453 research outputs found
Development of a 1 GS/s high-resolution transient recorder
With present-day detectors in high energy physics one is often faced with short analog pulses of a few nanoseconds length which may cover large dynamic ranges. In many experiments both amplitude and timing information have to be measured with high accuracy. Additionally, the data rate per readout channel can reach several MHz, which makes high demands on the separation of pile-up pulses. For such applications we have built the GANDALF transient recorder with a resolution of 12bit@1GS/s and an analog bandwidth of 500 MHz. Signals are digitized and processed by fast algorithms to extract pulse arrival times and amplitudes in real-time and to generate experiment trigger signals. With up to 16 analog channels, deep memories and a high data rate interface, this 6U-VME64x/VXS module is not only a dead-time free digitization unit but also has huge numerical capabilities provided by the implementation of a Virtex5-SXT FPGA. Fast algorithms implemented in the FPGA may be used to disentangle possible pile-up pulses and determine timing information from sampled pulse shapes with a time resolution in the picosecond range. Recently the application spectrum has been extended by implementing a 128-channel time-to-digital converter inside the FPGA and an appropriate input mezzanine card
Spatially resolved simulation of a radio frequency driven micro atmospheric pressure plasma jet and its effluent
Radio frequency driven plasma jets are frequently employed as efficient
plasma sources for surface modification and other processes at atmospheric
pressure. The radio-frequency driven micro atmospheric pressure plasma jet
(APPJ) is a particular variant of that concept whose geometry allows
direct optical access. In this work, the characteristics of the APPJ
operated with a helium-oxygen mixture and its interaction with a helium
environment are studied by numerical simulation. The density and temperature of
the electrons, as well as the concentration of all reactive species are studied
both in the jet itself and in its effluent. It is found that the effluent is
essentially free of charge carriers but contains a substantial amount of
activated oxygen (O, O and O). The simulation results are
verified by comparison with experimental data
Characterization of RNA content in individual phase-separated coacervate microdroplets
Condensates formed by complex coacervation are hypothesized to have played a crucial part during the origin-of-life. In living cells, condensation organizes biomolecules into a wide range of membraneless compartments. Although RNA is a key component of biological condensates and the central component of the RNA world hypothesis, little is known about what determines RNA accumulation in condensates and to which extend single condensates differ in their RNA composition. To address this, we developed an approach to read the RNA content from single synthetic and protein-based condensates using high-throughput sequencing. We find that certain RNAs efficiently accumulate in condensates. These RNAs are strongly enriched in sequence motifs which show high sequence similarity to short interspersed elements (SINEs). We observe similar results for protein-derived condensates, demonstrating applicability across different in vitro reconstituted membraneless organelles. Thus, our results provide a new inroad to explore the RNA content of phase-separated droplets at single condensate resolution
Probing collective excitations in helium nanodroplets: Observation of phonon wings in the infrared spectrum of methane
Reducing unnecessary prescriptions of antibiotics for acute cough: Adaptation of a leaflet aimed at Turkish immigrants in Germany
<p>Abstract</p> <p>Background</p> <p>The reduction in the number of unnecessary prescriptions of antibiotics has become one of the most important objectives for primary health care. German GPs report that they are under "pressure to prescribe" antibiotics particularly in consultations with Turkish immigrants. And so a qualitative approach was used to learn more about the socio-medical context of Turkish patients in regard to acute coughs. A German leaflet designed to improve the doctor-patient communication has been positively tested and then adapted for Turkish patients.</p> <p>Methods</p> <p>The original leaflet was first translated into Turkish. Then 57 patients belonging to 8 different GPs were interviewed about the leaflet using a semi-standardised script. The material was audio recorded, fully transcribed, and analysed by three independent researchers. As a first step a comprehensive content analysis was performed. Secondly, elements crucial to any Turkish version of the leaflet were identified.</p> <p>Results</p> <p>The interviews showed that the leaflets' messages were clearly understood by all patients irrespective of age, gender, and educational background. We identified no major problems in the perception of the translated leaflet but identified several minor points which could be improved. We found that patients were starting to reconsider their attitudes after reading the leaflet.</p> <p>Conclusion</p> <p>The leaflet successfully imparted relevant and new information to the target patients. A qualitative approach is a feasible way to prove general acceptance and provides additional information for its adaptation to medico-cultural factors.</p
Fast Photon Detection for Particle Identification with COMPASS RICH-1
Particle identification at high rates is an important challenge for many
current and future high-energy physics experiments. The upgrade of the COMPASS
RICH-1 detector requires a new technique for Cherenkov photon detection at
count rates of several per channel in the central detector region, and a
read-out system allowing for trigger rates of up to 100 kHz. To cope with these
requirements, the photon detectors in the central region have been replaced
with the detection system described in this paper. In the peripheral regions,
the existing multi-wire proportional chambers with CsI photocathode are now
read out via a new system employing APV pre-amplifiers and flash ADC chips. The
new detection system consists of multi-anode photomultiplier tubes (MAPMT) and
fast read-out electronics based on the MAD4 discriminator and the F1-TDC chip.
