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An investigation of high-energy fission models for use in the HETC code has been made. The validation work has been directed checking the accuracy of the high-energy radiation transport computer code HETC to investigate the appropriate model for routine calculations, particularly for spallation neutron source applications. Model calculations are given in terms of neutron production, fission fragment energy release, and residual nuclei production for high-energy protons incident on thin uranium targets. The effect of the fission models on neutron production from thick uranium targets is also shown.

Depth profiles for the production of stable and radioactive nuclides have been measured for a large variety of target elements in three thick spherical stony targets with radii of 5, 15 and 25 cm isotropically irradiated with 600 MeV protons at the CERN synchrocyclotron. These irradiation experiments (CERN SC96) were intended to simulate the irradiation of meteoroids by galactic cosmic ray protons. In order to combine this experimental approach with a theoretical one the intra-and internuclear cascades were calculated using Monte Carlo techniques via the high energy transport code HET/KFA 1. Together with transport calculations for low energy neutrons by the MORSE-CG code the depth dependent spectra of primary and secondary protons and of secondary neutrons were derived. On the basis of these spectra and a set of evaluated experimental excitation functions for p-induced reactions and of theoretical ones for n-induced reactions, calculated by the code ALICE LIVERMORE 82, theoretical depth profiles for the production of stable and radioactive nuclides in the three thick targets were calculated. This report is a comprehensive survey on all those target/ product combinations for which both experimental and theoretical data are available. It provides the basis for a detailed discussion of the various production modes of residual nuclides and on the depth and size dependence of their production rates in thick stony targets, serving as a simulation of the galactic cosmic ray irradiation of meteoroids in space. On the other hand the comparison of the experimental and theoretical depth profiles validates the high energy transport calculations, making them a promissing tool for further model calulations of the interactions of cosmic rays with matter.

HERMES ($\underline{H}$igh $\underline{E}$nergy $\underline{R}$adiation $\underline{M}$onte Carlo $\underline{E}$laborate $\underline{S}$ystem) is a system of Monte-Carlo computer codes that are necessary to treat the different physics to be considered in computer simulation of radiation Iransport and interaction problems. In addition HERMES offers powerful capabilities of Monte-Carlo analysis and of verging the outcomes of partial programs into final results. An interfacing system - the "HERMES submission file" - provides easy interchange of input/output data between programs by standardized date structures and aliows unproblematicextension of the HERMES System by introducing new programs. The HERMES collection of physics programs permits the simulation of secondary particle histories induced by primary particles of any energy up to the regime of high-energy physics and down to thermal energies, e. g. for neutrons. The particles, that are considered by the programs of the HERMES system are p, n, $\pi^{+}$, $\pi^{-}$, $\pi^{O}$, $\pi^{\pm}$, e$^{+}$, e$^{-}$, $\gamma$, and light ions to A=10. The development of particle cascades can be simulated within very complex geometries and material configurations wich only minor restrictions. The geometry description is identical for all Monte-Carlo programs incorporated in HERMES and made in input terms of the approved "Combinatorial Geometry (CG)" in a KFA extended version. The well established programs of the HERMES System in general have been taken as original Codes as far as possible. However, to satisfy the needs of some applications, e. g., the high energy calorimeter simulation, some extensions and changes became necessary. Also the interfacing technique by HERMES submission fites needs some additional programming. Therefore, the name of the original codes were extended by a KFA suffix. All changes made to the original codes are docuvented within this report. For simplicity reasons, however, we refer to the original names throughout this document, e. g. HETC rather than HETC-KFA 2. Several of the system codes, especially for analysis purposes, are provided by the authors. To achieve portability of the HERMES system, the original coding of the programs was converted to the FORTRAN77 standard. This, however, was verified only an two computer systems, the IBM 3081 and the CRAY-KMP22.

