High-precision half-life measurement of 123Xe and 125Xe for fuel areal density diagnosing in inertial confinement fusion.

The half-lives of 123Xe and 125Xe are important to diagnose deuterium-tritium (DT) fuel areal density in inertial confinement fusion (ICF). In this work, those two half-lives have been measured with HPGe γ-ray spectrometers using the reference source method. Data have been recorded over seven half-lives with three independent measurements for 123Xe and two for 125Xe. New values of 123Xe (2.040 ± 0.009) h and 125Xe (17.048 ± 0.032) h have been determined with significant reduction of the uncertainty compared to the currently recommended value of (2.08 ± 0.02) and (16.9 ± 0.2) h, respectively.

Half-life determination of 88Rb using the 4πß and 4πßγ-coincidence methods.

Samples of 88Rb were produced by the irradiation of U3O8. A series of procedures were applied to extract pure radioactive solution of 88Rb. Experimental data was recorded by a 4πßγ-coincidence measurement system. Two rounds of experiments were performed to obtain four sets of measurement data. The measured half-life of 88Rb obtained from the average of the 4πß and 4πßγ-coincidence methods was 17.78 ± 0.05 min, in good agreement with previously reported values but with a significantly reduced uncertainty.

Self-adaption Compton imaging algorithm for a quasi-point source.

Compton imaging is a promising technology for various applications including nuclear safety, nuclear medicine, and astrophysics. For quasi-point-source applications, which are widely found in practice, a novel Compton imaging algorithm incorporating the concept of self-adaption is proposed that provides excellent precision and high efficiency. In particular, this algorithm significantly improves the imaging precision of backward-scattering imaging events so that they can be revived for reconstruction without degrading image quality. From Monte Carlo simulations, a comparison between the self-adaption Compton imaging algorithm and the conventional Compton imaging algorithm was conducted, and the feasibility and reliability of this algorithm was verified in various scenarios.

Simulation study of the backward-scattering effect in Compton imager.

In the field of nuclear medicine, nuclear security and astrophysics, Compton imaging is a promising technique for gamma-ray source imaging. We are developing a Compton imager using two layers of CdZnTe pixel array detectors. In this paper, the backward-scattering effect within such imagers is numerically studied using Geant4 Monte Carlo Package. From images reconstructed based on forward-scattering and backward-scattering imaging events, the imaging precision was investigated in a comparative analysis, in regard to energy resolution and position resolution. Furthermore, to establish a method to use backward-scattering imaging events properly so that the imaging efficiency can be significantly improved, the difference between reconstruction from forward-scattering and backward-scattering imaging events was analyzed to uncover a causal mechanism.