The RICH-1 is in operation in its upgraded version for the 2006 CERN SPS run.
We present the photon detection design, constructive aspects and the first
Cherenkov light in the detector.Comment: Proceedings of the Imaging 2006 conference, Stockholm, Sweden, 27-30
June 2006, 5 pages, 6 figures, to appear in NIM A; corrected typo in caption
of Fig.
Fast photon detection for the COMPASS RICH detector
The COMPASS experiment at the SPS accelerator at CERN uses a large scale Ring
Imaging CHerenkov detector (RICH) to identify pions, kaons and protons in a
wide momentum range. For the data taking in 2006, the COMPASS RICH has been
upgraded in the central photon detection area (25% of the surface) with a new
technology to detect Cherenkov photons at very high count rates of several 10^6
per second and channel and a new dead-time free read-out system, which allows
trigger rates up to 100 kHz. The Cherenkov photons are detected by an array of
576 visible and ultra-violet sensitive multi-anode photomultipliers with 16
channels each. The upgraded detector showed an excellent performance during the
2006 data taking.Comment: Proceeding of the IPRD06 conference (Siena, Okt. 06
The Fast Read-out System for the MAPMTs of COMPASS RICH-1
A fast readout system for the upgrade of the COMPASS RICH detector has been
developed and successfully used for data taking in 2006 and 2007. The new
readout system for the multi-anode PMTs in the central part of the photon
detector of the RICH is based on the high-sensitivity MAD4
preamplifier-discriminator and the dead-time free F1-TDC chip characterized by
high-resolution. The readout electronics has been designed taking into account
the high photon flux in the central part of the detector and the requirement to
run at high trigger rates of up to 100 kHz with negligible dead-time. The
system is designed as a very compact setup and is mounted directly behind the
multi-anode photomultipliers. The data are digitized on the frontend boards and
transferred via optical links to the readout system. The read-out electronics
system is described in detail together with its measured performances.Comment: Proceeding of RICH2007 Conference, Trieste, Oct. 2007. v2: minor
change
Collins and Sivers asymmetries in muonproduction of pions and kaons off transversely polarised proton
Measurements of the Collins and Sivers asymmetries for charged pions and
charged and neutral kaons produced in semi-inclusive deep-inelastic scattering
of high energy muons off transversely polarised protons are presented. The
results were obtained using all the available COMPASS proton data, which were
taken in the years 2007 and 2010. The Collins asymmetries exhibit in the
valence region a non-zero signal for pions and there are hints of non-zero
signal also for kaons. The Sivers asymmetries are found to be positive for
positive pions and kaons and compatible with zero otherwise.Comment: 15 pages, 13 figures and 1 tabl
Measurement of the charged-pion polarisability
The COMPASS collaboration at CERN has investigated pion Compton scattering,
, at centre-of-mass energy below 3.5 pion
masses. The process is embedded in the reaction
, which is initiated by
190\,GeV pions impinging on a nickel target. The exchange of quasi-real photons
is selected by isolating the sharp Coulomb peak observed at smallest momentum
transfers, \,(GeV/). From a sample of 63\,000 events the
pion electric polarisability is determined to be $\alpha_\pi\ =\ (\,2.0\ \pm\
0.6_{\mbox{\scriptsize stat}}\ \pm\ 0.7_{\mbox{\scriptsize syst}}\,) \times
10^{-4}\,\mbox{fm}^3\alpha_\pi=-\beta_\pi$, which
relates the electric and magnetic dipole polarisabilities. It is the most
precise measurement of this fundamental low-energy parameter of strong
interaction, that has been addressed since long by various methods with
conflicting outcomes. While this result is in tension with previous dedicated
measurements, it is found in agreement with the expectation from chiral
perturbation theory. An additional measurement replacing pions by muons, for
which the cross-section behavior is unambigiously known, was performed for an
independent estimate of the systematic uncertainty.Comment: Published version: 9 pages, 3 figures, 1 tabl
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