Planar geometry silicon pixel and strip sensors for the high luminosity upgrade of the LHC (HL-LHC) require a high bias voltage of 1000V in order to withstand a radiation damage caused by particle ...fluences of 1×1016 1MeVneq/cm2 and 1×1015 1MeVneq/cm2 for pixel and strip detectors, respectively. In order to minimize the inactive edge space that can withstand a bias voltage of 1000V, edge regions susceptible to microdischarge (MD) should be carefully optimized. We fabricated diodes with various edge distances (slim-edge diodes) and with 1–3 multiple guard rings (multi-guard diodes). AC coupling insulators of strip sensors are vulnerable to sudden heavy charge deposition, such as an accidental beam splash, which may destroy the readout AC capacitors. Thus various types of punch-through-protection (PTP) structures were implemented in order to find the most effective structure to protect against heavy charge deposition. These samples were irradiated with 70MeV protons at fluences of 5×1012 1MeVneq/cm2–1×1016 1MeVneq/cm2. Their performances were evaluated before and after irradiation in terms of an onset voltage of the MD, a turn-on voltage of the PTP, and PTP saturation resistance.
► We have evaluated radiation tolerance of n-in-p sensors up to 1×1016 1MeVneq/cm2. ► Both n-bulk and p-bulk require a field width≥450μm in order to withstand 1000V. ► The MD onset voltage was found to be independent of the edge width. ► With increasing number of guard rings, bias voltage tolerance improved before irrad. ► BZ4D-5 (with full extension) performs the best among the samples.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The purpose of this study was to compare the changes and resumption of sports and physical activities (SPA) between older and younger patients after opening wedge high tibial osteotomy (OWHTO).
One ...hundred and one patients (120 knees) with medial compartment knee osteoarthritis were investigated. The 53 patients aged>65 years were defined as the O group and the 48 patients aged<64 years were defined as the Y group. The ratios of SPA cases, time points at which SPA was started after surgery, frequencies of SPA, and Lysholm scores were compared between the two groups. The level of significance was set at P<0.05.
The preoperative and postoperative ratios of SPA cases were 28.3% and 26.4% in the O group, respectively (P=0.82). The corresponding ratios were 20.8% and 41.6% in the Y group, respectively (P=0.027). The mean time points for starting SPA after surgery were 12.3±7.5 months in the O group and 11.2±11.0 months in the Y group (P=0.18). The mean frequencies of SPA after surgery were 4.04±2.15 days/week in the O group and 2.7±1.99 days/week in the Y group (P=0.021). The mean postoperative Lysholm scores were 89.5±5.4 in the O group and 88.8±4.9 in the Y group (P=0.61).
The postoperative ratio of SPA cases showed a significant increase compared with the preoperative ratio in the Y group only. However, older patients performed SPA more often than younger patients postoperatively. Both older and younger patients required a relatively long time to resume or start SPA.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We have been developing highly radiation-tolerant n+-in-p planar pixel sensors for use in the high-luminosity LHC. Novel n+-in-p structures were made using various combinations of the bias structures ...(punch-through or polysilicon resistor), isolation structures (p-stop or p-spray), and thicknesses (320μm or 150μm). The 1-chip pixel modules with thin FE-I4 pixel sensors were evaluated using test beams, before and after 2×1015neq/cm2 irradiation. The full depletion voltages were estimated to be 44±10V and 380±70V, in the non-irradiated and the irradiated modules, respectively. A reduction of efficiency was observed in the vicinity of the four pixel corners and underneath the bias rail after the irradiation. The global efficiencies were >99% and >95% in the non-irradiated and the irradiated modules, respectively. The collected charges were uniform in the depth direction at bias voltages well above the full depletion voltages. The encapsulation of vulnerable edges with adhesive or parylene prevented HV sparking. Bump bonding with the SnAg solder bumps was performed at HPK with 150μm- and 320μm-thick sensors and chips. No disconnection of bumps was observed after 10 thermal cycles between −40 and +50°C, with a temperature slew rate of >70K/min.
