Rotunda and K. John, J. Cassata, P. Blake, J. Rotunda, M. Ramlo, K. Velbeck and L. DeWerd, J. Cameron, D. Wu, T. Papini and I. Shinde and R. Bhatt, Comparative dosimetric studies of three LiF phosphors, Radiat. Pradhan and R. Kim, S. Chang and J. Schulman, R. Kirk, E. Annalakshmi, M. Jose and G. Amarendra, Dosimetric characteristics of manganese doped lithium tetraborate — An improved TL phosphor, Radiat.
Scharmann, , pp. Pradhan, R. Bhatt, K. Prokic, Lithium borate solid TL detectors, Radiat. Furetta, M. Prokic, R. Salamon, V. Prokic, G. Kitis, Dosimetric characteristics of tissue equivalent thermoluminescent solid TL detectors based on lithium borate, Nucl. A Rawat, D. Desai, S. Singh, M. Tyagi, P.
Ratna, S. Gadkari, M. Rawat, M. Kulkarni, M. Ratna, D. Mishra, S. Singh, B. Tiwari, A. Soni, S. Gadkari, S. Martini, F. Meinardi, L. Rzyski and S. Morato, Luminescence studies of rare earth doped lithium tetraborate, Nucl. Singh, Vibha Chopra, S. Patra, S. Tiwari, S. Sen, D. Gadkari, Thermally stimulated luminescence process in copper and silver co-doped lithium tetraborate single crystals and its implication to dosimetry, J.
Lakshmanan, B. Chandra and R. Kazanskaya, V. Kuzmin, E. Minaeva, A. Sokolov, Magnesium borate radiothermoluminescent detectors, In: Proc. Dosimetry, Krakow, Poland, pp. Lakshmanan, Bhuwan Chandra, A. Prokic, New sintered thermoluminescent dosimeters for personnel and environmental dosimetry, Health Phys. Kitis, C. Prokic, V. Prokic, Kinetic parameters of some tissue equivalent thermoluminescent materials, J. Prokic, Individual monitoring based on magnesium borate, Radiat.
PDF, Vienna, April , , pp. Salamon, G. Campos and O. Rao, B. Rao, K. Somaiah and K. Pure Appl. Jose, U. Madhusoodanan, B. Venkatraman, G. Fukuda, K. Mizuguchi and N. Tekin Ekdal , A. Ege, T. Karali, P. Townsend, M. Furetta, C. Bacci, B. Rispoli, C. Sanipoli and A. Moharil, S. Dhoble, S. Dhopte, P. Muthal, V. Bacci, S. Fioravanti, C. Missouri, G. Ramogida, R. Rossetti, C. Sanipoli, and A. Le Masson, A. Bos, C. Van Eijk, C.
Furetta and J. Furetta, F. Santopietro, C. Sanipoli, G. Madhusoodanan, M. Jose, R. Indira, T. Furetta and C. Bernal, K. Alday-Samaniego, C. Furetta, E. Cruz-Zaragoza, G. Kitis, F. Brown and C. Bhatt, B. Dhabekar, S. Shinde, S. Moharil and T. Accepted manuscript , Doi: Aghalte, S. Omanwar, and S. Pappalwar and N. Kharisov, O. Kharissova, U. Puppalwar, N. Dhoble and A. Pure and Appl. Menon, E. Alagu Raja, A. Bakshi, A. Chougaonkar, Y. B — Anishia, M.
Jose, O. Annalakshmi, V. Ponnusamy, V. Ramasamy, Thermoluminescence properties of rare earth doped lithium magnesium borate phosphors, J. Shinde and S. More, S. Wankhede, M.
Kumar, G. Chourasiya and S. Ayyangar, A. Lakshmanan, Bhuwan Chandra, and K. Toryu, H. Kotera, H. Yumada, Compositions dependency of thermoluminescence of new phosphors for radiation dosemetry. Lakshmanan and K. Lakshmanan, S. Shinde, and R. Jun and K. Bhasin, R. Sasidharan and C. Sunta, Preparation and thermoluminescent characteristics of terbium doped magnesium orthosilicate phosphor, Health Phys.
