Precision energy determination of gamma-rays from the 66Ga(β++ϵ)66Zn decay

doi:10.1016/0168-9002(93)90273-K

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

Volume 335, Issues 1–2, 15 October 1993, Pages 219-226

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Abstract

The energies of 29 γ-rays from the ⁶⁶Ga(β⁺ + ϵ)⁶⁶Zn decay have been measured with Ge(Li) detectors, of which one in a Compton suppression shield. Energy calibration standards were provided by ⁴⁶Sc, ⁵⁶Co, ⁶⁵Zn, ¹¹⁰Ag^m and ¹²⁴Sb radioactive sources. The resulting excitation energies of 18 ⁶⁶Zn levels, obtained in a least-squares fit, then provide the energies for 26 strong lines (E_γ = 0.83−4.81 MeV) with a final precision of better than 10 ppm. Of particular importance are the five E_γ = 3.76−4.81 MeV lines, which now can serve as calibration standards in this hitherto uncovered high-energy region.

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A consistent set of γ-ray energies, generally with uncertainties of less than 10 ppm, is recommended for use in the energy calibration of γ-ray spectra. The energy scale used for the previously recommended standards (1979) has been modified to take into account subsequent adjustments in the fundamental constants (−7.71 ppm) and in the γ-ray wavelengths deduced from a revised estimate of the lattice spacing of Si crystals (+1.91 ppm). On this revised energy scale, the strong line from ¹⁹⁸Au, the “gold standard”, has an energy of 411 802.05±0.17 eV, which is 2.4 eV (or 5.80 ppm) lower than the 1979 value. A significant improvement has come from the reduction in the uncertainty in the wavelength-to-keV conversion factor from 2.6 to 0.3 ppm. The criteria for the selection of γ rays to include are described. The list of γ-ray energies recommended for calibration, especially for Ge semiconductor detectors, has values for about 260 γ-rays from 50 radionuclides ranging from 24 to 4806 keV. Also, γ-ray energies are also given for about 70 additional lines, including 5 other radionuclides.
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Precision energy determination of gamma-rays from the 66Ga(β++ϵ)66Zn decay

Abstract

Atom. Data Nucl. Data Tables

Nucl. Instr. and Meth.

Nucl. Phys.

Nucl. Phys.

Precision energy determination of gamma-rays from the ⁶⁶Ga(β⁺+ϵ)⁶⁶Zn decay