high temperature TL (HTTL) peaks 7 and 8 are underestimated by an order of magnitude suggesting that the HTTL efficiencies are affected by other factors in addition to radial electron dose. (iii) The dose response supralinearity of peaks 7 and 8 change rapidly with photon energy: this behavior is explained in the framework of the Unified Interaction Model as due to a very strong dependence on photon energy of the relative intensity of localized recombination, (iv) The increased width and decrease in Tmax of composite peak 5 as a function of ionization density is due to the greater relative intensity of peak 5a (a low temperature component of peak 5 arising from two-energy-transfer events which leads to localized recombination).

Purpose: Cone beam computed tomography (CBCT) is fast becoming standard on modern linear accelerators. CBCT increases the dose to regions within and outside the treatment field, potentially increasing secondary cancer induction and toxicity. This study quantified megavoltage (MV) CBCT skin dose and compared it to skin dose delivered during standard tangential breast radiotherapy. Method: Dosimetry was performed both in- and out-of-field using thermoluminescent dosimeters (TLDs) and a metal-oxide-semiconductor-field-effect-transistor (MOSFET) detector specifically designed for skin dosimetry; these were placed superficially on a female anthropomorphic phantom. Results: The skin dose from a single treatment fraction ranged from 0.5 to 1.4 Gy on the ipsilateral breast, 0.031–0.18 Gy on the contralateral breast, and 0–0.02 Gy in the head and pelvic region. An 8 MU MV CBCT delivered a skin dose that ranged from 0.02 to 0.05 Gy in the chest region and was less than 0.01 Gy in the head and pelvis regions. One MV CBCT per fraction was found to increase the outof- field skin dose from both the CBCT and the treatment fields by approximately 20%. The imaging dose as a percentage of treatment doses in the ipsilateral breast region was 3% for both dosimeters. Conclusion: Imaging increases the skin dose to regions outside the treatment field particularly regions immediately adjacent the target volume. This small extra dose to the breasts should be considered when developing clinical protocols and assessing dose for clinical trials.

The dose response of LiF:Mg,Ti (TLD-100) chips was measured from 1 to 50 000 Gy using 100 keV X rays at the European Synchroton Radiation Facility. Glow curves were deconvoluted into component glow peaks using a computerised glow curve deconvolution (CGCD) code based on first-order kinetics. The normalised dose response, f(D), of glow peaks 4 and 5 and 5b (the major components of composite peak 5), as well as peaks 7 and 8 (two of the major components of the high-temperature thermoluminescence (HTTL) at high levels of dose) was separately determined and theoretically interpreted using the unified interaction model (UNIM). The UNIM is a nine-parameter model encompassing both the irradiation/absorption stage and the thermally induced relaxation/recombination stage with an admixture of both localised and delocalised recombination mechanisms. The effects of radiation damage are included in the present modelling via the exponential removal of luminescent centres (LCs) at high dose levels. The main features of the experimentally measured dose response are: (i) increase in f(D)max with glow peak temperature, (ii) increase in Dmax (the dose level at which f(D)max occurs) with increasing glow peak temperature, and (iii) decreased effects of radiation damage with increasing glow peak temperature. The UNIM interpretation of this behaviour requires both strongly decreasing values of ks (the relative contribution of localised recombination) as a function of glow peak temperature and, as well, significantly different values of the dose-filling constants of the trapping centre (TC) and LC for peaks 7 and 8 than those used for peaks 4 and 5. This suggests that different TC/LC configurations are responsible for HTTL. The relative intensity of peak 5a (a low-temperature satellite of peak 5 arising from localised recombination) was found to significantly increase at higher dose levels due to preferential electron and hole population of the trapping/recombination complex giving rise to

