A new determination of the 68Ga half-life and evaluation of literature data

Inconsistencies within the 68Ga half-life dataset have been repeatedly identified in nuclear decay data evaluations performed over the past decade. In this paper, a half-life has been determined using ionisation chambers measurements and HPGe gamma-ray spectrometry (T1/2 = 67.783(27) min). The current literature has been reviewed and possible causes of discrepancy have been identified, such as neglected contaminant effects, robustness of analysis, and underestimation of systematic effects. This could lead to a significant improvement of the half-life in future evaluations.

Liquid scintillation efficiencies, gamma-ray emission intensities, and half-life for Gd-153

Gadolinium-153 was standardized for activity by live-timed anticoincidence counting and an ampoule was submitted to the international reference system (SIR). Absolute emission intensities for the main γ rays were determined with calibrated high-purity germanium (HPGe) and lithium-drifted silicon (Si(Li)) detectors. A revised decay scheme is indicated, with no probability of direct electron capture to the 153Eu ground state. Triple-to-double coincidence ratio (TDCR) efficiency curves indicate that the revised decay scheme is consistent with experiment. Half-life measurements agree with a previous NIST determination and show no sensitivity to chemical environment.

226Th nuclear decay data evaluation

Following the recent evaluation of the nuclear decay data of ²³⁰U, a similar evaluation for its daughter, ²²⁶Th, a radionuclide of interest for targeted alpha therapy, was undertaken within the Decay Data Evaluation Project (DDEP) and an IAEA Coordinated Research Project. The nuclear decay data presented are: the half-life, decay energy, alpha-particle emission energies and probabilities, internal conversion coefficients and gamma-ray energies and emission intensities. These new data will be included in the DDEP database NUCLEIDE.

Towards high-precision calculation of electron capture decays

Based on previous study, the calculation of electron capture decays has been improved by considering a more accurate atomic model with precise atomic energies, and different radiative corrections have been tested. The computer code has been revised in order to greatly speed-up the calculation and has then been coupled with the BetaShape code. The influence of the nuclear component has also been explored using a simple nuclear model. All the calculations are compared with precise measurements available in the literature.

Alpha-particle emission probabilities of 231Pa derived from first semiconductor spectrometric measurements

The nuclide ²³¹Pa is a member of the ²³⁵U decay chain. It is a complex alpha emitter with 25 identified alpha emissions. Formerly published alpha-particle emission probabilities were derived from measurements taken with magnetic spectrometers. This work presents the first measurements made with semiconductor detectors. High-resolution alpha-particle spectrometry was carried out at CIEMAT and JRC using ion-implanted planar silicon detectors. Alpha-particle emission probabilities of 23 transitions were derived from deconvolutions of the spectra. For the major lines, uncertainties are lower than 1%, a significant improvement to existing data. The new data set will allow a more accurate evaluation of the decay scheme of ²³¹Pa.

Standardization of 64Cu activity

The complex decay scheme that makes 64Cu promising as both an imaging and therapeutic agent in medicine also makes the absolute measurement of its activity challenging. The National Institute of Standards and Technology (NIST) has completed a primary activity standardization of a 64CuCl2 solution using the 4πβ(LS)-γ(NaI) live-timed anticoincidence (LTAC) counting method with a combined standard uncertainty of 0.51 %. Two liquid scintillation (LS) counting methods were employed for confirmatory measurements. Secondary measurements were made by high-purity germanium detectors, pressurized ionization chambers (IC), and a well-type NaI(Tl) counter. Agreement between the LTAC-based standard and standards from other laboratories was established via IC calibration factors. Poor agreement between methods and with theoretical IC responses may indicate a need for improved β+/- branching probabilities and a better treatment of β+/- spectra.

230U nuclear decay data evaluation

The evaluation of the nuclear decay data of ²³⁰U, a radionuclide of interest in nuclear medicine (targeted alpha therapy), was performed within the Decay Data Evaluation Project (DDEP) and an IAEA Coordinated Research Project. The nuclear decay data presented are: the half-life, decay energy, alpha-particle emission energies and probabilities, internal conversion coefficients and gamma-ray energies and emission intensities. These new data, obtained using the DDEP methodology and software tools, will be included in the DDEP database NUCLEIDE.

Decay Data Evaluation Project: Evaluation of (52)Fe nuclear decay data

Within the Decay Data Evaluation Project (DDEP) and the IAEA Coordinated Research Project no. F41029, the evaluation of the nuclear decay data of (52)Fe, a radionuclide of interest in nuclear medicine, was performed. The main nuclear decay data evaluated are: the half-life, decay energy, energies and probabilities of the electron capture and β(+) transitions, internal conversion coefficients and gamma-ray energies and emission intensities. This new evaluation, made using the DDEP methodology and tools, was included in the DDEP database NUCLEIDE.