A low background Micromegas detector for the CAST experiment
P. Abbon, S. Andriamonje, S. Aune, D. Besin, S. Cazaux, P. Contrepois, T. Dafni, T. Decker, N. Duportail, G. Fanourakis, E. Ferrer Ribas, T. Geralis, A. Giganon… 展开作者
P. Abbon, S. Andriamonje, S. Aune, D. Besin, S. Cazaux, P. Contrepois, T. Dafni, T. Decker, N. Duportail, G. Fanourakis, E. Ferrer Ribas, T. Geralis, A. Giganon, I. Giomataris, M. Gros, R. Hill, I. G. Irastorza, K. Kousouris, J. Morales, M. Pivovaroff, M. Riallot, R. Soufli, K. Zachariadou, G. Zaffanela
备注：
6 pages, 3 figures To appear on the proceedings of the 9th ICATPP Conference on AStroparticle, Particle, Space Physics, Detectors and Medical Physics Applications
在欧洲核子研究中心的CAST实验第一阶段（2002-2004年），一个低本底Micromegas探测器一直在运行，用于搜索太阳轴子。由于其良好的空间和能量分辨率以及在探测器构造中使用的低放射性材料，该探测器有效运行并实现了非常低水平的背景抑制（$5\times 10^{-5}$计数keV $^{-1}$ cm $^{-2}$ s $^{-1}$）。在实验的第二阶段（2005-2007年），将对探测器进行升级，增加一个屏蔽装置并包括聚焦光学系统。这些改进应允许优于两个数量级的背景抑制。
英文摘要：
A low background Micromegas detector has been operating on the CAST experiment at CERN for the search of solar axions during the first phase of the experiment (2002-2004). The detector operated efficiently and achieved a very low level of background rejection ($5\times 10^{-5}$ counts keV$^{-1}$cm$^{-2}$s$^{-1}$) thanks to its good spatial and energy resolution as well as the low radioactivity materials used in the construction of the detector. For the second phase of the experiment (2005-2007), the detector will be upgraded by adding a shielding and including focusing optics. These improvements should allow for a background rejection better than two orders of magnitude.
Micromegas detectors are a relatively modern design concept for micropattern gas detectors, designed to handle high particle flux while providing high gain, high spatial resolution, and fast response times for a variety of radiation detection applications. Due to the advancement of industry, building a micromegas detector without advanced in-house capabilities is now possible. In this work, we present an innovative method to build micromegas detectors utilizing precision manufacturers to fabricate the core components. Two detectors were built using the newly described method and are experiment…
Micromegas detector is considered to be a promising candidate for a large variety of high-rate experiments. Micromegas of various geometries have already been established as appropriate for these experiments for their performances in terms of gas gain uniformity, energy and space point resolution, and their capability to efficiently pave large read-out surfaces with minimum dead zone. The present work investigates the effect of spacers on different detector characteristics of Micromegas detectors having various amplification gaps and mesh hole pitches. Numerical simulation has been used as a t…
The most compelling candidates for Dark Matter to day are WIMPs and axions. The applicability of gasesous Time Projection Chambers (TPCs) with Micromesh Gas Structures (Micromegas) to the search of these particles is explored within this work. Both particles would produce an extremely low rate at very low energies in particle detectors. Micromegas detectors can provide both low background rates and low en- ergy threshold, due to the high granularity, radiopurity and uniformity of the readout. Small (few cm wide) Micromegas detectors are used to image the axion-induced x-ray signal expected in …
For manufacturing Micromegas detectors, the "bulk" method based on photoetching, was successfully developed and widely used in nuclear and particle physics experiments. However, the complexity of the method requires a considerable number of advanced instruments and processing, limiting the accessibility of this method for production of Micromegas detectors. In view of these limitations with the bulk method, a new method based on thermal bonding technique (TBM) has been developed to manufacture Micromegas detectors in a much simplified and efficient way without etching. This paper describes the…
Axions are well motivated particles proposed in an extension of the SM as a solution to the strong CP problem. Also, there is the category of Axion-Like Particles (ALPs) which appear in extensions of the SM and share the same phenomenology of the axion. Axions and ALPs are candidates to solve the Dark Matter problem. CAST, the CERN Axion Solar Telescope is looking for solar axions since 2003. CAST exploit the helioscope technique using a decommissioned LHC dipole magnet in which solar axions could be reconverted into photons. Three of the four detectors operating at CAST are of the Micromegas …
