473 research outputs found
Development of a front end ASIC for Dark Matter directional detection with MIMAC
A front end ASIC (BiCMOS-SiGe 0.35 \mum) has been developed within the
framework of the MIMAC detector project, which aims at directional detection of
non-baryonic Dark Matter. This search strategy requires 3D reconstruction of
low energy (a few keV) tracks with a gaseous \muTPC. The development of this
front end ASIC is a key point of the project, allowing the 3D track
reconstruction. Each ASIC monitors 16 strips of pixels with charge
preamplifiers and their time over threshold is provided in real time by current
discriminators via two serializing LVDS links working at 320 MHz. The charge is
summed over the 16 strips and provided via a shaper. These specifications have
been chosen in order to build an auto triggered electronics. An acquisition
board and the related software were developed in order to validate this
methodology on a prototype chamber. The prototype detector presents an anode
where 2 x 96 strips of pixels are monitored.Comment: 12 pages, 10 figure
MIMAC : A micro-tpc matrix for directional detection of dark matter
Directional detection of non-baryonic Dark Matter is a promising search
strategy for discriminating WIMP events from background. However, this strategy
requires both a precise measurement of the energy down to a few keV and 3D
reconstruction of tracks down to a few mm. To achieve this goal, the MIMAC
project has been developed. It is based on a gaseous micro-TPC matrix, filled
with CF4 and CHF3. The first results on low energy nuclear recoils (H, F)
obtained with a low mono-energetic neutron field are presented. The discovery
potential of this search strategy is discussed and illustrated by a realistic
case accessible to MIMAC.Comment: 6 pages, Proc. of the fifth international symposium on large TPCs for
low energy rare event detection, Paris, France, Dec. 2010. To appear in
Journal of Physic
Dark matter directional detection with MIMAC
MiMac is a project of micro-TPC matrix of gaseous (He3, CF4) chambers for
direct detection of non-baryonic dark matter. Measurement of both track and
ionization energy will allow the electron-recoil discrimination, while access
to the directionnality of the tracks will open a unique way to distinguish a
geniune WIMP signal from any background. First reconstructed tracks of 5.9 keV
electrons are presented as a proof of concept.Comment: 4 pages, proc. of the 44th Rencontres De Moriond: Electroweak
Interactions And Unified Theories, 7-14 Mar 2009, La Thuile, Ital
Evaluation of building envelope retrofit techniques for reducing energy needs for space cooling.
One of the fastest growing sources of new energy demand is space cooling. According to EU-studies a four-fold growth in air-conditioned space is likely to take place between 1990 and 2020. The energy savings achievable in the end-use space cooling depend on a number of variables related to the building envelope, the plants and to some extent the behaviour of occupants. They are hence complex to evaluate and consequently often underrepresented in energy efficiency programmes and National Plans.
This paper is based on some preliminary results of the IEE project KeepCool 2. It discusses in particular:
a methodology for bottom-up assessment of the energy savings related to "sustainable summer comfort" solutions; reference base case building typologies are analyzed in 5 European climates, and dynamic simulations are used to calculate the reductions in the energy need for cooling which can be achieved by specific retrofit actions (e.g. additions of effective solar protections, increased thermal insulation, night ventilation, increase of active mass by PCM, low solar absorbance surfaces,...); situations where mechanical cooling can be avoided are evaluated using the Adaptive Comfort model, according to the norm EN 15251.
case studies of buildings with good summer comfort and low energy consumption performances, according to the ten steps of the KC2 procedure.
