Well-type scintillation counters have found use in many radiochemical laboratories. A gamma scintillation well counter has been used to measure the gamma activity of liquid samples in the 325 Building counting room for about a year. This well counter has been built and calibrated so that gamma activity measurements made with it can be easily compared with measurements made with the gamma scintillation counter (GSC). The well counter is electronically identical to the present GSC and differs only in the shape of the crystal used and the physical arrangement of the lead shield. The crystal contains a well which allows a tube containing the sample to be inserted in the crystal. The physical arrangement of the detector greatly simplifies the preparation of liquid samples for activity measurement. The 325 Building well counter and its application to chemical research and plant process analysis will be discussed in the following paragraphs. An operating procedure is also included.

The Lindemann assumption of direct contact of neighboring atoms at fusion is replaced by the criterion that melting occurs when the root-mean-square amplitude of thermal vibration reaches a critical fraction ρ, presumed the same for all isotropic monatomic solids, of the distance of separation of nearest-neighbor atoms. The Debye-Waller theory of the temperature dependence of the intensity of Bragg reflection of x-rays is used, without further assumptions, to derive a generalized Lindemann law. In contrast to the Lindemann form, all physical quantities involved in this formulation are evaluated at the fusion point, and departure of the average energy of an atomic oscillation from the equipartition value is taken into account by the quantization factor of the Debye-Waller theory. If the Grüneisen constant γm of the solid at fusion is evaluated by its definition from the Debye frequency of the solid, use of the generalized Lindemann law and Clapeyron's equation permits one to express γm in terms of the bulk modulus of the solid at melting and the latent heat and volume change of fusion. By means of Grüneisen's law applied to the solid at fusion, γm can be expressed likewise in terms of the corresponding bulk modulus, thermal expansion, volume, …

Technical report covering chemistry of source, fissionable, and structural elements, nuclear chemistry, radio-organic chemistry, chemistry of separations processes, chemical physics, radiation chemistry, and instrumentation at the Oak Ridge National Laboratory for the period ending September 30, 1950. [From Abstract]