Neutron transmutation doping

J. Guldberg, ed., Neutron-Transmutation-Doped Silicon, Proceedings of the Third International Conference on Transmutation Doping of Silicon, Copenhagen, Denmark, Plenum Press, Inc., New York, 1981. 

NTD (neutron transmutation doped) germanium chips are used as resistive thermometers in low-temperature detectors/calorimeters. 

Fig. 12.16. Heat capacity per unit volume of the two neutron transmutation doped (NTD) Ge wafers.

The measurement of the cosmic microwave background. Far infrared astronomers were the first to develop thermal detectors. Some of the resulting technologies, such as neutron transmutation doping (NTD) [3], have been transferred to particle detection sensors and have allowed many groups (e.g., ref. [4-11] to make rapid progress). 

Fig. 15.1. Electrical resistivity for T < 300 mK of neutron transmutation doping Ge 33-38 series.

Neutron transmutation doping is specific to silicon. In this process, phosphorus-doped silicon can be obtained by using a stream of thermal neutrons to transmute silicon atoms to phosphorus. The nuclear reaction provides an even doping distribution throughout the silicon. 

Neutron transmutation doping is the nuclear conversion of Si atoms into P dopant atoms by exposing undoped Si crystals to a suitable flux of neutrons. The mixture of Si isotopes is Si = 92.21, Si" = 4.7, and °Si" = 3.09. These isotopes are homogeneously distributed. During irradiation with thermal neutrons ... 

In neutron transmutation-doped Si, radiation damage is caused by primary y-rays, by fast neutron bombardment, and by recoils from reaction and decay processes. 

E. E. Haller, K. M. Itoh, J. W. Beeman, W. L. Hansen, V. I. Ozhogin, Neutron transmutation doped natural and isotopically engineered germanium thermistors, SPIE Proc., 2198,630 (1994). 

Suitable sample sizes for irradiation are usually a gram or less. There is no Inherent lower limit, and the upper limit is set by the finite transparency of thick samples to neutrons and by the practical problems of inserting a sample into a neutron field. Very large samples, such as entire silicon ingots for neutron-transmutation doping (23) and even oil paintings (24.25). have been studied by NAA with special facilities. 

Guldberg, J., Ed. "Neutron-Transmutation-Doped Silicon" Plenum New York, 1 981. 

Different techniques have been developed to produce CZ doped crystals with a good longitudinal homogeneity [65], Radial fluctuations of the dopant concentration in the melt are also related to the convection current in the molten phase and to the speed of rotation of the crystal, and this can be troublesome for some technological applications. This problem has been solved in the n-type silicon by neutron transmutation doping (NTD), as shown in... 

B.D. Stone, D.B. Hines, S.L. Gunn, D. McKown, in Neutron Transmutation Doping in Semiconductors, ed. by J.M. Geese (Plenum Press, NewYork, 1979),... 

B. Pajot, D. Debarre, in Neutron-Transmutation-Doped Silicon, ed. by J. Guldberg (Plenum, 1981), pp. 423-435... 

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