¹⁴⁴Ce - ¹⁴⁴Pr spectrum measurement with 4π semiconductor β-spectrometer

Abstract

Precision β-spectra measurement always had a great importance in some fundamental physics problems including neutrino physics. Magnetic and electrostatic spectrometers have high resolution, but at the same time usage of such kinds of equipment involves the size and cost issues. Since electron mean free path at the energy of 3 MeV (which is basically the maximum energy of a β-transition for the long-lived nuclei) does not exceed 2 g/crn2 , electron registration could be effectively performed with the solid state scintillators and semiconductors. A strong probability of backscattering from detector surface is present in case of semiconductor detectors and is dependent upon the detector material. Such problem can be solved with 4π geometry detector development, which fully covers the radioactive source and is able to register the backscattered electrons. In this work we present the newly developed technology of 4π geometry β-spectrometer based on two semiconductor detectors. This spectrometer was used for measurement of the 144Ce - 144Pr spectrum, that is the perspective anti-neutrino source due to endpoint energy at 3 MeV and can be used for the sterile neutrino search experiments. The form-factor parameters that were obtained are: C(W) = 1 + (-0.02877 ± 0.00028)W + (-0.11722 ± 0.00297)W-1. The measurement accuracy was sufficiently enhanced with respect to the previous results.

A Silicon 4π Spectrometer of β-Decay Electrons with Energies of up to 3 MeV

“…In combination with the scintillation BGO detector, the spectrometer can be employed for acquisition of spectra that correspond to the transitions to the excited states of the daughter nuclei. The designed spectrometer was successfully employed for measurements of -spectra of 144 Ce-144 Pr and 210 Bi sources [12][13][14][15].…”

“…The designed spectrometer is capable of registering electron's full energy, thus solving the problem of crystal surface backscattering, whose probability can reach tens of percent, depending on the electron energy and incidence angle. The initial results of 144 Ce-144 Pr and 210 Bi -spectra measurements via the 4 spectrometer consisting pair of Si(Li) detectors were published in [12][13][14][15].…”