435 research outputs found
Scintillation proportional Xe counter with WLS fiber readout for low-energy X-rays
A gas Xe based scintillation proportional counter with cylindrical geometry
and wavelength shifting (WLS) fiber readout for X-rays of energy 0.5 - 100 keV
is proposed. With such a design large sizes and sensitive area of the counter
with a fairly well uniformity is possible. The counter could be used for "dark
matter" search and neutrino magnetic moment measurement and for detection of
small amounts or traces of radioactive elements in substances or environment.Comment: LaTeX 4 pages, 3 figures in eps, Submitted to NI
Development of liquid xenon detectors for medical imaging
In the present paper, we report on our developments of liquid xenon detectors
for medical imaging, positron emission tomography and single photon imaging, in
particular. The results of the studies of several photon detectors
(photomultiplier tubes and large area avalanche photodiode) suitable for
detection of xenon scintillation are also briefly described.Comment: 13 pages, 5 figures, presented on the International Workshop on
Techniques and Applications of Xenon Detectors (Xenon01), ICRR, Univ. of
Tokyo, Kashiwa, Japan, December 3-4, 2001 (submitted to proceedings
Resistive plate chambers for time-of-flight measurements
The applications of Resistive Plate Chambers (RPCs) have recently been
extended by the development of counters with time resolution below 100 ps sigma
for minimum ionising particles. Applications to HEP experiments have already
taken place and many further applications are under study. In this work we
address the operating principles of such counters along with some present
challenges, with emphasis on counter aging.Comment: Presented at "PSD6 - 6th International Conference on Position
Sensitive Detectors", 9-13 September 2002, Leicester, UK. Submitted to
Nuclear Instruments and Methods
From Junk to Function: LncRNAs in CNS Health and Disease
Recent advances in RNA sequencing technologies helped to uncover the existence of tens of thousands of long non-coding RNAs (lncRNAs) that arise from the dark matter of the genome. These lncRNAs were originally thought to be transcriptional noise but an increasing number of studies demonstrate that these transcripts can modulate protein-coding gene expression by a wide variety of transcriptional and post-transcriptional mechanisms. The spatiotemporal regulation of lncRNA expression is particularly evident in the central nervous system, suggesting that they may directly contribute to specific brain processes, including neurogenesis and cellular homeostasis. Not surprisingly, lncRNAs are therefore gaining attention as putative novel therapeutic targets for disorders of the brain. In this review, we summarize the recent insights into the functions of lncRNAs in the brain, their role in neuronal maintenance, and their potential contribution to disease. We conclude this review by postulating how these RNA molecules can be targeted for the treatment of yet incurable neurological disorders
Development of high-rate timing RPCs
For many applications of RPCs to time-of-flight counters in heavy ion experiments the expansion to much higher values of the counting rate capability, so far limited to around 2 kHz/cm2 is of fundamental importance. To address this issue we developed single-gap timing RPCs with resistive electrodes made from a commercially available plastic material. Tests performed in photon beams yielded a time resolution around 90 ps [sigma], essentially unchanged from 2 kHz/cm2 to 27 kHz/cm2. This result establishes the basic feasibility of timing measurements with RPCs at rates of tens of kHz/cm2, keeping a time resolution below 100 ps [sigma] and using plastic electrode materials.http://www.sciencedirect.com/science/article/B6TJM-4CXHH16-1/1/294a04bd430f914a4663436357d765d
Modelling of an IR scintillation counter
A systematic study of the excitation and de-excitation mechanisms in ternary gas mixtures Ar+CO2+N2 is presented regarding the possibility of developing a proportional scintillation counter based on the detection of the infrared molecular emissions associated with the lowest vibrational states of molecules. The use of visible or near-infrared photons ([lambda]<1Â [mu]m) for applications like imaging and quality control of microstructure detectors has been reported. In view of these applications we analyse the processes leading to near-infrared emissions in pure argon and give an estimation of the number of photons emitted per electron, at several pressures, as a function of the charge gain.http://www.sciencedirect.com/science/article/B6TJM-3YXB101-2M/1/b5bfeb3739389bb6dbe4d84c8746dbf
Perspectives for Positron Emission Tomography with RPCs
In this study we address the feasibility and main properties of a positron
emission tomograph (PET) based on RPCs. The concept, making use of the
converter-plate principle, takes advantage of the intrinsic layered structure
of RPCs and its simple and economic construction. The extremely good time and
position resolutions of RPCs also allow the TOF-PET imaging technique to be
considered. Monte-Carlo simulations, supported by experimental data, are
presented and the main advantages and drawbacks for applications of potential
interest are discussed.Comment: Presented at "RPC2001-VI Workshop on Resistive Plate Chambers and
Related Detectors", Coimbra, Portugal, 26-27 November 2001 (5 pages
A Simplified and Accurate Front-End Electronics Chain for Timing RPCs
Recent advances in electronics and construction techniques have pushed the timing resolution of Resistive Plate Chambers below 50 ps sigma with detection efficienciesclose to 99% for MIPs. In this paper we describe a new front-end electronics chain for accurate time and charge measurement in these devices, having in view a possibleapplication in ALICE's T0 counter.(Abstract only available, full text to follow)
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