N3C4  Gaseous Detectors: Applications in Large Experiments

Wednesday, Nov. 4  14:00-16:00  Pacific Salon 1&2

Session Chair:  Hiroyuki Takahashi, Department of Nuclear Engineering and Management, The University of Tokyo, Japan; Craig Woody, Brookhaven Nat Lab, United States

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(14:00) N3C4-1, Commissioning of the KLOE-2 Inner Tracker: the First Cylindrical GEM Detector

A. Di Cicco1, A. Balla2, G. Bencivenni2, P. Branchini3, P. Ciamobrone2, E. Czerwinsky4, E. De Lucia2, D. Domenici2, G. Felici2, G. Morello2

1DEPT. OF MATHEMATICS AND PHYSICS, ROMA TRE UNIVERISITY, ROME, ITALY
2FRASCATI NATIONAL LABORATORY OF I.N.F.N., FRASCATI, ITALY
3I.N.F.N. ROMA TRE, ROME, ITALY
4INSITUTE OF PHYSICS, JAGELLONIAN UNIVERISTY, CRACOW, POLAND

The KLOE-2 Inner Tracker, the first fully-cylindrical triple-GEM detector, is being commissioned at the Frascati Laboratory of INFN (LNF), together with other detector upgrades and the DAFNE F-factory. The novel idea of exploiting kapton properties to build a transparent and compact Inner Tracker (IT) for the experiment was fully developed at LNF. This ultra-light detector, with its total material budget below 2% of the radiation length X_0, allows to limit the multiple scattering of low-momentum charged particles and to minimize dead spaces. The IT is composed of 4 cylindrical triple-GEM coaxial layers, inserted around the DAFNE beam pipe in July 2013 and operated in the KLOE-2 0.52 T magnetic field. Space coordinates are reconstructed using a dedicated XV strips multi-layer readout circuit, coupled to the GASTONE-ASIC front-end with digital output developed for the experiment. Data collection is then performed with a dedicated General Interface Board (GIB) with a configurable FPGA architecture and Gigabit Ethernet. The tracking performance of this new GEM-based detector with cylindrical geometry is being studied using both cosmic-ray muon and Bhabha scattering events. Alignment and calibra- tion procedures to reach optimal 3-D spatial resolution are ongoing and will be reported. KLOE-2 is the first high energy physics experiment to benefit from the presence of this novel detector concept.

(14:20) N3C4-2, Performance of Large Area Micromegas Detectors for the ATLAS Muon Spectrometer Upgrade Project

P. Loesel

Fakultät für Physik, Ludwig-Maximilians-Universität München, München, Germany

On behalf of the ATLAS Muon Collaboration

Four German institutes are building the 32 high-rate capable SM2 Micro- megas quadruplets, for the upgrade of the Small Wheels of the ATLAS muon spectrometer. The cathodes and strip-anodes of the 2 m2 in size quadruplets consist of stable honeycomb sandwiches with a requested planarity better than 80 �m. The qualification of a full-size SM2 quadruplet, foreseen by ATLAS time schedule for August 2015, will be performed in the Munich Cosmic Ray Measurement Facility (CRMF). Two fully working 4 m ? 2.2 m ATLAS drift- tube chambers provide muon tracking, a RD51 SRS based data acquisition system provides readout of all 12288 electronic channels using 96 APV25 frontend boards. We report on homogeneity of pulse-height and efficiency and will present measurements of the planarity of the sandwich planes and the positions of the readout-strips. This has been pioneered by studying a 102 ? 92 cm2 Micromegas chamber with similar readout pitch in the CRMF using the TPC-like analysis method. At trigger rates above 100 Hz data taking takes only a few days for sufficient statistics. Shifts of readout planes and buldging due to overpressure were resolved with an accuracy better 50 �m, single plane angular resolution with an accuracy of about 5

(14:40) N3C4-3, Micro-Pattern Gaseous Detectors for the Phase-II Upgrade of the CMS Muon System

A. Colaleo

INFN, Bari, Italy

On behalf of the CMS Collaboration

After the upgrades of the Large Hadron Collider (LHC) planned for the second and the third Long Shutdown (LS), the LHC luminosity will approach values like 2×10^34cm-2s-1 and 5×10^34cm-2 s-1 respectively. Such a conditions will deeply affect the performance of the CMS muon system, especially in the very forward region, due to the harsh expected background environment and the reduced magnetic field, together with high pile-up conditions. The CMS collaboration considers upgrading the muon forward region with two additional muon detectors, GE1/1 and GE2/1 stations, to be installed in the second and third LS respectively, in the region 1.6<|?|<2.4 to increase redundancy and enhance the trigger and reconstruction capabilities. To take advantage of the pixel tracking coverage extension a new detector, ME0 station, behind the new forward calorimeter will be installed in the third LS, covering up to |?| = 3 or more. For GE1/1 and the GE2/1 stations the well established GEM technology will be adopted as its high spatial resolution allows to combine tracking and triggering capabilities. For the ME0 station the CMS Collaboration is considering a new micro-pattern gaseous detectors able to handle the very demanding spatial, time resolution and rate capability. This contribution will present the status and plans for the CMS Muon Upgrade with micro-pattern gaseous detector architectures, technological solution and performances.

