M.K. Singh

Limits on light weakly interacting massive particles from the CDEX-1 experiment with ap-type point-contact germanium detector at the China Jinping Underground Laboratory

We report results of a search for light Dark Matter WIMPs with CDEX-1 experiment at the China Jinping Underground Laboratory, based on 53.9 kg-days of data from a p-type point-contact germanium detector enclosed by a NaI(Tl) crystal scintillator as anti-Compton detector. The event rate and spectrum above the analysis threshold of 475 eVee are consistent with the understood background model. Part of the allowed regions for WIMP-nucleus coherent elastic scattering at WIMP mass of 6-20 GeV are probed and excluded. Independent of interaction channels, this result contradicts the interpretation that the anomalous excesses of the CoGeNT experiment are induced by Dark Matter, since identical detector techniques are used in both experiments.

A Search of Low-Mass WIMPs with p-type Point Contact Germanium Detector in the CDEX-1 Experiment

The CDEX-1 experiment conducted a search of low-mass (< 10 GeV/c2) Weakly Interacting Massive Particles (WIMPs) dark matter at the China Jinping Underground Laboratory using a p-type point-contact germanium detector with a fiducial mass of 915 g at a physics analysis threshold of 475 eVee. We report the hardware set-up, detector characterization, data acquisition and analysis procedures of this experiment. No excess of unidentified events are observed after subtraction of known background. Using 335.6 kg-days of data, exclusion constraints on the WIMP-nucleon spin-independent and spin-dependent couplings are derived.

Differentiation of bulk and surface events in p-type point-contact germanium detectors for light WIMP searches

The p-type point-contact germanium detectors are novel techniques offering kg-scale radiation sensors with sub-keV sensitivities. They have been used for light dark matter WIMPs searches and may have potential applications in neutrino physics. There are, however, anomalous surface behaviour which needs to be characterized and understood. We describe the methods and results of a research program whose goals are to identify the bulk and surface events via software pulse shape analysis techniques, and to devise calibration schemes to evaluate the selection efficiency factors. Efficiencies-corrected background spectra from the low-background facility at Kuo-Sheng Neutrino Laboratory are derived.

Pattern of two wheeler road traffic accidents in rural setting: a retrospective study

BACKGROUND: Roads and vehicles which are for making life comfortable and faster, can result in miserable life when one meet a road traffic accident. By 2020 road traffic accident is projected to become the third leading contributor to the global burden of disease in the world and 6th place as a major cause of mortality worldwide. Motor cyclists are about 25 times more risk than passenger car occupants to die because of road traffic accidents. OBJECTIVEs of the study were, to study pattern of two wheeler road traffic accidents in rural setting. Methods: The present research is a retrospective analysis of all the two-wheeler accidents victim admitted in emergency, during the period ranging from September 2015 to February 2016. Results: Among the total 2,544 patient of RTA admitted within the study period; 1,257 patients (i.e.49.41%) were due to two-wheeler accidents. Next is pedestrian (n=516, 20.2%), light motor vehicle (n=464, 18.23%), and heavy motor vehicle accidents contribute (n=307, 12.06%). Conclusions: lack of road driving sense and lack of knowledge of traffic rules. Regarding the type of vehicles involved in these accidents, the maximum number of accidents was due to two wheeler vehicles (scooter/motorcycle). Keywords: Two wheeler RTA, Stray animals, Rural RTA

Low Energy Neutrino and Dark Matter Physics with sub‐keV Germanium Detectors

A TEXONO collaboration research program on low energy neutrino and dark matter physics is going on at the Kuo‐Sheng Neutrino Laboratory (KSNL). Collaboration main goals are to measure the neutrino‐nucleus coherent scattering cross section, neutrino magnetic moments, and the searches of WIMP dark matter. To achieve these goals various prototype detectors and their sub‐keV background are under study. A threshold of 220 eV was achieved with prototype detectors at the KSNL. New limits were set for WIMPs with mass between 3‐6 GeV. Data are being taken with a 500 g Point Contact Germanium detector, where a threshold of ∼350 eV was demonstrated. A 20 g ULEGe detector is taking data at CJPL in Sichuan, China.