我们测量了一种新的组合的两个气体电子倍增器与Micromegas作为放大装置在高速率气体时间投影室使用的属性。这种设计的目标是最大限度地减少这种探测器的漂移体积中的空间电荷的积累，以消除标准的门控网格及其产生的死区时间，同时保持良好的跟踪和粒子识别性能。我们测量了正离子回流和能量分辨率在各种元素的增益和电场，使用各种气体，并另外研究了串扰效应和放电率。在增益为2000时，该配置实现了低于0.4%的离子回流和优于$^{55}$ Fe X射线的$σ/\text{E}=12\%$的能量分辨率。
英文摘要：
We measured the properties of a novel combination of two Gas Electron Multipliers with a Micromegas for use as amplification devices in high-rate gaseous time projection chambers. The goal of this design is to minimize the buildup of space charge in the drift volume of such detectors in order to eliminate the standard gating grid and its resultant dead time, while preserving good tracking and particle identification performance. We measured the positive ion back-flow and energy resolution at various element gains and electric fields, using a variety of gases, and additionally studied crosstalk effects and discharge rates. At a gain of 2000, this configuration achieves an ion back-flow below 0.4% and an energy resolution better than $σ/\text{E}=12\%$ for $^{55}$Fe X-rays.
T2K is a long baseline neutrino experiment that has been operating since 2009 providing some of the world-wide leading measurements for neutrino oscillation parameters. An upgrade for the Near Detector, ND280, of T2K has been proposed. It includes the installation of two new Time Projection Chambers (TPC) based on a new read-out technology: the resistive anode MicroMegas (RMM). This technology is expected to reduce the number of electronic channels while maintaining or improving the current ND280 TPCs' bulk MicroMegas perfomance. A series of tests have been performed and further studies are on…
We report the design, construction, and initial commissioning results of a large high pressure gaseous Time Projection Chamber (TPC) with Micromegas modules for charge readout. The detector vessel has an inner volume of about 600 L and an active volume of 270 L. At 10 bar operating pressure, the active volume contains about 20 kg of xenon gas and can image charged particle tracks. Drift electrons are collected by the charge readout plane, which accommodates a tessellation of seven Micromegas modules. Each of the Micromegas covers a square of 20 cm by 20 cm. A new type of Microbulk Micromegas i…
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…
Test in a beam of large-area Micromegas chambers for sampling calorimetry
Micromegas在取样量热法中的应用对这种气体检测器的设计和性能提出了具体的限制。特别是，均匀和线性的响应，低噪声和稳定性对高电离密度沉积物是实现良好的能量分辨率的先决条件。提出了一种基于Micromegas的强子量能器，用于未来的直线对撞机实验，并建造了三个技术先进的1 $\times$ 1 m $^{2}$原型。他们的优点相对于上述标准进行了讨论的基础上进行的测量在欧洲核子研究中心SPS试验束设施。
The readout electronics of a Micromegas (MM) module consume nearly 26 W of electric power, which causes the temperature of electronic board to increase upto $70\,^{\circ}{\rm C}$. Increase in temperature results in damage of electronics. Development of temperature gradient in the Time Projection Chamber (TPC) may affect precise measurement as well. Two-phase CO$_2$ cooling has been applied to remove heat from the MM modules during two test beam experiments at DESY, Hamburg. Following the experimental procedure, a comprehensive study of the cooling technique has been accomplished for a single M…
An upgrade of the Near Detector of the T2K long baseline neutrino oscillation experiment, ND280, has been proposed. This upgrade will include two new Time Projection Chambers, each equipped with 16 resistive MicroMegas modules for gas amplification. A first prototype of resistive MicroMegas has been designed, built, installed in the HARP field cage, and exposed to a beam of charged particles at CERN. The data have been used to characterize the performances of the resistive MicroMegas module. A spatial resolution of 300 $μm$ and a deposited energy resolution of 9% were observed for horizontal e…
本文评述了1 m ~ 3半数字式强子量能器的研制和测试工作。原型采样平面将由1平方米的Micromegas室组成，具有1平方厘米的粒度和嵌入式2位读数，适用于ILC检测器处的PFA量热法。首先介绍1平方米腔室的设计，然后概述小型原型的基本性能。构成1 m2腔室的基本单元是32个\times 48 cm 2板，带有集成电子器件和微网。示出了这些板的特征化测试的结果。Micromegas作为比例探测器非常适合于半数字强子量热法。为了量化使用一个或多个阈值时的性能增益，正在进行模拟研究，其中一些将在本文中报道。
The second phase of the T2K experiment is expected to start data taking in autumn 2022. An upgrade of the Near Detector (ND280) is under development and includes the construction of two new Time Projection Chambers called High-Angle TPC (HA-TPC). The two endplates of these TPCs will be paved with eight Micromegas type charge readout modules. The Micromegas detector charge amplification structure uses a resistive anode to spread the charges over several pads to improve the space point resolution. This innovative technique is combined with the bulk-Micromegas technology to compose the "Encapsula…
