938 research outputs found
Further developments and tests of microstrip gas counters with resistive electrodes
We present results from further tests of Microstrip Gas Counters (MSGCs) with
resistive electrodes. The maim advantage of this detector is that it is
spark-protected: in contrast to "classical" MSGCs with metallic electrodes,
sparks in this new detector do not destroy its electrodes. As a consequence the
MSGC with resistive electrodes is more reliable in operation which may open new
avenues in applications. One of them which is under investigation now is the
use of Resistive electrodes MSGC (R-MSGC) as photodetector in some particular
designs of noble liquid dark matter detectors.Comment: Presented at the RD-51 mini-week at CERN, January 17, 201
First Tests of Gaseous Detectors Made of a Resistive Mesh
We describe here various detectors designs: GEM type, MICROMEGAStype,
PPACtype as well as cascaded detectors made of a resistive mesh manufactured
from a resistive Kapton foil, (20 microns thick, resistivity a few MOhm per
square) by a laser drilling technique. As in any other micropattern detectors
the maximum achievable gas gain of these detectors is restricted by the Raether
limit, however, the resistive mesh makes them and the front end electronics
fully spark protected. This approach could be an alternative or complimentary
to the ongoing efforts in developing MICROMEGAS and GEMs with resistive anode
readout plates and can be especially beneficial in the case of micropattern
detectors combined with a micropixel-type integrated front end electronic
An improved design of spark-protected microstrip gas counters (R-MSGC)
We have developed microstrip gas counters manufactured on standard printed
circuit board and having the following features: resistive cathode strips, thin
(10 micron) metallic anode strips and electrodes protected against surface
discharges by a Coverlay layer at their edges. These features allow the
detector to operate at gas gains as high as can be achieve with the best
microstrip gas counters manufactured on glass substrates. We believe that after
further developments this type of detectors can compete in some applications
with other micropattern detectors, for example MICROMEGAS.Comment: Presented at the 7th RD51 Collaboration meeting, CERN, April 201
COVID-19. Update of the Italian situation
On the March 11, 2020, the World Health Organization (WHO) declared the novel coronavirus disease 2019 (COVID-19) outbreak as a pandemic. The first cases in Italy were reported on January 30, 2020, and quickly the number of cases escalated. On March 20, 2020, according to the Italian National Institute of Health (ISS) and National Institute of Statistics (ISTAT), the peak of COVID-19 cases reported in Italy reached the highest number, surpassing those in China. The Italian government endorsed progressively restrictive measures initially at the local level, and finally, at the national level with a lockdown of the entire Italian territory up to 3 May 2020. The complete Italian territory closing slowed down the contagion. This review retraces the main numbers of the pandemic in Italy. Although in decline, the new reported cases remain high in the northern regions. Since drugs or vaccines are still not available, the described framework highlights the importance of the containment measures to be able to quickly identify all the potential transmission hotspots and keep control subsequent epidemic waves of COVID-19
Demonstration of new possibilities of multilayer technology on resistive microstrip/ microdot detectors
The first successful attempts to optimize the electric field in Resistive
Microstrip Gas Chamber and resistive microdot detectors using additional field
shaping strips located inside the detector substrate are describedComment: Presented at the RD-51 mmini week, CERN, June 201
Genetic Diversity of the Noncoding Control Region of the Novel Human Polyomaviruses.
The genomes of polyomaviruses are characterized by their tripartite organization with
an early region, a late region and a noncoding control region (NCCR). The early region encodes
proteins involved in replication and transcription of the viral genome, while expression of the late
region generates the capsid proteins. Transcription regulatory sequences for expression of the early
and late genes, as well as the origin of replication are encompassed in the NCCR. Cell tropism of
polyomaviruses not only depends on the appropriate receptors on the host cell, but cell-specific
expression of the viral genes is also governed by the NCCR. Thus far, 15 polyomaviruses have
been isolated from humans, though it remains to be established whether all of them are genuine
human polyomaviruses (HPyVs). The sequences of the NCCR of these HPyVs show high genetic
variability and have been best studied in the human polyomaviruses BK and JC. Rearranged NCCRs
in BKPyV and JCPyV, the first HPyVs to be discovered approximately 30 years ago, have been
associated with the pathogenic properties of these viruses in nephropathy and progressive multifocal
leukoencephalopathy, respectively. Since 2007, thirteen novel PyVs have been isolated from humans:
KIPyV, WUPyV, MCPyV, HPyV6, HPyV7, TSPyV, HPyV9, HPyV10, STLPyV, HPyV12, NJPyV, LIPyV
and QPyV. This review describes all NCCR variants of the new HPyVs that have been reported in the
literature and discusses the possible consequences of NCCR diversity in terms of promoter strength,
putative transcription factor binding sites and possible association with diseases
First tests of "bulk" MICROMEGAS with resistive cathode mesh
We present the first results from tests of a MICROMEGAS detector manufactured
using the so-called "bulk" technology and having a resistive cathode mesh
instead of the conventional metallic one. This detector operates as usual
MICROMEGAS, but in the case of sparks, which may appear at high gas gains, the
resistive mesh reduces their current and makes the sparks harmless. This
approach could be complementary to the ongoing efforts of various groups to
develop spark-protected MICROMEGAS with resistive anode planes
Detection of the primary scintillation light from dense Ar, Kr and Xe with novel photosensitive gaseous detectors
The detection of primary scintillation light in combination with the charge
or secondary scintillation signals is an efficient technique to determine the
events t=0 as well as particle / photon separation in large mass TPC detectors
filled with noble gases and/or condensed noble gases. The aim of this work is
to demonstrate that costly photo-multipliers could be replaced by cheap novel
photosensitive gaseous detectors: wire counters, GEMs or glass capillary tubes
coupled with CsI photocathodes. We have performed systematic measurements with
Ar, Kr and Xe gas at pressures in the range of 1-50 atm as well as some
preliminary measurements with liquid Xe and liquid Ar. With the gaseous
detectors we succeeded in detecting scintillation light produced by 22 keV
X-rays with an efficiency of close to 100%. We also detected the scintillation
light produced by bs (5 keV deposit energy) with an efficiency close to 25%.
Successful detection of scintillation from 22 keV gammas open new experimental
possibilities not only for nTOF and ICARUS experiments, but also in others,
like WIMPs search through nuclear recoil emission
Hybrid Superconducting Neutron Detectors
A new neutron detection concept is presented that is based on superconductive
niobium (Nb) strips coated by a boron (B) layer. The working principle of the
detector relies on the nuclear reaction 10B+n + 7Li ,
with and Li ions generating a hot spot on the current-biased Nb strip
which in turn induces a superconducting-normal state transition. The latter is
recognized as a voltage signal which is the evidence of the incident neutron.
The above described detection principle has been experimentally assessed and
verified by irradiating the samples with a pulsed neutron beam at the ISIS
spallation neutron source (UK). It is found that the boron coated
superconducting strips, kept at a temperature T = 8 K and current-biased below
the critical current Ic, are driven into the normal state upon thermal neutron
irradiation. As a result of the transition, voltage pulses in excess of 40 mV
are measured while the bias current can be properly modulated to bring the
strip back to the superconducting state, thus resetting the detector.
Measurements on the counting rate of the device are presented and the future
perspectives leading to neutron detectors with unprecedented spatial
resolutions and efficiency are highlighted.Comment: 8 pages 6 figure
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