The dose response of LiF:Mg,Ti (TLD-100) chips was measured from 1 to 50 000 Gy using 100 keV X rays at the European Synchroton Radiation Facility. Glow curves were deconvoluted into component glow peaks using a computerised glow curve deconvolution (CGCD) code based on first-order kinetics. The normalised dose response, f(D), of glow peaks 4 and 5 and 5b (the major components of composite peak 5), as well as peaks 7 and 8 (two of the major components of the high-temperature thermoluminescence (HTTL) at high levels of dose) was separately determined and theoretically interpreted using the unified interaction model (UNIM). The UNIM is a nine-parameter model encompassing both the irradiation/absorption stage and the thermally induced relaxation/recombination stage with an admixture of both localised and delocalised recombination mechanisms. The effects of radiation damage are included in the present modelling via the exponential removal of luminescent centres (LCs) at high dose levels. The main features of the experimentally measured dose response are: (i) increase in f(D)max with glow peak temperature, (ii) increase in Dmax (the dose level at which f(D)max occurs) with increasing glow peak temperature, and (iii) decreased effects of radiation damage with increasing glow peak temperature. The UNIM interpretation of this behaviour requires both strongly decreasing values of ks (the relative contribution of localised recombination) as a function of glow peak temperature and, as well, significantly different values of the dose-filling constants of the trapping centre (TC) and LC for peaks 7 and 8 than those used for peaks 4 and 5. This suggests that different TC/LC configurations are responsible for HTTL. The relative intensity of peak 5a (a low-temperature satellite of peak 5 arising from localised recombination) was found to significantly increase at higher dose levels due to preferential electron and hole population of the trapping/recombination complex giving rise to

The dose response of LiF:Mg,Ti (TLD-100) chips was measured from 1 to 50 000 Gy using 100 keV X rays at the European Synchroton Radiation Facility. Glow curves were deconvoluted into component glow peaks using a computerised glow curve deconvolution (CGCD) code based on first-order kinetics. The normalised dose response, f(D), of glow peaks 4 and 5 and 5b (the major components of composite peak 5), as well as peaks 7 and 8 (two of the major components of the high-temperature thermoluminescence (HTTL) at high levels of dose) was separately determined and theoretically interpreted using the unified interaction model (UNIM). The UNIM is a nine-parameter model encompassing both the irradiation/absorption stage and the thermally induced relaxation/recombination stage with an admixture of both localised and delocalised recombination mechanisms. The effects of radiation damage are included in the present modelling via the exponential removal of luminescent centres (LCs) at high dose levels. The main features of the experimentally measured dose response are: (i) increase in f(D)max with glow peak temperature, (ii) increase in Dmax (the dose level at which f(D)max occurs) with increasing glow peak temperature, and (iii) decreased effects of radiation damage with increasing glow peak temperature. The UNIM interpretation of this behaviour requires both strongly decreasing values of ks (the relative contribution of localised recombination) as a function of glow peak temperature and, as well, significantly different values of the dose-filling constants of the trapping centre (TC) and LC for peaks 7 and 8 than those used for peaks 4 and 5. This suggests that different TC/LC configurations are responsible for HTTL. The relative intensity of peak 5a (a low-temperature satellite of peak 5 arising from localised recombination) was found to significantly increase at higher dose levels due to preferential electron and hole population of the trapping/recombination complex giving rise to

The dose response of LiF:Mg,Ti (TLD-100) chips was measured from 1 to 50 000 Gy using 100 keV X rays at the European Synchroton Radiation Facility. Glow curves were deconvoluted into component glow peaks using a computerised glow curve deconvolution (CGCD) code based on first-order kinetics. The normalised dose response, f(D), of glow peaks 4 and 5 and 5b (the major components of composite peak 5), as well as peaks 7 and 8 (two of the major components of the high-temperature thermoluminescence (HTTL) at high levels of dose) was separately determined and theoretically interpreted using the unified interaction model (UNIM). The UNIM is a nine-parameter model encompassing both the irradiation/absorption stage and the thermally induced relaxation/recombination stage with an admixture of both localised and delocalised recombination mechanisms. The effects of radiation damage are included in the present modelling via the exponential removal of luminescent centres (LCs) at high dose levels. The main features of the experimentally measured dose response are: (i) increase in f(D)max with glow peak temperature, (ii) increase in Dmax (the dose level at which f(D)max occurs) with increasing glow peak temperature, and (iii) decreased effects of radiation damage with increasing glow peak temperature. The UNIM interpretation of this behaviour requires both strongly decreasing values of ks (the relative contribution of localised recombination) as a function of glow peak temperature and, as well, significantly different values of the dose-filling constants of the trapping centre (TC) and LC for peaks 7 and 8 than those used for peaks 4 and 5. This suggests that different TC/LC configurations are responsible for HTTL. The relative intensity of peak 5a (a low-temperature satellite of peak 5 arising from localised recombination) was found to significantly increase at higher dose levels due to preferential electron and hole population of the trapping/recombination complex giving rise to