Single Event Effects (SEE), caused generally by single energetic particles, pose an important issue when implementing electronics in a harsh radiation environment. In this work, we present an ...electronic system for measuring SEEs temporally and spatially correlated with Timepix3 detectors. The Timepix detector is a semiconductor pixel detector, which contains 256 x 256 pixels. It provides energy or time information for each hit pixel. Our experimental setup consists of FPGA based board synchronized Timepix readout and a Device Under Test (DUT).
•New concept for SEE detection.•The last generation of Timepix detector used in the telescope setup.•First tests of this concept.•New plugins for the existing software.
Growing energies of particles at modern or planned particle accelerator experiments as well as cosmic ray experiments require particle identification at gamma-factors (γ) of up to ∼105. At present ...there are no detectors capable of identifying charged particles with reliable efficiency in this range of γ. New developments in high granular pixel detectors allow one to perform simultaneous measurements of the energies and the emission angles of generated transition radiation (TR) X-rays and use the maximum available information to identify particles. First results of studies of TR energy-angular distributions using gallium arsenide (GaAs) sensors bonded to Timepix3 chips are presented. The results are compared with those obtained using a silicon (Si) sensor of the same thickness of 500 μm. The analysis techniques used for these experiments are discussed.
The performance and response of a Timepix3 detector with a 500 μm thick GaAs:Cr sensor layer was investigated in different radiation fields. The sensor resistivity was ρ≈109Ω cm. Fitting different ...modified Hecht functions, which take the small pixel effect into account, the mobility-lifetime products of μeτe=(0.773±0.018)×10−4 cm2V−1 and μeτe=(0.996±0.056)×10−4 cm2V−1 were determined. Hereby, the latter value is favored due to the better agreement of fit and data. In a measurement in a 40 GeV/c pion beam, the drift times and charge collection efficiencies were studied as a function of the interaction depth. We present the measured drift velocity as a function of the electric field strength and compare the determined dependence with a model. In a measurement in a mixed ion beam, we study the capability of the detector to separate different ion species. We show the detector response in the form of tracks and discuss heavy ion track features.
The capability of Timepix3 detectors installed in ATLAS to measure luminosity is evaluated. It is described how noisy pixels are identified and excluded. Two different methods for luminosity ...determination, i.e. cluster counting and thermal neutron counting are described and compared with each other. The achieved short-term relative precision with both methods is determined by modeling the luminosity curve. It is shown that using cluster counting a short-term relative precision of <0.5 % can be achieved for 60 s time intervals. For thermal neutrons, a short-term relative precision (for 60 s intervals) of ≈2 % was found. Hereby statistics was the limiting factor. The findings are discussed in view of Timepix3 upgrade plans for LHC Run-3.
New developments of pixel detectors based on GaAs sensors offer effective registration of the transition radiation (TR) X-rays and perform simultaneous measurements of their energies and emission ...angles. This unique feature opens new possibilities for particle identification on the basis of maximum available information about generated TR photons. Results of studies of TR energy-angular distributions using a 500 |j.m thick GaAs sensor attached to a Timepix3 chip are presented. Measurements, analysis techniques and a comparison with Monte Carlo (MC) simulations are described and discussed.
The Timepix3—the latest generation of hybrid particle pixel detectors of Medipix family—yields a lot of new possibilities, i.e. a high hit-rate, a time resolution of 1.56 ns, event data-driven ...readout mode, and the capability of measuring the Time-over-Threshold (ToT - energy) and the Time-of-Arrival (ToA) simultaneously. This paper introduces a newly developed readout device for the Timepix3, called "Katherine", featuring a Gigabit Ethernet interface. The primary benefit of the Katherine is the operation of Timepix3 at long distance (up to 100 m) from computer or server, which is advantageous for the installation at beam lines, where the access is difficult or where radiation levels are too high for human interventions. The maximal hit-rate is limited by the bandwidth of the Ethernet connection (peer-to-peer connection; up to 16 Mhit/s). Since the Katherine interface is equipped with a processor of high computational power (ARM Cortex-A9 dual-core processor), it permits the use as a stand-alone (autonomous) radiation detector. The key features of the device are described in detail. These are the implemented high voltage power supply offering both polarities of bias voltage (up to ±300 V), the automatic data sending to a sever via SSH, the automatic compensation of ToA values from columns with shifted matrix clock, etc. A dedicated control software was developed, which can be used for the detector preparation (sensor equalization, the DACs dependency scan, and the THL scan) and measurement control. Measured energy spectra from photon fields are shown.
