Timepix4, a large area pixel detector readout chip which can be tiled on 4 sides providing sub-200 ps timestamp binning

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).

Download Full-text

Subpixel resolution in CdTe Timepix3 pixel detectors

Journal of Synchrotron Radiation ◽

10.1107/s1600577518013838 ◽

2018 ◽

Vol 25 (6) ◽

pp. 1650-1657 ◽

Cited By ~ 5

Author(s):

Mohamad Khalil ◽

Erik Schou Dreier ◽

Jan Kehres ◽

Jan Jakubek ◽

Ulrik Lund Olsen

Keyword(s):

Single Photon ◽

Weighted Average ◽

European Synchrotron Radiation Facility ◽

Time Of Arrival ◽

Pixel Detector ◽

Step Size ◽

X Ray ◽

Pixel Detectors ◽

Individual Photon ◽

Subpixel Resolution

Timepix3 (256 × 256 pixels with a pitch of 55 µm) is a hybrid-pixel-detector readout chip that implements a data-driven architecture and is capable of simultaneous time-of-arrival (ToA) and energy (ToT: time-over-threshold) measurements. The ToA information allows the unambiguous identification of pixel clusters belonging to the same X-ray interaction, which allows for full one-by-one detection of photons. The weighted mean of the pixel clusters can be used to measure the subpixel position of an X-ray interaction. An experiment was performed at the European Synchrotron Radiation Facility in Grenoble, France, using a 5 µm × 5 µm pencil beam to scan a CdTe-ADVAPIX-Timepix3 pixel (55 µm × 55 µm) at 8 × 8 matrix positions with a step size of 5 µm. The head-on scan was carried out at four monochromatic energies: 24, 35, 70 and 120 keV. The subpixel position of every single photon in the beam was constructed using the weighted average of the charge spread of single interactions. Then the subpixel position of the total beam was found by calculating the mean position of all photons. This was carried out for all points in the 8 × 8 matrix of beam positions within a single pixel. The optimum conditions for the subpixel measurements are presented with regards to the cluster sizes and beam subpixel position, and the improvement of this technique is evaluated (using the charge sharing of each individual photon to achieve subpixel resolution) versus alternative techniques which compare the intensity ratio between pixels. The best result is achieved at 120 keV, where a beam step of 4.4 µm ± 0.86 µm was measured.

Download Full-text

Phase Unwrapping in Spectral X-Ray Differential Phase-Contrast Imaging With an Energy-Resolving Photon-Counting Pixel Detector

IEEE Transactions on Medical Imaging ◽

10.1109/tmi.2014.2349852 ◽

2015 ◽

Vol 34 (3) ◽

pp. 816-823 ◽

Cited By ~ 12

Author(s):

Franz M. Epple ◽

Franz Pfeiffer ◽

Sebastian Ehn ◽

Pierre Thibault ◽

Thomas Koehler ◽

...

Keyword(s):

Phase Contrast ◽

Photon Counting ◽

Phase Unwrapping ◽

Phase Contrast Imaging ◽

Pixel Detector ◽

Contrast Imaging ◽

X Ray ◽

Differential Phase ◽

Differential Phase Contrast

Download Full-text

Pixel readout IC for CdTe detectors operating in single photon counting mode with interpixel communication

Journal of Instrumentation ◽

10.1088/1748-0221/17/01/c01036 ◽

2022 ◽

Vol 17 (01) ◽

pp. C01036

Author(s):

P. Grybos ◽

R. Kleczek ◽

P. Kmon ◽

A. Krzyzanowska ◽

P. Otfinowski ◽

...

Keyword(s):

Integrated Circuit ◽

Single Photon ◽

Photon Counting ◽

Recognition Algorithm ◽

Total Charge ◽

Readout Integrated Circuit ◽

Single Photon Counting ◽

X Ray ◽

Pixel Detectors ◽

Photon Counting Mode

Abstract This paper presents a readout integrated circuit (IC) of pixel architecture called MPIX (Multithreshold PIXels), designed for CdTe pixel detectors used in X-ray imaging applications. The MPIX IC area is 9.6 mm × 20.3 mm and it is designed in a CMOS 130 nm process. The IC core is a matrix of 96 × 192 square-shaped pixels of 100 µm pitch. Each pixel contains a fast analog front-end followed by four independently working discriminators and four 12-bit ripple counters. Such pixel architecture allows photon processing one by one and selecting the X-ray photons according to their energy (X-ray colour imaging). To fit the different range of applications the MPIX IC has 8 possible different gain settings, and it can process the X-ray photons of energy up to 154 keV. The MPIX chip is bump-bonded to the CdTe 1.5 mm thick pixel sensor with a pixel pitch of 100 µm. To deal with the charge sharing effect coming from a thick semiconductor pixel sensor, multithreshold pattern recognition algorithm is implemented in the readout IC. The implemented algorithm operates both in the analog domain (to recover the total charge spread between neighboring pixels, when a single X-ray photon hits the border of the pixel) and in the digital domain (to allocate a hit position to a single pixel).

