pixel detector
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2022 ◽  
Vol 163 (2) ◽  
pp. 39
Author(s):  
John Rankin ◽  
Fabio Muleri ◽  
Allyn F. Tennant ◽  
Matteo Bachetti ◽  
Enrico Costa ◽  
...  

Abstract The Gas Pixel Detector (GPD) is an X-ray polarimeter to fly onboard IXPE and other missions. To correctly measure the source polarization, the response of IXPE’s GPDs to unpolarized radiation has to be calibrated and corrected. In this paper, we describe the way such response is measured with laboratory sources and the algorithm to apply such correction to the observations of celestial sources. The latter allows to correct the response to polarization of single photons, therefore allowing great flexibility in all the subsequent analysis. Our correction approach is tested against both monochromatic and nonmonochromatic laboratory sources and with simulations, finding that it correctly retrieves the polarization up to the statistical limits of the planned IXPE observations.


2022 ◽  
Vol 17 (01) ◽  
pp. C01044
Author(s):  
X. Llopart ◽  
J. Alozy ◽  
R. Ballabriga ◽  
M. Campbell ◽  
R. Casanova ◽  
...  

Abstract Timepix4 is a 24.7 × 30.0 mm2 hybrid pixel detector readout ASIC which has been designed to permit detector tiling on 4 sides. It consists of 448 × 512 pixels which can be bump bonded to a sensor with square pixels at a pitch of 55 µm. Like its predecessor, Timepix3, it can operate in data driven mode sending out information (Time of Arrival, ToA and Time over Threshold, ToT) only when a pixel has a hit above a pre-defined and programmable threshold. In this mode hits can be tagged to a time bin of <200 ps and Timepix4 can record hits correctly at incoming rates of ∼3.6 MHz/mm2/s. In photon counting (or frame-based) mode it can count incoming hits at rates of up to 5 GHz/mm2/s. In both modes data is output via between 2 and 16 serializers each running at a programmable data bandwidth of between 40 Mbps and 10 Gbps. The specifications, architecture and circuit implementation are described along with first electrical measurements and measurements with radioactive sources. In photon counting mode X-ray images have been taken at a threshold of 650 e− (with <10 masked pixels). In data driven mode images were taken of ToA/ToT data using a 90Sr source at a threshold of 800 e− (with ∼120 masked pixels).


2022 ◽  
Vol 17 (01) ◽  
pp. C01003
Author(s):  
C. Oancea ◽  
C. Bălan ◽  
J. Pivec ◽  
C. Granja ◽  
J. Jakubek ◽  
...  

Abstract This work aims to characterize ultra-high dose rate pulses (UHDpulse) electron beams using the hybrid semiconductor pixel detector. The Timepix3 (TPX3) ASIC chip was used to measure the composition, spatial, time, and spectral characteristics of the secondary radiation fields from pulsed 15–23 MeV electron beams. The challenge is to develop a single compact detector that could extract spectrometric and dosimetric information on such high flux short-pulsed fields. For secondary beam measurements, PMMA plates of 1 and 8 cm thickness were placed in front of the electron beam, with a pulse duration of 3.5 µs. Timepix3 detectors with silicon sensors of 100 and 500 µm thickness were placed on a shifting stage allowing for data acquisition at various lateral positions to the beam axis. The use of the detector in FLEXI configuration enables suitable measurements in-situ and minimal self-shielding. Preliminary results highlight both the technique and the detector’s ability to measure individual UHDpulses of electron beams delivered in short pulses. In addition, the use of the two signal chains per-pixel enables the estimation of particle flux and the scattered dose rates (DRs) at various distances from the beam core, in mixed radiation fields.


2022 ◽  
Vol 29 (1) ◽  
Author(s):  
Kewin Desjardins ◽  
Cristian Mocuta ◽  
Arkadiusz Dawiec ◽  
Solenn Réguer ◽  
Philippe Joly ◽  
...  

