3,358 research outputs found
Monte Carlo simulations of fluid vesicles with in plane orientational ordering
We present a method for simulating fluid vesicles with in-plane orientational
ordering. The method involves computation of local curvature tensor and
parallel transport of the orientational field on a randomly triangulated
surface. It is shown that the model reproduces the known equilibrium
conformation of fluid membranes and work well for a large range of bending
rigidities. Introduction of nematic ordering leads to stiffening of the
membrane. Nematic ordering can also result in anisotropic rigidity on the
surface leading to formation of membrane tubes.Comment: 11 Pages, 12 Figures, To appear in Phys. Rev.
PD-0455: Investigating a correlation between chemoradiotherapy schedule and survival in limited disease SCLC
Commissioning of the MEG II tracker system
The MEG experiment at the Paul Scherrer Institut (PSI) represents the state
of the art in the search for the charged Lepton Flavour Violating (cLFV) decay. With the phase 1, MEG set the new world best
upper limit on the \mbox{BR}(\mu^+ \rightarrow e^+ \gamma) < 4.2 \times
10^{-13} (90% C.L.). With the phase 2, MEG II, the experiment aims at reaching
a sensitivity enhancement of about one order of magnitude compared to the
previous MEG result. The new Cylindrical Drift CHamber (CDCH) is a key detector
for MEG II. CDCH is a low-mass single volume detector with high granularity: 9
layers of 192 drift cells, few mm wide, defined by wires in a
stereo configuration for longitudinal hit localization. The filling gas mixture
is Helium:Isobutane (90:10). The total radiation length is
\mbox{X}_0, thus minimizing the Multiple Coulomb Scattering (MCS)
contribution and allowing for a single-hit resolution m and an
angular and momentum resolutions of 6 mrad and 90 keV/c respectively. This
article presents the CDCH commissioning activities at PSI after the wiring
phase at INFN Lecce and the assembly phase at INFN Pisa. The endcaps
preparation, HV tests and conditioning of the chamber are described, aiming at
reaching the final stable working point. The integration into the MEG II
experimental apparatus is described, in view of the first data taking with
cosmic rays and beam during the 2018 and 2019 engineering runs. The
first gas gain results are also shown. A full engineering run with all the
upgraded detectors and the complete DAQ electronics is expected to start in
2020, followed by three years of physics data taking.Comment: 10 pages, 12 figures, 1 table, proceeding at INSTR'20 conference,
accepted for publication in JINS
Contamination Level of Staphylococcus spp. in Raw Goat Milk and Associated Risk Factors
This study was aimed to investigate the presence of pathogenic bacteria in raw goat milk by using Staphylococcus spp. as indicator bacteria, and also to evaluate the potential risk factors associated with them. Information regarding potential risk factors was collected by questionnaire. The conventional bacteriological method for bacterial isolation and the indirect test (California Mastitis Test (CMT)) for determining udder inflammation status were employed. A sample size of 300 udder halves milk samples from three commercial dairy goat farms in the Bogor District, West Java Province, Indonesia were investigated for counts and prevalence of indicator bacteria. Ten potential risk factors were also evaluated in relation to counts and prevalence of indicator bacteria. The results showed that the median value of indicator bacterial count from overall udder-half milk samples was 3.00 log cfu/ml. The indicator bacterial count from udder-half milk samples was significantly different (P < 0.05) among farms. Overall prevalence of Staphylococcus spp. was 78.7%. As one of potential risk factors, udder inflammation status was found to be risk factor for Staphylococcus spp. contamination in milk. Udders with inflammation had significant association and a higher chance of having contaminated samples by Staphylococcus spp. as compared to udders without inflammation. Additionally, according to these study results, CMT can be used as an effective, reliable, cheap and “farm and farmer friendly test" for screening test of intramammary infection (IMI) or sub clinical mastitis in dairy goats. Key words: goat milk, Staphylococcus spp., prevalence, risk factor, California Mastitis Tes
A photogrammetric method for target monitoring inside the MEG II detector
An automatic target monitoring method based on photographs taken by a CMOS photo-camera has been developed for the MEG II detector. The technique could be adapted for other fixed-target experiments requiring good knowledge of their target position to avoid biases and systematic errors in measuring the trajectories of the outcoming particles. A CMOS-based, high resolution, high radiation tolerant, and high magnetic field resistant photo-camera was mounted inside the MEG II detector at the Paul Scherrer Institute (Switzerland). MEG II is used to search for lepton flavor violation in muon decays. The photogrammetric method’s challenges, affecting measurements of low momentum particles’ tracks, are the high magnetic field of the spectrometer, high radiation levels, tight space constraints, and the need to limit the material budget in the tracking volume. The camera is focused on the dot pattern drawn on the thin MEG II target, about 1 m away from the detector endcaps where the photo-camera is placed. Target movements and deformations are monitored by comparing images of the dots taken at various times during the measurement. The images are acquired with a Raspberry board and analyzed using custom software. Global alignment to the spectrometer is guaranteed by corner cubes placed on the target support. As a result, the target monitoring fulfills the needs of the experiment
