The particle detector based on a low concentration 4H-SiC epitaxial layer shows promising properties for the detection of various types of ionizing radiation. The wide bandgap energy of the 4H-SiC ...semiconductor material (3.23 eV at room temperature) allows the detector to operate reliably at room temperature and at elevated temperatures up to several hundred degrees Celsius. The 80 >m thick 4H-SiC epitaxial layer grown on a 350 >m 4H-SiC substrate was used for detector preparation. The active area of the detector was defined by a 3 mm Schottky contact. The current-voltage measurement shows a reverse current of less than 30 pA up to 1000 V. Capacitance-voltage measurements show that the epitaxial layer is completely depleted at bias voltages above 250 V. The detector has been tested with neutrons of energies from 370 keV up to 14.9 MeV. Neutrons were produced by three nuclear reactions p-T, d-D and d-T. The measured spectra clearly identified the elastic and inelastic scattering at silicon and carbon atoms of detector material.
We describe a newly developed compact micro-CT scanner with rotating gantry equipped with a Timepix Quad hybrid pixel semiconductor detector and a micro-focus X-ray tube providing spatial resolution ...down to 30µm. The resolving power of the device in relation to soft tissue sensitivity is demonstrated using a tissue-equivalent phantom and different types of biological samples. The results demonstrate that the use of noiseless particle counting detectors is a promising way to achieve sufficient soft tissue contrast even without any contrast agents.
•We developed a new micro-CT scanner for small animal imaging.•Application of Timepix technology to obtain enhanced soft tissue contrast.•Spatial resolution below 30µm achieved.•Performance demonstrated using a tissue equivalent phantom and biological samples.
The Space Application of Timepix based Radiation Monitor (SATRAM) is a spacecraft platform radiation monitor on board the Proba-V satellite launched in an 820km altitude low Earth orbit in 2013. The ...is a technology demonstration payload is based on the Timepix chip equipped with a 300µm silicon sensor with signal threshold of 8keV/pixel to low-energy X-rays and all charged particles including minimum ionizing particles. For X-rays the energy working range is 10–30keV. Event count rates can be up to 106cnt/(cm2s) for detailed event-by-event analysis or over 1011cnt/(cm2s) for particle-counting only measurements. The single quantum sensitivity (zero-dark current noise level) combined with per-pixel spectrometry and micro-scale pattern recognition analysis of single particle tracks enables the composition (particle type) and spectral characterization (energy loss) of mixed radiation fields to be determined. Timepix׳s pixel granularity and particle tracking capability also provides directional sensitivity for energetic charged particles. The payload detector response operates in wide dynamic range in terms of absorbed dose starting from single particle doses in the pGy level, particle count rate up to 106–10/cm2/s and particle energy loss (threshold at 150eV/µm). The flight model in orbit was successfully commissioned in 2013 and has been sampling the space radiation field in the satellite environment along its orbit at a rate of several frames per minute of varying exposure time. This article describes the design and operation of SATRAM together with an overview of the response and resolving power to the mixed radiation field including summary of the principal data products (dose rate, equivalent dose rate, particle-type count rate). The preliminary evaluation of response of the embedded Timepix detector to space radiation in the satellite environment is presented together with first results in the form of a detailed visualization of the mixed radiation field at the position of the payload and resulting spatial- and time-correlated radiation maps of cumulative dose rate along the satellite orbit.
•Detailed description of design and operation in orbit on board the Proba-V satellite.•Outline of data products and presentation of radiation response of the spacecraft payload SATRAM.•First results namely in terms of quantum imaging detection, wide-dynamic range radiation monitoring.•Systematic preliminary physics results in the form of precise dose rate including spatial- and time-correlated radiation maps.
We evaluate and characterize the directional response of the semiconductor pixel detector Timepix to charged particles and secondary cosmic rays. The detector granularity and per-pixel spectrometric ...response enable to perform directional sensitive tracking of energetic charged particles in wide field-of-view. In the highly integrated MiniPIX readout the detector serves as a miniaturized, low-power and easily deployable particle micro-tracker. Angular measurements require normalization for the acceptance angle and geometric factor which are described and taken into account. The methodology and evaluation of directional response are developed for light charged particles and atmospheric secondary cosmic rays. Tests and calibration of angular resolution were performed with electron and proton beams. Resulting angular distributions are expressed in terms of elevation and azimuth angles in 14 bins and 36 bins, respectively, over the full 2π acceptance range. For zenith angle β > 28° the angular distribution is fitted by ∼ cos n (β) with n = 2.0 ± 0.2 expected from secondary cosmic ray muon distribution.
•Evaluation and description of directional response of Timepix detector.•Wide field-of-view low-power miniaturized particle camera.•Solid angle and angular resolution for tracking of energetic light charged particles.•Angular distributions of charged particles and secondary cosmic rays.
