Dosimetric characteristics of tissue equivalent thermoluminescent solid TL detectors based on lithium borate

Demirtaş

2013

Radiation Measurements

h i g h l i g h t sLi 2 B 4 O 7 :Cu as a personal dosimetry was firstly investigated by OSL techniques. Prepared phosphor has good OSL repeatability. Beta dose can be determined with less than 3e4% error by using OSL technique. This is the first study on dose measurement of Li 2 B 4 O 7 :Cu using OSL technique. a b s t r a c t Dosimetric phosphors of Cu-doped lithium tetraborate (Li 2 B 4 O 7 :Cu) were produced using a sintering technique in a laboratory environment and characterized using Scanning Electron Microscopy (SEM) and X-ray Diffractometry (XRD). The thermoluminescence (TL) and optically stimulated luminescence (OSL) properties of powdered (Li 2 B 4 O 7 ) phosphor doped with copper at different concentrations (0.020 e0.025 wt %) were studied. The Cu-doped Li 2 B 4 O 7 phosphor material has two dominant TL glow peaks, and the maximum TL responses of the peaks are at 115 C and 243 C in the range of 0 Ce310 C. The TL response of the Cu-doped lithium tetraborate is approximately 900 times more sensitive than undoped lithium tetraborate. The TL and OSL signal intensities increase as the beta radiation doses increase up to approximately 150.00 Gy and 76.50 Gy, respectively. The OSL doseeresponse curve is linear up to a dose range of 12.00 Gy for Cu-doped Li 2 B 4 O 7 dosimetric phosphors. The time-dependent fading behavior of the Cu-doped lithium tetraborate was found to be quite stable over long time durations. In addition, the repeatability of the OSL dose measurements were determined to be 2/3 lower compared to the TL measurements. The reproducibility of the OSL measurements was approximately 5%. Based on the TL and OSL results, the prepared phosphors can be used to measure beta doses ranging from 10 mGy to 150.00 Gy and 76.50 Gy, respectively, by using the TL and OSL techniques, with confidence limits of approximately 7% and 3e4%, respectively. a r t i c l e i n f o

Section: Tl Measurementsmentioning

confidence: 99%

Section: Dose Responsementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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TL/OSL studies of Li2B4O7:Cu dosimetric phosphors

Demirtaş

2013

Radiation Measurements

“…The second technique is the wet reaction. This method was applied by Furetta [12] who performed wet reaction with stoichiometric amounts of Li 2 CO 3 and H 3 BO 3 . The same method was applied by Prokic [9] in 2001 and Ege in 2007 [13].…”

Section: Synthesis Of Lithium Tetraboratementioning

confidence: 99%

An Overview on Preparation and TL Characterization of Lithium Borates for Dosimetric Use

Pekpak¹,

Yılmaz²,

Özbayoğlu³

2010

TOMPJ

Boron that appears in borate form in nature is an essential additive to a variety of industrial products. Recently, certain boron compounds have attracted attention in high technology utilization areas owing to their special crystal and optical characteristics. Thermoluminescent (TL) dosimetry that is used to record amount of radiation exposure is one of such areas. Two borates searched for candidacy in TL dosimetry are lithium tetraborate and lithium triborate. These materials are synthesized and metal doped by numerous researchers to be tested for thermoluminescence response. Lithium tetraborate has aroused interest of scientists since 1960s by the courtesy of the thermoluminescence (TL) property. However, lithium triborate is rather new in this area. This study compromises a broad overview including synthesis methods employed for the production of these two materials. Furthermore, the TL properties that have significant effect on the TL dosimetry potential of a compound are noted along with the detailed information on TL measurement procedure specifications.Keywords: Thermoluminescence, dosimetry, lithium borates, synthesis, doping, characterization. BORATESThere are several natural and synthetic borates used in different branches of industry. Natural borates are generally cleaned from their impurities in processing plants and are further treated to more qualified end products (like boric acid, anhydrous boric acid, anhydrous borax, borax pentahydrate,borax decahydrate and sodium perborate) in recrystallizer units. Besides, the variability of borate crystal chemistry [1] allows researchers synthesize numerous borate structures usable in high technology areas. Thermoluminescent (TL) dosimetry used to measure radiation exposure is an important high technology utilization area for these synthetic borates. General Uses of Borates in High TechnologyIt is certain that the interesting crystal structure of borates play an important role for its utilization in high technology. Although the utilization variety of borates is strongly related to its structural variety, in this communication we will concentrate on results of these characteristics rather than chemical background. Indeed, there is extensive number of studies devoted to the crystal structures of borates [1][2][3] which may be refered for detailed information.Owing to the varied crystallinity borates possess large electronic band gaps, attractive nonlinear optical (NLO) properties, chemical and environmental stability, and mechanical strength [3]. Hence, they found wide use in *Address correspondence to this author at the Middle East Technical University, Mining Engineering, Ankara, Turkey; Tel: +903122102664; Fax: +903122105822; E-mails: epekpak@metu.edu.tr, ayseny@metu.edu.tr nonlinear optical technologies as well as in thermoluminescence dosimetry.Borates have high UV transmittance at wavelengths down to 155 nm [4]. Therefore, they are appropriate for the use in plasma displays and in laser technology. Furthermore they are strong phosphors which ...

Thermoluminescence characterization of Dy³⁺‐activated Mg₅(BO₃)₃F low Z_eff phosphor

Wani

Dhoble²,

Dhoble

2012

Luminescence

Thermoluminescence characteristics of Dy(3+) -activated Mg₅ (BO₃ )₃ F low Z(eff) phosphor are described. The Mg₅ (BO₃ )₃ F phosphor doped with Dy(3+) as activator was prepared by the modified solid-state reaction. Formation of the compound was confirmed by use of X-ray powder diffraction. The X-ray powder diffraction pattern of the as-prepared compound shows a good match with the available JCPDS data. The γ-irradiated Mg₅ (BO₃ )₃ F:Dy(3+) phosphor shows a simple glow curve peaking at about 148°C indicating that only one type of trap is being activated within a particular temperature range. The kinetic parameters, including activation energy and frequency factor were determined using Chen's method. The activation energy and frequency factors were 0.75 eV and 4.508 × 10(9) /s respectively. The Z(eff) ofMg₅ (BO₃ )₃ F:Dy(3+) phosphor was 9.84.