A photogrammetric method for target monitoring inside the MEG II detector
An automatic target monitoring method based on photographs taken by a CMOS photo-camera has been developed for the MEG II detector. The technique could be adapted for other fixed-target experiments requiring good knowledge of their target position to avoid biases and systematic errors in measuring the trajectories of the outcoming particles. A CMOS-based, high resolution, high radiation tolerant, and high magnetic field resistant photo-camera was mounted inside the MEG II detector at the Paul Scherrer Institute (Switzerland). MEG II is used to search for lepton flavor violation in muon decays. The photogrammetric method's challenges, affecting measurements of low momentum particles' tracks, are the high magnetic field of the spectrometer, high radiation levels, tight space constraints, and the need to limit the material budget in the tracking volume. The camera is focused on the dot pattern drawn on the thin MEG II target, about 1 m away from the detector endcaps where the photo-camera is placed. Target movements and deformations are monitored by comparing images of the dots taken at various times during the measurement. The images are acquired with a Raspberry board and analyzed using custom software. Global alignment to the spectrometer is guaranteed by corner cubes placed on the target support. As a result, the target monitoring fulfills the needs of the experiment
can concomitant diseases predict the compliance with cisplatin plus rt in patients with la scchn an exploratory endpoint analysis of the comply trial
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muCool: A novel low-energy muon beam for future precision experiments
Experiments with muons () and muonium atoms () offer
several promising possibilities for testing fundamental symmetries. Examples of
such experiments include search for muon electric dipole moment, measurement of
muon and experiments with muonium from laser spectroscopy to gravity
experiments. These experiments require high quality muon beams with small
transverse size and high intensity at low energy.
At the Paul Scherrer Institute, Switzerland, we are developing a novel device
that reduces the phase space of a standard beam by a factor of
with efficiency. The phase space compression is achieved by
stopping a standard beam in a cryogenic helium gas. The stopped
are manipulated into a small spot with complex electric and magnetic
fields in combination with gas density gradients. From here, the muons are
extracted into the vacuum and into a field-free region. Various aspects of this
compression scheme have been demonstrated. In this article the current status
will be reported.Comment: 8 pages, 5 figures, TCP 2018 conference proceeding
MEG Upgrade Proposal
We propose the continuation of the MEG experiment to search for the charged
lepton flavour violating decay (cLFV) \mu \to e \gamma, based on an upgrade of
the experiment, which aims for a sensitivity enhancement of one order of
magnitude compared to the final MEG result, down to the
level. The key features of this new MEG upgrade are an increased rate
capability of all detectors to enable running at the intensity frontier and
improved energy, angular and timing resolutions, for both the positron and
photon arms of the detector. On the positron-side a new low-mass, single
volume, high granularity tracker is envisaged, in combination with a new highly
segmented, fast timing counter array, to track positron from a thinner stopping
target. The photon-arm, with the largest liquid xenon (LXe) detector in the
world, totalling 900 l, will also be improved by increasing the granularity at
the incident face, by replacing the current photomultiplier tubes (PMTs) with a
larger number of smaller photosensors and optimizing the photosensor layout
also on the lateral faces. A new DAQ scheme involving the implementation of a
new combined readout board capable of integrating the diverse functions of
digitization, trigger capability and splitter functionality into one condensed
unit, is also under development. We describe here the status of the MEG
experiment, the scientific merits of the upgrade and the experimental methods
we plan to use.Comment: A. M. Baldini and T. Mori Spokespersons. Research proposal submitted
to the Paul Scherrer Institute Research Committee for Particle Physics at the
Ring Cyclotron. 131 Page
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