Triple-GEM detectors with pad readout have been employed to equip the innermost region (R1) of the first station (M1) within the Muon system of the LHCb experiment. The GEM detectors have been ...operated with an Ar/CO2/CF4 = 45/15/40 gas mixture at a gas gain of about 4000 with an average particle flux of about 250 kHz/cm2. Throughout RUN1 and RUN2, spanning approximately 440 days of colliding beams, the GEM detectors accumulated a charge of up to 0.5 C/cm2. This paper presents a comparative analysis between a global irradiation test of GEM detectors at the Calliope facility (ENEA-Casaccia, 1.25 MeV γ ray flux from a 60Co source) and the GEMs operated at LHCb, focusing on the impacts of a CF4-based gas mixture. In both instances, the detectors were opened and the GEM foils were examined by the EN-MME-MM CERN group with a Field Emission Gun Scanning Electron Microscope (FEG-SEM) for a magnified image analysis and an X-Max Energy Dispersive X-ray Spectroscopy (EDS) for the chemical one.
Particle tracking for future experiments at colliders is an incredible challenge in terms of sensor technology and readout. Simulation tools are a crucial ingredient to investigate new layouts able ...to cope with harsh radiation conditions and, at the same time, provide valuable timing information for track finding algorithms. Detailed and numerous simulations of energy deposits as well as sensor and front-end electronics responses imply a heavy usage of computing resources. In this paper, we present two software packages that,
via
massive parallelization and dedicated algorithms, allow for a significant speed-up in simulation time.
Abstract
This paper presents the detailed simulation of a
double-pixel structure for charged particle detection based on the
3D-trench silicon sensor developed for the TIMESPOT project and a
...comparison of the simulation results with measurements performed at
the π-M1 beam at PSI laboratory. The simulation is based on the
combined use of several software tools (TCAD, GEANT4, TCoDe and
TFBoost) which allow to fully design and simulate the device physics
response in very short computational time,
O(1–100 s) per simulated signal, by exploiting
parallel computation using single or multi-thread processors. This
allowed to produce large samples of simulated signals, perform
detailed studies of the sensor characteristics and make precise
comparisons with experimental results.
Abstract
In this paper the results of a beam test characterization campaign of 3D trench silicon pixel sensors are presented. A time resolution in the order of 10 ps was measured both for ...non-irradiated and irradiated sensors up to a fluence of 2.5 × 10
16
1 MeV n
eq
cm
−2
. This feature and a detection efficiency close to 99% make this sensors one of the best candidates for 4D tracking detectors in High-Energy-Physics experiments.
Abstract We present first results obtained with a prototype 4D-tracking demonstrator, using sensors and electronics developed within the TimeSPOT project, and tested on a positive charged pion beam ...at CERN SPS. The setup consists of five small tracking layers in a row, having area of about 3 mm 2 each, three of which equipped with 3D-trench silicon sensors and two with 3D-column diamond sensors. The five layers are then read-out by a KC705 Xilinx board on a PC. We describe the demonstrator structure and operation and illustrate preliminary results on its tracking capabilities.
•Established cysts of Echinococcus granulosus in sheep are associated with CD3+ T cells.•Most established cysts are in the lung.•Foxp3+ cells make up part of the local inflammatory infiltrate.
Ovine ...hydatidosis (OH; Echinococcus granulosus) is endemic in several European countries surrounding the Mediterranean basin. There have been a limited number of studies aimed at evaluating the local immune response to established tissue cysts in the ovine host. In the present study, immunohistochemical analysis of lymphocyte populations surrounding established cysts showed a predominance of CD3+ T cells compared to CD79+ B cells. A percentage of infiltrating lymphocytes were also FoxP3+, suggesting that established ovine cysts may be protected from immune aggression through the suppressive action of T regulatory cells. The present study contributes to the understanding of local immune responses to ovine echinococcosis.
For the next generation of vertex detectors, the accurate measurement of the charged particle timing at the pixel level is considered to be the ultimate solution in experiments operating at very high ...instantaneous luminosities. This work shows that the 55 μm × 55 µm wide 150 µm thick 3D trench-type pixels, developed by the TimeSPOT Collaboration, achieve a time resolution close to 10 ps with minimum ionizing particles while maintaining a detection efficiency close to 100% when operated at a tilt angle larger than 10° from normal incidence. This record performance is obtained with software-based constant-fraction algorithms applied to signal waveforms. However, time resolutions as good as 25 ps can be achieved using a simple leading-edge discriminating technique, without any amplitude correction. Similar timing performances can also be achieved when the charged particles cross two nearby pixels if both signal amplitudes are measured. 3D trench-type pixels, as of today, are the fastest charged-particles pixel detectors available and represent a very promising solution for the future upgrade of tracking systems of many HEP experiments operating in extreme conditions.
The muon detector of LHCb, which comprises 1368 multi-wire-proportional-chambers (MWPC) for a total area of 435 m
2
, is the largest instrument of its kind exposed to such a high-radiation ...environment. In nine years of operation, from 2010 until 2018, we did not observe appreciable signs of ageing of the detector in terms of reduced performance. However, during such a long period, many chamber gas gaps suffered from HV trips. Most of the trips were due to Malter-like effects, characterised by the appearance of local self-sustained high currents, presumably originating from impurities induced during chamber production. Very effective, though long, recovery procedures were implemented with a HV training of the gaps in situ while taking data. The training allowed most of the affected chambers to be returned to their full functionality and the muon detector efficiency to be kept close to 100%. The possibility of making the recovery faster and even more effective by adding a small percentage of oxygen in the gas mixture has been studied and successfully tested.
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