Impact of GEM foil hole geometry on GEM detector gain
Detailed 3D imaging of Gas Electron Multiplier (GEM) foil hole geometry was realized. Scanning White Light Interferometry was used to examine six topological parameters of GEM foil holes from both sides of the foil. To study the effect of the hole geometry on detector gain, the ANSYS and Garfield ++ software were employed to simulate the GEM detector gain on the basis of SWLI data. In particular, the effective gain in a GEM foil with equally shaped holes was studied. The real GEM foil holes exhibited a 4% lower effective gain and 6% more electrons produced near the exit electrode of the GEM foil than the design anticipated. Our results indicate that the GEM foil hole geometry affects the gain performance of GEM detectors.
Study of the optimal configuration for a Gas Electron Multiplier aimed at plasma impurity radiation monitoring
Abstract For the purpose of monitoring the level of plasma impurity (especially tungsten) and its distribution reconstruction at tokamaks (ITER in particular), a Soft X-Ray (SXR) tomographic diagnostics based on Gas Electron Multiplier (GEM) detectors with energy discrimination has been extensively considered for a while. Coupled with advanced electronics, GEM detectors offer excellent time and space resolution, as well as a charge spectrum from which the SXR photon spectrum can be deconvolved. In addition, they are less subjected to a neutron damage as compared to standard semiconductor diodes. This contribution highlights the latest studies supporting the development of such diagnostics focusing on laboratory tests to examine: (a) the impact of GEM holes geometry on the properties and distribution of the electron avalanche; (b) the effect of the high rate photon flux on GEM foil performance; and (c) the optimal electric field distribution.
Comparative Industrial Sociology and the Convergence Hypothesis
Industrial sociology grew spectacularly after World War II, concentrating on three areas: workers' relations with each other, their managers, and their unions; the social organization of the factory; and the impact of technology on social systems extending from the factory to the society. Unable to sus­ tain leadership in all of these areas, industrial sociology shrivelled as other fields invaded its domains. Human relations became the ideological property of the business schools; labor economics maintained its grip on industrial relations; industry-community relations waned as interest in community power soared; industrial organizations were absorbed into the study of com­ plex organizations; occupational sociology maintained research impetus in labor force analysis; and the sociology of the economy dominated the study of industry's institutional relationships. Industrial sociology survived on remnants: worker-machine relationships (job satisfaction, alienation, un­ employment), organizational responses to technological changes. and a bit of working-class ethnology. Enduring interest in technology, however, en­ abled industrial sociology to take part in sociology's expanding interest in comparative studies.