Utilization of parallel processing computers to perform radiation transport calculations means to perform parallel computing on problems that are of merely consecutive nature, namely the histories of single particles interacting with matter. Parallelism can be achieved with some success orily by considering a certain number of particle histories simultaneously, i. e. one must try, to do what nature does, when particles interact independently with matter at the same time. We must find an algorithmthat can treat an ensemble of particles in a similar way. We must, however, be aware of the fact that the today available supercomputers are SIMD machines, i.e. they can only perform the same action on all elements of a vector (Single Instruction - Multiple Data). This makes a big difference compared to nature, and most of the difficulties in vectorization of Monte Carlo programs arise from this fact.

The intranuclear-cascade evaporation model (INCE) as implemented in the high energy radiation transport code HETC, subsystem of HERMES (1) is used in the calculation of double differential cross sectionsl of proton induced neutron production. The investigations were done on target elements C, Al, Ta, Ni, W, Pb, and U at 318 MeV incident proton energy and on C, Al, Pb, and U at 800 MeV, respectively. The predictions of the INCE model were compared with experimental data for double differential cross sections taken at 7.5 and 30 degrees scattering angles at the Los Aamos WNR facility utilizing the Time of Flight (ToF) technique at LANL. The calculations performed here are part of a experimental-theoretical program within the LANL-KFA collaboration concernign medium energy cross section measurements mainly neutrons and state of the art computer code validations of these measurements. In general, the model predictions reproduce the correct neutron production for evaporation neutrons and are also in good agreement with the experimental data at high neutron energies. In the energy range dominated by preequilibrion processes an underestimation of experimental yields has to be remarked.

A deep penetration experiment conducted at the Los Alamos WNR facility's Spallation Neutron Target is compared with calculations using intra-nuclear-cascade and S$_{N}$-transport codes installed at KFA-IRE. In the experiment medium energy reactions induced by neutrons between 15 MeV and about 150 MeV inside a quasi infinite slab of iron have been measured using copper foil monitors. Details of the experimental prodedure and the theoretical methods are described. A comparison of absolute reaction rates for both experimentally and theoretically derived reactions is given. The present knowledge of the corresponding monitor reaction cross sections is discussed.

Die in dieser Arbeit durchgeführten Messungen zeigen die Brauchbarkeit des He$^{3}$-Halbleiterspektrometers mit Sandwich-Detektor zur Spektrometrie schneller Neutronen. Das Spektrum einer Am-Be-Quelle konnte gemessen werden, auch über die Energie von 5-6 MeV hinaus, die bisher als obere Grenze des Einsatzbereiches des He$^{3}$-Halbleiterspektrometers angesehen wurde. Bis zum Ende des Spektrums bei 11 MeV wurde mit gutem Auflösungsvermögen gemessen. Die Messung beweist auch, daß das Problem der Kernreaktionen der schnellen Neutronen mit dem Halbleitermaterial beim He$^{3}$-Spektrometer lösbar ist im Gegensatz zum Li$^{6}$-Halbleiterspektrometer, bei dem diese störende Erscheinung nach unserer Erfahrung nicht befriedigend bewältigt werden kann. Es zeigte sich, daß Spektrumsmessungen mit dem He$^{3}$-Halbleiterspektrometer an Neutronen, die unter den Schwellenenergien der oben erwähnten Silizium-Störreaktionen liegen, zu ausgezeichneten Ergebnissen führen, bei denen sich so gut wie keine Schwierigkeiten ergeben; als Beispiel dafür mögen die Messungen des Spektrums der DD-Neutronen dienen, die außerdem das gute Energieauflösungsvermögen des He$^{3}$-Spektrometers erkennen lassen. Schwierigkeiten ergaben sich jedoch bei hohen $\gamma$-Flüssen, die eine Spektrometrie in den unteren Bereichen nicht zulassen. So konnte etwa das Spektrum der Am-Be-Quelle nur ab 2,5 MeV gemessen werden, das Spektrum der $Cf^{252}$-Spaltneutronen ab 2 MeV. Zur Theorie der verwendeten Sandwich-Detektoren konnten einige Beiträge geleistet werden, die alle auf die genaue Bestimmung des Ansprechvermögens in Abhängigkeit von der Neutronenenergie abzielten. Betrachtet wurde der Einfluß von Energieschwellen sowie das sogenannte geometrische Ansprechvermögen nach einfachen Modellen.