# LXX International conference "NUCLEUS – 2020. Nuclear physics and elementary particle physics. Nuclear physics technologies"

Oct 11 – 17, 2020
Online
Europe/Moscow timezone

## Precision beta-spectrum measurement of RaE with semiconductror spectrometers

Oct 14, 2020, 6:10 PM
1h
Online

#### Online

Poster report Section 5. Neutrino physics and astrophysics.

ilia Drachnev

### Description

Precise knowledge of forbidden transition beta-spectra plays a significant role in both nuclear and particle physics.
In this work we present a precision measurement of the beta-spectrum shape for $^{210}$Bi (historically RaE) performed with spectrometers based on semiconductor Si(Li) detectors. This first forbidden non-unique transition has the transition form-factor strongly deviated from unity and knowledge of its spectrum would play an important role in low-background physics in presence of $^{210}$Pb background. The studies were performed with spectrometers in target-detector and 4-$\pi$ geometries. The measured transition form-factor could be approximated as $H(W) = 1 + (-0.433 \pm 0.002) W + (0.0510 \pm 0.0004) W^2$ and $H(W) = 1 + (-0.433 \pm 0.002) W + (0.0510 \pm 0.0004) W^2$ for the target-detector and 4-$\pi$ spectrometer respectively that is in good agreement between the two experiments as well as with the previous studies. The form-factor parameter precision has been substantially increased with respect to the previous experimental results. This work was supported by the Russian Foundation for Basic Research (project nos. 16-29-13014 and 19-02-00097).

### Primary authors

Prof. Alexander Derbin (Petersburg Nuclear Physics Institute NRC KI) Mrs Irina Lomskaya (PNPI NRC KI) Dr Valentina Muratova (PNPI NRC KI) Mr Evgenii Unzhakov (Petersburg Nuclear Physics Institute) Dr Dmitry Semenov (PNPI NRC KI) Mrs Nelly Pilipenko (PNPI NRC KI) Dr Igor Alexeev (V.G. Khlopin Radium Institute)