STATUS OF THE SIAM PHOTON LABORATORY

Abstract The Present status of the Siam Photon Laboratory is reported. The assembly of the accelerator complex with a 1 GeV storage ring has been completed. The commissioning of the accelerator complex has just started. However, there remain some problems to be solved. The work of conceptual design and the determination of the specifications of the undulator to be installed in the storage ring have been completed. The installation of the first two beam lines has started already. Other items such as the infrastructure reformation, the organization development, and the human resources development are also described

STATUS OF THE SIAM PHOTON LABORATORY

Abstract The Present status of the Siam Photon Laboratory is reported. The assembly of the accelerator complex with a 1 GeV storage ring has been completed. The commissioning of the accelerator complex has just started. However, there remain some problems to be solved. The work of conceptual design and the determination of the specifications of the undulator to be installed in the storage ring have been completed. The installation of the first two beam lines has started already. Other items such as the infrastructure reformation, the organization development, and the human resources development are also described

Selectivity of the Nucleon Induced Deuteron Breakup and Relativistic Effects

Theoretical predictions for the nucleon induced deuteron breakup process based on solutions of the three-nucleon Faddeev equation including such relativistic features as the relativistic kinematics and boost effects are presented. Large changes of the breakup cross section in some complete configurations are found at higher energies. The predicted relativistic effects, which are mostly of dynamical origin, seem to be supported by existing data.Comment: 4 pages, 4 figure

Inclusive neutron cross-sections at forward angles from Nb Nb and Au Au collisions at 800-MeV/nucleon

Inclusive neutron spectra were measured at 0°, 4°, 8°, 15°, 30°, and 42° from Nb-Nb and Au-Au collisions at 800 MeV/nucleon. A peak that originates from neutron evaporation from the projectile appears in the spectra at angles out to 8°. The shapes and magnitudes of the spectra are compared with those calculated from models of nucleus-nucleus collisions. The differential cross sections for Au-Au collisions are about four times those for Nb-Nb collisions. The predictions of the Vlasov-Uehling-Uhlenbeck (VUU) and QMD theories agree with the angular distributions of the differential cross sections except at small angles; the VUU prediction overestimates the angular distributions from a few degrees to about 20°, whereas the QMD prediction underestimates the angular distributions below 8°. The Firestreak model overestimates the angular distribution for Nb-Nb collisions and underestimates it for Au-Au collisions. Also, the VUU and QMD models agree with the measured double-differential cross sections in more angular and energy regions than the Firestreak and intranuclear cascade models; however, none of the models can account for the peaks at small angles (θ≤15°)

Relativistic effects in exclusive neutron-deuteron breakup

We extended the study of relativistic effects in neutron-deuteron scattering to the exclusive breakup. To this aim we solved the three-nucleon Faddeev equation including such relativistic features as relativistic kinematics and boost effects at incoming neutron lab. energies E_n^{lab}=65 MeV, 156 MeV and 200 MeV. As dynamical input a relativistic nucleon-nucleon interaction exactly on-shell equivalent to the CD Bonn potential has been used. We found that the magnitude of relativistic effects increases with the incoming neutron energy and, depending on the phase-space region, relativity can increase as well as decrease the nonrelativistic breakup cross section. In some regions of the breakup phase-space dynamical boost effects are important. For a number of measured exclusive cross sections relativity seems to improve the description of data.Comment: 27 pages, 4 png figures and 7 ps figure

(d,n) Reaction Studies at 80 MeV

This research was sponsored by the National Science Foundation Grant NSF PHy 87-1440

Three-Nucleon Force Effects in Nucleon Induced Deuteron Breakup: Comparison to Data (II)

Selected Nd breakup data over a wide energy range are compared to solutions of Faddeev equations based on modern high precision NN interactions alone and adding current three-nucleon force models. Unfortunately currently available data probe phase space regions for the final three nucleon momenta which are rather insensitive to 3NF effects as predicted by current models. Overall there is good to fair agreement between present day theory and experiment but also some cases exist with striking discrepancies. Regions in the phase space are suggested where large 3NF effects can be expected.Comment: 33 pages, 24 ps figures, 9 gif figure

The roles of science and technology park in the entrepreneurial ecosystem: A case study of the Northern Science Park, Thailand

The purpose of this project is to study the roles and impact of science and technology parks in the entrepreneurial ecosystem. The project consists of three research papers including one conceptual paper and two empirical studies. The empirical studies are based on 31 semi- structured interviews with a wide range of entrepreneurial ecosystem actors and institutions. Each interview lasted between 58 and 173 minutes, for a total of 3,264 minutes, or an average of 105 minutes per session.The first paper addresses the gap in the entrepreneurial ecosystem literature that commonly overlooks the science and technology parks. Both entrepreneurial ecosystem and science and technology park literature were explored. This study highlights the conceptual roles of science and technology parks in the entrepreneurial ecosystem. The first study also provided the theoretical foundation for the later studies in this project.The second paper investigates a case study of Northern Science Park and the entrepreneurial ecosystem in Chiang Mai, Thailand. This case study provides not only the interrelationship between the two but also insights into the context of developing entrepreneurial ecosystems which is another gap in the literature. This study demonstrates the case that the science and technology park can play a leadership role in the ecosystem and has a significant influence on the evolution of a developing entrepreneurial ecosystem. The findings also reveal the importance of the entrepreneurial culture in the entrepreneurial ecosystem evolution.The third paper re-examines the dataset used in the second paper and focuses on how the science and technology park influences the entrepreneurial culture in the ecosystem. We revisit the entrepreneurial ecosystem literature to unpack the dimensions of entrepreneurial culture. Based on the previous work, support mechanisms of science and technology parks are identified. As a result, the model of entrepreneurial culture development is constructed.Overall, this research brings attention to the importance of the science and technology park, as a leader, in a developing entrepreneurial ecosystem. Moreover, this research highlights the importance of entrepreneurial culture in the entrepreneurial ecosystem evolution. This research provides policy implications by offering a theoretical framework to develop entrepreneurial ecosystem elements, particularly entrepreneurial culture

Performance of Large-Volume Mean-Timed Neutron Detectors

This work was supported by the National Science Foundation Grant NSF PHY 81-14339 and by Indiana Universit