One of the challenges of all synchrotron facilities is to offer the highest performance detectors for all their specific experiments, in particular for X-ray diffraction imaging and its high throughput data collection. In that context, the DiffAbs beamline, the Detectors and the Design and Engineering groups at Synchrotron SOLEIL, in collaboration with ImXPAD and Cegitek companies, have developed an original and unique detector with a circular shape. This detector is based on the hybrid pixel photon-counting technology and consists of the specific assembly of 20 hybrid pixel array detector (XPAD) modules. This article aims to demonstrate the main characteristics of the CirPAD (for Circular Pixel Array Detector) and its performance – i.e. excellent pixel quality, flat-field correction, high-count-rate performance, etc. Additionally, the powder X-ray diffraction pattern of an LaB6 reference sample is presented and refined. The obtained results demonstrate the high quality of the data recorded from the CirPAD, which allows the proposal of its use to all scientific communities interested in performing experiments at the DiffAbs beamline.


2022 ◽  
Vol 17 (01) ◽  
pp. C01029
Author(s):  
T. Fritzsch ◽  
F. Huegging ◽  
P. Mackowiak ◽  
K. Zoschke ◽  
M. Rothermund ◽  
...  

Abstract The through silicon via (TSV) technology has been introduced in a wide range of electronic packaging applications. Hybrid pixel detectors for X-ray imaging and for high-energy physics (HEP) can benefit from this technology as well. A 3D TSV prototype using the ATLAS FE-I4 readout electronic chip is described in this paper. This type of readout chip is already prepared for the TSV backside process providing a TSV landing pad in the first metal layer of the backend-of-line (BEOL) layer stack. Based on this precondition a TSV backside via-last process is developed on ATLAS FE-I4 readout chip wafer. The readout chip wafers were thinned to 100 µm and 80 µm final thickness and straight sidewall vias with 60 µm in diameter has been etched into the silicon from wafer backside using deep reactive ion etching (DRIE). The filling of the TSVs and the formation of the wafer backside interconnection were provided by a copper electroplating process. ATLAS FE-I4 readout chips with through silicon vias has been successfully tested, tuned and operated. In addition, hybrid pixel detector modules have been flip chip bonded using ATLAS FE-I4 TSV readout chips and planar sensor chips. After mounting the bare modules onto a support PCB, its full functionality has been verified with a source scan.


2022 ◽  
Vol 17 (01) ◽  
pp. P01003
Author(s):  
M. Li ◽  
W. Wei ◽  
X. Jiang ◽  
S. Cui ◽  
J. Zhang ◽  
...  

Abstract HYLITE (High dYmamic range free electron Laser Imaging deTEctor) is a hybrid pixel detector readout chip, which is designed for advanced light sources such as X-ray Free Electron Laser (XFEL) and diffraction-limited storage rings. It is a charge-integration readout chip which has three gains for different dynamic ranges and automatic gain-switching function. The full dynamic range covered by HYLITE is 1 ∼ 104 photons with an energy of 12 keV for each pixel in every shot. In-pixel ADC is designed to achieve front-end digitization and a 10 kHz continuous frame rate. HYLITE0.1 is the first prototype chip for functional verification that was produced in CMOS 0.13 μm technology. It consists of a pixel array with 6 × 12 pixels and a periphery with full standalone operation features. The size of each pixel is 200 μm × 200 μm. Three design variations of pixels with different integrating capacitance and structures were designed to optimize between area and performance. A 10-bit Wilkinson ADC is integrated in each pixel to digitize the outputs of the pre-amplifier. Therefore, analog signal transmission of long distance is avoided and a frame rate of 10 kHz can be achieved. In this paper, we present the design of HYLITE0.1 and the test results of this prototype chip.


2022 ◽  
Vol 17 (01) ◽  
pp. C01020
Author(s):  
E. Fröjdh ◽  
J.P. Abrahams ◽  
M. Andrä ◽  
R. Barten ◽  
A. Bergamaschi ◽  
...  

Abstract Speed, dynamic range, and radiation hardness make hybrid pixel detectors suitable image detectors for diffraction experiments. At synchrotrons and X-ray free electron lasers they are ubiquitous. However, for electron microscopy their spatial resolution is limited by multiple scattering in the sensor layer. In this paper we examine the use of two high Z sensor materials: CdTe and GaAs, as a way to mitigate this problem. The sensors were bonded to a JUNGFRAU readout chip which is a charge integrating hybrid pixel detector developed for use at X-ray free electron lasers. Using in-pixel gain switching, it can detect single particles down to 2 keV while maintaining a dynamic range of 120 MeV/pixel/frame. The characteristics of JUNGFRAU, besides being a capable detector, make it a good tool for sensor characterization since we can measure dark current and energy deposition per pixel. The high Z material shows better spatial resolution than silicon at 200 and 300 keV, however, their practical use with integrating detectors is still limited by material defects.


