No Arabic abstract
LEGEND, the Large Enriched Germanium Experiment for Neutrinoless $betabeta$ Decay, is a ton-scale experimental program to search for neutrinoless double beta ($0 ubetabeta$) decay in the isotope $^{76}$Ge with an unprecedented sensitivity. Building on the success of the low-background $^{76}$Ge-based GERDA and MAJORANA DEMONSTRATOR experiments, the LEGEND collaboration is targeting a signal discovery sensitivity beyond $10^{28},$yr on the decay half-life with approximately $10,text{t}cdottext{yr}$ of exposure. Signal readout electronics in close proximity to the detectors plays a major role in maximizing the experiments discovery sensitivity by reducing electronic noise and improving pulse shape analysis capabilities for the rejection of backgrounds. However, the proximity also poses unique challenges for the radiopurity of the electronics. Application-specific integrated circuit (ASIC) technology allows the implementation of the entire charge sensitive amplifier (CSA) into a single low-mass chip while improving the electronic noise and reducing the power consumption. In this work, we investigated the properties and electronic performance of a commercially available ASIC CSA, the XGLab CUBE preamplifier, together with a p-type point contact high-purity germanium detector. We show that low noise levels and excellent energy resolutions can be obtained with this readout. Moreover, we demonstrate the viability of pulse shape discrimination techniques for reducing background events.
We propose the construction of LEGEND-1000, the ton-scale Large Enriched Germanium Experiment for Neutrinoless $beta beta$ Decay. This international experiment is designed to answer one of the highest priority questions in fundamental physics. It consists of 1000 kg of Ge detectors enriched to more than 90% in the $^{76}$Ge isotope operated in a liquid argon active shield at a deep underground laboratory. By combining the lowest background levels with the best energy resolution in the field, LEGEND-1000 will perform a quasi-background-free search and can make an unambiguous discovery of neutrinoless double-beta decay with just a handful of counts at the decay $Q$ value. The experiment is designed to probe this decay with a 99.7%-CL discovery sensitivity in the $^{76}$Ge half-life of $1.3times10^{28}$ years, corresponding to an effective Majorana mass upper limit in the range of 9-21 meV, to cover the inverted-ordering neutrino mass scale with 10 yr of live time.
The MAJORANA Collaboration will seek neutrinoless double beta decay (0nbb) in 76Ge using isotopically enriched p-type point contact (PPC) high purity Germanium (HPGe) detectors. A tonne-scale array of HPGe detectors would require background levels below 1 count/ROI-tonne-year in the 4 keV region of interest (ROI) around the 2039 keV Q-value of the decay. In order to demonstrate the feasibility of such an experiment, the MAJORANA DEMONSTRATOR, a 40 kg HPGe detector array, is being constructed with a background goal of <3 counts/ROI-tonne-year, which is expected to scale down to <1 count/ROI-tonne-year for a tonne-scale experiment. The signal readout electronics, which must be placed in close proximity to the detectors, present a challenge toward reaching this background goal. This talk will discuss the materials and design used to construct signal readout electronics with low enough backgrounds for the MAJORANA DEMONSTRATOR.
The MAJORANA DEMONSTRATOR is a planned 40 kg array of Germanium detectors intended to demonstrate the feasibility of constructing a tonne-scale experiment that will seek neutrinoless double beta decay ($0 ubetabeta$) in $^{76}mathrm{Ge}$. Such an experiment would require backgrounds of less than 1 count/tonne-year in the 4 keV region of interest around the 2039 keV Q-value of the $betabeta$ decay. Designing low-noise electronics, which must be placed in close proximity to the detectors, presents a challenge to reaching this background target. This paper will discuss the MAJORANA collaborations solutions to some of these challenges.
One of candidates for the International Linear Collider(ILC)s vertex detector is the Fine Pixel CCD (FPCCD) with a pixel size of 5 times 5 (mum^2). Sensor and readout systems are currently being studied and prototypes have been developed. In this paper we will report on the performance of latest developed readout ASIC prototype as well as the outline of the design strategy for the next ASIC prototype.
The aim of this work is to show the potential capabilities of monolithic crystals coupled to large SiPM arrays, to be considered as detector blocks for PET scanners enabling Time Of Flight (TOF) capabilities. Monolithic blocks allow one to decode the 3D photon impact position. This approach, along with TOF information, can be of high interest in clinical Positron emission tomography (PET) applications where a typical ring configuration is used. In this manuscript, we evaluate an ASIC- based readout for digitizing all signals coming from analog photosensors. Validation results with one-to-one coupling resulted in a Coincidence Time Resolution (CTR) of 202 ps FWHM. Providing timing resolution when using detectors based on monolithic crystals is however challenging. The wide distribution of scintillation light on the photosensors causes a poor SNR, which makes the system sensible to false triggering and to time walk errors. In this direction, we present a calibration method, designed to correct all recorded timestamps and also to compensate variations in time-paths among all channels. Thereafter, a CTR improvement nearing 45% is observed for all measurements. Moreover, we show a novel approach that describes the use of averaging methods to assign a single timestamp to each gamma impact. This approach results in a further improvement of the CTR in the range of 100 ps FWHM, reaching a time resolution of 585 ps FWHM when using a large 50x50x10 mm3 LYSO scintillator coupled to an 8x8 SiPM (6x6 mm2) array. These pilot studies show detector capabilities regarding TOF information when using monolithic scintillators.