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INSTITUTE OF PHYSICS PUBLISHING JOURNAL OF PHYSICS D: APPLIED PHYSICS

J. Phys. D: Appl. Phys. 39 (2006) 262268 doi:10.1088/0022-3727/39/2/005

Onset of supralinear response in TLD-100

exposed to 60Co gamma-raysG Massillon-JL 1, I Gamboa-deBuen 2 and M E Brandan 1

1 Instituto de F sica, UNAM, AP 20-364, 01000 DF, Mexico2 Instituto de Ciencias Nucleares, UNAM, 04510 DF, Mexico

E-mail: [email protected]

Received 15 September 2005Published 6 January 2006Online at stacks.iop.org/JPhysD/39/262

AbstractThe onset of the supralinear response of peaks 49 in LiF:Mg,Ti (TLD-100)induced by 60Co gamma ray irradiation at doses from 4.18mGy to 8.32kGyhas been studied reading the thermoluminescence signal at 8 C s 1. Glowcurves were decomposed into individual peaks by a controlled deconvolutionprocedure. The response of the low-temperature peaks (4 and 5) as afunction of dose is linear up to 10005000mGy and supralinear for higherdoses; the high-temperature peaks (6a9) exhibit a supralinear behaviour atdoses higher than about 50200mGy. The f(D) supralinearity function hasbeen evaluated, obtaining f(D) max equal to 3 .6 0.3 for peak 5 and from23 up to 207 for the high temperature peaks. To assess the contribution tothe glow curve from the high-temperature peaks, two methods were studied:ratios of peak heights (peak 7 with respect to peak 5) and ratios of areas of the deconvoluted high-temperature peaks (added area of peaks 6b, 7 and 8)with respect to peak 5. The shape of the glow curve ceases to be constant,abruptly, at a dose near 100 mGy, if the ratio of areas is evaluated.

1. Introduction

Of the many types of thermoluminescent detectors (TLD)available, LiF:Mg,Ti (TLD-100) remains one of the mostwidely used dosemeters in routine personal dosimetry,environmental monitoring and space dosimetry. Thispopularity is due, in part, to its approximate tissue equivalence

(effective atomic number of 8.2, similar to 7.4 for tissue) andlow signal fading characteristics. The thermoluminescence(TL) signal dependence on the absorbed dose is thought tobe linear for at least 7 decades of dose up to approximatelya few gray [ 1]. At higher doses, above 10 Gy, it exhibits anon-desirable supralinear behaviour, understood as the slopeof ln(TL signal) versus ln(dose) being greater than 1. Thiseffect, observed in the integrated thermally-induced light, isdue to the strong supralinear response of the high-temperaturepeaks in the glow curve. Supralinearity has been one of themain barriers for the use of this material in practical high-dosedosimetry and, for this reason, the precise knowledge of theonset of the supralinear response is of practical importance.

From the standpoint of basic research, the supralinearresponse of TLD-100 is a subject of great interest [ 15],and the advances in the investigation of this phenomenon

haverequired both experimental and theoretical achievements.Horowitz data compilation up to 1984 [ 6] concludes that, evenif the detailed results vary from author to author, the onset of supralinearity inTLD-100 forpeak5 after irradiationwith 60Cogamma rays occurs at about 10100Gy. For the strongest hightemperature peak (called here peak 7), the linear behaviour issubstituted by the supralinear at about 15Gy. Independently,

Gamboa-deBuen et al [7] in 1998 reported measurements of the total and peaks 5 to 8 supralinearity in TLD-100 inducedby 60Co -rays, analysed with computerized glow curvedeconvolution (CGCD) and conclude that peak 7 ( 274 C)supralinearity starts at approximately 2 Gy. Earlier studiesby Shachar and Horowitz [ 8], also using CGCD analysis toseparate the overlapping peaks in a glow curve, had reportedthat the dose response of peak 7 in TLD-700 (centred at about260 C ) induced by 60Co -rays and 95 keV (effective) x-rayswas supralinear all the way down to a measurable dose levelof 2.5 mGy. Nariyama et al [9] have presented data for60Co gamma rays showing that the response of the high-temperature peaks (integrated area of the glow curve from

210 to 320

C, corresponding to peaks 6a9, using the currentnomenclature [ 10]) ceases to be linear at about 1 Gy. It isimportant to mention that these studies have been carried out

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under different annealing procedures and different heatingrates.

