Timing performance of a Micro-Channel-Plate Photomultiplier Tube Bortfeldt, J.; Brunbauer, F.; David, C. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2020, Letnik:
960, Številka:
C
Journal Article
Recenzirano
Odprti dostop
The spatial dependence of the timing performance of the R3809U-50 Micro-Channel-Plate PMT (MCP-PMT) by Hamamatsu was studied in high energy muon beams. Particle position information is provided by a ...GEM tracker telescope, while timing is measured relative to a second MCP-PMT, identical in construction. In the inner part of the circular active area (radius r<5.5 mm) the time resolution of the two MCP-PMTs combined is better than 10 ps. The signal amplitude decreases in the outer region due to less light reaching the photocathode, resulting in a worse time resolution. The observed radial dependence is in quantitative agreement with a dedicated simulation. With this characterization, the suitability of MCP-PMTs as t0 reference detectors has been validated.
Timing performance of a multi-pad PICOSEC-Micromegas detector prototype Aune, S.; Bortfeldt, J.; Brunbauer, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2021, Letnik:
993, Številka:
C
Journal Article
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The multi-pad PICOSEC-Micromegas is an improved detector prototype with a segmented anode, consisting of 19 hexagonal pads. Detailed studies are performed with data collected in a muon beam over four ...representative pads. We demonstrate that such a device, scalable to a larger area, provides excellent time resolution and detection efficiency. As expected from earlier single-cell device studies, we measure a time resolution of approximately 25 picoseconds for charged particles hitting near the anode pad centres, and up to 30 picoseconds at the pad edges. Here, we study in detail the effect of drift gap thickness non-uniformity on the timing performance and evaluate impact position based corrections to obtain a uniform timing response over the full detector coverage.
Recent interest in pile-up mitigation through fast timing at the HL-LHC has focused attention on technologies that now achieve minimum ionising particle (MIP) time resolution of 30 picoseconds or ...less. The constraints of technical maturity and radiation tolerance narrowed the options in this rapidly developing field for the ATLAS and CMS upgrades to low gain avalanche detectors and silicon photomultipliers. In a variety of applications where occupancies and doses are lower, devices with pixel elements of order 1 cm2, nevertheless achieving 30ps, would be attractive.
In this paper, deep diffused Avalanche Photo Diodes (APDs) are examined as candidate timing detectors for HL-LHC applications.
Devices with an active area of 8 × 8 mm2 are characterised using a pulsed infrared laser and, in some cases, high energy particle beams. The timing performance as well as the uniformity of response are examined.
The effects of radiation damage on current, signal amplitude, noise, and timing of the APDs are evaluated using detectors with an active area of 2 × 2 mm2. These detectors were irradiated with neutrons up to a 1-MeV neutrons fluence Φeq=1015 cm−2. Their timing performance was characterised using a pulsed infrared laser.
While a time resolution of 27±1 ps was obtained in a beam test using an 8 × 8 mm2 sensor, the present study only demonstrates that gain loss can be compensated by increased detector bias up to fluences of Φeq=6⋅1013 cm−2. So it possibly falls short of the Φeq=1014 cm−2 requirement for the CMS barrel over the lifetime of the HL-LHC.
The PICOSEC Micromegas detector can time the arrival of Minimum Ionizing Particles with a sub-25 ps precision. A very good timing resolution in detecting single photons is also demonstrated in laser ...beams. The PICOSEC timing resolution is determined mainly by the drift field. The arrival time of the signal and the timing resolution vary with the size of the pulse amplitude.
Detailed simulations based on GARFIELD++ reproduce the experimental PICOSEC timing characteristics. This agreement is exploited to identify the microscopic physical variables, which determine the observed timing properties. In these studies, several counter-intuitive observations are made for the behavior of such microscopic variables. In order to gain insight on the main physical mechanisms causing the observed behavior, a phenomenological model is constructed and presented. The model is based on a simple mechanism of “time-gain per interaction” and it employs a statistical description of the avalanche evolution. It describes quantitatively the dynamical and statistical properties of the microscopic quantities, which determine the PICOSEC timing characteristics, in excellent agreement with the simulations. In parallel, it offers phenomenological explanations for the behavior of these microscopic variables. The formulae expressing this model can be used as a tool for fast and reliable predictions, provided that the input parameter values (e.g. drift velocities) are known for the considered operating conditions.
