A lot of research work has been carried out in fine tuning model parameters to reproduce experimental data for neutron induced reactions. This however is not the case for proton induced reactions where large deviations still exist between model calculations and experiments for some cross sections. In this work, we present a method for searching both the model and model parameter space in order to identify the 'best' nuclear reaction models with their parameter sets that reproduces carefully selected experimental data. Three sets of experimental data from EXFOR are used in this work: (1) cross sections of the target nucleus (2) cross sections of the residual nuclei and (3) angular distributions. Selected models and their parameters were varied simultaneously to produce a large set of random nuclear data files. The goodness of fit between our adjustments and experimental data was achieved by computing a global reduced chi square which took into consideration the above listed experimental data. The method has been applied for the adjustment of proton induced reactions on Co-59 between 1 to 100 MeV. The adjusted files obtained are compared with available experimental data and evaluations from other nuclear data libraries.

The 6th SINQ Target Irradiation Program (STIP VI) was conducted in SINQ Target 9 during 2011 and 2012. A radiation damage assessment based on a simulation using the MCNPX code was performed to obtain the irradiation parameters of displacement damage, helium and hydrogen concentrations in each specimen rod placed in the target. The gamma mapping performed on the proton beam entrance window after irradiation provided the proton fluence distribution used for implementing the source definition in the simulation. The proton and neutron fluences along the target as well as the energy deposition were calculated. Corresponding to the average beam current of 1.42 mA, the maximum neutron flux obtained is 5.95 x 10(14) n/(cm(2). s) and the maximum energy deposition in the Zircaloy-2 cladding tubes is 568 W/cm(3). The irradiation parameters of selected materials in each specimen rod were calculated by multiplying the proton and neutron fluences with the corresponding cross section data. The maximum displacement damage was obtained for Zircaloy-2 in Row 2 with a value of 72.1 dpa (displacement per atom). The maximum helium concentration was obtained for tantalum in Row 1 with a value of 3630 appm and the maximum hydrogen concentration was obtained for tungsten in Row 1 with a value of 17590 appm. All these values are the highest for the corresponding materials ever reached in a spallation target irradiation environment. The helium concentrations are also the highest ever obtained in bulk specimens.

Changing the configuration of the cold neutron source during a planned extended shutdown of the Swiss Spallation Neutron Source (SINQ) is being considered for improving performance of instruments at SINQ that use cold neutrons. The cold neutron source consists of a 20 L volume of liquid D-2 at approximately 25 K. This study includes making the re-entrant hole external, redesigning the re-entrant hole geometry, adding a Pb-208 reflector, replacing the zirconium safety hulls, adding cryogenic beryllium reflector/filters, and incorporating an active ortho-D-2 conversion loop. The optimization methods and the effects of the best-case modifications at all six neutron guides are presented. The best case design is predicted to yield a maximum gain factor of 1.5 in cold neutron intensity.

Changing the configuration of the cold neutron source during an extended shutdown of the Swiss Spallation Neutron Source (SINQ) at the Paul Scherrer Institut is being considered for improving performance of the instruments that use the cold source. Proposed plans include making the REH external (ensuring that it is not filled with liquid D2) and using a REH that has been optimized to provide maximum gains between 3 and 6 Å. The optimization study was done using the MCNP Monte Carlo particle transport code, but was made tenable by developing a quick flux reconstruction technique that allows the neutron guide reflectivity to be approximated and accounted for in the optimization figure of merit. Ultimately, a wedgeshaped REH that penetrates the D2 volume to about 4 cm from its center was determined to be optimal, and should provide an average gain of 24% from 3 and 6 Å and a peak gain of 29% at 5.5.

High frequency (f > 1 MHz) electrostatic fluctuations have been observed in high-beta plasma created in the Levitated Dipole Experiment (LDX). We have previously identified these fluctuations as the Hot Electron Interchange (HEI) instability(1). New observations have been made in the presence of the magnetic levitation fields. We find the HEI mode is characterized by frequency sweeping at the drift-resonance of trapped energetic electrons. The fluctuations often appear with coherent structures that have been detected on fast high-impedance electrostatic probes and edge Mirnov sensors. We observe phase shifts using multiple probes that will enable us to determine the toroidal mode number (m) and a higher sampling rate reveals frequency sweeping as high as 40 MHz. Measurements that characterize these modes now incorporate fast magnetic measurements in an attempt to put together a coherent picture of plasma behavior during these modes, including the consequences of these instabilities on plasma formation and pressure limits. (1) E.Ortiz to appear in J. Fus. Energy (2006).