Basic Standards and Calibrations

The sum-peak counting system consists of two 0.19 cm thick by 2.54 cm diameter NaI(Tl) scintillation crystals mounted end on with the source to be assayed between the two in a very tight geometry. The spectra from the crystals are summed and fed into a multichannel analyzer. The data are analyzed using the sum-peak coincidence equations. ¹²⁵I sources are routinely measured using this instrument.

Reference: Sum-Peak Counting with Two Crystals. J.M.R. Hutchinson, W.B. Mann and P.A. Hodge. First International Summer School on Radionuclide Metrology, Herceg-Novi, Yugoslavia, Aug.21-Sept.1, 1992. Nucl. Instr. Meth., 112 187 (1973).

Inquiries or comments: lisa.karam@nist.gov
Online: November 1997   Last update: March 1999