In addition, the transition from linearity to supralinearitydepends on the impurity content of the material [ 6, 11, 12].Also, it has been reported that the onset and the degree of

LiF:Mg,Ti supralinearity (quantied by the dose responsefunction [ 6] or supralinearity index, f(D)) is dependenton experimental conditions such as the annealing procedure[13]. Nariyama et al [9], who studied the TLD-100 responseinduced by photons at various heating rates (0.55 C s 1) haveconcluded that peak heights and their maximum temperaturesaredependent on theheating rate, while the integrated intensityis independent of it.

Many authors [ 2, 7, 8] have independently reported thatf(D) increases rapidly with increasing gamma ray energy (i.e.decreasing ionization density). McKeever and collaborators[11, 12] have shown that low linear-energy-transfer (LET)radiations(photonsor electrons)generallyinduce muchgreater

supralinearity than high-LET radiation, and for a givenradiation type, the supralinearity increases with the increasingheating rate during TL readout.

From a practical point of view, TLD-100 and its isotopicrelatives, TLD-600 and TLD-700, are commonly used todetermine total dose and to estimate the high-LET componentof the radiation eld encountered by astronauts in space[1417]. The high-temperature ratio (HTR) method has beenproposed by Vana et al [14] for the determination of theaverage LET and the radiation eld quality factor required forthe assessment of the biologically relevant dose during spacemissions. HTR estimates the average cosmic ray LET fromthe quotient of two ratios: the high-temperature (225300 C)

structure intensity to that of peak 5 in the glow curve for ions,and the same for 60Co irradiation. This method relies on aunique correlation of glow curve shape with LET, as well ason a rigorous linear response of the TLD to both ions and60Co gamma ray, over the pertinent dose interval. In spite of its critical importance for the application of HTR, we are notaware of any reported dose-response curve (at doses less than1 Gy, relevant to the use of the method in space dosimetry) forthe high temperature peaks following 60Co irradiation. Theconicting results mentioned above, concerning the onset of supralinearity in the response of TLDs, require that a carefulmeasurement of TL response to ions and 60Co gamma ray isperformed prior to the application of the HTR method.

From a basic point of view, a precise knowledge of theTL response induced by gamma-rays will be useful for track structure (TST) [ 18] and modied track structure theories(MTST)[ 19], which have been proposed to explain the relativeefciency of charged particles inducing physical or biologicaleffects. In TST, the damage from energetic ions is attributed tosecondary electrons produced along the ion track. The effectscaused by energetic ions are correlated with those of gamma-rays, assuming that the response in sensitive sites near the pathof the ion is similar to the response of a large system irradiatedwith gamma-rays at the same dose. Thus, the knowledgeof the gamma-ray response function is required to determinethe response of the system to ions. In MTST, the response

of the system (particularly thermoluminescent materials) to aphoton beam with a secondary-electron spectrum similar tothat generated by the radiation of interest is required.

In this work, a study was designed to determine the onsetof the supralinear response of peaks 4 to 9 [ 10] in TLD-100after exposure to 60Co gamma rays. We present measuredTLD-100 dose-response curvesfrom 4.18 mGyup to 8.32 kGy.The supralinearity function f(D) has been obtained for the

total TL signal, low- (peaks 4 and 5) and high- (peaks 6ato 9) temperature peaks using a CGCD procedure designedto provide an accurate evaluation of the high-temperaturepeaks,whichareweakly populatedand comparable in intensitywith the background emission at the lowest doses. Theonset of supralinearity for the relative contribution of the hightemperature region with respect to peak 5, crucial for methodsused to evaluate LET in space dosimetry, is investigated indetail.

2. Experimental procedure

2.1. Dosemeter preparation and readout

TLD-100 Harshaw/Bicron chips 3 .1 3.1 0.89 mm from asingle batch were used. Each dosemeter was used only once,and two dosemeters were irradiated at each dose. Dosemeterswere annealed in air at 400 C for 1h, followed by a 2hannealing at 100 C and by rapid cooling to room temperature.The reading of the TL signal was carried out at a controlledlaboratory temperature of 19 C, approximately 48 h afterirradiation, integrating from room temperature to 400 C in anitrogen atmosphere, using a Harshaw 3500 reader. Nitrogengas was owed through the reader 30 min before each readingsession to reduce non-radiation induced signals, as reportedin [20]. In order to optimize the TL signal-to-background ratioin the high-temperature region, a heating rate of 8 C s 1 wasused, according to Massillon-JL[ 21]. An added BG-39 opticallter was used to decrease the thermal background signal athigh planchet temperatures for doses up to 2 Gy. For dosesgreater than 15 Gy a calibrated neutral optical lter was usedto attenuate the high TL signal. The glow curve data werestored in disk les for subsequent analysis.

