# Online Program Overview Session: N-25

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## Gaseous Detectors II

Session chair: Daniel Teyssier; Marcus Hohlmann

Shortcut: N-25
Date: Wednesday, October 25, 2017, 13:40
Room: Centennial II
Session type: NSS Session

### Contents

1:40 pm N-25-1

#### Operational experience with the GEM detector assembly lines for the CMS forward muon upgrade(#1942)

S. Colafranceschi1, I. Vai2

1 Florida Institute of Tecnology, Physics and Space Science, Melbourne, Florida, United States of America
2 Universita di Pavia, Dipartimento di Fisica, Pavia, Italy

On behalf of the CMS Muon Group

Content

The CMS Collaboration has been developing large-area Triple-GEM detectors to be installed in the muon endcap regions of the CMS experiment in 2019 to maintain forward muon trigger and tracking performance at the HL-LHC. Ten pre-production detectors were built at CERN to commission the first assembly line and the quality controls. These were installed in the CMS detector in early 2017 and are currently participating in the 2017 LHC run. The collaboration has prepared several additional assembly and quality control lines for distributed mass production of 160 GEM detectors at various sites worldwide. During 2017, these additional production sites have been optimizing construction techniques and quality control procedures and validating them against common specifications by constructing additional pre-production detectors. Using the specific experience from one production site as an example, we discuss how the quality controls make use of independent hardware and trained personnel to ensure fast and reliable production. Preliminary results on the construction status of CMS GEM detectors will be presented.

1:58 pm N-25-2

#### ORANGE: A high resolution TPC based on GEM optical readout(#1198)

D. Pinci1, G. Mazzitelli3, E. Baracchini3, M. Marafini1, G. Cavoto2, C. Voena1, F. Renga1, E. Di Marco1, S. Tomassini3, C. V. Antiochi2

1 INFN, Sezione di Roma, Roma, Italy
2 Sapienza Università di Roma, Dipartimento di Fisica, Roma, Italy
3 INFN, Laboratori Nazionali di Frascati, Frascati, Italy

Content

In this presentation the R&D of a gas detector prototype for high precision particle tracking over large gas volumes will be presented. In our prototype, the scintillation light accompanying the electronic avalanches in a triple GEM structure is detected by a CMOS-based camera through a suitable lens. A CMOS-based sensor provides a very high granularity along with a very low noise (of the order of a single photon) and a very high sensitivity (70% of quantum efficiency). Once operated with a large aperture and suitable focal length lens, large areas can be imaged at reduced costs.

The performance of a triple-GEM structure filled with a He/CF4 (60/40) is analyzed. About 200 photons are collected per each primary electron ionized (i.e. about 1000 photons per millimetre for a m.i.p.). The dependence of the light collection on the gas gain and on the energy release was studied and will be presented in details. The device showed to be very sensitive even to small energy deposit: 6 photons are collected per each released electronvolt.

An innovative element is the concurrent readout of the light by means of a suitable photomultiplier system. It will complement the readout by providing the time resolution necessary to the reconstruction of third coordinate of each cluster.

Recent tests on beam demonstrated the achievement of resolutions of the order on tens of μm in the XY plane and hundreds of μm in Z.

The idea is to use such a detector in future large scale experiments for directional Dark Matter searches and for measurements of coherent neutrino scattering on nuclei. Additional applications of this detector might be in the realm of neutron detection, X-ray polarimetry and particle therapy.

Keywords: Gas Electron Multiplier, CMOS, Particle Tracking
2:16 pm N-25-3

#### 3D Printing Gaseous Radiation Detectors(#2465)

S. J. Fargher1, L. F. Thompson1, C. Steer2

1 University of Sheffield, Department of Physics and Astronomy, Sheffield, South Yorkshire, United Kingdom of Great Britain and Northern Ireland
2 AWE plc, Aldermaston, United Kingdom of Great Britain and Northern Ireland

Content

Fused Deposition Modelling has been used to produce a single wire Iarocci-style drift tube to demonstrate the feasibility of using the Additive Manufacturing technique to produce cheap detectors, quickly. Recent developments have extended the scope of Additive Manufacturing, or “3D printing”, to the possibility of fabricating Gaseous Radiation Detectors, such as Single Wire Proportional Counters and Time Projection Chambers, allowing for the production of customizable, modular detectors, that can be easily created and replaced. The 3D printed drift tube has been found to be operational proving Additive Manufacturing could be a viable production method, and giving rise to the possibility that more complex detectors can also be 3D printed.