Nakajima, Magnesium silicate, In: Thermoluminescent materials, D. Kitamura, Calcium sulphate activated by rare earth, In: Proc. Second Int. Azorin, R. Salvi, A. Li and P. Lakshmanan, photoluminescence and thermostimulated luminescence processes in rare-earth-doped CaSO4 phosphors, Progr. Lakshmanan, M.
Jose and O. Annalakshmi, High-sensitive CaSO4: thermoluminescent phosphor synthesis by co-precipitation technique, Radiat. Rivera, J. Romana, J. Sosa, J. Guzman, A. Serrano, M. Garcia, G. Rao, R. Iyer, Y. Gokhale, S. Gupta, S. Deshpande and S.
Sunta, A review of thermoluminescence of calcium fluoride, calcium sulphate and calcium carbonate, Radiat.
Azorin and A. Atone, S. Jose, A. Tomita, A. Muthal and V. Sahare and S. Moharil, A new high-sensitivity phosphor for thermoluminescence dosimetry, J. Gedam, S. Omanwar and S. Moharil, TL in halosulphate phosphors prepared by wet chemical method, Eur. Gedam and S. For that reason several alternative routes such as prepared using the CS method, with respect to dopant concentra- a electrochemical oxidation of aluminum in organic acids Aze- tion and annealing temperature.
The resulting powder was E-mail address: vdbarros terra. Barros et al. This can be seen in Fig. This effect is probably a Harshaw-Bicron TL reader, model , equipped with a Hama- related to the g—a phase transformation which occurs at around matsu R photomultiplier tube.
Results clearly indicate that the highest sensitivity was found for the concentration 0. The reason for this TL behaviour is still Figs. From crystalline g phase of alumina and the stabilized crystalline a phase this result we can see that both samples have a linear TL response of alumina. On the other hand the XRD for the samples after the within the dose range of 0. In summary, the results showed that a 0.
These results strongly indicate that this material is suitable for dosimetric applications. More work is under way to optimize the sensitivity of the material to lower dose measurements. References Akselrod, M. Highly sensitive thermo- luminescent anion-defective a-Al2O3:C single crystal detectors. Dosim 32, 15— Azevedo, W.
Highly sensitive thermoluminescent carbon doped nanoporous aluminium oxide detectors. Dosim , — Prepa- ration and thermoluminescence properties of aluminium oxide doped with europium.
Barros, V. This was measured with a micrometer by comparing the slide plus TLD thickness with the bare slide thickness. Sanding was accomplished by fixing a grit or finer piece of sandpaper on a flat surface and wetting the paper with distilled water. The chip-bearing slide and holder was next moved unidirectionally as opposed to back-and-forth sanding over the sandpaper to sand the respective chips. Some of the TLD chips were fractured in the sanding process, but this can be minimized by careful sanding.
The chip-bearing slide was next removed from its holder, rinsed step 5 with distilled water, and allowed to dry. This vaporized the cyanoacrylate glue and freed the TLD chips from the slide. The wafers were extremely fragile in this state and were handled step 7 by sliding them from one position to another using tweezers or the like. The wafer thickness may be calculated by weighing the wafer on a microbalance and computing the thickness from the known density and size dimensions; in the alternative, a thickness determination can be made by measuring the radiation sensitivity of the sanded chips after backing thereof against known thickness standards.
The appropriate number of graphite blocks were next glued to a glass slide step 14 in the same manner as set forth with respect to the TLD chips. This slide was placed in a holder, and the graphite blocks were wet sanded lightly step 15 Using grit wet sandpaper to ensure that all blocks are the same thickness.
Dust was wiped step 16 from the blocks with an acetone or alcohol dampened cloth. After removal from the oven, the top glass slide was immediately pressed down hard and held for one minute step 22 to compress the composite dosimeters.
While these dosimeters are quite rugged, care should be taken not to get carbon dust on the TL chips from stacking, sliding in and out of envelopes, etc. In the final dosimeters, the thin TLD chips provided the radiation dose information, while the graphite backings were nearly tissue equivalent and supported the fragile chips.
