A partial-wave analysis of NN elastic scattering data has been completed. This analysis covers an expanded energy range, from threshold to a laboratory kinetic energy of 2.5 GeV, in order to include recent elastic pp scattering data produced by the EDDA collaboration at COSY. The results of both single-energy and energy-dependent analyses are described.

Nucleon-Nucleon Partial Wave Analysis to 2.5 GeV

For neutrons 25, 30 and 65 MeV, the response functions and detection efficiencies of an NE213 liquid scintillator were measured. Quasi-monoenergetic neutrons produced by the 7Li(p,N0.1) reaction were employed for the measurement and the absolute flux of incident neutrons was determined within 4% accuracy using a proton recoil telescope. Response functions and detection efficiencies calculated with the Monte Carlo codes, CECIL and SCINFUL, were compared with the measured data. It was found that response functions calculated with SCINFUL agreed better with experimental ones than those with CECIL, however, the deuteron light output used in SCINFUL was too low. The response functions calculated with a revised SCINFUL agreed with the experimental ones quite well even for the deuteron bump and peak due to the C(n,d0) reaction. It was confirmed that the detection efficiencies calculated with the original and the revised SCINFULs agreed with the experimental data within the experimental error, while those with CECIL were about 20% higher in the energy region above 30 MeV.

Measurements of the response function and the detection efficiency of an NE213 scintillator for neutrons between 20 and 65 MeV

The Monte Carlo code, designeted SCINFUL-QMD, has been developed to calculate neutron detection efficiency up to 3 GeV for liquid organic scintillators such as NE-213. The existing Monte Carlo code, SCINFUL, is known to reproduce a response function and detection efficiency at incident neutron energies below 80 MeV. We incorporate the quantum molecular dynamics plus statistical decay model (QMD+SDM) into SCINFUL to extend the upper limit of incident neutron energy to 3 GeV. The results by SCINFUL-QMD are compared with experimental data and those of CECIL. The SCINFUL-QMD exhibits an increase in detection efficiency above 300 MeV. This tendency agrees with one of the experimental data. The increase is achived by taking charged pion production into account.

Development of SCINFUL-QMD Code to Calculate the Neutron Detection Efficiencies for Liquid Organic Scintillator up to 3 GeV

Neutron-Proton Scattering at 91 Mev.

A telescope proton recoil spectrometer for fast neutron beam-lines C. Cazzaniga1,3,∗, M. Rebai2,3, M. Tardocchi3, G. Croci2,3, M. Nocente2,3, S. Ansell1, C. D. Frost1, and G. Gorini2,3 1ISIS Facility, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK 2Universita degli Studi di Milano-Bicocca, Dipartimento di Fisica, Piazza della Scienza 3, Milano, Italy 3Istituto di Fisica del Plasma “P. Caldirola”, Associazione EURATOM-ENEA/CNR, Via Cozzi 53, Milano, Italy ∗E-mail: carlo.cazzaniga@mib.infn.it

A telescope proton recoil spectrometer for fast neutron beam-lines

The neutron cross sections of hydrogen (1H) have been evaluated in the energy region from 20 MeV to 1 GeV. Evaluated quantities are the total, elastic and inelastic scattering and capture cross sections, covariance matrix of total cross section and photon production cross section associated with the capture process. The total cross section was evaluated by combining the results obtained from the generalized least-squares method and the phase-shift data. The phase-shift data have been also used to calculate the elastic and inelastic scattering cross sections and their angular distributions. The capture cross section was calculated from the deuteron photo-disintegration cross section in conjunction with the principle of detailed balance. The presently evaluated data give a good description of the available experimental data in general and are also in good accord with those values given in ENDF-B/VI that are available below 100 MeV.

https://www.tandfonline.com/doi/pdf/10.1080/18811248.1996.9731973

Sin-ichi Morioka

Papers

Evaluation of Neutron Cross Sections of Hydrogen from 20 MeV to 1 GeV