2.2. Irradiation conditions

Irradiations were performed in air, approximately 48 h afterthe annealing, using two calibrated sources: a GammaCellirradiator (Instituto de Ciencias Nucleares, ICN), dose rate inwater 0.63 Gy min 1, for doses in LiF from 0.42 to 8 .32

103 Gy and a 60Co source (Instituto de F sica, IF), dose rate inwater 31 Gy min 1, for doses in LiF from 0.0042 to 0.46Gy(conversion factor 0.836 from dose in water to dose in LiF[22]). Data obtained with both sources show good agreement.Thedosemeters were covered by 0.4cm of Lucitethat providedcharged particle equilibrium conditions.

2.3. Glow curve deconvolution

Off-line glow curve deconvolution was performed usingthe Harshaw software CGCD that uses the Podgorsak approximation to the RandallWillkins rst-order kineticspeak shape [ 23]. Before deconvolution, background (signal

not originating in the irradiated crystal) and peak 2 weresubtracted from each glow curve using the option offeredby the CGCD software, as follows. The software denes a

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G Massillon-JL et al

Table 1. Glow curve deconvolution parameters at selected doses.

Temperature difference with respect topeak 5 ( C)

Peak FWHM 4.3 105 8.4 105 4.2 106 8.3 106number ( C) mGy mGy mGy mGy

3 Free Free Free Free Free4 25.00 Free Free Free Free5 27.33 0 0 0 06a 30.00 15 16 17 186b 30.00 38 38 37 367 38.00 64 64 63 628 38.00 89 90 91 929 38.00 120 122 125 124

constant + exponential background, which passes throughthe data after the user indicates a low-temperature andtwo high-temperature points outside the glow curve region.In the present low-temperature data, the TL signal showsuctuations around a at background (the constant term),and its value was determined after an ofine mathematicalaverage of the signal at temperatures below 50 C. Thehigh temperature background, described as an exponentialfunction of temperature, was rst tted ofine to data above350 C, and two points where the t coincided with the TLdata were chosen for CGCD to dene the high temperaturebehaviour. Once the background was thus subtracted, inorder to eliminate unstable peak 2, the software required anindication of the valley between this peak and peak 3; to keepinternal consistency among the many glow curves, a constanttemperature difference (62 C) with respect to peak 5 was keptin thedenitionof this point. Thenetintegralof theglow curveafter these subtractions is referred to as the total TL signal.

A strict deconvolution protocol was followed to assure aconsistent description of up to 8 peaks in the TLD-100 glowcurve after the background subtraction. The widths of peaks49, and the relative temperature differences among peaks 5 to9 were kept xed at values determined after preliminary trialsbased on our previous experience [ 24] with heavy-chargedparticle glow curve shapes. Table 1 shows the values usedfor the deconvolution parameters.

The error induced in the peak deconvolution due to theeffect from the background subtraction was quantied. Oneexpects this error to be of importance for the high-temperaturepeaks populated at the lowest doses, such as the case shown

in gure 1(a ). We studied the dependence of the backgroundsignal on the dose, and found it to be independent of the dose(within 20%) for doses from 4 to 400 mGy. The absoluteerror in thesubtracted i -th peakheightis assumed tobe equal tothe quadratic sum ofthe errors inthe i -thmaximum peak signalbefore subtraction and the error in the background, at the peak maximum temperature. The error in thebackground was takenas the standard deviation of the distribution of backgroundvalues from all the glow curves. The error in the peak signalwastaken as thestandard deviation aroundthe mean forthe twodosemeters exposed at each dose. Given that the peak widthswere kept constant during deconvolution, the relative error inthe peak height determination is equal to the relative error in

the peak area calculation. Typical values are 14% and 53% forpeaks 7 and 8, respectively, at 8 mGy shown in gure 1(a ),and 10% and 30% for the same peaks, at 84 mGy shown

Figure 1. Glow curves of TLD-100 following 8.32 ( a ) and83.6mGy ( b). Solid circles show the experimental glow curve,dashed curve is the (exponential + constant) background t, opencircles show the glow curve after subtraction of the background, thinsolid curves show the deconvolution into 8 peaks and the thick solidcurve is the total deconvolution. Note the semi-log display.

in gure 1(b). At higher doses the background subtractionbecomes of smaller relative importance. The uncertainties,and their propagation, are shown in all the gures that follow.

