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Radiometry
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
A common material used in thermoluminescence dosimeters is lithium fluoride (LiF), which exhibits several desirable properties. The dose-response is linear or supra-linear over a wide range of absorbed doses (Table 5.1), and the sensitivity to γ-rays is high, giving detection limits on the order of a few tenths of a μGy. Also, the dose response is independent of the energy of the radiation and the long-lived energy states (i.e., latent luminescence) are stable. The stability of the long-lived energy states thus permits read-out of the detector signal even years after exposure.
Borate Phosphors for Radiation Dosimetery
Published in S. K. Omanwar, R. P. Sonekar, N. S. Bajaj, Borate Phosphors, 2022
The use of thermoluminescence (TL) as a method for radiation dosimetry of ionizing radiation has been established for many decades and has found many useful applications in various fields, such as personnel, environmental, medical, archaeological, geological dating and space dosimetry. Several highly sensitive TL phosphor materials and thermoluminescent dosimeters (TLDs) are now commercially available in different physical forms. There are many commercial TLD systems that are being used for various dosimetric applications and even presently, TL is a popular technique in the field of radiation dosimetry, particularly in personnel monitoring [3–6].
Measurement of Radiation
Published in Philip T. Underhill, Naturally Occurring Radioactive Material, 2018
TLD material is somewhat similar to scintillating material, except that TLD material will “store” the energy from radiation until heated whereas scintillators give up that energy immediately. The most widely used thermoluminescent materials are lithium fluoride, calcium fluoride, and calcium sulfate. TLD material may be used in powder form but is most widely used in the form of small crystals known as chips. It can also be impregnated into silicone-based material or PTFE (Teflon). A TLD badge is the most common means of dosimetry among oil field workers. In some industries where radioactive materials are literally handled with the hands, it is common to find TLDs incorporated into a finger ring.
Luminescence and thermoluminescence of Er3+-doped CaF2 nanomaterials
Published in Radiation Effects and Defects in Solids, 2023
Vu Thi Thai Ha, Thi Anh Thu Do, Trong Thanh Nguyen, Thi Dieu Thuy Ung
In the field of radiation measurement, thermoluminescence (TL) properties of natural CaF2 minerals have often been used in the personal dosimetry and archeology dating. Nowadays, RE-doped synthetic calcium fluoride nanostructure is one of the most sensitive materials for thermoluminescent applications. The material has a relatively low Z effective, making it suitable for ionizing radiations used in radiotherapy. Fukuda reported the possibility of estimating UV radiation dose using CaF2:Tb3+ and Sm3+ (23). Zahedifar synthesized and studied TL properties of CaF2:Tm3+ and Ce3+ nanoparticles (24). Pandurangappa and co-workers studied the optical properties of gamma-irradiated CaF2:Eu3+ nanocrystallines (25), while Daniel reported thermoluminescent response of CaF2:Tm3+ to γ (60Co) radiation (26). The effect of dopants on TL characteristics of CaF2 nanostructure activated by Eu, Tb, Dy, Cu and Ag has been studied (27). However, there are still few studies on the TL response of nanomaterials with low Z effective, particularly CaF2:Er3+ nanocrystallines, although this property makes them suitable for ionizing radiations used in radiotherapy. The application possibility of this kind of material to other radiations such as beta radiation has also been under-studied.
Improvement of dose range of thermoluminescence dosimeters applied in radiotherapy
Published in Radiation Effects and Defects in Solids, 2020
Shrouk F. Rawash, Arafa I. Abd El-Hafez, Nashaat A. Deiab, Nabil A. El-Faramawy
Nowadays, Thermoluminescence dosimeters (TLD’s) were used in a wide range in different fields. They were used as essential dosimeters as personal detectors in the radiation occupational sites (1). Also, they were used for assessment of depth dose distribution (DDD) in boron neutron capture therapy (BNCT) and brachytherapy (2,3) and as radio-diagonstic and radiotherapy dosimeters (4,5). Thermoluminescence is the thermally stimulated emission of light from an insulator or semiconductor following the absorption of energy from radiation (6–9). This process forms characteristics glow curves for each phosphor material and these glow curves are different from a material to another. Over the last two decades, computerized deconvolution of thermoluminescence glow curves has become the method of choice for TL glow-curve analysis. This method is used to evaluate TL kinetics parameters for a given peak in the glow-curve.
Study on the comprehensive countermeasures for coastal erosion of Kujukuri Beach
Published in Coastal Engineering Journal, 2019
Ryotaro Shibata, Shinji Sato, Yusuke Yamanaka
Quartz or feldspar in sand particles includes electrons excited by natural radiation. When they are exposed to light or heat, some of the excited electrons return to ground state with light emission (luminescence) depending on their energy level (Aitken, 1998). The luminescence induced by heat is called thermoluminescence (TL), whereas that induced by light is called optically stimulated luminescence (Aitken, 1998). By measuring the luminescence intensity, the number of excited electrons can be measured, which reflects the sedimentation and the transport process; excited electrons increase with the natural radiation while the particle is buried underground and decrease with the exposure to light during fluvial/nearshore transportation (Rink 2003).