Readout technologies for directional WIMP Dark Matter detection

The measurement of the direction of WIMP-induced nuclear recoils is a compelling but technologically challenging strategy to provide an unambiguous signature of the detection of Galactic dark matter. Most directional detectors aim to reconstruct the dark-matter-induced nuclear recoil tracks, either in gas or solid targets. The main challenge with directional detection is the need for high spatial resolution over large volumes, which puts strong requirements on the readout technologies. In this paper we review the various detector readout technologies used by directional detectors. In particular, we summarize the challenges, advantages and drawbacks of each approach, and discuss future prospects for these technologies

Previable preterm rupture of membranes: gestational and neonatal outcomes

Previable (less than 24 weeks) premature rupture of membranes complicates about 1 in every thousand births and is responsible for substantial perinatal mortality. In this paper, we retrospectively analyzed one twin and 35 singleton pregnancies. Twenty cases occurred before and 16 after 20 weeks. Latency period ranged from 0 to 137 days, with an average of 35 days. Amniotic fluid index was reduced in 27 cases and normal in 6 cases. Expectant management was adopted in 31 cases (86%), five patients declined and opted for termination (14%) at admission or during the course of pregnancy. Steroids were prescribed for 12 patients at or after 24 weeks (39%), leukocyte count at admission varied from 6,000 to 16,200/mm(3), with an average of 11,310, in only 9% it was greater than 15,000, immature forms were present in 10 cases (28%). Clinical chorioamnionitis occurred in 71%, being three times more frequent in parous women. Bacteriuria was present in 2 of 30 cases (6.6%). Two women developed laboratorial and clinical signs of sepsis, none of them needed hysterectomy. There were no maternal deaths. Mean gestational age at delivery was 24 weeks, ranging from 16 to 39 weeks. In the expectant group, preterm delivery rate was 68%. There was one case of abruption. Cesarean rate was 31%. Neonatal mortality was 42% (8 cases). Overall neonatal survival was 35% (11 in 32 newborns). Perinatal mortality is high in pregnancies complicated by previable rupture of membranes, however gestational age at occurrence is a strong predictor of outcome. An individualized approach is the best management option regarding maternal risks and fetal outcomes.28561529153

Performance of a tracking device based on the GEM scintillation

A tracking device based on gas electron multiplier scintillation using a high-resolution cooled charge-coupled device (CCD) camera was developed. The CCD is sensitive to the 400-1000 nm band, and standard glass photographic lenses are used. The active gas is an Ar-CF4 mixture. The prototype detector is described and images of single alpha tracks are presented. The light yield and detector performance for several other gaseous mixtures, such as 4He-CF4, are also investigate

Optical readout of GEMs

We present an overview of results from our recent studies on the use of the visible and NIR scintillation emitted by the gas electron multiplier (GEM) and on the possibility of using detectors operated with cascaded GEMs to build tracking chambers.http://www.sciencedirect.com/science/article/B6TJM-44DHYY7-10/1/0076b77e06804d2654d892c3d6126c9