The Kapton XP adhesive product is manufactured and sold by the E. This film was developed primarily as an electrical insulator in high temperature environments such as for motor and generator windings. The Kapton XP film has a coating of Teflon PFA a copolymer of tetrafluoroethylene with a fully fluorinated alkoxy side chain on one or both sides to act as a high temperature adhesive and allow heat sealing of the Kapton to many materials.
This product is described in a manufacturer's new product information bulletin entitled "Kapton Type XP New Product Information", E; and additional information is contained in publications referenced in the foregoing.
All of these publications are incorporated by reference herein. Since Kapton XP film was used to make composite dosimeters which would potentially be exposed to a high temperature annealing environment for extended periods of time, its stability at high temperatures was of great interest.
The gradual darkening of the film did not produce any observable change in the radiation dose response of the thin TLD layer. It is believed that the black graphite backing of the dosimeter made its response insensitive to the color of the Kapton XP film.
Other composite dosimeters in accordance with the invention can be produced using the methods outlined above. In addition, the backing support can be formed from a large number of materials, including a thick 0. In all cases, however, the thin TLD component is obtained using the sanding techniques of the invention. Actual test results demonstrate that the physical abrading sanding of the TLD chips substantially reduces non-radiation-induced thermoluminescence, which is important in obtaining the most accurate low absorbed doses.
In order to obtain this lessening, it is not necessary to sand the TLD material to the preferred thinness, and in fact only a light sanding suffices. Therefore, the sanding step may prove beneficial even in the case of conventional thick TLD's, but should be sufficient to significantly reduce non-radiation induced thermoluminescence, as compared with an otherwise identical, unabraded or unsanded body.
Advantageously, the reduction in non-radiation induced thermoluminescence attributable to sanding should be at least about a factor of two. The test results referred to above demonstrate up to about a factor of 5 reduction in non-radiation-induced thermoluminescence, to the point that the dosimeters of the invention exhibit virtually no non-radiation-induced TL.
In addition, tests to date indicate that the reduction in non-radiation-induced thermoluminescence is substantially long lived, and may be permanent.
While the reason for this phenomenon is not completely understood, it is hypothesized that the sanding removes monomolecular surface layers of the TLD material, and with these absorbed hydroxyl ions on the material surface. Such hydroxyl ions are believed to contribute to non-radiation-induced thermoluminescence. Energy response experiments were performed using two different energy beta sources to determine the response of conventional thick and thin LiF TLD's the latter being in accordance with the present invention.
Dosimeters were covered with 1. Based upon these calibration results, the radiation dose from a Tl beta source maximum energy of 0. Therefore an improvement of a factor of 3. These results and additional data for thin TLD's, exposed without a covering material, are shown in Table I. We claim: 1. A radiation dosimeter comprising an essentially pure, self-sustaining, solid body of thermoluminescent material of substantially constant density and having a thickness of less than about 0.
The dosimeter of claim 1, said body having length and width dimensions of at least about 0. The dosimeter of claim 2, said length and width dimensions being at least about 3 millimeters. The dosimeter of claim 1, said thickness being less than about 0. The dosimeter of claim 1, said body presenting at least one sanded face.
The dosimeter of claim 1, said body presenting a pair of opposed sanded faces. The dosimeter of claim 1, including a block for said body, and means for securing said body to said block. The dosimeter of claim 1, said body having a volume of at least about 0. The dosimeter of claim 9, said volume being from about 0. The dosimeter of claim 1, said body being in the form of a pressed or extruded initially powder material.
A method of fabricating a radiation dosimeter comprising the steps of: providing a solid, self-sustaining body of thermoluminescent material having a substantially constant density; and. The method of claim 12, said abrading step comprising sanding at least one face of said body.
The method of claim 12, said abrading step comprising sanding a pair of opposed faces of said body. The method of claim 12, said thickness being less than about 0. The method of claim 12, said body, after said abrading step, having a volume of at least about 0.
The method of claim 12, said body, after said abrading step, having length and width dimensions of at least about 0. The method of claim 12, including the step of attaching said abraded body to a block.
The method of claim 19, said attaching step comprising adhesively securing said abraded body to said block. The method of claim 19, said block being approximately tissue equivalent material. The method of claim 19, said block being non-tissue equivalent. The method of claim 12, said body being substantially pure thermoluminescent material.
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