2:34 pm N-25-4

#### Combined Optical and Electronic Readout for Event Reconstruction in a GEM-based TPC(#1240)

F. M. Brunbauer1, 2, F. García3, M. Lupberger1, H. Müller1, E. Oliveri1, L. Ropelewski1, P. Thuiner1, M. van Stenis1

1 CERN, EP-DT-DD, Geneva, Genève, Switzerland
2 Technische Universität Wien, Wien, Wien, Austria
3 Helsinki Institute of Physics, University of Helsinki, Finland

Content

Combining the outstanding spatial resolution of optical readout with the high gain factors achievable by MicroPattern Gaseous Detector (MPGD) technologies such as Gaseous Electron Multipliers (GEMs), highly sensitive 2D detectors can be realised. Augmenting 2D projections obtained by optically read out MPGDs with timing information obtained from a photomultiplier tube (PMT), an optically read out Time Projection Chamber (TPC) has been constructed and successfully operated. Taking advantage of the high granularity and the intuitive readout provided by state-of-the-art image sensors and the inherent insensitivity to electronic noise, this TPC allowed 3D reconstruction of alpha tracks by using the time between primary and secondary scintillation signals from the PMT to determine the depth of interaction of alpha tracks in the detector volume. While this approach is compatible with particles moving along straight trajectories, it cannot be used for 3D reconstruction of curved particle tracks. To overcome this limitation, a pixelated transparent anode was developed and integrated in the optically read out TPC. While scintillation light produced in the GEMs can pass through the anode and is recorded by a camera for high-resolution 2D readout, electrical signals from the electron avalanches in the GEMs can be read out with high-speed electronics and provide arrival time information, which translates to depth of interaction information. Therefore, more complex particle trajectories can be resolved and reconstructed, multiple particles in a single event can be disentangled and the topology of particle tracks can be determined even if the intensity of primary scintillation is too low to be recorded. The presented combination of optical and electronic readout enables reconstruction of intricate particle tracks and makes TPCs based on this concept an attractive candidate for nuclear physics experiments studying rare events or for the search for neutrinoless double beta decay.

Keywords: Optical readout, TPC, Scintillation, GEM, ITO, Event reconstruction
2:52 pm N-25-5

#### Performance of a large aperture GEM-like gating device for the International Linear Collider(#1702)

T. Ogawa1

on behalf of the LCTPC collaboration

Content

For the future International Linear Collider (ILC) project a detector concept called the International Large Detector (ILD) is proposed, where a Micro Pattern Gaseous Detector (MPGD)-based Time Projection Chamber (TPC) is a candidate as the central tracking detector. A spatial resolution $\sigma_{r\phi}$ of less than 100 $\mu m$ is required over the full drift length. A intrinsic problem of the TPC is the effect of ions. Ions generated by charged tracks and avalanche processes through gas amplification cause disarrangement of the electric field inside of a drift volume of the TPC and distort reconstructed tracks, and consequently the spatial resolution is degraded. The degradation of the spatial resolution due to the ions is 60 $\mu m$ with ion stopping power of $O(10^{-3})$, which gives a non-negligible effect on the requirement of the spatial resolution and some gating device to absorb the ions is necessary. A loss of signal electrons also directly brings a degradation of the spatial resolution. Therefore the gating device needs to possess a high transmission rate for the electrons with the high stopping power for the ions. In order to fit the gating device to the ILD-TPC structure, a GEM-like gating device (gating GEM) has been developed. We manufactured a 82.3\% large aperture gating GEM and have measured the electron transmission rate and the ion stopping power with the prototype gating GEM. The performance has been estimated that more than 80\% and $O(10^{-4})$ are achievable for the electrons and the ions, respectively. We also developed a 17$\times$22~$cm^{2}$ large area gating GEM which corresponds to a real module size of the ILD-TPC, and we evaluated the performance for electron tracks using 5 GeV electron beam under the 1 T magnetic field. In this report we will demonstrate the overall performance of the developed gating GEM including the electron transmission rate, the ion stopping power, and the spatial resolution which the ILD-TPC module can provide.

Keywords: ILC, TPC, gating GEM
3:10 pm N-25-6

#### Performance of the micro-TPC Reconstruction for GEM Detectors at High Rate(#3542)

G. Cibinetto1, L. Lavezzi2

1 INFN, Ferrara, Ferrara, Italy
2 IHEP, Beijing, China

BESIII CGEM group

Content

Gas detectors are one of the pillars of the research in fundamental physics. Since several years, a new concept of detectors, called Micro Pattern Gas Detectors (MPGD), allows to overcome several of the problems of other types of commonly used detectors, like the drift chambers and microstrip detectors, reducing the rate for discharge and increasing the radiation tolerance.

One of the most commonly used are Gas Electron Multipliers (GEMs). GEMs have become an important reality for fundamental physics detectors. Commonly deployed as fast timing detectors and triggers, due to their fast response, high rate capability and high radiation hardness, they can also be used as tracking detectors.

The readout scheme is one of the most important feature in tracking technology. Center of gravity technique allows to overcome the limit of the digital pads, which spatial resolution is limited by the pitch dimension. The presence of a high external magnetic field can distort the electronic cloud and affect the spatial resolution. The microTPC readout, a new technique that allows to reconstruct the 3-dimensional particle position, as traditional Time Projection Chambers, but within a drift gap of few millimeters, bring these detectors into new perspective for what concerns the spatial resolution in strong magnetic field. In this presentation, the basis of this new technique compared to the traditional center of gravity readout will be shown. The results of a series of test beam performed with 10x10cm^2 planar prototypes in magnetic field will be also presented.

The results are one of the first implementation of this technique for GEM detectors in magneti field and allows to reach unprecedented performance for gas detectors, up to a limit of 120 micrometers at 1 Tesla, one of the world best results for MPGDs in strong magnetic field. The microTPC reconstruction has been recently tested at very high rate test beam at the MAMI facility; preliminary result of the test will be presented.

Keywords: GEM, micro-TPC, MPGD, gas detectors, test beam