A full-size prototype of a Micromegas precision tracking chamber for the upgrade of the ATLAS detector at the LHC Collider has been built between October 2015 and April 2016. This paper describes in detail the procedures used in constructing the single modules of the chamber in various INFN laboratories and the final assembly at the Laboratori Nazionali di Frascati (LNF). Results of the chamber exposure to the CERN SPS/H8 beam line in June 2016 are also presented. The performances achieved in the construction and the results of the test beam are compared with the requirements, which are impose…
The MICROMEGAS (MICRO-MEsh GAseous Structure) charge amplification structure has found wide use in many detection applications, especially as a gain stage for the charge readout of Time Projection Chambers (TPCs). Here we report on the behavior of a MICROMEGAS TPC when operated in a high-energy (up to 800 MeV) neutron beam. It is found that neutron-induced reactions can cause discharges in some drift gas mixtures that are stable in the absence of the neutron beam. The discharges result from recoil ions close to the MICROMEGAS that deposit high specific ionization density and have a limited dif…
Characterization of Charge Spreading and Gain of Encapsulated Resistive Micromegas Detectors for the Upgrade of the T2K Near Detector Time Projection Chambers
Micromegas TPC studies at high magnetic fields using the charge dispersion signal
国际直线对撞机（ILC）时间投影室（TPC）的横向空间点分辨率目标是100微米的所有轨道，包括刚性90度轨道与完整的2米漂移。微图案气体检测器（MPGD）读出TPC可以以增加的检测器成本和复杂性为代价，利用使用1 mm或更窄的焊盘的现有技术来实现目标分辨率。新的电荷分散MPGD读出技术可以实现良好的分辨率，而不诉诸窄垫。这已经在之前的宇宙射线测试和1特斯拉磁体中的KEK束测试中针对具有GEM和Micromegas的2 mm x 6 mm垫进行了证明。我们最近在DESY的高场超导磁体中测试了使用电荷分散读出概念的Micromegas-TPC。测得的Micromegas增益被发现是恒定的磁场高达5特斯拉的0.5%。在高磁场的横向扩散的强烈抑制，我们测量了一个平坦的50微米的分辨率在5特斯拉超过我们的原型TPC的整个15厘米的漂移长度。
First operation and drift field performance of a large area double phase LAr Electron Multiplier Time Projection Chamber with an immersed Greinacher high-voltage multiplier
The ALICE Time Projection Chamber has just been upgraded by replacing the readout chambers, which cover the two ends of the cylinder, with new detectors based on the Gas Electron Multiplier (GEM) technology. We report here on the related activities at GSI Darmstadt: GEM framing and chamber production, as well as the quality assurance accompanying both procedures.
We report on a systematic characterization of microbulk Micromegas readouts in high-pressure Ar+1%iC4H10 and Ne+2%iC4H10 mixtures. Experimental data on gain, electron transmission and energy resolution are presented for a wide range of drift and amplification voltages and pressures from 1 bar to 10 bar for argon and from 5 bar to 10 bar in neon, in steps of 1 bar. Maximum gains higher than 1.7e3 (1.7e4) in argon (neon) are measured for all pressures, remarkably without the significant decrease with pressure typically observed in other amplification structures. A competitive energy resolution a…
Absolute measurements of neutron flux are an essential prerequisite of neutron-induced cross section measurements, neutron beam lines characterization and dosimetric investigations. A new gaseous detector has been developed for measurements of 0.2 to 2 MeV neutron flux based on proton-recoil process. The detector, consisting of two segmented ionization chambers read by Micromegas technology, has beed conceived to provide quasi-absolute neutron flux measurements with an accuracy of \simeq3%. The gas pressure flexibility makes the telescope non sensitive to γ and electrons background, and theref…
In experiments searching for rare signals, background events from the detector itself are some of the major factors limiting search sensitivity.Screening for ultra-low radioactive detector materials is becoming ever more essential. We propose to develop a gaseous time projection chamber (TPC) with a Micromegas readout for radio screening. The TPC records three-dimensional trajectories of charged particles emitted from a flat sample placed in the active volume of the detector. The detector can distinguish the origin of an event and identify the particle types with information from trajectories,…
A hybrid structure gaseous detector for ion backflow suppression*
提出了一种用于未来圆对撞机时间投影室的混合结构离子回流抑制气体探测器组件的新概念。它是一个混合结构级联气体电子倍增器（GEM）与Micromegas检测器。Micromegas和GEM都有能力自然减少放大区产生的大部分离子。GEM还充当前置放大器设备，并与Micromegas一起增加气体增益。混合探测器的可行性测试使用${}^{55}$ Fe X射线源进行。对于5.9keV的X射线，能量分辨率优于27%。结果表明，在增益为5000的混合读出结构中，回流比可以达到优于0.2%。
Performance of a Time-Projection-Chamber with a Large-Area Micro-Pixel-Chamber Readout
研制了探测体积为23*28*31 cm ^3的微型时间投影室，并对其基本性能进行了测试。微TPC由一个探测面积为31*31 cm ^2的微像素室作为二维成像装置和一个有效面积为23*28 cm ^2的气体电子倍增器作为前置气体倍增器组成。微型TPC在50，000的气体增益下运行，并测量了能量分辨率和空间分辨率。
Construction and operation of a Double Phase LAr Large Electron Multiplier Time Projection Chamber
我们成功地运行了一种新型的基于大电子倍增器（LEM）读出系统的LAr时间投影室。原型，约3升的有效体积，是在液-气（双）相纯Ar。在LAr体积中漂移后，电离电子被一组网格提取到气相中，并被驱动到双级LEM的孔中，在那里发生电荷放大。每个LEM都是一个10 x 10 cm $^2$厚的宏观孔倍增器，采用标准PCB技术制造。电子信号通过两个正交坐标读出，一个使用LEM本身的分段上电极上的感应信号，另一个通过收集分段阳极上的电子。定制的前置放大器已专门为此目的而开发。在室温纯气体和双相Ar操作中，已成功地观测到宇宙线径迹。我们相信，这一原则的证明是一个重要的里程碑，在实现非常大，长漂移（成本效益）LAR探测器的下一代中微子物理和质子衰变实验，以及直接搜索暗物质与成像设备。