3. Results

3.1. TL response and supralinearity

Typical glow curves (after background subtraction), normal-ized to the peak 5 maximum are shown in gure 2(a);the increasingly strong relative contribution of the high-temperature structure as a function of the dose can be appre-ciated. Figure 2(b) shows a magnied view of the normalized

high temperature region for 21, 42, 84 and 167 mGy. Notethat the TL signal in this region, for doses about 84 mGyincreases as a function of the dose faster than peak 5. Thesemi-log representation of typical glow curves deconvolutedinto peaks 39 is shown in gure 1. We have chosen thisdisplay in order to indicate how the background signal was re-moved and to appreciate the presence of the high-temperaturepeaks at low doses.

TheTL response (integrated area) as a function of thedosefor the total signaland individual peaks is presented in gure 3.Note that a good agreement exists between irradiations usingthe two 60Co sources. Straight dashed lines in gure 3 indicatea linear dependence on dose, consistent with the behaviour

observed at the lowest doses. The response shows a linear-supralinear-sublinear behaviour for all peaks. Peaks 4 and 5are linear up to 15 Gy and then supralinear, while the onset

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Figure 4. Dose-response function f(D) for the total signal and for peaks 46a.

Figure 5. Dose-response function f(D) for peaks 6b9.

same dose. Peak 8 contributes little to the integrated area atdoses lower than 200 mGy, and thus, even if it is supralinear

from 50 mGy, its effect in AR is weak. The behaviour atthe highest doses ( > 100 Gy) is explained by the decrease of peak 5 supralinearity.

Thesimilar general dependence on dose observed for bothmethods can be attributed to the dominant role of peak 7 in

the high-temperature region. The constraints on peak shapesand positions during deconvolution explain the equivalencebetween peak heights and areas. However, the evaluation of

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Table 2. Onset of supralinearity and maximum supralinearity forpeaks 4 to 9.

Peak number D onset (mGy) D max (mGy) f(D) max

4 5000 4.3E+05 2 .3 0.15 1000 4.3E+05 3 .6 0.36a 100 4.3E+05 23 46b 200 4.3E+05 24 47 100 8.4E+05 31 88 50 8.4E+05 207 529 100 4.2E+06 93 32

Figure 6. (a ) Height ratio of peak 7 with respect to peak 5 and(b) ratio of areas for added peaks 6b, 7 and 8 with respect to peak 5.

the area ratio AR is more precise than that of peak heightsPHR, due to statistics.

4. Discussion

The observed peak 5 supralinearity starts at doses lower thanthose reported previously [ 1, 5, 7, 9]; this can be interpreted

as a consequence of different experimental conditions. Inparticular, although we have followed the same annealingprocedure and used a deconvolution routine, the supralinearity

measured in this work starts at lower doses than those reportedin [7]. This discrepancy could be due to the heating rate(1 C s 1 in [7] and 8 C s 1 in this work) or to a differencebetween the dosemeter batches. In this work, peak 5 f(D) maxequals 3 .6 0.3; in [7], 3.1 0.3 was reported, a value of

approximately 4 (using peak height) was observed in [ 11] at10 C s 1, and 3.9 was measured at 2 C s 1 in [9]. Thesevalues are similar and do not seem to display a denitedependence on the heating rate. The dose D max , where thesupralinearity function for peak 5 reaches its maximum, issimilar to that reported previously [ 6, 7].

For thehigh-temperature peak region, [ 9] reports f(D) maxequal to 13, whereas [ 7] measured 10 for deconvoluted peak 7.Our values are 31 for peak 7 and up to 207 for peak 8,much higher than the previous measurements. This importantdifference implies a strong dependence of the measuredsupralinearity for peak 7 (and higher), either on the heatingrate or the batch composition. A previous study by our group

[26] showed that the high-temperature region showed similarf(D) max for slightly different deconvolution protocols, and,based on this, we do not think that this could explain the largediscrepancy in f(D) max .

