HARD RADIATION DETECTORS ON A3B6- BASED SEMICONDUCTORS AND THEIR COMPLEX ANALOGUES
Kerimova E.M., Mustafaeva S.N., Huseinova D.A. Institute o f Physics, Academy o f Sciences o f Azerbaijan,
G.JavidProspect, 33, 370143 Baku, Azerbaijan e-mail: Phvsic@lan.ab.az
Investigation results of roentgenoconductivity of A3B6 single crystals and their complex analogues [1-5] formed the basis for development and production samples of X-ray detectors on their base. Sensitive elements for X-ray detectors of size 3x3x0.3mm3 are obtained by spalling of grown single crystals along the plane of natural spall. Indium electrodes are sealed to mirrow surface of spall. The source of X-radiation in determination of dosimetric parameters of detectors under investigation is set-up URS-60.
Values of X-ray dose at each given value of accelerating voltage on the tube within the range 10- 60keV have been measured by X-ray dosimeter of DRGZ-03-typed.
Dosimetric parameters of laboratory samples of X-ray detectors on the base of complex semiconductors A'B' and A3BAN" at 300K have been given in Table 1.
Table 1. Crystal composition Dose sensitivity ( A
V
. R / m i n V ' / Range of measured power (R/'min) Registered interval of radiation energy (keV) Operating voltage (Volts) Drift GaSe <Sn> 2.MO"8 0.2-140 10-120 20 5-10 s InSe 3.2-10"8 0.08-140 10-120 20 10-15 s TlInSe2 5.7T0"9 1-140 10-60 40 shares of s TlGaSe2 1.5T0"7 0.01-140 10-60 20 15-20 s TlInS2 1.1T0"11 1.5-140 10-60 40 1-5 sDose sensitivity of detectors depends on radiation hardness, and also on power of X-ray at given hardness (for exponential behaviour of their dosimetric characteristics). In Table 1 its value is given for quantum energy 50 keV at power 10R/min.
In this work, we report also x-ray dosimetry properties of (TlGaS2)i.x(TlInSe2)x single crystals. Roentgenosensitivity Ka of these crystals was characterized by the relative change in conductivity per unit dose rate,
Kü
Aa ü 0
E ,0
~E
where a0 is the conductivity of the conductivity of the unirradiated crystal and A ü E 0 = a E - a 0 is
the change in conductivity under X-ray irradiation with dose rate E(R/min).
Table 2 lists Ka values obtained at accelerating voltages from 25 to 30 keV and dose rates from 0.75 to 10 R/min. Table 2 Composition Ka , min/R TlGaS2 0.063-0.159 (TlGaS2)0.9(TlInSe2)0.1 0.75-0.178 (TlGaS2)0.8(TlInSe2)0.2 0.089-0.198 (TlGaS2)0.7(TlInSe2)0.3 0.098-0.213 (TlGaS2)0.6(TlInSe2)0.4 0.107-0.219 (TlGaS2)0.5(TlInSe2)0.5 0.142-0.252
One can see that Ka of (TlGaS2)i-x(TlInSe2)x solid solutions exceeds that of pure TlGaS2. As the TlInSe2 content increases, Ka rises to 0.142-0.252 at x=0.5
Thought suggested X-ray detectors are at a disadvantage in relation to sensitive detectors on the base of CdS single crystals, but they have a number of advantages. First, at low dose powers studied detectors have considerably less pick-up time than CdS. Second, our detectors gave no indications of saturation up to dose powers in 140 R/min and illumination fatigue effects. Besides, detectors made on the base of TlInSe2 and TlGaSe2 single crystals are distinguished by high radioresistance. Mentioned advantages of suggested X-ray detectors can be used in hard radiation dosimetry, medicine and radiation therapy, industrial defectoscopy, space technology.
REFERENCES
1. E.M.Kerimova, S.N.Mustafaeva, A.Z.Abasova. Materials of 12th International Conference on Ternary and Multinary Compounds. HsinCHu, Taiwan, 27 Sept.-1 Oct., 1999. P.P2-79.
2. S.N.Mustafaeva, M.M.Asadov, V.A.Ramazanzade. Materials of the 11th International Conference on Ternary and Multinary Compounds, Salford, UK., 8-12 Sept. 1997. P.P1-71. 3. A.Z.Abasova, E.M.Kerimova, G.A.Muradova, A.M.Pashaev. Inst.Phys. Conf.Ser. NO 152:
Section H: Single crystal and Thin Film Devices. 1998. IOP Publishing Ltd. P.983-988. 4. G.D.Guseinov, G.I.Iskenderov, Z.A.Aliev. Neorgan. Materials. 1991. V.27.N°9. P.1972-1973. 5. A.U.Sheleg, K.V.Iodkovskaya, N.F.Kurilovich. Fizika Tverdogo Tela
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