► Novel n+-in-p pixel sensors were made of punch-through/poly-Si biasing, p-stop/p-spray isolation, and 320/150μm thickness. ► The thin pixel modules were evaluated in testbeams, before and after 2×1015neq/cm2 irradiation. ► A reduction of efficiency was observed in the vicinity of four-corners of pixels and underneath the bias rail after irradiation. ► Encapsulating the vulnerable edges with adhesive or parylene achieved prevention of HV sparking up to 1000V. ► No disconnection of SnAg bump-bonds was observed in dummy modules after 10 thermal cycles with a slew rate of >70K/min.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
In this paper we present R&D of n-in-p pixel sensors, aiming for a very high radiation environment up to a fluence of 10
16
n
eq/cm
2. To fabricate these sensors, two batches with different mask sets ...were employed: the first resulted in pixel sensors compatible with the ATLAS pixel readout frontend chip called FE-I3, and the second in FE-I3 and a new frontend chip, FE-I4, compatible sensors; small diodes were employed to investigate the width from the active diode to the dicing edge and the guard rings. Tests involving the diodes showed that the strong increase of leakage current was attributed to the edge current when the lateral depletion zone reaches the dicing edge and the lateral depletion along the silicon surface was correlated with the ‘field’ width. The onset was observed at a voltage of 1000
V when the width was equal to ∼400
μm. The pixel sensors that were diced at a width of 450
μm could successfully maintain a bias voltage of 1000
V. Hybrid flip-chip pixel modules with dummy and real chips were also fabricated. Lead (PbSn) solder bump bonding proved to be successful. However, lead-free (SnAg) solder bump bonding requires further optimization.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
An in situ synchrotron powder X-ray diffraction study on (Fe0.89,Ni0.11)3S was conducted up to 141 GPa and 1590 K. (Fe0.89,Ni0.11)3S has a tetragonal structure, which is the same structure as Ni-free ...Fe3S. Fitting a third-order Birch-Murnaghan equation of state to data at ambient temperature yielded a bulk modulus of K0=138.1(7.2) GPa and its pressure derivative K0'=4.5(3) with a zero pressure volume V0=375.67(4) Å3. The density of (Fe0.89,Ni0.11)3S under the core-mantle boundary condition is 1.7% greater than that of Fe3S. The axial ratio (c/a) of (Fe0.89,Ni0.11)3S decreases with increasing pressure. The addition of nickel to Fe3S leads to a softening of the c-axis. Assuming that the nickel content of the outer core is about 5 at%, we estimated 12.3-20.8 at% sulfur in the outer core for the given 6-10% density deficit between the outer core and pure iron at 136 GPa.
Apoptosis is induced by various stresses generated from the extracellular and intracellular environments. The fidelity of the cell cycle is monitored by surveillance mechanisms that arrest its ...further progression if any crucial process has not been completed or damages are sustained, and then the cells with problems undergo apoptosis. Although the molecular mechanisms involved in the regulation of the cell cycle and that of apoptosis have been elucidated, the links between them are not clear, especially that between cell cycle and death receptor-mediated apoptosis. By using the HeLa.S-Fucci (fluorescent ubiquitination-based cell cycle indicator) cells, we investigated the relationship between the cell cycle progression and apoptotic execution. To monitor apoptotic execution during cell cycle progression, we observed the cells after induction of apoptosis with time-lapse fluorescent microscopy. About 70% of Fas-mediated apoptotic cells were present at G(1) phase and about 20% of cells died immediately after cytokinesis, whereas more than 60% of etoposide-induced apoptotic cells were at S/G(2) phases in random culture of the cells. These results were confirmed by using synchronized culture of the cells. Furthermore, mitotic cells showed the resistance to Fas-mediated apoptosis. In conclusion, these findings suggest that apoptotic execution is dependent on cell cycle phase and Fas-mediated apoptosis preferentially occurs at G(1) phase.
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