High Voltage Power Supply Design for Photo Multiplier Tube

CubeSats are playing a vital role in the development of new compact technologies for small satellites and because of their promising potential, the CubeSats have been widely embraced by universities for conducting space research projects. IITMSAT is a student driven Nano-satellite embraced by IIT Madras leading to the development of Space-based Proton-Electron Energy Detector (SPEED). It is a payload that is being developed to be launched on-board IITMSAT. The scientific objective of the payload is to gather data on the variations in the charge particle flux below the inner Van Allen radiation belts. SPEED is designed to obtain energy spectra of high-energy protons and electrons, specifically designed to investigate correlations between variations in these spectra and seismic activity, solar flares and lightning storms. The SPEED electronics consists of Peak hold Detector, Charge-Sensitive Pre-Amplifier, TIVVA microcontroller and Photo Multiplier Tubes. This paper describes the development of the high voltage power supply for the photo multiplier tubes (PMT) of SPEED. In SPEED, photo multiplier tubes operates at around 1000 V to 1300 V with very strict ripple requirements and requires very precise and controlled high voltage. Due to their high gain and extremely light sensitivity photomultipliers (PMTs) can easily be damaged by applying excessive light to the photocathode and thus exceeding the maximum output current. A novel compact and controllable high voltage power supply based on integrated DC-DC converters is developed which provides ultralow ripple of about 0.3% to 0.5% at an output of 1000 volts which is further reduced by the 5th order low-pass filter circuitry. Innovative automatic current protection circuitry is developed for protecting PMT from being damaged by saturation current. We are able to develop voltage monitoring and regulation system for high voltage with a voltage regulation of 0.1%. Voltage regulation is achieved by control software based on TIVA microcontroller based solution. A number of tests have been performed to provide very reliable and efficient high voltage power supply for PMT. This poster reflects upon the development of ultra-low noise and ripple power supply for the photo multiplier tube. The goal is to creat a very reliable high voltage power supply for the photo multiplier tubes of SPEED and this poster reflects upon the development of same

Ultrahigh flux gas-selective nanoporous carbon membrane and manufacturing method thereof

The present relates to a nanoporous carbon membrane manufacturing method comprising coating a block copolymer film with hydrophilic and hydrophobic blocks, on a sacrificial non-porous substrate so as to prepare an block copolymer film coated foil, transferring the block copolymer film on a porous support, pyrolizing the block copolymer film to form a nanoporous carbon film, wherein the transfer step consists in a wet-transfer process comprising placing the block copolymer film coated foil in an etchant bath in an etching chamber and the porous support above the height of said etching bath, etching the underlying sacrificial foil of block copolymer film coated foil, raising the height of the etching bath above the porous support, bringing the free-floating etched block copolymer film on top of the porous support, and lowering the etching bath height below the porous support so as to deposit the copolymer film on top of the porous support

GRAS-microparticle microarrays identify dendritic cell tolerogenic marker-inducing formulations

Microarrays, miniaturized platforms used for high-content studies, provide potential advantages over traditional in vitro investigation in terms of time, cost, and parallel analyses. Recently, microarrays have been leveraged to investigate immune cell biology by providing a platform with which to systematically investigate the effects of various agents on a wide variety of cellular processes, including those giving rise to immune regulation for application toward curtailing autoimmunity. A specific embodiment incorporates dendritic cells cultured on microarrays containing biodegradable microparticles. Such an approach allows immune cell and microparticle co-localization and release of compounds on small, isolated populations of cells, enabling a quick, convenient method to quantify a variety of cellular responses in parallel. In this study, the microparticle microarray platform was utilized to investigate a small library of sixteen generally regarded as safe (GRAS) compounds (ascorbic acid, aspirin, capsaicin, celastrol, curcumin, epigallocatechin-3-gallate, ergosterol, hemin, hydrocortisone, indomethacin, menadione, naproxen, resveratrol, retinoic acid, α-tocopherol, vitamin D3) for their ability to induce suppressive phenotypes in murine dendritic cells. Two complementary tolerogenic index ranking systems were proposed to summarize dendritic cell responses and suggested several lead compounds (celastrol, ergosterol, vitamin D3) and two secondary compounds (hemin, capsaicin), which warrant further investigation for applications toward suppression and tolerance