The Total Neutron Cross Section of Ni-61

The total neutron cross section of 61Ni was measured between 40 eV and 300 keV at GELINA, the neutron time-of-flight facility at IRMM. The derived cross section data were analyzed using the R-matrix code REFIT. The obtained set of resonance parameters is given together with the values for the s-wave mean neutron strength S0 and level spacing D0. Furthermore the obtained parameters are used to look for non-statistical effects in the neutron capture process.JRC.D.5-Neutron physic

Thin Liquid Sample Fabrication for Neutron Resonance Spectroscopy

In neutron resonance spectroscopy, preparation of thin cylindrical samples of large diameter containing 10_4210_5 atoms per barn of raw materials in powder form make pressing a uniform thickness sample difficult. The use of liquid samples is a suitable alternative to overcome the technical limits inherent to the fabrication of pressed solid samples by compaction methods. This paper presents the fabrication of a 2mm thick cylindrical sample, with a inner diameter of 65 mm, filled with an aqueous solution of lithium iodide. The sample was designed to measure the low neutron energy range of the 127I total cross-section by means of the neutron resonance transmission technique. The resonance shape analysis provided results consistent with those obtained by measuring a 17.5mm thick lead iodine sample under the same experimental conditions as for LiI sample. Such liquid sample could be used to repeat similar measurements on a large variety of stable isotopes and low radioactive materials.JRC.D.5-Neutron physic

Neutron Resonance Spectrometry of 99-Tc from 3 eV to 150 keV.

Abstract not availableJRC.D-Institute for Reference Materials and Measurements (Geel

Reinvestigation of 85-Kr Branching in the Light of New 82,84,86-Kr Neutron Cross Section Measurements.

Abstract not availableJRC.D-Institute for Reference Materials and Measurements (Geel

Neutron Capture and Transmission Measurements on 103Rh down to Thermal Energies

The neutron total and capture cross sections of 103Rh have been measured in the energy region from 0.01 eV to 1 keV at the Time-of-Flight facility GELINA of the Institute for Reference Materials and Measurements in Geel (B). The transmission measurements on two samples of rhodium were carried out at a 50-m flight path using a Li-glass scintillator. The capture-detection system, which is installed at a 14.5-m flight path, is based on the total-energy detection principle. The system consists of two C6D6 detectors and a 10B ionisation chamber that determines the shape of the neutron flux. A pulse-height weighting function was used to ensure that the efficiency for a neutron-capture event was independent from the gamma cascade. The data have been normalized to the well-isolated and saturated 103Rh resonance at 1.26 eV. The resonance parameters for 103Rh were obtained from a simultaneous shape analysis of the capture and transmission data using the REFIT code.JRC.D.5-Neutron physic

Determination of the 232Th(n,gamma) Cross Section from 4 to 140 keV at GELINA

The neutron capture cross section of thorium has been masured in the energy region between 4 and 140 keV at the GELINA time-of-flight facility of the Institute for Reference Materials and Measurements in Geel, Belgium. The gamma-rays from capture events were detected by two C6D6 liquid scintillators, placed 14.37 m from the neutron source. The shape of the neutron flux was measured with a 10B-loaded ionization chamber. To obtain a detection efficienct independent of the gamma cascade and proportional to the total excitation energy, the pulsheight weighting technique was applied. The data have been normalized to the well-isolated and almost saturated 232Th resonance at 23.5 eV. The systematic uncertainties related to the normalization and weighting function, using an internal saturated resonance, are +- 1.5%. An additional systematic uncertainty of 0.5% results from the self-shielding and multiple scattering corrections. Between 4 and 140 keV, our date are +- 9 and 6.5% higher than the data of Kabayashi et al. and Macklin et al. respectively, and in good agreement with the data of Poenitz and Smith. below 15 keV our data deviate by up to 30% from the data reported by Wisshiak et al. Our dat have been analyzed in terms of average level parameters. The resulting parameters are consistent with the resolved resonance parameters deduced from the transmission measurements of Olsen et al.JRC.D.5-Neutron physic

Determination of the 232Th(n,gamma) Cross Section from 4 to 140 keV at GELINA.

Abstract not availableJRC.D-Institute for Reference Materials and Measurements (Geel