THE IMPACT OF NEW ICRU95 QUANTITIES AND SPECTRUM DATA ON THE DOSIMETRIC QUANTITIES OF THE NEUTRON REFERENCE FIELDS AT PTB.

In 2020, the ICRU released a new report which includes the re-definition of the operational quantities used in radiation protection and new conversion coefficients from physical quantities to operational radiation protection quantities. An assessment of the ambient and personal dose conversion coefficients for the reference neutron fields of radionuclide sources at PTB is necessary based on these new definitions. In this work, a numerical estimation of the conversion coefficients of moderated and unmoderated 252Cf and 241Am-Be neutron sources based on ICRU57 and ICRU95 reports and using spectrum data available in the ISO 8529-1 standard and at PTB are discussed.

CALCULATIONS FOR THE HEAVY WATER MODERATED 252CF REFERENCE FIELDS AT PTB.

Knowledge of the neutron spectra of reference fields is very important for calibration purposes. This paper presents new calculations of the neutron spectra and dosimetric parameters of a D2O moderated 252Cf source assembly used to produce a neutron reference field at the Physikalisch-Technische Bundeanstalt (PTB), based on recent 252Cf fission neutron spectrum data and conversion coefficients for operational radiation protection units recommended by the International Commission on Radiological Protection (ICRP) report 57. Neutron fluence and dose calculations were carried out using a detailed simulation model of the source assembly implemented using MCNP6 and the cross-section data library ENDF/B-VIII.

Improved Upper Limit on the Neutrino Mass from a Direct Kinematic Method by KATRIN.

We report on the neutrino mass measurement result from the first four-week science run of the Karlsruhe Tritium Neutrino experiment KATRIN in spring 2019. Beta-decay electrons from a high-purity gaseous molecular tritium source are energy analyzed by a high-resolution MAC-E filter. A fit of the integrated electron spectrum over a narrow interval around the kinematic end point at 18.

A Bayesian Approach for Measurements of Stray Neutrons at Proton Therapy Facilities: Quantifying Neutron Dose Uncertainty.

Bonner sphere measurements are typically analyzed using unfolding codes. It is well known that it is difficult to get reliable estimates of uncertainties for standard unfolding procedures. An alternative approach is to analyze the data using Bayesian parameter estimation.

CHARACTERISATION OF THE PTB THERMAL NEUTRON CALIBRATION FACILITY WITH THE BONNER SPHERE SPECTROMETER NEMUS.

The neutron field of the PTB Thermal Neutron Calibration Facility was characterised with the help of the Bonner sphere spectrometer of PTB, NEutron MUltisphere Spectrometer (NEMUS). For the analysis of the Bonner sphere data an analytical model of the neutron energy distribution was used. The unfolding of neutron spectra was performed via the method of Bayesian parameter estimation.