In this paper, the design and the performance of two prototype detectors based on Micromegas technology with a pad readout geometry is discussed. In addition, two alternative implementations of a spark-resistent protection layer on top of the readout pads have been tested to optimize the charge-up behavior of the detector under high rates. The prototype detectors consist of 500 pads with a size of 5x4 mm, each connected to one independent readout channel, and cover an active area of 10x10 cm. The design of these prototypes and its associated readout infrastructure was developed in such a way t…
To fulfill needs in oncological research a new Micromegas detector has been developed to follow radiolabelled drugs in living organisms at the single cell level. This article describes the proof-of-concept of such a detector and compares its ability to detect and assess sub-becquerel \tritium~activities with a commercial $β$-imager
The operation of gas detectors is often limited by secondary effects, originating from avalanche-induced photons and ions. Ion backflow is one of the effects limiting the operation of a gas detector at high flux, by giving rise to space charge which disturbs the electric field locally. For the Micromegas detector, a large fraction of the secondary positive ions created in the avalanche can be stopped at the micro-mesh. The present work involves measurements of the ion backflow fraction (using an experimental setup comprising of two drift planes) in bulk Micromegas detectors as a function of de…
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…
CAST microbulk micromegas in the Canfranc Underground Laboratory
在CAST实验的最后一次数据采集活动中，微兆气体探测器已经实现了$\approx 5 \times 10^{-6}$ keV $^{-1}$ cm $^{-2}$ s $^{-1}$在2和9 keV之间的背景水平。这种性能是可能的，这要归功于微批量技术的引入，屏蔽的实施和歧视算法的发展。它激发了新的研究，以更深入地了解CAST探测器的背景。其中一条工作线包括建造一个微型气体探测器在CAST中使用的装置的复制品，并将其安装在Canfranc地下实验室。由于地下和地面探测器性能之间的比较，屏蔽升级等，对探测器背景的不同贡献进行了评估。特别地，已经获得了检测器的本征背景的上限$< 2 \times 10^{-7}$ keV $^{-1}$ cm $^{-2}$ s $^{-1}$。这项工作意味着在地下实验室中对最新的micromegas技术的潜力进行了首次评估，这是最适合稀有事件探测的环境。
We report on the construction and initial performance studies of two micromegas detector quadruplets with an area of 0.5 m$^2$. They serve as prototypes for the planned upgrade project of the ATLAS muon system. Their design is based on the resistive-strip technology and thus renders the detectors spark tolerant. Each quadruplet comprises four detection layers with 1024 readout strips and a strip pitch of 415 $μ$m. In two out of the four layers the strips are inclined by $\pm$1.5$^{\circ}$ to allow for the measurement of a second coordinate. We present the detector concept and report on the exp…
Solar axions could be converted into x-rays inside the strong magnetic field of an axion helioscope, triggering the detection of this elusive particle. Low background x-ray detectors are an essential component for the sensitivity of these searches. We report on the latest developments of the Micromegas detectors for the CERN Axion Solar Telescope (CAST), including technological pathfinder activities for the future International Axion Observatory (IAXO). The use of low background techniques and the application of discrimination algorithms based on the high granularity of the readout have led to…
The present work involves the comparison of various bulk Micromegas detectors having different design parameters. Six detectors with amplification gaps of $64,~128,~192,~220 ~μ\mathrm{m}$ and mesh hole pitch of $63,~78 ~μ\mathrm{m}$ were tested at room temperature and normal gas pressure. Two setups were built to evaluate the effect of the variation of the amplification gap and mesh hole pitch on different detector characteristics. The gain, energy resolution and electron transmission of these Micromegas detectors were measured in Argon-Isobutane (90:10) gas mixture while the measurements of t…
Spatial resolution improvement of PICOSEC Micromegas precise timing detectors
CERN（欧洲核子研究组织）；Aristotle University of Thessaloniki（塞萨洛尼基亚里士多德大学）；Ludwig Maximilian University of Munich（慕尼黑路德维希-马克西米利安大学）；Stony Brook University（石溪大学）；NCSR Demokritos（德谟克利特国家科学研究中心）；Laboratório de Instrumentação e Física Experimental de Partículas (LIP)（粒子物理与实验仪器实验室）；University of Helsinki（赫尔辛基大学）；Jefferson Lab（杰斐逊国家加速器装置）；University of Zagreb（萨格勒布大学）；University of Science and Technology of China（中国科学技术大学）；University of Bonn（波恩大学）；CEA-Saclay（法国原子能和替代能源委员会萨克雷中心）；National Technical University of Athens（雅典国立技术大学）；Ruđer Bošković Institute（鲁杰尔·博什科维奇研究所）；University of Virginia（弗吉尼亚大学）
