747 research outputs found
Performance Results of the AMS-01 Aerogel Threshold Cherenkov
The Alpha Magnetic Spectrometer (AMS) was flown in june 1998 on board of the
space shuttle Discovery (flight STS-91) at an altitude ranging between 320 and
390 km. This preliminary version of AMS included an Aerogel Threshold Cherenkov
detector (ATC) to separate antiprotons from electron background, for momenta
less than 3.5 GeV/c. In this paper, the design and physical principles of ATC
will be discussed briefly, then the performance results of the ATC will be
presented.Comment: 3 pages, 3 figures, to be published in the proceedings of the XIth
Rencontres de Blois (Frontiers of Matter), held in Blois (France), June
27-July 3, 199
A review on the discovery reach of Dark Matter directional detection
Directional detection of galactic Dark Matter offers a unique opportunity to
identify Weakly Interacting Massive Particle (WIMP) events as such. Depending
on the unknown WIMP-nucleon cross section, directional detection may be used to
: exclude Dark Matter, discover galactic Dark Matter with a high significance
or constrain WIMP and halo properties. We review the discovery reach of Dark
Matter directional detection.Comment: Proceedings of the 4th international conference on Directional
Detection of Dark Matter (CYGNUS 2013), 10-12 June 2013, Toyama, Japa
MIMAC : Detection of low energy recoils for Dark Matter search
The MIMAC project is based on a matrix of Micro Time Projection Chambers
(micro-TPC) for Dark Matter search, filled with He3 or CF4 and using ionization
and tracks. The first measurement of the energy resolution of this micro-TPC is
presented as well as its low thresholdComment: Dark Energy and Dark Matter conference, Lyon : France (2008
Supersymmetric dark matter search via spin-dependent interaction with He3
The potentialities of MIMAC-He3, a MIcro-tpc MAtrix of Chambers of Helium 3,
for supersymmetric dark matter search are discussed within the framework of
effective MSSM models without gaugino mass unification at the GUT scale. A
phenomenological study has been done to investigate the sensitivity of the
MIMAC-He3 detector to neutralinos (m > 6 GeV/c2) via spin-dependent interaction
with He3 as well as its complementarity to direct and indirect detection
experiments. Comparison with other direct dark matter searches will be
presented in a WIMP model-independent framework.Comment: 13 pages, 5 figure
Identification of Dark Matter with directional detection
Directional detection is a promising search strategy to discover galactic
Dark Matter. Taking advantage on the rotation of the Solar system around the
Galactic center through the Dark Matter halo, it allows to show a direction
dependence of WIMP events. Data of directional detectors are composed of energy
and a 3D track for each recoiling nuclei. Here, we present a Bayesian analysis
method dedicated to data from upcoming directional detectors. However, we focus
only on the angular part of the event distribution, arguing that the energy
part of the background distribution is unknown. Two different cases are
considered: a positive or a null detection of Dark Matter. In the first
scenario, we will present a map-based likelihood method allowing to recover the
main incoming direction of the signal and its significance, thus proving its
Galactic origin. In the second scenario, a new statistical method is proposed.
It is based on an extended likelihood in order to set robust and competitive
exclusion limits. This method has been compared to two other methods and has
been shown to be optimal in any detector configurations. Eventually, prospects
for the MIMAC project are presented in the case of a 10 kg CF4 detector with an
exposition time of 3 years.Comment: Proceeding of the 8th International Workshop on the Identification of
Dark Matter (IDM 2010), July 2010, Montpellier, France. To appear in
Proceedings of Science (PoS
Directional detection of galactic dark matter
Directional detection is a promising Dark Matter search strategy. Taking
advantage on the rotation of the Solar system around the galactic center
through the Dark Matter halo, it allows to show a direction dependence of WIMP
events that may be a powerful tool to identify genuine WIMP events as such.
