4$\pi$ detector for study of Zeno effect using 220Rn -> 216Po alpha->alpha correlated chains

TL;DR

This paper presents the first test of a 4π detector designed to study the exponential decay law and Zeno effect by measuring the mean life of 216Po in alpha-alpha correlated decay chains.

Contribution

It introduces a novel 4π detector setup for observing the Zeno effect in radioactive decay and reports the measurement of 216Po's mean life using this system.

Findings

Measured half-life of 216Po is 143.5 ms, consistent with literature.

Background correlation counts are mainly due to 220Rn-216Po alpha activities.

Decreasing background levels below a few percent is challenging in the relevant time region.

Abstract

First test of the 4pi detector for study of exponential law of radioactive decay and possibility of observation of Zeno effect [1-3], measuring the mean life of 216Po is presented. This detector consists of two surface-barrier n-Si(Au) detectors placed in the close contact ( <1mm) to each other. Th foil is used as a generator of Rn- gas. The foil was covered by nuclear filter with 0.4 mm pores and placed in the bottom of vacuum chamber. So, direct alpha-particles can not reach the detector active surface. The measured half-live of 216Po of 143.5 (0.6) ms is in agreement with literature sources. It is shown, that for the definite source the random background correlation counts are mostly caused by the 220Rn - 216Po alpha activities and that it is not an easy task to decrease a background level of units of percents in the time region >4T1/2. Both, the data acquisition system and the vacuum chamber design are presented in brief.