We present recent results of an extensive aging test, performed at the CERN Gamma Irradiation Facility on two single--gap RPC prototypes, developed for the LHCb Muon System. With a method based on a model describing the behaviour of an RPC under high particle flux conditions, we have periodically measured the electrode resistance R of the two RPC prototypes over three years: we observe a large spontaneous increase of R with time, from the initial value of about 2 MOhm to more than 250 MOhm. A corresponding degradation of the RPC rate capabilities, from more than 3 kHz/cm2 to less than 0.15 kHz/cm2 is also found.
Study of Performance of Bakelite Resistive Plate Chamber (RPC)
电阻板室（RPC）是一种具有良好时间和位置分辨率的气体探测器。VECC参与了本土开发的胶木RPC的研发。在印度开发的酚醛树脂RPC的最大尺寸是100 cm $\times$ 100 cm。本文介绍了胶木样品的测试结果以及在VECC制造的胶木RPC（30 cm $\times$ 30 cm $\times$ 0.2 cm）的宇宙射线测试结果。还讨论了研制大尺寸（240 cm $\times$ 120 cm $\times$ 0.2 cm）酚醛树脂RPC所采取的步骤。
Development and Characterization of 6-gap Bakelite Multi-gap Resistive Plate Chamber
多间隙电阻板室（MRPC）是电阻板室（RPC）探测器的一种先进形式，其中气体间隙被划分为子间隙。MRPC以其良好的时间分辨率和对带电粒子的检测效率而闻名。他们已经在几个高能物理实验中找到了合适的应用，如LHC的ALICE，CERN，日内瓦，瑞士，RHIC，BNL，美国的STAR。由于它们具有非常好的时间分辨率并且成本低，因此它们可以是用于正电子发射断层成像成像的非常昂贵的闪烁器的合适替代品。现在使用的MRPC是用玻璃电极开发的。我们尝试用胶木电极研制了一种6间隙MRPC。外电极的尺寸为15 cm $\times$ 15 cm $\times$ 0.3 cm，内电极的尺寸为14 cm $\times$ 14 cm $\times$ 0.05 cm。光滑的成品电极表面没有经过任何油处理，如亚麻籽，硅油，以获得光滑度。用宇宙射线测量了探测器的效率、噪声率和时间分辨率。这项工作的目标是使用MRPC开发具有飞行时间技术的正电子发射断层成像原型。开发程序和性能研究的详细信息已在此处介绍。
The Muon Chamber (MuCh) is a sub-system of the Compressed Baryonic Matter (CBM) experiment for the detection of low-mass-vector mesons produced in high energy heavy-ion collisions at beam energies ranging from 2 AGeV to 11 AGeV and decaying in the di-muon channel. MuCh consists of a segmented absorber and four detector triplet stations sandwiched between the absorber segments. At the 3rd and 4th stations of MuCh, Resistive Plate Chambers (RPCs) have been conceived for muon tracking. We have tested the performance of a low resistivity bakelite RPC prototype equipped with self-triggered front en…
In the High Luminosity Large Hadron Collider (HL-LHC) program, during the next years, the instantaneous luminosity will increase up to 5 $\times$ 10$^{34}$ cm$^{-2}$ s$^{-1}$ which means a factor five higher than the nominal LHC. In that period, the present CMS Resistive Plate Chambers (RPC) system will be subjected to background rates higher than those for which the detectors have been designed, which could affect the detector properties and induce aging effects. To study whether the present RPC system can sustain the hard background conditions during the HL-LHC running period, a dedicated lo…
Due to their simplicity and comparatively low cost Resistive Plate Chambers are gaseous detectors widely used in high-energy and cosmic rays physics when large detection areas are needed. However, the best gaseous mixtures are currently based on tetrafluoroethane, which has the undesirable characteristic of a large Global Warming Potential (GWP) of about 1400 and because of this, it is currently being phased out from industrial use. As a possible replacement, tetrafluoropropene (which has a GWP close to 1) has been taken into account. Since tetrafluoropropene is more electronegative than tetra…
Due to their simplicity and comparatively low cost, Resistive Plate Chambers are gaseous detectors widely used in high-energy and cosmic rays physics, when large detection areas are needed. However, the best gaseous mixtures are currently based on tetrafluoroethane, which has the undesirable characteristic of a large Global Warming Potential (GWP) of about 1400 and, because of this, it is currently being phased out from industrial use. Tetrafluoropropene (which has a GWP close to 1) is being considered as a possible replacement. Since tetrafluoropropene is more electronegative than tetrafluoro…
The ALICE Muon IDentifier is composed of 72 single-gap bakelite Resistive Plate Chambers, which have been operational since 2009 in maxi-avalanche mode (discrimination threshold:7 mV without amplification) with a Tetrafluoroethane/Isobutane/Sulfur Hexafluoride gas mixture, undergoing counting rates of the order of tens of Hz/cm^2. In this talk, the long-term performance and stability of the RPC system will be discussed, in terms of efficiency, dark current and dark rate. An assessment of potential signs of ageing observed on the detectors will be presented, together with a summary of the most …
