25 research outputs found
A Charge-Sensitive Amplifier Associated with APD or PMT for Positron Emission Tomography Scanners
to be presented at the 32nd International Convention MIPRO (Microeectronics, Electronics, and Electronic Technology (MEET)), Opatija, Croatia, May 25-29 2009We present a Charge-Sensitive Amplifier (CSA) to be coupled with a 511-KeV 2-photon detector for positron emission tomography scanners. The circuit has been designed to be associated with an Avalanche Photodiode (APD) or Photo-Multiplier Tube (PMT) with large capacitance. It is a two-stage structure. The input stage consists of a foldedcascode fully-differential part and a common-mode feedback (CMFB) circuit. The output stage employs complementary source followers. The amplifier has been designed in a 0.35μm BiCMOS process with optimization of noise and speed performances to meet specific constraints. Its main characteristics evaluated by post-layout simulations are: 70-dB DC gain, 4.6-GHz GBW, 20-ns peaking time for pulsed stimulus, 3900-electron equivalent input noise charge (ENC), 135-mW power consumption at 3.5 V supply
Cyclostationarity-based model for noise analysis of charge amplification with correlated double sampling
International audienc
NMR planar microcoil for microanalysis
This article deals with the analysis of small sample volume by using a
planar microcoil and a micromachined cavity. This microcoil is used as a
nuclear magnetic resonance (NMR) radio frequency detection coil in order to
perform in vitro NMR analysis of the sample introduced into the microcavity.
It is a real challenging task to develop microsystem for NMR spectrum
extraction for smaller and smaller sample volume. Moreover, it is
advantageous that these microsystems could be integrated in a Micro Total
Analysing System (-TAS) as an analysing tool.
In this paper, NMR theory, description, fabrication process and electrical
characterization of planar microcoils receiver are described. Results
obtained on NMR microspectroscopy experiments have been performed on water
and ethanol, using a 1 mm diameter planar coil. This microcoil is tuned and
matched at 85.13 MHz which is the Larmor frequency of proton in a 2 T
magnetic field
Reconstructing patterns of vegetation recovery and landscape evolution after a catastrophic landslide (Mont Granier, French Alps, 1248 CE)
International audienc
Design guidelines for the integration of Geiger-mode avalanche diodes in standard CMOS technologies
International audienc
A time-integration based quenching circuit for Geiger-mode avalanche diodes
International audienc
Sister cytotoxic CD8+ T cell clones differing in natural killer inhibitory receptor expression in human astrocytoma
Natural killer (NK) inhibitory receptors are thought to play a critical role in the regulation of cytotoxicity of NK cells and certain self-reactive T cells. In the present study, we investigated whether astrocytoma infiltrating T lymphocytes may be functionally compromised by NK receptors (NKRs). The NK inhibitory receptor CD94/NKG2A was found on a significant proportion of CD8+ astrocytoma infiltrating lymphocytes. The functional consequences of CD94/NKG2A expression were explored at the clonal level, using a T cell clone that exhibited substantial variation in the expression of this heterodimer. Triggering of CD94/NKG2A inhibited the killing properties of T cells with a high level of this receptor, but not those from T cells with a low level. Our data indicate that some astrocytoma infiltrating lymphocytes express functional inhibitory CD94/NKG2A, raising the possibility that they may represent silent T cells specific for self-antigens (Ags) expressed on tumor cells. Understanding the mechanisms of regulation of these receptors may bring new insights for optimizing an anti-tumor immune response