The resolving power of the Timepix detector for wide-range charged particle detection has been examined and evaluated in defined radiation fields. The goal is to broadly characterize mixed-radiation ...fields consisting namely of X-rays and charged particles in terms of particle-types (species), spectral response (energy loss) and direction in wide field-of-view (essentially 2π) with a single compact tracking detector. Tests and calibration measurements were performed with the same device at electron, proton and ion fields at various energies and incident directions. Event-by-event detection, together with pattern recognition analysis of the single particle tracks, are exploited to analyze events according to three degrees of freedom—the particle type (X-rays, light and heavy charged particles), energy range (low or high energy—depending on their range being smaller or larger than the pixel size of the detector semiconductor sensor) and direction (incident angle to the sensor plane). Characteristic values are determined for the cluster analysis morphology parameters, the particles stopping power or Linear Energy Transfer and derived correlated quantities. Ratios and correlations between selected parameters are analyzed including 2D-scatter plots. A physics-based wide-range classification is proposed for a total of 8 broad event groups—in terms of light charged particles (electrons, muons) of both low and high energy incident perpendicular (type 1, including X-rays) or high energy non-perpendicular (type 5), protons of low energy omnidirectional (type 2) and high energy non-perpendicular (type 6), alpha particles and light ions of low energy omnidirectional (type 3) and high energy non-perpendicular (type 7), and heavy ions of low energy omnidirectional (type 4) and high energy non-perpendicular (type 8).
•Tests and calibration of response of Timepix detector.•Resolving power and dynamic range according particle type, energy, direction.•Physics-based classification of event types.•Intended for characterization of mixed radiation fields such as space radiation.
A network of Timepix (TPX) devices installed in the ATLAS cavern measures the LHC luminosity as a function of time as a stand-alone system. The data were recorded from 13-TeV proton-proton collisions ...in 2015. Using two TPX devices, the number of hits created by particles passing the pixel matrices was counted. A van der Meer scan of the LHC beams was analyzed using bunch-integrated luminosity averages over the different bunch profiles for an approximate absolute luminosity normalization. It is demonstrated that the TPX network has the capability to measure the reduction of LHC luminosity with precision. Comparative studies were performed among four sensors (two sensors in each TPX device) and the relative short-term precision of the luminosity measurement was determined to be 0.1% for 10-s time intervals. The internal long-term time stability of the measurements was below 0.5% for the data-taking period.
The hybrid architecture of the Timepix (TPX) family of detectors enables the use of different semiconductor sensors, most commonly silicon (Si), as well as high-density materials such as Cadmium ...Telluride (CdTe) or Gallium Arsenide (GaAs). For this purpose, we explore the potential of a silicon carbide (SiC) sensor bump-bonded on a Timepix3 detector as a radiation imaging and particle tracking detector. SiC stands as a radiation-hard material also with the ability to operate at elevated temperatures up to several hundreds of degrees Celsius. As a result, this sensor material is more suitable for radiation harsh environments compared to conventional e.g., Si sensors. In this work, we evaluate the response for precise radiation spectrometry and high-resolution particle tracking of newly developed SiC Timepix3 detector which is built and operated as a compact radiation camera MiniPIX-Timepix3 with integrated readout electronics. Calibration measurements were conducted with mono-energetic proton beams with energies of 13, 22, and 31 MeV at the U-120M cyclotron at the Nuclear Physics Institute Czech Academy of Science (NPI CAS), Prague, as well as 100 and 226 MeV at the Proton Therapy Center Czech (PTC) in Prague. High-resolution pattern recognition analysis and single-particle spectral tracking are used for detailed inspection and understanding of the sensor response. Results include distributions of deposited energy and linear energy transfer (LET) spectra. The spatial uniformity of the pixelated detector response is examined in terms of homogeneously distributed deposited energy.
A network of Timepix (TPX) devices installed in the ATLAS cavern measures the LHC luminosity as a function of time as a stand-alone system. The data were recorded from 13 TeV proton-proton collisions ...in 2015. Using two TPX devices, the number of hits created by particles passing the pixel matrices was counted. A van der Meer scan of the LHC beams was analysed using bunch-integrated luminosity averages over the different bunch profiles for an approximate absolute luminosity normalization. It is demonstrated that the TPX network has the capability to measure the reduction of LHC luminosity with precision. Comparative studies were performed among four sensors (two sensors in each TPX device) and the relative short-term precision of the luminosity measurement was determined to be 0.1% for 10s time intervals. The internal long-term time stability of the measurements was below 0.5% for the data-taking period.
A network of 15 Timepix pixel detectors was installed within the ATLAS experiment at CERN, Geneva. The network is capable of measuring the composition and spectral characteristics of the radiation ...fields in real-time. Its operation is managed by a dedicated software system. The presented article describes primary software components of this system responsible for communication with detector hardware, online operation monitoring, remote acquisition control, automated data verification and analysis. The processed data can be accessed through an interactive web-based Data Visualization Application, which is available to the scientific community.
A network of Timepix (TPX) devices installed in the ATLAS cavern measures the LHC luminosity as a function of time as a stand-alone system. The data were recorded from 13 TeV proton-proton collisions ...in 2015. Using two TPX devices, the number of hits created by particles passing the pixel matrices was counted. A van der Meer scan of the LHC beams was analysed using bunch-integrated luminosity averages over the different bunch profiles for an approximate absolute luminosity normalization. It is demonstrated that the TPX network has the capability to measure the reduction of LHC luminosity with precision. Comparative studies were performed among four sensors (two sensors in each TPX device) and the relative short-term precision of the luminosity measurement was determined to be 0.1% for 10 s time intervals. The internal long-term time stability of the measurements was below 0.5% for the data-taking period.
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