the analysis of case studies of "comfort policies" adopted by public and private bodies to ensure summer comfort with low energy consumption (commitments to give priority to heat load reductions instead of introducing mechanical cooling, relaxed dress codes, low thermal insulation chairs, local air velocity increase)
Micromegas micro-TPC for direct Dark Matter search with MIMAC
The MIMAC project is a multi-chamber detector for Dark Matter search, aiming
at measuring both track and ionization with a matrix of micromegas micro-TPC
filled with He3 and CF4. Recent experimental results on the first measurements
of the Helium quenching factor at low energy (1 keV recoil) are presented,
together with the first simulation of the track reconstruction. Recontruction
of track of alpha from Radon impurities is shown as a first proof of concept.Comment: 5 pages, Proc. of the fourth international symposium on large TPCs
for low energy rare event detection, Paris, France, Dec. 2008. To appear in
Journal of Physic
Data acquisition electronics and reconstruction software for directional detection of Dark Matter with MIMAC
Directional detection of galactic Dark Matter requires 3D reconstruction of
low energy nuclear recoils tracks. A dedicated acquisition electronics with
auto triggering feature and a real time track reconstruction software have been
developed within the framework of the MIMAC project of detector. This
auto-triggered acquisition electronic uses embedded processing to reduce data
transfer to its useful part only, i.e. decoded coordinates of hit tracks and
corresponding energy measurements. An acquisition software with on-line
monitoring and 3D track reconstruction is also presented.Comment: 17 pages, 12 figure
Immunohistochemical characteristics of Renomedullary interstitial cell tumor: a study of 41 tumors with emphasis on differential diagnosis of mesenchymal neoplasms
Renomedullary interstitial cell tumors (RMICT) are almost always incidentally identified either at autopsy or resection of the kidney for other reasons. However, rare cases have been reported which are large, resulting in a clinical mass. The immunohistochemical phenotype of usual, incidental RMICT using modern soft tissue tumor markers in is largely unknown, however, providing little information to aid in classification of larger or atypical tumors. We retrieved 41 RMICTs from 36 patients, and studied pathologic characteristics including morphology, immunohistochemistry (S100, keratin AE1/AE3, smooth muscle actin, desmin, estrogen and progesterone receptors, calponin, CD34, CD35), and histochemical staining. Data collected included age, gender, tumor size, laterality, and indication for kidney examination. RMICTs (n = 41) were identified in 23 men and 13 women, with mean age 57 years (range 24–83), tumor sizes ranged from <1 to 13 mm (median 4 mm). Kidneys were resected for 32 tumors, 1 chronic pyelonephritis, 1 trauma, and 2 autopsies. All (41, 100%) had entrapped renal tubules, 5 (12%) of which included cystic or dilated tubules. Most (35, 85%) had collagenous fibers, all of which were negative for Congo red. RMICT demonstrates a largely negative immunohistochemical phenotype with weak to moderate labeling for smooth muscle actin and calponin that is substantially less than myofibroblastic lesions. Positive staining for estrogen and progesterone receptor is common (61%), which could overlap with mixed epithelial and stromal tumor and other entities; however, staining is typically weak. CD34 is usually negative, with occasional weak labeling, in contrast to solitary fibrous tumor
Low energy measurements with Helium Micromegas micro-TPC
The measurement of the ionization produced by particles in a medium presents
a great interest in several fields from metrology to particule physics and
cosmology. The ionization quenching factor is defined as the fraction of energy
released by ionisation by a recoil in a medium compared with its kinetic
energy. At low energy, in the range of a few keV, the ionization falls rapidly
and systematic measurement are needed. We have developped an experimental setup
devoted to the measurement of low energy (keV) ionization quenching factor for
the MIMAC project. The ionization produced in the gas has been measured with a
Micromegas detector filled with Helium gas mixture.Comment: Proceedings of the fourth international symposium on large TPCs for
low energy rare event detection, Paris, France, Dec. 2008 To appear in
Journal of Physic
Malignant paraganglioma with skeletal metastases and spinal cord compression: Response and palliation with chemotherapy
Paragangliomas (carotid body tumours, chemodectomas) may arise in any area of the body where sympathetic ganglia are present, including chemoreceptors, the adrenal medulla and retroperitoneal ganglia. Increasing numbers of patients are being reported with vertebral metastases and spinal cord compression for which either decompression laminectomy or external beam radiotherapy, or both, are required. Patients with vertebral metastases may develop progression of disease after radiation therapy.There is little published information on the use of chemotherapy in this clinical situation. We report a case of metastatic paraganglioma complicated by spinal cord compression showing evidence of clinical benefit from chemotherapy after progressive disease and symptoms developed in a region previously treated by radiation therapy.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31018/1/0000694.pd
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