Silicon-on-insulator (SOI) technology provides an optimal structure for realizing monolithic radiation imaging devices as it involves the preparation of a separate thick silicon layer for the sensing ...region in addition to a circuit layer. However, several difficult issues exist in the use of commercial SOI-CMOS processes to fabricate the imaging devices. We have developed an SOI pixel process based on an 0.2 µm fully-depleted (FD)-SOI CMOS process. To achieve a thick sensing region, we have bonded a high-resistivity floating-zone (FZ) wafer as the handle wafer. Since the device must be radiation-hardened, a new double SOI process technology is developed to improve the radiation hardness to more than 100 kGy(Si) and reduce the coupling between sensors and circuits. The SOI pixel process and sensors we developed are shown.
As railroad rails are an important social infrastructure, monetary and human resources are spent on their maintenance and inspection for people’s safety and security. In particular, rails are ...uniformly ground periodically to reduce noise and vibration during railroad operations and avoid damage to the rail tops. However, due to cost reduction and lack of human resources, the damage mechanism of rails is being elucidated for more efficient grinding. Factors such as passing tonnage, transit speed, and weather conditions affect rail damage; however, the details of the damage mechanism are not clear. In this study, we measured a large amount of residual stresses and the full width at half maximum (FWHM) of the diffraction rings using a high-speed X-ray residual stress measurement system and explored the possibility of detecting abnormal areas of rails and diagnosing the signs of damage using statistical analysis methods and machine learning.For verification, 2D mapping measurements of the x-axis component of the vertical stress σx, shear stresses τxy, τxz, and τyz, and FWHM of the diffraction ring at the head of a cracked rail were used. The data were subjected to dimensionality reduction by principal component analysis, kernel principal component analysis, and an autoencoder. These normal models were built using the data of the normal areas without cracks. The anomaly score was defined as the differences from the normal models, and the detection accuracies of the models were compared using the area under the receiver operating characteristic curve; the autoencoder showed the best performance.
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 μm
2
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.
A fundamental study was conducted on the effectiveness of a silicon-on-insulator (SOI) pixel detector for industrial applications. In this study, we developed a measurement system for X-ray tri-axial ...stress analysis by using an INTPIX4, an integrated SOI pixel detector developed by Arai et al. This system measured the diffraction ring diffracted backward from the polycrystalline sample by using a CrKα characteristic X-ray, and performed a tri-axial residual stress analysis by applying the generalised cosα method. To verify this measurement system, we measured the residual stress of a rail used in service and examined the state of rolling contact fatigue due to contact with wheels. In this measurement, diffraction rings generated from 211 diffraction lines of the ferrite phase in the rail steel were measured. The results of this system were compared with those obtained from a commercial device using an image plate (IP). As a result, this measurement system was found to be able to effectively measure the tri-axial residual stress component 30 times faster than the commercial device, and proved to be promising for rail inspection.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
This paper presents a novel full-depletion Si X-ray detector based on silicon-on-insulator pixel (SOIPIX) technology using a pinned depleted diode structure, named the SOIPIX-PDD. The SOIPIX-PDD ...greatly reduces stray capacitance at the charge sensing node, the dark current of the detector, and capacitive coupling between the sensing node and SOI circuits. These features of the SOIPIX-PDD lead to low read noise, resulting high X-ray energy resolution and stable operation of the pixel. The back-gate surface pinning structure using neutralized p-well at the back-gate surface and depleted n-well underneath the p-well for all the pixel area other than the charge sensing node is also essential for preventing hole injection from the p-well by making the potential barrier to hole, reducing dark current from the Si-SiO₂ interface and creating lateral drift field to gather signal electrons in the pixel area into the small charge sensing node. A prototype chip using 0.2 μm SOI technology shows very low readout noise of 11.0 e
, low dark current density of 56 pA/cm² at -35 °C and the energy resolution of 200 eV(FWHM) at 5.9 keV and 280 eV (FWHM) at 13.95 keV.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
In this study, a silicon on insulator (SOI) pixel detector was applied to the X-ray stress measurement of steel. Two integration-type SOI pixel sensor chips, INTPIX4, were used to measure a ...Debye–Scherrer ring. Stresses were determined through data analysis of the ring and using the cos(α) method. To examine the validity of the system for practical use, stress measurements were conducted at several points on a steel sample manufactured with welding. The sample consisted of various surfaces with crystallographic conditions, such as coarse-grains on welding beads, crystal grains covered by oxide films, and crystallographic textured grains. The results obtained using the SOI pixel detector were compared with those obtained using an image plate.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
7.