(15:00) N3C4-4, Development and Characterisation of Large Area RPC Detectors for the INO-ICAL Experiment

M. Naimuddin, A. Kumar, A. Gaur

Department of Physics, University of Delhi, Delhi, India

The India-based Neutrino Observatory (INO) is an approved underground laboratory for doing basic science experiments. It will house multiple non-accelerator based experiments. One such experiment it will host is the massive 51 kton magnetised Iron Calorimeter (ICAL) detector to study atmospheric neutrinos and parameters related to their oscillations. Resistive Plate Chambers (RPCs) detectors will be used as an active detector element for ICAL. The ICAL detector will have three modules each of 17 ktons and 16m X 16m X 14.5m in dimensions. A total number of about 28,000 RPCs of 2m X 2m in size will be used to construct the active part of the ICAL. The RPC detectors were chosen for the ICAL experiment because of their excellent timing resolution of few nanoseconds, high detection efficiency for minimum ionising particles and low cost per unit area. But, to improve the efficiency, time resolution and overcome the ageing problem, the electrode materials are required to have high resistivity and homogeneous smooth surface. Because of the huge numbers of detectors required for ICAL experiment and keeping in mind the long life span of the experiment, it is pertinent to perform a vigorous $R\&D$ to carefully optimise the various detector design and operational parameters like the electrode material, gas composition, operational conditions, etc. to fully exploit all the advantages of the RPC detectors. We first fabricated RPC prototypes of 30 cm x 30 cm in size with different glass and bakelite electrodes and performed the characterisation studies. We then moved on to fabricate large area RPC of 2m X 2m size and constructed a stack of 12 layers of these RPC. We then performed variety of measurements related with effciency, count rate, cross talk, dark current, time resolution and charge spectra as a function of various gas mixtures and environmental conditions. The results from these studies along with the present status of ICAL RPC detectors will be presented in this talk.

(15:20) N3C4-5, Hybrid MPGD-Based Detectors of Single Photons for the Upgrade of COMPASS RICH-1

S. Dalla Torre

Sezione di Trieste, INFN, Trieste, Italy

On behalf of the Alessandria-Aveiro-Freiburg-Liberec-Munich-Prague-Torino-Trieste Collaboration

In Cherenkov imaging counters, gaseous photon detectors are still the unique option when insensitivity to magnetic field, low material budget, and affordable costs in view of large detection surfaces are required. Novel gaseous photon counters must overcome the limitations of the present generation of gaseous photon detectors: in particular large gains and intrinsically fast response are required, two requirements that can be matched by appropriate MicroPattern Gaseous Detectors (MPGD). A seven year-long R&D programme has been performed and the resulting detector architecture is a hybrid MPGD including two THick GEM (THGEM) multiplication stages followed a MICROMEGAS. The first THGEM board forms the photocathode support: its upper face is CsI coated. The properties of THGEM-based photocathodes have been studied in details. The two THGEM layers act as pre-amplification stages and, thanks to a staggered configuration, namely by the misalignment of the holes of the two THGEMs, the electron shower produced in the pre-amplification phase is distributed onto a larger surface portion of the following MICROMEGAS unit, where the final multiplication takes place: it is so possible to operate at gains as high as 105 and more even in radioactive environments; this gain-figure has to be compared with the gain-values of the MPGDs operated in experiments so far, which are always lower than 104. COMPASS RICH-1 is a large-size Cherenkov imaging counter with gaseous radiator for hadron identification up to 50 GeV/c. The construction of a set of large-size (unit size: 60 x 60 cm2) gaseous photon detectors based on the hybrid MPGD architecture for the upgrade of COMPASS RICH-1 is ongoing and the upgraded detector will be in operation in 2016. The R&D studies, the engineering aspects and the construction status and challenges are presented.

(15:40) N3C4-6, Performance and Operation of the Straw Detector in the NA62 Rare Kaon Decay Experiment

H. Danielsson

PH, CERN, Geneva, Switzerland

On behalf of the NA62 Collaboration

The NA62 spectrometer should measure with good accuracy the direction and momentum of secondary charged particle originating from the decay region. In order to minimize multiple scattering, the spectrometer is operated in vacuum without physical separation from the upstream decay volume. The straw tracker has been chosen as the most promising detector to be operated in vacuum. The design is made without frames and flanges close to the beam and limits interactions from accompanying beam particles. The detector was successfully installed and commissioned in the fall of 2014. After a short overview of of the design, construction and testing of the detector, the first results of the performance and operation from the 2014 run are presented and discussed in detail.