Particle tracks and differential energy loss measured in high pressure gaseous detectors can be exploited for event identification in neutrinoless double beta decay~($0νββ$) searches. We develop a new method based on Kalman Filter in a Bayesian formalism (KFB) to reconstruct meandering tracks of MeV-scale electrons. With simulation data, we compare the signal and background discrimination power of the KFB method assuming different detector granularities and energy resolutions. Typical background from $^{232}$Th and $^{238}$U decay chains can be suppressed by another order of magnitude than that in published literatures, approaching the background-free regime. For the proposed PandaX-III experiment, the $0νββ$ search half-life sensitivity at the 90\% confidence level would reach $2.7 \times 10^{26}$~yr with 5-year live time, a factor of 2.7 improvement over the initial design target.
We have developed a dedicated front-end-electronics board for a high-pressure xenon gas time projection chamber for a neutrinoless double-beta decay search. The ionization signal is readout by detecting electroluminescence photons with SiPM's. The board readout the signal from 56~SiPM's through the DC-coupling and record the waveforms at 5 MS/s with a wide dynamic range up to 7,000 photons/200 ns. The SiPM bias voltages are provided by the board and can be adjusted for each SiPM. In order to calibrate and monitor the SiPM gain, additional auxiliary ADC measures 1 photon-equivalent dark current…
Measurement of scintillation and ionization yield with high-pressure gaseous mixtures of Xe and TMA for improved neutrinoless double beta decay and dark matter searches
We propose a novel charge sensing concept for high-pressure Time Projection Chamber (TPC) to search for Neutrinoless Double-Beta Decay (NLDBD) with ton-scale isotope mass and beyond. A meter-sized plane, tiled with an array of CMOS integrated sensors called Topmetal that directly collect charge without gas avalanche gain, is to be deployed into a high-pressure gaseous TPC with working gases containing suitable NLDBD candidate isotopes such as Xe-136 and Se-82. The Topmetal sensor has an electronic noise <30 e- per pixel, which allows the detector to reach <1% FWHM energy resolution at the NLDB…
Measurement of scintillation and ionization yield with high-pressure gaseous mixtures of Xe and TMA for improved neutrinoless double beta decay and dark matter searches
A MIDAS-based Data Acquisition System for Gaseous Detectors
INPAC and School of Physics and Astronomy, Shanghai Jiao Tong University（上海交通大学物理与天文学院）；Shanghai Jiao Tong University Sichuan Research Institute（上海交通大学四川研究院）；SPEIT (SJTU-Paris Elite Institute of Technology), Shanghai Jiao Tong University（上海交通大学巴黎精英高等研究院）；School of Physics, Sun Yat-Sen University（中山大学物理学院）
Low radioactive material screening is becoming essential for rare event search experiments, such as neutrinoless double beta decay and dark matter searches in underground laboratories. A gaseous time projection chamber (TPC) can be used for such purposes with large active areas and high efficiency. A gaseous TPC with a Micromegas readout plane of approximately 20$\times$20 cm$^2$ is successfully constructed for surface alpha contamination measurements. We have characterized the energy resolution, gain stability, and tracking capability with calibration sources. With the unique track-related ba…
Xenon time projection chambers (TPCs) have become a well-established detection technology for neutrinoless double beta decay searches in $^{136}$Xe. I discuss the motivations for this choice. I describe the status and prospects of both liquid and gaseous xenon TPC projects for double beta decay.
The nature of the neutrino is one of the major open questions in experimental nuclear and particle physics. The most sensitive known method to establish the Majorana nature of the neutrino is detection of the ultra-rare process of neutrinoless double beta decay. However, identification of one or a handful of decay events within a large mass of candidate isotope, without obfuscation by backgrounds is a formidable experimental challenge. One hypothetical method for achieving ultra-low-background neutrinoless double beta decay sensitivity is the detection of single $^{136}$Ba ions produced in the…
The PandaX-III experiment plans to search for neutrinoless double beta decay (0$νββ$) of $^{136}$Xe in the China JinPing underground Laboratory (CJPL). The experiment will use a high pressure gaseous Time Projection Chamber (TPC) to register both the energy and the electron track topology of an event. This article is devoted to the software side of the experiment. As software tool we use REST, a framework developed for the reconstruction and simulation of TPC-based detector systems. We study the potential for background reduction by introducing appropiate parameters based on the properties of …
An important issue for rare-event-search experiments, such as the search for dark matter or neutrinoless double beta decay, is to reduce radioactivity of the detector materials and the experimental environment. The selection of materials with low radioactive impurities, such as isotopes of the uranium and thorium chains, requires a precise measurement of surface and bulk radioactivity. Focused on the first one, an alpha-particle detector has been developed based on a gaseous micro-time-projection chamber. A low-alpha mu-PIC with reduced alpha-emission background was installed in the detector. …
Pattern recognition of $^{136}$Xe double beta decay events and background discrimination in a high pressure Xenon TPC
高压气体探测器为检测罕见事件提供了优势，其中背景减少至关重要。高压氙气时间投影室（TPC）对136氚的无中微子双β衰变具有很好的能量分辨率和详细的拓扑信息。气态氙中136氘的双β衰变事件的电离拓扑结构具有由两个离散电子径迹定义的特征形状，这两个电子径迹最终形成两个较高电离电荷密度的斑点。通过适当的像素化读出，这种拓扑信息对于执行强大的背景区分是非常宝贵的。在这项研究中，我们进行了详细的模拟信号的拓扑结构，以及竞争的拓扑结构，从伽马事件，通常构成在这些能量的背景。我们基于图论概念定义了可观测量，并开发了自动判别算法，该算法将背景水平降低了约三个数量级，同时保持了40%的信号效率。这一结果支持了目前或未来基于气体TPC的双β实验的竞争力，例如目前正在Canfranc Subaragio de Canfranc（LSC）建造的中微子氙TPC（NEXT）。