2021 ◽  
Vol 16 (12) ◽  
pp. P12014
Author(s):  
W. Adam ◽  
T. Bergauer ◽  
D. Blöch ◽  
M. Dragicevic ◽  
R. Frühwirth ◽  
...  

Abstract The CMS Inner Tracker, made of silicon pixel modules, will be entirely replaced prior to the start of the High Luminosity LHC period. One of the crucial components of the new Inner Tracker system is the readout chip, being developed by the RD53 Collaboration, and in particular its analogue front-end, which receives the signal from the sensor and digitizes it. Three different analogue front-ends (Synchronous, Linear, and Differential) were designed and implemented in the RD53A demonstrator chip. A dedicated evaluation program was carried out to select the most suitable design to build a radiation tolerant pixel detector able to sustain high particle rates with high efficiency and a small fraction of spurious pixel hits. The test results showed that all three analogue front-ends presented strong points, but also limitations. The Differential front-end demonstrated very low noise, but the threshold tuning became problematic after irradiation. Moreover, a saturation in the preamplifier feedback loop affected the return of the signal to baseline and thus increased the dead time. The Synchronous front-end showed very good timing performance, but also higher noise. For the Linear front-end all of the parameters were within specification, although this design had the largest time walk. This limitation was addressed and mitigated in an improved design. The analysis of the advantages and disadvantages of the three front-ends in the context of the CMS Inner Tracker operation requirements led to the selection of the improved design Linear front-end for integration in the final CMS readout chip.


2021 ◽  
Vol 16 (12) ◽  
pp. P12038
Author(s):  
F. Martinelli ◽  
C. Magliocca ◽  
R. Cardella ◽  
E. Charbon ◽  
G. Iacobucci ◽  
...  

Abstract This paper presents a small-area monolithic pixel detector ASIC designed in 130 nm SiGe BiCMOS technology for the upgrade of the pre-shower detector of the FASER experiment at CERN. The purpose of this prototype is to study the integration of fast front-end electronics inside the sensitive area of the pixels and to identify the configuration that could satisfy at best the specifications of the experiment. Self-induced noise, instabilities and cross-talk were minimised to cope with the several challenges associated to the integration of pre-amplifiers and discriminators inside the pixels. The methodology used in the characterisation and the design choices will also be described. Two of the variants studied here will be implemented in the pre-production ASIC of the FASER experiment pre-shower for further tests.


2021 ◽  
Vol 16 (12) ◽  
pp. C12002
Author(s):  
N.J.S. Bal ◽  
C.S. Schmitzer ◽  
A. De Franco ◽  
S. Enke

Abstract The Medipix3, a hybrid pixel detector with a silicon sensor, has been evaluated as a beam instrumentation device with proton and carbon ion measurements in the non-clinical research room (IR1) of MedAustron Ion Therapy Center. Protons energies are varied from 62.4 to 800 MeV with 104 to 108 protons per second impinging on the detector surface. For carbon ions, energies are varied from 120 to 400 MeV/amu with 107 to 108 carbon ions per second. Measurements include simultaneous high resolution, beam profile and beam intensity with various beam parameters at up to 1000 FPS (frames per second), count rate linearity and an assessment of radiation damage after the measurement day using an x-ray tube to provide a homogeneous radiation measurement. The count rate linearity is found to be linear within the uncertainties (dominated by accelerator related sources due to special setup) for the measurements without degraders. Various frequency components are identified within the beam intensity over time firstly including 49.98 Hz with standard deviation, σ = 0.29, secondly 30.55 Hz σ = 0.55 and thirdly 252.51 Hz σ = 0.83. A direct correlation between the number of zero counting and noisy pixels is observed in the measurements with the highest flux. No conclusive evidence of long term radiation damage was found as a result of these measurements over one day.


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