Pierre Macq

Fast neutron yields and spectra from targets of varying atomic number bombarded with deuterons from 16 to 50 MeV [for radiobiology and radiotherapy]

Neutron production from targets of Be, C, Mo, Cu, Ta and Au bombarded with deuterons of 16, 33 and 50 MeV has been studied at the isochronous cyclotron at Louvain-la-Neuve. Neutron spectra were measured by the time of flight method. The yields of neutrons and gamma rays were also measured, and the greatest ratio of neutrons to gamma rays in the forward direction was found to occur with 50 MeV deuterons on a Be target. The angular distribution of neutrons from Be was measured at 16, 33 and 50 MeV, and neutron spectra were measured as function of angle with 50 MeV deuterons on Be.

An experimental test of the analogy between muon and radiative pion capture

Abstract Rate-measurements are reported on muon capture and radiative pion capture reactions in 6 Li yielding the ground state of 6 He.

A Novel Design for a Fast Intense Neutron Beam

Abstract A novel design for the production of fast (40−75 MeV) and intense monokinetic neutron beam from the Li(p,n) reaction is described. The primary charged beam is dumped in a Faraday cup immediately behind the Li target. Both the production target and Faraday cup are enclosed inside a compact shielding. With respect to the conventional method where the primary beam is deflected, the advantage of this design is twofold: the neutron beam intensity is enhanced and the background is decreased. The properties of this neutron beam, i.e. its intesity, time width and spatial profile are reported.

Hyperfine effect in the MU - mesonic 11B atom and information on 11Be from muon capture measurements

Abstract The partial rates in the capture of muons by 11B were measured for the ground state and first excited level of 11Be. The transition between the hyperfine states of the μ-+11B mesonic atom was observed indirectly. The 320 keV γ-ray in 11Be, which follws the capture of the muon in 11B, was found to be broadened. Nuclear structure informations were obtained on the ground state and first excited state of 11Be.

A method to measure neutrino-gamma angular correlation in muon-capture

Abstract We consider the Doppler-broadening of the gamma-ray emitted by a bound-state excited in muon-capture in complex nuclei. This Doppler-broadened gamma spectrum is illustrated for special cases assuming realistic neutrino-gamma directional correlations and taking into account the finite energy-resolution of the Ge(Li) detector. It appears that the observation of the Doppler-broadened deexcitation gamma-ray spectrum offers a practical method to measure the neutrino-gamma directional correlation in muon-capture reactions.

Study of the Reaction C-12(n,3-alpha)n From Threshold To en = 35 Mev

Kinematically complete measurement of the reaction 12C(n,3 α)n has been performed using nuclear emulsions exposed to neutrons of continuous energy. Alpha particle energy spectra and cross sections for the reaction (n,3 α) as well as for specific channels 12C(n, 8Begs)nα. and 12C(n,12C9.63)n have been measured up to 35 MeV incident energy with an accuracy of about 20%.

Measurement of the total cross section for the /sup 1/H(n, gamma )/sup 2/H reaction between 37 and 72 MeV

The total cross section for radiative neutron-proton capture has been measured at 37, 42, 47, 52, 63 and 73 MeV. The inverse process, the photodisintegration of the deuteron, was measured in the same energy range by different authors with contradictory results, some of them in large disagreement with all theoretical predictions of the cross section. The submitted data are in agreement with theory and the results of a recent total absorption experiment.

Total cross section for the H(n, d)γ reaction between 45 and 70 MeV

Abstract The total cross section for neutron-proton capture was measured between 45 and 70 MeV neutron energy. The results, which were normalized to the neutron-proton differential cross section at 90† center-of-mass, were found to be in agreement with a global fit of the photodisintegration data, but in slight disagreement with potential model calculations.

Measurement of muon partial capture rates in 16O and the induced pseudoscalar coupling constant in muon capture

The partial rates in the capture of muons by 16O were measured for the Jπ = 0− and 1− excited bound states of 16N. The energy spectrum and the time dependence of the γ-rays emitted by the target were observed using a Ge(Li) detector. On the basis of the Rho-Migdal theory [5], the observed λ0−λ1−ratio led for the induced pseudoscalar coupling to a value of Cp = 10.6 ± 1.0.

Study of a collimated fast neutron beam

Abstract Neutrons obtained through the Li(p, n)Be reaction were collimated to produce a clean, small aperture beam. The collimator geometry is adapted to the incoming proton beam spot and sized to maximize the central direct beam with respect to the parasitic transmitted beam (penumbra and halo region). Calculations of the neutron spatial distributions are in agreement with measurements.