Directional detection strategy requires the simultaneous measurement of the
energy and the 3D track of low energy recoils, which is a common challenge for
all current projects of directional detectors.Comment: Proceedings of UCLA Dark Matter 2012, 10th Symposium on Sources and
Detection of Dark Matter and Dark Energy in the Universe, Marina del Rey
Marriott, CA, USA, February 22-24, 201
An analysis method for time ordered data processing of Dark Matter experiments
The analysis of the time ordered data of Dark Matter experiments is becoming
more and more challenging with the increase of sensitivity in the ongoing and
forthcoming projects. Combined with the well-known level of background events,
this leads to a rather high level of pile-up in the data. Ionization,
scintillation as well as bolometric signals present common features in their
acquisition timeline: low frequency baselines, random gaussian noise, parasitic
noise and signal characterized by well-defined peaks. In particular, in the
case of long-lasting signals such as bolometric ones, the pile-up of events may
lead to an inaccurate reconstruction of the physical signal (misidentification
as well as fake events). We present a general method to detect and extract
signals in noisy data with a high pile-up rate and qe show that events from few
keV to hundreds of keV can be reconstructed in time ordered data presenting a
high pile-up rate. This method is based on an iterative detection and fitting
procedure combined with prior wavelet-based denoising of the data and baseline
subtraction. {We have tested this method on simulated data of the MACHe3
prototype experiment and shown that the iterative fitting procedure allows us
to recover the lowest energy events, of the order of a few keV, in the presence
of background signals from a few to hundreds of keV. Finally we applied this
method to the recent MACHe3 data to successfully measure the spectrum of
conversion electrons from Co57 source and also the spectrum of the background
cosmic muons
MIMAC-He3 : MIcro-tpc MAtrix of Chambers of He3
The project of a micro-TPC matrix of chambers of He3 for direct detection of
non-baryonic dark matter is outlined. The privileged properties of He3 are
highlighted. The double detection (ionization - projection of tracks) will
assure the electron-recoil discrimination. The complementarity of MIMAC-He3 for
supersymmetric dark matter search with respect to other experiments is
illustrated. The modular character of the detector allows to have different
gases to get A-dependence. The pressure degreee of freedom gives the
possibility to work at high and low pressure. The low pressure regime gives the
possibility to get the directionality of the tracks. The first measurements of
ionization at very few keVs for He3 in He4 gas are described
Mirage: a new iterative Map-Making code for CMB experiments
A major goal of CMB experiments is to obtain highly sensitive CMB maps in
order to extract Spherical Harmonic Power Spectrum (SHPS) and cosmological
parameters with unprecedented accuracy. We present a new map-making code
(Mirage), based on a two-phase iterative algorithm, involving low frequency
drift treatment, Butterworth high-pass filtering and conjugate gradient method.
This work was strongly motivated by Archeops CMB experiment data analysis. We
believe that Archeops was a good test bench for the future Planck Surveyor data
analysis, and Mirage was designed in order to be used for Planck data
processing with minimal work. A strong feature of Mirage is that it handles
experimental problems in data, such as holes in data stream, bright sources,
and galaxy side effects, without jeopardising speed. The other advantage is its
processing speed, allowing to run Monte Carlo simulations of Archeops data
processing on a single processor workstation overnight. Algorithms are
explained. Systematic effects on SHPS are investigated on various simulated
data, including typical Archeops observational systematics.
This code is available at adress http://www-dapnia.cea.fr/Telechargement/
Preprint with full resolution figures is available at
http://www-dapnia.cea.fr/Doc/Publications/Archives/dapnia-03-378.pdfComment: 11 pages, accepted in Astron. and Astrophysisc
Extracting constraints from direct detection searches of supersymmetric dark matter in the light of null results from the LHC in the squark sector
The comparison of the results of direct detection of Dark Matter, obtained
with various target nuclei, requires model-dependent, or even arbitrary,
assumptions. Indeed, to draw conclusions either the spin-dependent (SD) or the
spin-independent (SI) interaction has to be neglected. In the light of the null
results from supersymmetry searches at the LHC, the squark sector is pushed to
high masses. We show that for a squark sector at the TeV scale, the framework
used to extract contraints from direct detection searches can be redefined as
the number of free parameters is reduced. Moreover, the correlation observed
between SI and SD proton cross sections constitutes a key issue for the
development of the next generation of Dark Matter detectors.Comment: Figure 3 has been updated. Conclusions unchange
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