Deep diffused Avalanche photodiodes for charged particles timing Centis Vignali, M.; Dias De Almeida, P.; Franconi, L. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2020, Letnik:
958, Številka:
C
Journal Article
Recenzirano
Odprti dostop
The upgrades of ATLAS and CMS for the High Luminosity LHC (HL-LHC) highlighted physics objects timing as a tool to resolve primary interactions within a bunch crossing. Since the expected pile-up is ...around 200, with an r.m.s. time spread of 180ps, a time resolution of about 30ps is needed. The timing detectors will experience a 1-MeV neutron equivalent fluence of about Φeq=1014 and 1015cm−2 for the barrel and end-cap regions, respectively. In this contribution, deep diffused Avalanche Photo Diodes (APDs) produced by Radiation Monitoring Devices are examined as candidate timing detectors for HL-LHC applications. To improve the detector’s timing performance, the APDs are used to directly detect the traversing particles, without a radiator medium where light is produced. Devices with an active area of 8 × 8mm2 were characterized in beam tests. The timing performance and signal properties were measured as a function of position on the detector using a beam telescope and a microchannel plate photomultiplier (MCP-PMT). Devices with an active area of 2 × 2mm2 were used to determine the effects of radiation damage and characterized using a ps pulsed laser. These detectors were irradiated with neutrons up to Φeq=1015cm−2.
This contribution describes the PICOSEC-Micromegas detector which achieves a time resolution below 25ps. In this device the passage of a charged particle produces Cherenkov photons in a radiator, ...which then generate electrons in a photocathode and these photoelectrons enter a two-stage Micromegas with a reduced drift region and a typical anode region. The results from single-channel prototypes (demonstrating a time resolution of 24ps for minimum ionizing particles, and 76ps for single photoelectrons), the understanding of the detector in terms of detailed simulations and a phenomenological model, the issues of robustness and how they are tackled, and preliminary results from a multi-channel prototype are presented (demonstrating that a timing resolution similar to that of the single-channel device is feasible for all points across the area covered by a multi-channel device).
Abstract The CMS detector will be upgraded for the HL-LHC to include a MIP Timing Detector (MTD). The MTD will consist of barrel and endcap timing layers, BTL and ETL respectively, providing ...precision timing of charged particles. The BTL sensors are based on LYSO:Ce scintillation crystals coupled to SiPMs with TOFHIR2 ASICs for the front-end readout. A resolution of 30–60 ps for MIP signals at a rate of 2.5 Mhit/s per channel is expected along the HL-LHC lifetime. We present an overview of the TOFHIR2 requirements and design, simulation results and measurements with TOFHIR2 ASICs. The measurements of TOFHIR2 associated to sensor modules were performed in different test setups using internal test pulses or blue and UV laser pulses emulating the signals expected in the experiment. The measurements show a time resolution of 24 ps initially during Beginning of Operation (BoO) and 58 ps at End of Operation (EoO) conditions, matching well the BTL requirements. We also showed that the time resolution is stable up to the highest expected MIP rate. Extensive radiation tests were performed, both with x-rays and heavy ions, showing that TOFHIR2 is not affected by the radiation environment during the experiment lifetime.
Abstract
The PICOSEC Micromegas (MM) detector is a precise timing gaseous detector consisting of
a Cherenkov radiator combined with a photocathode and a MM amplifying structure. A 100-channel
PICOSEC ...MM prototype with 10 × 10 cm
2
active area equipped with a Cesium Iodide (CsI)
photocathode demonstrated a time resolution below
σ
= 18 ps. The objective of this work
is to improve the PICOSEC MM detector robustness aspects, i.e. integration of resistive MM and
carbon-based photocathodes, while maintaining good time resolution. The PICOSEC MM prototypes
have been tested in laboratory conditions and successfully characterised with 150 GeV/c muon
beams at the CERN SPS H4 beam line. The excellent timing performance below
σ
= 20 ps for
an individual pad obtained with the 10 × 10 cm
2
area resistive PICOSEC MM of
20 MΩ/□ showed no significant time resolution degradation as a result of adding a
resistive layer. A single-pad prototype equipped with a 12 nm thick Boron Carbide (B
4
C)
photocathode presented a time resolution below
σ
= 35 ps, opening up new possibilities for
detectors with robust photocathodes. The results made the concept more suitable for the
experiments in need of robust detectors with good time resolution.
Abstract
The PICOSEC Micromegas precise timing detector is based on a Cherenkov radiator coupled to a photocathode operating in a semi-transparent mode and a Micromegas amplification structure. The ...first proof of concept single-channel prototype was able to achieve a time resolution below 25 ps. One of the crucial aspects in the development of precise timing gaseous detectors applicable in high-energy physics experiments is a modular design that enables large area coverage. The first 19-channel multi-pad prototype with an active area of approximately 10 cm
2
suffered from degraded timing resolution due to the non-uniformity of the preamplification gap thickness. A new 100 cm
2
detector module with 100 channels based on a rigid hybrid ceramic/FR4 Micromegas board for improved drift gap uniformity was developed. Initial measurements with 80 GeV/c muons showed improvements in timing response over the measured pads and a time resolution below 25 ps. More recent measurements with a thinner drift gap detector module and newly developed RF pulse amplifiers show that the pad centre resolution can be enhanced to the level of 17 ps. This work will present the development of the detector from structural simulations, design, and beam test commissioning with a focus on the timing performance of a thinner drift gap detector module in combination with new electronics using an automated timing scan method.
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