This study has shown that the intensity of the high-temperature peaks relative to peak 5 is independent of dose upto approximately 200 mGy, using the PHR and AR methods,respectively. For greater doses, the relative intensity dependsstrongly on dose, that is the shape of the glow curve isnot constant. This has a practical consequence for theapplication of theHTRmethod[ 1416] to extract average LETfrom the high-temperature peaks intensity, for an unknownradiation eld. As discussed in the introduction, this methoddepends on the constancy of the glow peak shape with dose,simultaneously for heavy-charged particle as for gamma rayirradiation of the same dosemeter material. Our results limit,in principle, the application of the technique to doses lowerthan, typically, 100 mGy, if the experimental protocol wasthe one used in this work. Dose rates encountered in space(low-Earth orbits), where astronauts are exposed to heavycharged particles, are 0.052mGy/day, depending on theorbital altitude and inclination [ 27]. The limit of the techniqueto obtain LET information, and thus equivalent dose [ 28],would then be exposures between 50 and 2000 days for low-Earth orbits.

5. Summary and conclusions

This study was performed to determine the onset and themagnitude of the supralinear response of peaks 49 inTLD-100 following 60Co gamma rays irradiation. The high-temperature peaks (beyond peak 5) exhibit much highersupralinearity than peaks 4 and 5. The maximum observedvalues of f(D) max are of the order of 24 for peaks 4 and5 and 200 for peak 8. We have found that peaks 4 and 5are linear up to 10005000 mGy, whereas individual high-temperature peaks are linear up to 50200mGy. The doseswhere thestrictlinear response is lost arelowerthan previously

established [ 1] but, since independent studies have identiedthe inuence that experimental conditions might have on thespecic pointsof departure fromlinearity, a precise application

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of these results to measurements of dose would require its owncalibration.

We have investigated the evolution of the high-temperature structure with respect to peak 5 as a function of the dose. As a consequence of the linear dependence on dose

of all peaks up to about 100 mGy, the relative intensity amongpeaks is a constant for doses lower than 100mGy. Afterwards,the different supralinear behaviours reect into the glow curveshape. We have tested two alternative methods to quantifythe evolution of the glow curve shape, one based on the ratioof peak heights and the other on the ratio of areas. This lastmethod gives the most precise results, at the price of requiringa careful deconvolution. Both methods indicate an abruptchange of the glow curve shape at doses where peaks 6b and 7cease to be linear. In view of these results, any comparisonamong peak ratios requires a previous evaluation of the glowcurve shape constancy under identical conditions of annealing,TL readout and dosemeter batch.

Acknowledgments

We thank Francisco Garc a-Flores and Ana-Elena BuenlBurgos for technical assistance. This work was partiallyfunded by PAPIIT-UNAM IN109302 and PAEP-UNAM102001.

References

[1] Horowitz Y S, Mahajna S, Rosenkrantz M and Yossian D 1996Unied theory of gamma and heavy charged particle TLsupralinearity: the track/defect interaction model Radiat.Prot. Dosim. 65 712

[2] Mahajna S and Horowitz Y S 1997 The unied track interaction model applied to the gamma inducedsupralinearity and sensitization of Peak 5 in LiF:Mg,Ti(TLD-100) J. Phys. D: Appl. Phys. 30 , 260319

[3] Rodr guez-Villafuerte M 1999 A Monte Carlo approach to thetrack interaction model to explain supralinearity in thethermoluminescence response Nucl. Instrum. Methods B152 10514

[4] Horowitz Y S, Satinger D, Oster L, Issa N, Brandan M E,Avila O, Rodr guez-Villafuerte M, Gamboa-deBuen I,Buenl A E and Ruiz-Trejo C 2001 The extended track interaction model. Supralinearity and saturation. He-ionuence response in sensitised TLD-100 Radiat. Meas. 3345973

[5] Horowitz Y S 2001 Theory of thermoluminescence gammadose response: the unied interaction model Nucl. Instrum. Methods B 84 6884

[6] Horowitz Y S 1984 TL Dose Response Thermoluminescenceand Thermoluminescent Dosimetry vol 2 (Boca Raton, FL:CRC) pp 210

[7] Gamboa-deBuen I, Buenl A E, Ruiz C G,Rodr guez-Villafuerte M, Flores A and Brandan M E 1998Thermoluminescent response and relative efciency of TLD-100 exposed to low-energy x-rays Phys. Med. Biol. 43207383

[8] Shachar B B and Horowitz Y S 1988 Dosimetriccharacterisation of the high temperature peaks of LiF:Mg,Tiand CaF 2:Tm using computerised glow curve deconvolution Radiat. Prot. Dosim. 22 8796