Radiation hardness of silicon-on-insulator pixel devices Hara, Kazuhiko; Aoyagi, Wataru; Sekigawa, Daisuke ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2019, Volume:
924
Journal Article
Peer reviewed
Open access
Silicon-on-Insulator (SOI) CMOS is an attractive technology because of pixel sensor applications for its inherent advantages such as superior isolation of each FET by the surrounding insulator. We ...have been developing SOI pixel devices since 2005 using the FD-SOI technology and noticed that the insulator layers impose significant sensitivity to the total ionization dose (TID) effect. Research activities in the last ten years to improve radiation hardness are reviewed, such as introduction of buried wells and double SOI wafers.
•Radiation hardness of silicon-on-insulator (SOI) devices improved significantly by adopting double SOI wafer.•Total ionization dose (TID) effect suppressed by applying negative voltages to the second SOI layer of double SOI.•Device irradiated to 100 kGy showed complete recovery examined with high-energy protons.•Latest device with modified concentration profile in lightly-doped drain showed radiation tolerance up to 1 MGy.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Abstract Background The purpose of this study was to investigate the prognostic value of quadriceps isometric strength (QIS) in coronary artery disease (CAD). Methods The study population consisted ...of 1314 patients aged >30 years (64.7 ± 10.6 years, 1051 male) with CAD who were hospitalized for acute coronary syndrome or coronary artery bypass grafting. Maximal QIS was evaluated as a marker of leg strength and expressed relative to body weight (% body weight). The primary and secondary endpoints were all-cause death and cardiovascular (CV) death, respectively. Results During a mean follow-up of 5.0 ± 3.5 years, corresponding to 6537 person-years, there were 118 all-cause deaths and 63 CV deaths. A higher QIS remained associated with decreased all-cause mortality and CV mortality risks (hazard ratio for increasing 10% body weight of QIS 0.77, 95% confidence interval 0.67-0.89, P < .001 for all-cause death; hazard ratio 0.66, 95% confidence interval 0.54-0.82, P < .001 for CV death) after adjustment for other prognostic factors. The inclusion of QIS significantly increased both continuous net reclassification improvement (cNRI) and integrated discrimination improvement (IDI) for all-cause death (cNRI: 0.25, P = .009; IDI: 0.007, P = .030) and CV death (cNRI: 0.34, P = .008; IDI: 0.013, P = .008). Conclusions A high level of quadriceps strength was strongly associated with a lower risk of both all-cause and CV mortality in patients with CAD. Evaluation of QIS offered incremental prognostic information beyond pre-existing risk factors.
First results of a Double-SOI pixel chip for X-ray imaging Lu, Yunpeng; Ouyang, Qun; Arai, Yasuo ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2016, Volume:
831
Journal Article
Peer reviewed
Aiming at low energy X-ray imaging, a prototype chip based on Double-SOI process was designed and tested. The sensor and pixel circuit were characterized. The long lasting crosstalk issue in SOI ...technology was understood. The operation of pixel was verified with a pulsed infrared laser beam. The depletion of sensor revealed by signal amplitudes is consistent with the one revealed by I–V curve. An s-curve fitting resulted in a sigma of 153 e− among which equivalent noise charge (ENC) contributed 113 e−. It's the first time that the crosstalk issue in SOI technology was solved and a counting type SOI pixel demonstrated the detection of low energy radiation quantitatively.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
10.
Low-energy X-ray performance of SOI pixel sensors for astronomy, “XRPIX” Kodama, Ryota; Tsuru, Takeshi Go; Tanaka, Takaaki ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
01/2021, Volume:
986
Journal Article
Peer reviewed
Open access
We have been developing a new type of X-ray pixel sensors, “XRPIX”, allowing us to perform imaging spectroscopy in the wide energy band of 1–20keV for the future Japanese X-ray satellite “FORCE”. The ...XRPIX devices are fabricated with complementary metal-oxide-semiconductor silicon-on-insulator technology, and have the “Event-Driven readout mode”, in which only a hit event is read out by using hit information from a trigger output function equipped with each pixel. This paper reports on the low-energy X-ray performance of the “XRPIX6E” device with a Pinned Depleted Diode (PDD) structure. The PDD structure especially reduces the readout noise, and hence is expected to largely improve the quantum efficiencies for low-energy X-rays. While F-K X-rays at 0.68keV and Al-K X-rays at 1.5keV are successfully detected in the “Frame readout mode”, in which all pixels are read out serially without using the trigger output function, the device is able to detect Al-K X-rays, but not F-K X-rays in the Event-Driven readout mode. Non-uniformity is observed in the counts maps of Al-K X-rays in the Event-Driven readout mode, which is due to region-to-region variation of the pedestal voltages at the input to the comparator circuit. The lowest available threshold energy is 1.1keV for a small region in the device where the non-uniformity is minimized. The noise of the charge sensitive amplifier at the sense node and the noise related to the trigger output function are ∼18e− (rms) and ∼13e− (rms), respectively.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
PDF