India-based Neutrino Observatory (INO) facility is going to have a 50 kton magnetized Iron CALorimeter (ICAL) detector for precision measurements of neutrino oscillations using atmospheric neutrinos. The proposed ICAL detector will be a stack of magnetized iron plates (acting as target material) interleaved with glass Resistive Plate Chambers (RPCs) as the active detector elements. An RPC is a gaseous detector made up of two parallel electrode plates having high bulk resistivity like that of float glass and bakelite. For the ICAL detector, glass is preferred over bakelite as it does not need a…
The intrinsic rate capability and the ageing properties of the Resistive Plate Chambers are closely related to the electrodes material and to the front-end electronics threshold. The development of a low noise pre-amplifier led us to improve the intrinsic rate capability of High Pressure Laminate (bakelite) up to $\sim10\;kHz/cm^2$, nevertheless the effective rate is significantly limited by electrodes ageing. To further improve the effective rate capability new materials are investigated. A Resistive Plate Chamber with crystalline semi-insulating Gallium Arsenide electrodes has been character…
ALICE μ子触发器目前由一个探测器产生，该探测器目前由72个以最大雪崩模式运行的胶木单间隙电阻板室组成，排列在四个5.5x6.5平方米的探测平面上。为了满足即将从2021年开始的LHC高亮度运行的要求，其中ALICE将以连续模式读出，μ子触发器将成为μ子标识符，并将进行重大升级。在当前设置中，来自约21k条的信号由2400个非放大前端（FEE）卡区分，其阈值由外部模拟电压提供（每个腔室侧一个）。所有这些卡将被配备有前置放大级的鉴别器所取代，这将允许降低探测器的操作高压，从而延长其寿命。此外，它们的参考阈值将通过无线（和每个腔室侧链接的I2C）传递，允许在单个卡级别调整值。此外，24个暴露最多的室将被更换为新的，配备高质量（即更光滑的表面）电木层压板。报告了在测试台和探测器上使用的新FEE卡以及在新RPC室（带有宇宙射线）上进行的测试。
The CMS Resistive Plate Chamber (RPC) system has been certified for 10 years of LHC operation. In the next years, during the High luminosity LHC (HL-LHC) phase, the LHC instantaneous luminosity will increase to a factor five more than the existing LHC luminosity. This will subject the present CMS RPC system to background rates and operating conditions much higher with respect to those for which the detectors have been designed. Those conditions could affect the detector properties and introduce nonrecoverable aging effects. A dedicated longevity test is set up in the CERN Gamma Irradiation Fac…
The Extreme Energy Events (EEE) experiment, dedicated to the study of secondary cosmic rays, is arguably the largest detector system in the world implemented by Multigap Resistive Plate Chambers. The EEE network consists of 60 telescopes distributed over all the Italian territory; each telescope is made of three MRPCs and allows to reconstruct the trajectory of cosmic muons with high efficiency and optimal angular resolution. A distinctive feature of the EEE network is that almost all telescopes are housed in High Schools and managed by groups of students and teachers, who previously took care…
The India-based Neutrino Observatory Project (INO) is a proposed underground high energy physics experiment at Theni, India to study the neutrino oscillation parameters using atmospheric neutrinos. The 50 kton magnetised INO-ICAL detector will require approximately 30,000 of 2m$\times$2m Resistive Plate Chambers (RPC) as sensitive detectors and proposed to operate for about 20 years. For success of the experiment, each of the RPCs has to function without showing any significant aging during the period of operation. Hence, various tests including a proper leak test are performed during and afte…
During the upcoming High Luminosity phase of the Large Hadron Collider (HL-LHC), the integrated luminosity of the accelerator will increase to 3000 fb$^{-1}$. The expected experimental conditions in that period in terms of background rates, event pileup, and the probable aging of the current detectors present a challenge for all the existing experiments at the LHC, including the Compact Muon Solenoid (CMS) experiment. To ensure a highly performing muon system for this period, several upgrades of the Resistive Plate Chamber (RPC) system of the CMS are currently being implemented. These include …
The ALICE RPCs are operated with a mixture of 89.7% $C_{2}H_{2}F_{4}$, 10% i-$C_{4}H_{10}$ and 0.3% $SF_{6}$. $C_{2}H_{2}F_{4}$ and $SF_{6}$ are fluorinated greenhouse gases with a high Global Warming Potential (GWP). New European Union regulations have imposed a progressive phase-down of the production and usage of F-gases, aiming to cut down their emission by two thirds in 2030 with respect to 2014. Even though research activities are excluded from these regulations, the phase-down will inevitably increase their price and CERN is also aiming to cut down on its emissions. For these reasons it…
