SOI Pixel Detector Research Articles

Development of a new high-speed data acquisition system prototype for SOI pixel detector using SiTCP-XG, a 10-gigabit Ethernet network processor

We are developing a new readout board with a newer generation field-programmable gate array (FPGA) and the 10-gigabit ethernet to improve the performance and usability of the current readout board based on the 1-gigabit ethernet. In this new readout board, the SiTCP-XG network processor supporting 10 Gigabit Ethernet was implemented. SiTCP is a network processor circuit running on FPGA, and SiTCP-XG is the newly developed version of the SiTCP that supports 10-gigabit ethernet. Before developing the new board, we constructed a prototype system using the Xilinx FPGA evaluation board KC705 to evaluate the SiTCP-XG. This prototype system was tested with the SOI pixel detector, which has 425,984 (column 832 × row 512 matrix) pixels and a pixel size of 17 × 17 μm2 at the synchrotron beamlines of the PhotonFactory (KEK). This was the first test of the X-ray imaging for this system. The results showed that this system worked stably with a transfer rate of 682 Mbps (equivalent to a frame rate of 100 fps, limited by detector operation parameters), and also worked stably with a transfer rate of 2.4 Gbps (equivalent to 350 fps, the maximum rate limited by the detector performance). These results suggest that the SiTCP-XG system has sufficient transfer performance to cover the SOIPIX detector performance.

Development of on-chip pattern processing in event-driven SOI pixel detector for X-ray astronomy with background rejection purpose

This paper reports on the development of on-chip pattern processing in the event-driven silicon-on-insulator pixel detector for X-ray astronomy with background rejection purpose. X-ray charge-coupled device (CCD) detectors, well-established pixel detectors used in this field, has proven that classification of detected events considering their spatial pattern is effective for particle background rejection. Based on the current architecture of our device and from the CCD images obtained in space, we first established a design concept and algorithm of the pattern processor to be implemented. Then, we developed a new device, including a prototype pattern-processing circuit. Experiments using X-ray and beta-ray radioisotopes demonstrated that the pattern processor properly works as expected, and the particle background rejection is realized in an on-chip fashion. This function is useful, especially in a limited-resource system such as the CubeSat.

Fine residual stress distribution measurement of steel materials by SOI pixel detector with synchrotron X-rays

Residual stress is an important factor governing evaluating and controlling the quality of metal materials in industrial products. X-ray measurements provide one of the most effective means of evaluating residual stress without destruction. In such measurements, the effects of residual stress on the crystal structure can be observed through the Debye ring deformation.In previous studies, we developed a residual stress measurement system based on the cosα method, using a two-dimensional (2D) silicon-on-insulator pixel (SOIPIX) detector known as INTPIX4. In a typical laboratory setup, this system requires only 1 s to measure a specified point. This is drastically faster than the conventional system based on the sin2ψ method, which requires more than 10 min, and the cosα-based system using an imaging plate, which requires 1 min. Compared to other systems, it can evaluate the 2D distribution of residual stress faster and provide more detailed information for evaluating materials. We first attempted to measure the 2D distribution in a laboratory setup with a Cr X-ray tube (Cr Kα 5.4 keV) and obtained satisfactory results. We subsequently took measurements using synchrotron monochromatic X-rays to determine the fine accuracy and fine sampling pitch distribution. In this paper, we report the results of the initial synchrotron experiment, including the residual stress distribution of the standard specimen obtained by the first prototype setup. Furthermore, we compare the synchrotron measurements with those from the laboratory.

Minimization of charge sharing effects in a counting type SOI pixel detector for synchrotron radiation

The charge sharing effect among adjacent pixels of a single photon counting detector, which comes from the lateral spread of charges generated from the interaction of X-ray quanta in silicon, has been a critical issue in the pixel detectors due to its influence on the count rate and resolution capability. Targeted on this issue, a single photon counting SOI pixel detector CNPTEG1 used for synchrotron radiation (SR) experiments was developed. It has 17k hexagonal pixels with 52 μm center-to-center pitch while keeping a circuit of charge sharing arbitration logic and 19-bit counter in each pixel. The effectiveness of the charge sharing arbitration logic was verified by using a micro beam with about 10 μm diameter scanning across pixels. The results showed that the count loss or multiple count in pixel boundary was effectively suppressed by the charge sharing arbitration logic with proper threshold setting. The impact of charge sharing on the pixel point spread function (PSF) has also been investigated.

Proton radiation damage experiment for X-ray SOI pixel detectors

In low earth orbit, there are many cosmic rays composed primarily of high energy protons. These cosmic rays cause surface and bulk radiation effects, resulting in degradation of detector performance. Quantitative evaluation of radiation hardness is essential in development of X-ray detectors for astronomical satellites. We performed proton irradiation experiments on newly developed X-ray detectors called XRPIX based on silicon-on-insulator technology at HIMAC in National Institute of Radiological Sciences. We irradiated 6 MeV protons with a total dose of 0.5 krad, equivalent to 6 years irradiation in orbit. As a result, the gain increases by 0.2% and the energy resolution degrades by 0.5%. Finally we irradiated protons up to 20 krad and found that detector performance degraded significantly at 5 krad. With 5 krad irradiation corresponding to 60 years in orbit, the gain increases by 0.7% and the energy resolution worsens by 10%. By decomposing into noise components, we found that the increase of the circuit noise is dominant in the degradation of the energy resolution.

Advancement of X-ray radiography using microfocus X-ray source in conjunction with amplitude grating and SOI pixel detector, SOPHIAS.

We show how to improve microfocus X-ray radiography by using the SOPHIAS silicon-on-insulator pixel detector in conjunction with an amplitude grating. Single-exposure multi-energy absorption and differential phase contrast imaging was performed using the single amplitude grating method. The sensitivity in differential phase contrast imaging in a two-pixel-pitch setup was enhanced by 39% in comparison with the previously reported method [Rev. Sci. Instrum. 81, 113702 (2010).] by analyzing charge-sharing effects. Small-angle-scattering imaging was also possible in the two-pixel-pitch setup by counting the number of X-ray photons passing the pixel boundaries.

Development of an X-ray imaging system with SOI pixel detectors

An X-ray imaging system employing pixel sensors in silicon-on-insulator technology is currently under development. The system consists of an SOI pixel detector (INTPIX4) and a DAQ system based on a multi-purpose readout board (SEABAS2). To correct a bottleneck in the total throughput of the DAQ of the first prototype, parallel processing of the data taking and storing processes and a FIFO buffer were implemented for the new DAQ release. Due to these upgrades, the DAQ throughput was improved from 6Hz (41Mbps) to 90Hz (613Mbps). The first X-ray imaging system with the new DAQ software release was tested using 33.3keV and 9.5keV mono X-rays for three-dimensional computerized tomography. The results of these tests are presented.

Monolithic SOI pixel detector with a wide dynamic range and a high frame rate for FEL-applications

Monolithic pixel detector implemented in 200 nmsilicon-on-insulator technology for x-ray imaging applications will bepresented. The detection is based on a fully-depleted high-resistancesubstrate, isolated by the buried silicon dioxide from the electronicslayer. The pixel electronics contains a wide dynamic range integrator thatis able to measure and to digitize the number of photons in a wide signalrange. The detector is a simple and cheap alternative for the hybrid pixelimaging detectors. The experimental results obtained with the secondprototype will be presented. The aimed application is the free electronlaser.

3D Integration for An SOI Pixel Detector (Invited Talk)

not Available.