Download Full-text

High-contrast X-ray micro-radiography and micro-CT of ex-vivo soft tissue murine organs utilizing ethanol fixation and large area photon-counting detector

Scientific Reports ◽

10.1038/srep30385 ◽

2016 ◽

Vol 6 (1) ◽

Cited By ~ 23

Author(s):

Jan Dudak ◽

Jan Zemlicka ◽

Jakub Karch ◽

Matej Patzelt ◽

Jana Mrzilkova ◽

...

Keyword(s):

Soft Tissue ◽

Ex Vivo ◽

Photon Counting ◽

Micro Ct ◽

High Contrast ◽

Large Area ◽

X Ray ◽

Photon Counting Detector

Download Full-text

X-Ray Imaging of the Filling of “T” Shaped Microchannel Using a MEDIPIX2 Pixel Detector

X-Rays in Mechanical Engineering Applications ◽

10.1115/imece2004-62532 ◽

2004 ◽

Author(s):

A. Vabre ◽

E. Manach ◽

O. Gal ◽

S. Legoupil

Keyword(s):

Measurement Technique ◽

Chemical Engineering ◽

Measurement Techniques ◽

Photon Counting ◽

Pixel Detector ◽

Lab On Chip ◽

X Ray ◽

Space Resolution ◽

Research Perspectives ◽

European Collaboration

Fluid flows in “T” or “Y” shaped structures of microchannels are studied in order to develop modeling approaches as well as adapted measurement techniques. The applications of these structures are numerous and concern in particular biology and chemical engineering for which the integration of microchannels in lab-on-chip and/or microreactor is an important challenge. Our works concern the development of a measurement technique for the study of the filling of a “T” shaped microchannel structure by a liquid. In the studied channels, the experimental constraints are strong. Indeed, the space steps involved within the phenomena are very much reduced and vary from 1 to 10 μm. Moreover, the dynamics of the flow implies a high acquisition frequency, ranging from 10 to 100 Hz. Our technological choice is based on the measurement of the attenuation of an X-ray beam in the matter. The main advantage of this non-intrusive technique is that it can be implemented even in media opaque to visible light. Also, that X-ray techniques can theoretically reach a better space resolution than optical ones. The measurement technique is quantitative and a 3D measurement is achievable by tomography. These methods are validated for problems located at centimetric space steps and high acquisition frequencies, [1], [2]. The objective of this work is to match the microfluidics field requirement (space steps and attenuation contrast), while preserving high time frequencies. Our experimental bench consists of a X-ray generator, that makes possible to obtain high enlargements of the observed object whit a reduced blur in the image. The image is obtained by a pixel detector called Medipix2. This detector is under development within a European collaboration which gathers 16 partners around the CERN, the CEA being a partner. The main assets of this detector are its high space resolution, its operational photon counting mode and its high acquisition frequency. The presented works constitute a very first implementation and validation of the proposed technique for the microfluidics field. Experimental results are obtained and presented. They allow a measurement of the filling conditions of the “T” shape structure of microchannels. The orientations and research perspectives to improve the obtained results by the technique could be evaluated accurately and important basis of our work are now established and quantified for the future.

Download Full-text

Protein crystallography with a novel large-area pixel detector

Journal of Applied Crystallography ◽

10.1107/s0021889806016591 ◽

2006 ◽

Vol 39 (4) ◽

pp. 550-557 ◽

Cited By ~ 39

Author(s):

Gregor Hülsen ◽

Christian Broennimann ◽

Eric F. Eikenberry ◽

Armin Wagner

Keyword(s):

Single Photon ◽

New Technology ◽

Photon Counting ◽

Data Sets ◽

Pixel Detector ◽

Large Area ◽

Single Photon Counting ◽

Continuous Rotation ◽

Under Construction ◽

Paul Scherrer

The PILATUS 1M detector, developed at the Paul Scherrer Institut, is a single-photon-counting hybrid pixel detector designed for macromolecular crystallography. With more than 1 million pixels covering an area of 243 × 210 mm, it is the largest such device constructed to date. The detector features a narrow point spread function, very fast readout and a complete absence of electronic noise. Unfortunately, this prototype detector has numerous defective pixels and sporadic errors in counting that complicate its operation. With appropriate experimental design, it was largely possible to work around these problems and successfully demonstrate the application of this technology to structure determination. Conventional coarse ϕ-sliced data were collected on thaumatin and a refined electron density map was produced that showed the features expected of a map at 1.6 Å resolution. The results were compared with the performance of a reference charge-coupled device detector: the pixel detector is superior in speed, but showed higherR-factors because of the counting errors. Complete fine ϕ-sliced data sets recorded in the continuous-rotation mode showed the predicted advantages of this data collection strategy and demonstrated the expected reduction ofR-factors at high resolution. A new readout chip has been tested and shown to be free from the defects of its predecessor; a PILATUS 6M detector incorporating this new technology is under construction.

Download Full-text