The Timepix3 readout chip—the latest member of the Medipix family of hybrid pixel detectors—brought several new functionalities in comparison with the older Timepix, i.e. a high hit-rate, a time ...granularity of 1.5625 ns, a data-driven readout scheme (with a per pixel dead time of approximately 475 ns), and the capability of measuring Time-over-Threshold (ToT) and Time-of-Arrival (ToA) in each pixel at the same time. However, the high power consumption of the Timepix3 in the standard setting prevents its use in applications with limited power budget. Moreover, the high power consumption poses the risk of overheating the sensor so that proper cooling is crucial. The presented work investigates the effect of different settings in the analogue and a digital part of the Timepix3 detector on its power consumption. Measurements were performed with the Timepix3 chipboard. The firmware of the Katherine readout was modified so that the user can monitor the power consumptions of analogue and digital part “on-line” (directly in the control software). In standard settings, a power consumption of approximately 1.3 W was found. By changes of internal DACs, the consumption could be reduced to 650 mW. Further reduction was achieved by the change of the clock management in the digital part of the Timepix3. In result, a power consumption of 216 mA could be achieved. In these low power settings, the ToA clock was reduced to 10 MHz and thus the time binning was 100 ns. The energy resolution was not affected significantly. The pixel dead time is also negatively affected when the matrix clock is reduced. In the case of 10 MHz, the minimal per pixel dead time is 1.9 μs.
This paper introduces a readout system for the Timepix2. Firstly, this chip is described and the readout modes are discussed in detail. The new readout system presented is based on the Gigabit ...Ethernet interface and implements pre-processing, i.e. decoding of the raw pixel data, directly in the hardware. The device suppresses zero pixels, so that only useful data are sent to the computer/server. In a special independent mode, the readout can send completed data files to a remote server via SSH and does not need to use a control software. In island mode, the device stores measured data to a local storage (SD card). The process of calibration and its results are also discussed. An energy resolution of approximately 1.5 keV was achieved for 60 keV gamma-rays from an 241Am source. We present enhanced features of the readout system facilitating measurements and data evaluation, such as the HW support of clustering and Matrix Occupation Control. The former implements the pixel clustering directly in the hardware and sends energy calibrated results of the cluster finding algorithm to the computer. The latter automatically controls acquisition time of detector in order to reduce cluster overlapping. Measurements with Timepix2 are presented in iron and electron test beams. Results show that pixels of Timepix2 saturate at a per-pixel energy deposition of 1.9 MeV.
Abstract
We characterize a novel instrument designed for radiation field decomposition and particle
trajectory reconstruction for application in harsh radiation environments. The device consists of
...two Timepix3 assemblies with 500 µm thick silicon sensors in a face-to-face geometry. These
detectors are interleaved with a set of neutron converters:
6
LiF for thermal neutrons,
polyethylene (PE) for fast neutrons above 1 MeV, and PE with an additional aluminum recoil proton
filter for neutrons above ∼4 MeV. Application of the coincidence and anticoincidence
technique together with pattern recognition allows improved separation of charged and neutral
particles, their discrimination against
γ
-rays and assessment of the overall directionality
of the fast neutron field. The instrument's charged particle tracking and separation capabilities
were studied at the Danish Center for Particle Therapy (DCPT), the Proton Synchrotron, and Super
Proton Synchrotron with protons (50–240 MeV), pions (1–10 GeV/c and 180 GeV/c). After developing
temporal and spatial coincidence assignment methodology, we determine the relative amount of
coincident detections as a function of the impact angle, present the device's impact angle
resolving power (both in coincidence and anticoicidence channels). The detector response to
neutrons was studied at the Czech Metrology Institute (CMI), at n_ToF and the Los Alamos Neutron
Science Center (LANSCE), covering the entire spectrum from thermal up to 600 MeV. The measured
tracks were assigned to their corresponding neutron energy by application of the time of flight
technique. We present the achieved neutron detection efficiency as a function of neutron kinetic
energy and demonstrate how the ratio of events found below the different converters can be used to
assess the hardness of the neutron spectrum. As an application, we determine the neutron content
within a PMMA phantom just behind the Bragg-peak during clinical irradiation condition with
protons of 160 MeV.
We describe the technical design and show results of first measurements of a network based on the Timepix3 and the Katherine readout (with Gigabit Ethernet interface) installed in the ATLAS cavern in ...the LHC in January 2018. The network consists of four Timepix3 detectors, arranged in two two-layer telescopes. All detectors in the network are synchronized with each other and the LHC orbit clock. The technical solution and the concept of the project are described in details. Since the radiation field inside ATLAS is rather harsh, only the detector units (sensors with power supplies) of the system are placed in the cavern. The detectors are connected to the readout electronics (situated in a rack room with radiation levels comparable to the natural background radiation) by 80 m long cables. The technical design was tested for distances up to 120 m. First measurements are presented, which demonstrate the capabilities of the ATLAS-TPX3 network.
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