For measurement of doses of ionizing radiation in biological fabrics use the radiation detectors allowing to register distribution of doses on a surface and depth. Similar tasks arise also in the radiation equipment at a research of radio sensitivity of separate products. For this purpose detectors on the basis of teflon with addition of fine powder of a thermophosphor which are rather difficult and expensive in production were abroad developed. In our country brand 4A detectors LiF-ftoroplast in the range of thickness of a film from 10 to 100 microns were developed. Detectors were used in the experimental purposes during rather long time, in particular in works at mitigation of consequences of the Chernobyl accidents. As at repeated heating ftoroplast changes the geometrical sizes and optical properties, there was a need of creation of new thermoluminescent films. As such use of heat-resistant polymers with good optical properties of films is possible. Thus, the production technology of a thermoluminescent dosimetric film on the basis of poliimidny PM-1 pitch was developed. Detectors from this film had satisfactory characteristics, however light output decreased due to light absorption by a film. There is a need of development of new matrixes with high thermal stability and the best svetovykhod which would eliminate defects of already existing systems. Thus, there is a need of use of new materials for matrixes of dosimeters of external radiation which have to meet all requirements imposed to dosimeters of external radiation. As alternative in this work films on the basis of aromatic polyamides, polyester, polyamidoimides and polisulfon which allow to eliminate the specified defects are used.
- Materials and methods
Radiation detectors should simulate energy absorption in sensitive tissue layers and meet the following requirements: tissue energy content, a wide range of recorded doses of beta radiation in the entire «practical» energy range, acceptable for the conditions of chronical and emergency irradiation measurement error, autonomy, ease of wearing during production operations and (depending on the price) multiple use.
As matrices in this study we used heat-resistant polymers: poly-m-phenyleneterephthalamide — Fenelon S2 (TU 6-06-32-274-89); polyarylate FV-1 and polyarylate DV (TU 6-05-2032-87); Torlon.
Solvents of two classes were used: amide solvent (N,N-dimethylformamide according to GOST 20289-74) for polyamides and polyimides; chlorinated solvent (methylene chloride according to GOST 9968-86) for polyarylates.
To dehydration and degreasing of a surface applied C2H5OH ethanol in accordance with GOST 9968-86, (CH3)2CHOH isopropanol according to TU 2632-015-11291058-95.
Magnesium tetraborate activated by dysprosium MgB4O7 → Dy was used as a thermoluminophor.
References1. Technology of obtaining thin-layer thermoluminescent detectors [Text] / A. I. Shaks, T. I. Gimadova // Equipment and news of radiation measurements. – 2007. – №1. – P. 68-71.
2. Encyclopedia of polymers [Text]. / V. A. Kabanov, etc.; ed. by Kabanov V. A. – In 3 volumes. Vol.2.: L-Polynomial fibers. – M.: Soviet encyclopedia, 1974 – 1032 p.: Il. – 35 000 copies.
3. Methodical instructions MU 188.8.131.52-2002. Control of equivalent doses of photon and beta radiation in the skin and lens of the eye [Text]. – M.: SSC Institute of Biophysics, 2002 – 43 p.: Il. – 100 copies.
4. Methods of measuring doses in the skin of fingers, face and eye lens of the staff [Text]. – M.: SSC Institute of Biophysics, 2004 – 15 p.: Il. – 100 copies.
5. Radiation safety standards (NRB-99) SP 184.108.40.2068-1999. Sanitary regulations. SP 220.127.116.118-99 "Ionizing radiation, radiation safety" [Text]. – M.: Ministry of health of Russia, 1999 – 21 p.: Il. – 100 copies.