Erin C. Finn

Single-electron detection and spectroscopy via relativistic cyclotron radiation

It has been understood since 1897 that accelerating charges must emit electromagnetic radiation. Although first derived in 1904, cyclotron radiation from a single electron orbiting in a magnetic field has never been observed directly. We demonstrate single-electron detection in a novel radio-frequency spectrometer. The relativistic shift in the cyclotron frequency permits a precise electron energy measurement. Precise beta electron spectroscopy from gaseous radiation sources is a key technique in modern efforts to measure the neutrino mass via the tritium decay end point, and this work demonstrates a fundamentally new approach to precision beta spectroscopy for future neutrino mass experiments.

Liquid scintillation counting of environmental radionuclides: a review of the impact of background reduction

Liquid scintillation counting (LSC) supports a range of environmental science measurements. At Pacific Northwest National Laboratory, we are constructing an LSC system with an expected background reduction of 10–100 relative to values reported in the literature. In this paper, a number of current measurement applications of LSC have been considered with an emphasis on determining which aspects of such measurements would gain the greatest benefit: improved minimum detectable activity (MDA), reduction in sample size, and reduction in total analysis time.

Integrated separation scheme for measuring a suite of fission and activation products from a fresh mixed fission and activation product sample

Mixed fission and activation materials resulting from various nuclear processes and events contain a wide range of isotopes for analysis spanning almost the entire periodic table. This work describes the production of a complex synthetic sample containing fission products, activation products, and irradiated soil, and determines the percent chemical recovery of select isotopes through the integrated chemical separation scheme. Based on the results of this experiment, a complex synthetic sample can be prepared with low atom/fission ratios and isotopes of interest accurately and precisely measured following an integrated chemical separation method.

Design and Testing of a Boron Carbide Capsule for Spectral Tailoring in Mixed-Spectrum Reactors

A boron carbide capsule has been designed and used for spectral-tailoring experiments at the TRIGA reactor at Washington State University. Irradiations were conducted in pulsed mode and in continuous operation for up to 4 h. A cadmium cover was used to reduce thermal heating. The neutron spectrum calculated with the Monte Carlo N-particle transport code was found to be in good agreement with reactor dosimetry measurements using the STAY’SL computer code. The neutron spectrum resembles that of a fast reactor. The design of a capsule using boron carbide fully enriched in 10B shows that it is possible to produce a neutron spectrum similar to that of 235U fission.

Methods to Collect, Compile, and Analyze Observed Short-lived Fission Product Gamma Data

A unique set of fission product gamma spectra was collected at short times (4 minutes to 1 week) on various fissionable materials. Gamma spectra were collected from the neutron-induced fission of uranium, neptunium, and plutonium isotopes at thermal, epithermal, fission spectrum, and 14-MeV neutron energies. This report describes the experimental methods used to produce and collect the gamma data, defines the experimental parameters for each method, and demonstrates the consistency of the measurements.

Project 8 Phase III Design Concept

We present a working concept for Phase III of the Project 8 experiment, aiming to achieve a neutrino mass sensitivity of

Results from the Project 8 phase-1 cyclotron radiation emission spectroscopy detector

2~\mathrm{eV}

Activation product analysis in a mixed sample containing both fission and neutron activation products

(

Fission product analysis of HEU irradiated within a boron carbide capsule: comparison of detection methodology at PNNL and AWE

90~\%

Separation and quantification of chemically diverse analytes in neutron irradiated fissile materials

C.L.) using a large volume of molecular tritium and a phased antenna array. The detection system is discussed in detail.