A First Mass Production of Gas Electron Multipliers

We report on the manufacture of a first batch of approximately 2,000 Gas Electron Multipliers (GEMs) using 3M's fully automated roll to roll flexible circuit production line. This process allows low-cost, reproducible fabrication of a high volume of GEMs of dimensions up to 30$\times$30 cm$^{2}$. First tests indicate that the resulting GEMs have optimal properties as radiation detectors. Production techniques and preliminary measurements of GEM performance are described. This now demonstrated industrial capability should help further establish the prominence of micropattern gas detectors in accelerator based and non-accelerator particle physics, imaging and photodetection.Comment: 11 pages, 10 figures, to be submitted to Nucl. Instr. Meth.

Physics of multi-GEM structures

We show that physics of multi-GEM structures is rather complex, regarding the number of phenomena affecting detector performance. The high-pressure operation in noble gases and the ion feedback are considered in more detail. It is proposed that the dominant avalanche mechanism in He and Ne, at high pressures, is the associative ionization. Ion feedback effects related to the dependence on gas, pressure and gain and to possible avalanche extension outside the GEM holes are discussed.Comment: Presented at the 8th International Conference on Instrumentation for Colliding Beam Physics, Novosibirsk, Febuary 28 - March 6, 2002. To be published in Nucl. Instr. and Meth.

How Well Do Drivers Understand Their Own Headlights?

The current research represents an initial investigation of drivers’ understanding of high beam and low beam headlight patterns in a nighttime driving environment. Fifty-four university students used a highlighter to indicate on a paper diagram of a roadway scene the portion of the scene that they felt their headlights would illuminate. Although the headlight patterns produced by participants varied more than expected, several consistent patterns emerged. Classification and evaluation of these drivers’ responses revealed that many drivers misunderstand the area of the roadway that is illuminated by their headlights. These misunderstandings fall into fairly distinct patterns. The results indicate many drivers possess an incomplete understanding of the pattern of illumination provided by their headlights. These results are consistent with earlier evidence that many road users fail to appreciate the visibility challenges that exist at night