X-ray detection with Micromegas with background levels below 10$^{-6}$ keV$^{-1}$cm$^{-2}$s$^{-1}$
Micromegas探测器是探测低能X射线的最佳技术选择。多年来，应用于这些探测器的低本底技术产生了显着的本底降低，成为这些发展的CAST实验受益者。在本文件中，我们报告了最新的升级，以进一步减少背景和更好地了解探测器的响应。升级包括读出电子设备，新的探测器设计和更有效的宇宙μ子否决系统的实施。首次在海平面获得了低于10 $^{-6}$ keV $^{-1}$ cm $^{-2}$ s $^{-1}$的本底能级，证明了下一代轴子日像仪IAO所提出的期望的可行性。本文还将介绍和讨论在CAST探测器实验室的X射线束中进行的一系列测量所获得的一些结果。
The search for weakly interacting, light particles that couple to photons received significant attention in recent years. When those particles are produced at high energies, they lead to two, nearly collinear photons after their decay and hence can be detected by an electromagnetic calorimeter system. The typical dominant background in searches for those high energetic weakly particles are single, high energetic photons, which leave similar signatures in a standard calorimeter system. One promising approach to separate signal from background events is to employ a dedicated pre-shower detector …
The Micro-Pattern Gaseous Detectors (MPGD) have been widely adopted in nuclear and particle physics experiments, for their fast response and other excellent characteristics. To achieve the required signal strength and detection efficiency, sometimes they are operated at a high voltage range. This often challenges the limit of high voltage stability of the detector. Discharge in gaseous detectors is a complex process and involves several responsible factors. The microscopic geometrical structures of the MPGDs may itself sometimes induce discharges. In this study, we are numerically investigatin…
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…
A MICROMEGAS detection amplifier has been incorporated into the design of the TAMU MDM focal plane detector with the purpose of improving the energy resolution and thus, the particle identification. Beam tests showed a factor of 2 improvement over the original design, from 10-12% to 4-6%, for ions with A<40 at E/A around 10-20 MeV.
This work aims at the development of signal processing algorithms that can explore the potential of a PICOSEC-MicroMegas detector and offers the ability for online, precise timing. The PICOSEC-MicroMegas detector is a novel gaseous detector offering precise timing resolution in experimental measurements. The performance of the proposed signal processing algorithms is evaluated by a variety of tests using experimental data. The data used in the present research were accumulated during a Laser Beam Test at CEA/IRAMIS-SACLAY. We use two sets of experimental events: the SPE-set comprises single ph…
In this paper, the design and the performance of a prototype detector based on MicroMegas technology with two detection planes in a common gas volume is discussed. The detector is suited for the forward region of LHC detectors, addressing the high-rate environment and limited available space. Each detection plane has an active area of 9x9 cm^2 with a two-dimensional strip readout and is separated by a common gas region with a height of 14 mm. A micro-mesh, working as a cathode, is placed in the middle of the common gas volume separating it into two individual cells. This setup allows for an an…
Micromegas detector is a gas detector with parallel plate structure, and it consists of a conversion gap in which radiations liberate ionization electrons and a thin amplification gap. The signal of the micromegas detector consists of two parts: the electron peak and the ion tail. The electronic signal just keeps few nanoseconds, which is used for precise time measurement. The ion signal carries most of the signal energy, and it is used to reconstruct particle energy. The micromegas detector has the advantages of high counting rate, high gain, good time resolution and position resolution, exce…
The prospect of pileup induced backgrounds at the High Luminosity LHC (HL-LHC) has stimulated intense interest in developing technologies for charged particle detection with accurate timing at high rates. The required accuracy follows directly from the nominal interaction distribution within a bunch crossing ($σ_z\sim5$ cm, $σ_t\sim170$ ps). A time resolution of the order of 20-30 ps would lead to significant reduction of these backgrounds. With this goal, we present a new detection concept called PICOSEC, which is based on a "two-stage" Micromegas detector coupled to a Cherenkov radiator and …
