CMOS Charge amplifier for liquid argon Time Projection Chamber detectors

We developed an integrated circuit (IC) for the readout of LAr (Liquid Argon) TPC (Time Projection Chamber) neutrino detectors. Typical signals are around 3 fC per particle per wire but they can go up to 120fC. They necessitate low noise electronics for the readout. The goal is to achieve 1000e- ENC (Equivalent Noise Charge) with a detector capacitance of 250pF. In order to limit cable capacitances (and therefore the noise), we studied the possibility to install the frontend electronics into the Argon vapours, above the LAr filled volume. Argon is liquid between 83 K and 87 K. A typical temperature around 120K is reached in the Argon vapours. In order to optimize the cost per channel ratio we selected a standard 0.35μ CMOS technology: AMSC35B4

The ESO-Sculptor Faint Galaxy Redshift Survey: The Photometric Sample

We present the photometric sample of a faint galaxy survey carried out in the southern hemisphere, using CCDs on the 3.60m and NTT-3.5m telescopes at La Silla (ESO). The survey area is a continuous strip of 0.2 deg x 1.53 deg located at high galactic latitude (-83 deg) in the Sculptor constellation. The photometric survey provides total magnitudes in the bands B, V (Johnson) and R (Cousins) to limiting magnitudes of 24.5, 24.0, 23.5 respectively. To these limits, the catalog contains about 9500, 12150, 13000 galaxies in B, V, R bands respectively and is the first large digital multi-colour photometric catalog at this depth. This photometric survey also provides the entry catalog for a fully-sampled redshift survey of ~ 700 galaxies with R < 20.5 (Bellanger et al. 1995). In this paper, we describe the photometric observations and the steps used in the data reduction. The analysis of objects and the star-galaxy separation with a neural network are performed using SExtractor, a new photometric software developed by E. Bertin (1996). The photometric accuracy of the resulting catalog is ~ 0.05 mag for R < 22. The differential galaxy number counts in B, V, R are in good agreement with previously published CCD studies and confirm the evidence for significant evolution at faint magnitudes as compared to a standard non evolving model (by factors 3.6, 2.6, 2.1). The galaxy colour distributions B-R, B-V of our sample show a blueing trend of ~ 0.5 mag between 21 < R < 23.5 in contrast to the V-R colour distribution where no significant evolution is observed.Comment: LATEX, 18 Postscript figures, 20 pages. To appear July 1997. Modified version of article. Abstract corrected for missing lin

Influence of Carbon on the Electrical Properties of Crustal Rocks

The report summarizes work to determine the nature and distribution of carbon on microcracks in crystalline rocks by time-of-flight secondary ion mass spectroscopy. It also summarizes the results of a workshop devoted to investigating how carbon in rocks influences electrical conductivity and whether carbon on fracture surfaces can account for the electrical conductivity structure of the crust

Carbon Distribution in the Stiliwater Complex and Evolution of Vapor During Crystallization of Stillwater and Bushveld Magmas

The occurrence and distribution of carbon in the Stillwater Complex have been investigated. In mineralized troctolite and associated rocks of olivine-bearing zone I (OB I), carbon is present as graphitic material and calcite. The assemblage forsterite-antigorite-calcite-graphite and the petro graphic relations indicate equilibration of the carbon-rich phases during serpentinization. Typical OB I troctolite contains 500-1100 ppm wt. carbon, 40-70% of which is in calcite, whereas troctolite from higher stratigraphic positions generally contains 2 log units below that of the Ni-NiO oxygen buffer. Upon the appearance of graphite, the fluid evolved to a more hydrogen-rich composition by graphite precipitation and loss of oxygen to the surrounding silicate-oxide assemblage. Cooling of fluid to 25°C below the first appearance of graphite resulted in reduction in the fluid mass by >70%, thus concentrating chlorine, sulfur and other residual species in the intercumulus fluid and melt. The model explains the presence of chlor-apatite and the enrichment of graphite in the Bushveld Critical Zone and predicts that chlor-apatite-bearing Stillwater rocks were similarly enriched in graphite during crystallizatio

The 8 bits 100 MS/s Pipeline ADC for the INNOTEP Project – TWEPP-09

This paper describes the Analog to Digital Converter developed for the front end electronic of the IN2P3 INNOTEP project by the “pole microelectronique Rhone-Auvergne”. (Collaboration between LPC Clermont-Ferrand and IPNL Lyon). This ADC is a 4 stages 2.5 bits per stage pipe line with open loops track and holds and amplifiers. It runs at 100MSamples/s and has 8 bits resolution. The stages used two lines, the gain line and the comparison line, with most operators running in current. The main idea of this current line is to make a first step toward an all in current structure. Currently, this ADC is designed with a 0,35μm SiGe technology