[9] Nariyama N, Tanaka S, Yoshizawa M, Hirayama H, Ban S,Nakashima H, Namito Y and Nakane Y 1993 Response of LiF TLDs to 1040 keV monoenergetic photons fromsynchrotron Radiation Radiat. Prot. Dosim. 49 4517

[10] Gamboa-deBuen I, Avil es P, Rodr guez-Villafuerte M,Buenl A E, Ruiz C G and Brandan M E 2001 Supralinearresponse and efciency of LiF:Mg,Ti to 0.7, 1.5 and 3 MeVprotons Nucl. Instrum. Methods B 183 48796

[11] Mische E F and McKeever S W S 1989 Mechanisms of supralinearity in lithium uoride thermoluminescence

dosemeters Radiat. Prot. Dosim. 29 15975[12] McKeever S W S 1990 Modelling supralinearity in gammairradiated TL dosimeters Radiat. Prot. Dosim. 338389

[13] McKeever S W S, Moscovitch M and Townsend P D 1995Thermoluminescence Dosimetry Materials. Properties and Uses (Ashford, UK: Nuclear Technology Publishing),pp 8092

[14] Vana N, Sch oner W, Fugger M and Akatov Y 1996 Absorbeddose measurement and LET determination with TLDs inSpace Radiat. Prot. Dosim . 66 14552

[15] Schoner W, Vana N, and Fugger M 1999 The LET dependenceof LiF:Mg,Ti dosemeters and its application for LETmeasurements in mixed radiation elds Radiat. Prot. Dosim. 85 2636

[16] Schoner W, Vana N, Fugger M and Pohn E 1997 Thepeak-height ratio (HTR)method for LET determinationwith TLDs and an attempt for a microdosimetricintepretation Microdosimetry: An Interdisciplinary Approach ed Goodhead D T et al (Cambridge, UK: RoyalSociety of Chemistry) pp 4114

[17] Yasuda H 2001 Conservative evaluation of space radiationdose equivalent using the glow curve of 7LiF:Mg,Ti(TLD-700) Health Phys. 80 57682

[18] Cucinotta F A, Katz R, Wilson J W and Dubey R R 1995Heavy ion track-structure calculation for radial dose inarbitrary materials NASA Technical Memorandum 3497

[19] Horowitz Y S, Avila O and Rodriguez-Villafuerte M 2001Theory of heavy charged particle response (efciency andsupralinearity) in TL materials Nucl. Instrum. Methods B184 85112

[20] Aguirre J F, Tailor R C, Ibbott G, Stovall M and Hanson W F2003 Thermoluminescence dosimetry as a tool for theremote verication of output for Radiotherapy beams:25 years of experience. Pro. Int. Symp. on Standards and Codes of Practice in Medical Radiation Dosimetry(Vienna, Austria, 2528 November 2002 ) vol 2 (Vienna,Austria: International Atomic Energy Agency)pp 1919

[21] Massillon-JL G 2003 Pruebas de optimizaci on de la senalTL/senal de fondo en el equipo Harshaw 3500 Internal Report FE037, Instituto de F sica UNAM

[22] Attix F H 1986 Introduction to Radiological Physics andRadiation Dosimetry (New York: Wiley)

[23] Moscovitch M, Horowitz Y S and Oduko J 1983 LiFthermoluminescence dosimetry via computerised rst orderkinetics glow curve analysis Radiat. Prot. Dosim.

6 1579[24] Brandan M E, Gamboa-deBuen I and Rodriguez-Villafuerte M2002 Thermoluminescence induced by heavy chargedparticles Radiat. Prot. Dosim. 100 3944

[25] Massillon-JL G, Gamboa-deBuen I and Brandan M E 2006LET and dose dependence of TLD-100 glow curve afterexposure to intermediate-energy ions Radiat. Prot. Dosim.at press

[26] Avil es P, Gamboa-deBuen I, Rodr guez-Villafuerte M,Buenl A E, Ruiz-Trejo C, L opez K and Brandan M E 1999Thermoluminescent response of TLD-100 to low energyprotons Radiat. Prot. Dosim. 84 836

[27] Benton E R and Benton E V 2001 Space radiation dosimetry inlow-Earth orbit and beyond Nucl. Instrum. Methods B 18425594

[28] ICRP 60 1990 Recommendations of the InternationalCommission on Radiological Protection The InternationalCommission on Radiological Protection (Oxford:Pergamon)

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