Lowering the energy threshold of large-mass bolometric detectors

The Topo-trigger: A new stereo trigger for lowering the energy threshold of IACTs

The purpose of the hardware presented in this contribution is to decrease the energy threshold of the MAGIC telescopes without significantly increasing the data acquisition rate. To achieve this purpose, we developed an additional level of trigger that relies on the location in both MAGIC cameras where the trigger is issued to rule out accidental events. This allows to decrease the Discriminator Threshold (DT), which results in a reduction of the energy threshold of the instrument. We simulated the Topo-trigger concept using the standard MAGIC Monte Carlo (MC) and tested it with real telescope…

Lowering the low-energy threshold of xenon detectors

We show that the energy threshold for nuclear recoils in the XENON10 dark matter search data can be lowered to ~1 keV, by using only the ionization signal. In other words, we make no requirement that a valid event contain a primary scintillation signal. We therefore relinquish incident particle type discrimination, which is based on the ratio of ionization to scintillation in liquid xenon. This method compromises the detector's ability to precisely determine the z coordinate of a particle interaction. However, we show for the first time that it is possible to discriminate bulk events from surf…

Lowering the background level and the energy threshold of Micromegas x-ray detectors for axion searches

Axion helioscopes search for solar axions by their conversion in x-rays in the presence of high magnetic fields. The use of low background x-ray detectors is an essential component contributing to the sensitivity of these searches. In this work, we review the recent advances on Micromegas detectors used in the CERN Axion Solar Telescope (CAST) and proposed for the future International Axion Observatory (IAXO). The actual setup in CAST has achieved background levels below 10$^{-6}$ keV$^{-1}$ cm$^{-2}$ s$^{-1}$, a factor 100 lower than the first generation of Micromegas detectors. This reductio…

使用塑料闪烁体与辐射损伤硅光电倍增管（SiPM）降低能量阈值

Lowering the Energy Threshold using a Plastic Scintillator and Radiation-Damaged SiPMs

针对卫星轨道上SiPM辐射损伤导致闪烁体探测器能量阈值升高的问题，通过电流波形放大器、双SiPM符合求和及低温测量三种方法，可将受辐射损伤SiPM的能量阈值降至原有的约15%。

Exploiting the time of arrival of Cherenkov photons at the 28 m H.E.S.S. telescope for background rejection: Methods and performance

In 2012, the High Energy Stereoscopic System (H.E.S.S.) was expanded by a fifth telescope (CT5). With an effective mirror diameter of 28m, CT5 is able to detect the Cherenkov light of very faint gamma-ray air showers, thereby significantly lowering the energy threshold of this telescope compared to the other four telescopes. Extracting as much information as possible from the recorded shower image is crucial for background rejection and to reach an energy threshold of a few tens of GeV. The camera of CT5 is conceived to register the time of the charge pulse maximum with respect to the beginnin…

Feasibility study of dark matter searches with the CUORE experiment

CUORE will be a 1 ton experiment made of about 1000 TeO$_2$ bolometers. It will probe the neutrinoless double beta decay (0$ν$DBD) of $^{130}$Te, a tool to test the neutrino nature and mass. The excellent energy resolution and the low background of these detectors will make CUORE a leading experiment in this field, improving the sensitivity to the half-life of 0$ν$DBD by more than an order of magnitude. Bolometric detectors, however, are also sensitive to nuclear recoils and can be used to search for dark matter interactions. In principle CUORE, thanks to its mass, could look for an annual mod…