A 3He beam stop for minimizing gamma-ray and fast-neutron background

Journal of Radioanalytical and Nuclear Chemistry - Prompt gamma-ray activation analysis facilities with high neutron currents (≥109 s−1) generate triton-induced fast neutrons from...     

The determination of acetaminophen using a carbon nanotube:graphite-based electrode

The oxidation of acetaminophen was studied at a glassy carbon electrode modified with multi-walled carbon nanotubes and a graphite paste. Cyclic voltammety, differential pulse voltammetry and square wave voltammetry at various pH values, scan rates, and the effect of the ratio of nanotubes to graphite were investigated in order to optimize the parameters for the determination of acetaminophen. Square wave voltammetry is the most appropriate technique in giving a characteristic peak at 0.52 V at pH 5. The porous nanostructure of the electrode improves the surface area which results in an increase in the peak current. The voltammetric response is linear in the range between 75 and 2000 ng.mL^?1, with standard deviations between 0.25 and 7.8%, and a limit of detection of 25 ng.mL^?1. The method has been successfully applied to the analysis of acetaminophen in tablets and biological fluids.     

Optical detection system for laser cooling and precision laser spectroscopy of relativistic highly charged ions at the CSRe

Laser cooling and precision laser spectroscopy experiments of relativistic highly charged ions are being prepared at the heavy-ion experimental cooler storage ring (CSRe). Optical detection of fluorescence photons, emitted from the laser-excited ions, is extremely important for both powerful methods. In this paper, we briefly report on the current status of the existing optical detectors and also on their performance during laser cooling of relativistic Li-like ¹⁶O⁵⁺ ion beams at the CSRe. In addition, we introduce the designs for our new optical detection systems, which have much higher photon detection efficiencies and can cover a much broader wavelength range. These detector systems will be used for the upcoming laser spectroscopy experiment of Li-like ¹⁶O⁵⁺ ions, as well as for future laser spectroscopy experiments with other highly charged ions.     

Characterization of a new external neutron beam facility at the Ohio State University

A thermal neutron beam facility has been designed and implemented at the Ohio State University Research Reactor. A project is underway to construct a large vacuum chamber such that the facility could have neutron depth profiling and neutron radiography capabilities as intended. The neutron beam is extracted from the reactor through a neutron collimator emplaced in Beam Port #2. The neutron spectrum entering the neutron collimator was unfolded from foil activation analysis results and also simulated with a full reactor core model in the MCNP Monte Carlo code. The neutron collimator uses polycrystalline bismuth as a gamma ray filter and single-crystal sapphire as a fast neutron filter. The beam is defined by multiple 3.0 cm diameter apertures made of borated aluminum. Characterization of the beam was performed using foil activation to find the flux and a low-budget neutron imaging apparatus to see the beam profile. The modulation transfer function was calculated to offer insight into the resolution of the imaging system and the collimation of the beam. The neutron collimator delivers the filtered thermal neutron beam with a ~4 cm diameter and a thermal equivalent flux of (1.27 ± 0.03) × 10⁷ n/(cm²s) at 450 kW power at the end of the collimator.