Ultraviolet and Laser Radiation Dosimetry Using Phototransferred Thermoluminescence in CaSO4:Dy

Potiens, Ademar J.; Campos, L.L.

doi:10.1093/oxfordjournals.rpd.a031789

Cited by 7 publications

(3 citation statements)

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“…The method could potentially lead to improved TL sensitivity and it offers new data for interpretation of the luminescence mechanisms as well as the appropriateness of the classical TL models for this form of excitation. However, laser pulse heating produces both thermal and optical effects and is important to note that the effect of UV illumination on CaSO 4 :RE has been studied in the past to assess its applicability to UV dosimetry [12,13].…”

Section: Introductionmentioning

confidence: 99%

Spectral comparison of Dy, Tm and Dy/Tm in thermoluminescent dosimeters

Karalı

Rowlands

Townsend

et al. 1998

J. Phys. D: Appl. Phys.

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Spectrally resolved thermoluminescence of co-doped Dy:Tm: shows that the maximum peak temperature for the nominal C dosimetry peak differs by C for Dy and Tm emission. This is interpreted as evidence that the rare earth ions form part of a complex defect which variously provides both the charge trapping and, during heating, the radiative decay. The peaks have the same activation energies but different pre-exponential factors. Modifications of the material by thermal treatments using furnace or laser pulse heating convert the state of dispersion of the rare earth ions between isolated, pair or defect clusters, which alter the dosimetry efficiency. In some cases the modified geometries are detectable via movement of the emission lines. For rapidly quenched materials, discontinuities in the thermoluminescence responses are suggested to be indicative of new microcrystalline phases. Slow cooling degrades the efficiency but also indicates the presence of further thermoluminescence glow peaks within the region of the main dosimetry signal. Pulsed laser heating with a UV laser altered the glow curve and resulted in strong signals. Mechanisms for this process are considered.

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Section: Introductionmentioning

confidence: 99%

Spectral comparison of Dy, Tm and Dy/Tm in thermoluminescent dosimeters

Karalı

Rowlands

Townsend

et al. 1998

J. Phys. D: Appl. Phys.

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“…PTTL is the thermoluminescence due to the light incident on a material that was exposed earlier to ionising radiation and partially annealed, leaving some residual charge carriers trapped in the deep traps which are localised in the band gap due to impurities and lattice defects (3) . The CaSO 4 :Dy pellets showed high sensitivity and reproducibility, linear response and good signal resolution for a wide range of absorbed energy (0.01-40 mJ) and gamma doses (5-100 Gy) (4,5) .…”

Section: Introductionmentioning

confidence: 99%

PTTL method applied to UV radiation detection during refractive surgery using excimer laser

Grossi¹,

Melo²,

Schor³

et al. 2005

Radiation Protection Dosimetry

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The method of phototransferred thermoluminescence (PTTL), using CaSO(4):Dy pellets produced at IPEN as sensitive material, was used to detect the spread laser radiation inside the surgery room during refractive surgical procedures using ArF excimer lasers. The purpose of this work was to study the viability of performing the ultraviolet radiation (UVR) exposure detection of patients and the hospital's surgical staff during a refractive surgery. The CaSO(4):Dy pellets were positioned at different distances from the laser source inside the surgery room: patient's ( congruent with 0.15 m), surgeon's ( congruent with 0.5 m) and nurse's ( congruent with 1.0 m) foreheads, lateral ( congruent with 1.5 m) and back ( congruent with 4.0 m) walls. The measurements of PTTL were carried out at two different conditions: five surgeries, each one taking approximately 10 min, and during a period of 4 h (cumulative), when several operations were performed. The detectors positioned as far as 4.0 m from the UV laser source were sensitised, making the UVR detection feasible at large source-detector distances. The absorbed energy was detected in the range from 40 microJ to 30 mJ during a surgery. This result indicates that the method studied can be used to detect the spread UVR.

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“…CaSO 4 :Dy has been shown to be an excellent dosimetric material for ionising radiation. It is also sensitive to non-ionising radiation, such as UV light and laser radiation (3,4) . Due to this sensitivity, it can be applied in UV and laser radiation dosimetry and gamma dose re-evaluation by means of PTTL analysis.…”

Section: Introductionmentioning

confidence: 99%

Studies of UV Induced Phototransferred Thermoluminescence in CaSO4:Dy Pellets

Grossi

Campos²

2002

Radiation Protection Dosimetry

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The ultraviolet (UV) radiation response of the CaSO4:Dy pellets produced at IPEN/SP was studied using phototransferred thermoluminescence (PTTL). The PTTL characteristics of three different types of CaSO4:Dy pellets were investigated. The main parameters studied were: thermal treatments, post UV exposure storage time, PTTL response as a function of gamma dose, exposure time, radiant energy response and lower detection limits.

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Ultraviolet and Laser Radiation Dosimetry Using Phototransferred Thermoluminescence in CaSO4:Dy

Cited by 7 publications

References 0 publications

Spectral comparison of Dy, Tm and Dy/Tm in thermoluminescent dosimeters

Spectral comparison of Dy, Tm and Dy/Tm in thermoluminescent dosimeters

PTTL method applied to UV radiation detection during refractive surgery using excimer laser

Studies of UV Induced Phototransferred Thermoluminescence in CaSO4:Dy Pellets

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