The Monte Carlo code MAR was developed to calculate the peak efficiency of of Ge detectors to voluminal sources of Marinelli-type shapes. Results evaluated with the present method are compared with experimental data. The applicability of the MAR code was demonstrated in a survey which included quantitative isotopic analysis of trace radioactivity in many water and mud samples.

Energy and angular distributions of neutrons were measured in coincidence with the projectile-like fragments in deep inelastic collisions of28Si on64Ni at 170 MeV. Our data are consistent with the assumption of isotropic emission of neutrons in the rest frame of the fully accelerated fragments. Neutron multiplicities suggest that thermal equilibrium is not reached at least for energy losses of the system around 50 MeV.

Energy and angular distributions of neutrons were measured in coincidence with the projectile-like fragments in deep inelastic collisions of28Si on64Ni at 170 MeV. Our data are consistent with the assumption of isotropic emission of neutrons in the rest frame of the fully accelerated fragments. Neutron multiplicities suggest that thermal equilibrium is not reached at least for energy losses of the system around 50 MeV.

The dissipative reactions of 32S on 24Mg at incident energies of 140 and 152 MeV have been studied by measuring inclusive fragment distributions and fragment-fragment coincidences. The experiment employed two multiparameter ion chambers. Fragment-fragment coincidences have been used to determine the production of fragments of different charge and mass, and related Q-value distributions.

A position-determining device has been developed for studying neutron emission in fission processes. The detector essentially consists of two photomultipliers at the ends of a cylinder of NE213 liquid scintillator (about 82 cm in length and 3 cm in diameter), yielding a position resolution of 8 cm and a time resolution of 1.2 ns for 3 MeV neutrons. The quality of the performance is illustrated by measuring the velocity and angular distributions of neutrons associated with the fission fragments from spontaneous fission of 252Cf. The experimental setup, adaptable for use with other neutron emitting fragments (e.g. heavy-ion reaction products), consisted of the position-sensitive n-detector, a thin scintillator film, and a solid-state detector.

Luminescence and timing properties of ultra-thin film detectors, with thicknesses ranging from 20 to 200 μg/cm 2 , are compared. The light collection system, coupled to two selected and matched phototubes, provides an effective method for testing and comparing the properties of different detectors. Typical responses to 252 Cf spontaneous fission fragments are presented in two-dimensional contour plots, relating to (i) residual energy of the fragments vs time-of-flight, (ii) light output vs time-of-flight, and (iii) light output vs residual energy.

The doop inelastic reactions of28Si at28Si at incident energies of 125 and 138 MeV, and28Si on27Al at 130 MeV, have been studied by measuring inclusive fragment distributions, and fragmentfragment coincidences. The experiment employed a coincidence spectrometer consisting of two multiparameter ion chambers. Inclusive measurements exhibit behaviour characteristic of strongly damped processes. Two-fragment exclusive measurements in the28Si-28Si reaction show interesting selective phenomena in both mass and charge spectra of the emitted fragments.

Deep inelastic reactions induced by32S bombardment on27Al were studied at 130 MeV incident energy. The experiment employed a coincidence spectrometer consisting of two ion chambers which measured the energy, position and nuclear charge of the heavy reaction products. Inclusive fragment measurements and fragment-fragment coincidences have been used to determine the production of fragments of differentZ, and relatedQ-value distributions.

A heavy-ion detector system is described for investigations on the nuclear fission process. It consists of two gridded, split anode ionization chambers for simultaneous, correlated measurements of various parameters of complementary fragments such as energy and angular distribution. Energy loss signals are used to discriminate the fission fragments from light elements. Timing adequate for fast coincidence (resolution ≤500 ps) is achieved by utilizing the chamber gas as a scintillation gas.

Described herein is an apparatus designed merely for the purpose of extending previous measurements of the differential cross section and polarization of fast neutrons to scattering angles lower than 1°. The principles and properties of the device are developed and dicussed in detail. The quality of the performance is illustrated by measuring absolute cross sections of 2.50 MeV neutrons scattered by Bi.

Differential cross sections and asymmetries of 2.50 MeV polarized neutrons elastically scattered by In, Ho, Hg, Bi and U have been determined for scattering angles from 2.1° to 9.1°. The measurements were carried out by the use of a neutron positional spectrometer. The results, when compared with the predictions of the electromagnetic interaction, indicate some deviation of 〈σ(θ)P(θ)〉 from the expected values. The observed cross sections are systematically greater than those evaluated within the framework of the optical model.

The sc~,ttering of neutrons by nuclei is inf luenced by the long-range e lec t romagnet ic in te rac t ion between a neu t ron and a ta rge t nucleus (~). The e lec t romagnet ic interact ion is of the spin-orbi t form and can give rise to large polar izat ion effects as well as large sca t ter ing cross-sectons at small scat ter ing angles. In the Born approx imat ion , the ampl i tude for the scat ter ing of 't neutron at an angh, 0 is ] ( 0 ) g,(O) di hn h~(O)a.n ,

A position-determining device has been developed for studying small-angle scattering of fast neutrons. The detector essentially consists of two photomultiplier tubes looking at a liquid scintillator: the time diference between both signals of the phototubes is used to determine the position of the light-producing region. The quality of the performance is illustrated by measuring absolute cross section and polarization of 2.5 MeV neutrons scattered by Bi. A critical examination is made of the properties of the device.

Accurate polarization data for energies of 3.4 and 7.8 MeV at a center- of-mass angle are given including the aysmmetries.

The polarization of the elastically scattered neutrons from 12C in the energy range E = 1.9–5.2 MeV has been measured at laboratory angles from 25° to 155°. Differential cross sections were also obtained for 4.7 and 5.2 MeV neutron energies. The data have been corrected for multiple scattering and finite geometry. A phase-shift analysis of polarization and cross-section data has been performed at 1.9, 4.7 and 5.2 MeV.

Energy dependent attenuation parameters for several important shielding materials have been measured by means of a Van de Graaff accelerator. These parameters serve for the determination of energy-dependent removal cross-sections which are to be fed into the removal diffusion codes.