- 标题
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- 实验方案
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Total Ionizing Dose Effects of 55-nm Silicon-Oxide-Nitride-Oxide-Silicon Charge Trapping Memory in Pulse and DC Modes
摘要： The 60Co-γ ray total ionizing dose radiation responses of 55-nm silicon-oxide-nitride-oxide-silicon (SONOS) memory cells in pulse mode (programmed/erased with pulse voltage) and dc mode (programmed/erased with direct voltage sweeping) are investigated. The threshold voltage and off-state current of memory cells before and after radiation are measured. The experimental results show that the memory cells in pulse mode have a better radiation-hard capability. The normalized memory window still remains at 60% for cells in dc mode and 76% for cells in pulse mode after 300 krad(Si) radiation. The charge loss process physical mechanisms of programmed SONOS devices during radiation are analyzed.
关键词： dc mode,pulse mode,total ionizing dose,radiation effects,SONOS memory
更新于2025-09-23 15:23:52
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Measurement of peripheral dose to pelvic region and associated risk for cancer development after breast intraoperative electron radiation therapy
摘要： This study aimed to measure received dose to the pelvic region of patients during breast intraoperative electron radiation therapy (IOERT). Furthermore, we compared the findings with those of external beam radiation therapy. Finally, secondary ovary and uterus cancer risks following breast IOERT were estimated. In the current study, the received dose to the pelvic surface of 18 female patients during breast IOERT boost were measured by thermoluminescent dosimeter (TLD-100) chips. All patients were treated with 12 Gy given in a single fraction. To estimate the dose to the ovary and uterus of the patients, conversion coefficients for depth from surface dose were obtained in a Rando phantom. Given the received dose to the pelvic region of the patients, secondary ovary and uterus cancer risks following breast IOERT were estimated. The received doses to ovary and uterus surface of the patients were 0.260±0.155 mGy to 31.460±6.020 mGy and 0.485±0.122 mGy to 22.387±15.476 mGy, respectively. Corresponding intra-pelvic (ovary and uterus) regional doses were 0.012±0.007 mGy to 1.479±0.283 mGy and 0.027±0.001 mGy to 1.164±0.805 mGy, respectively. Findings demonstrated that the ratio of the received dose by pelvic surface to regional dose during breast IOERT was much less than external beam energies were 135.722±117.331 × 10-6 and 69.958±28.072 × 10-6, and for uterus were 17.342±10.583 × 10-6 and 2.971±3.604 × 10-6, respectively. According to our finding, the use of breast IOERT in pregnant patients can be considered as a safe radiotherapeutic technique, because the received dose to the fetus was lower than 50 mGy. Furthermore, IOERT can efficiently reduce the unnecessary dose to the pelvis region and lowers the risk of a secondary ovary and uterus cancer following breast irradiation.
关键词： Breast cancer,peripheral dose,Radiation therapy,IOERT,Secondary cancer risk,pelvic region
更新于2025-09-23 15:23:52
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Determination of Differential Emission Measure from Solar Extreme Ultraviolet Images
摘要： The Atmospheric Imaging Assembly (AIA) on board the Solar Dynamic Observatory (SDO) has been providing high-cadence, high-resolution, full-disk UV-visible/extreme ultraviolet (EUV) images since 2010, with the best time coverage among all the solar missions. A number of codes have been developed to extract plasma differential emission measures (DEMs) from AIA images. Although widely used, they cannot effectively constrain the DEM at ?aring temperatures with AIA data alone. This often results in much higher X-ray ?uxes than observed. One way to solve the problem is by adding more constraint from other data sets (such as soft X-ray images and ?uxes). However, the spatial information of plasma DEMs are lost in many cases. In this Letter, we present a different approach to constrain the DEMs. We tested the sparse inversion code and show that the default settings reproduce X-ray ?uxes that could be too high. Based on the tests with both simulated and observed AIA data, we provided recommended settings of basis functions and tolerances. The new DEM solutions derived from AIA images alone are much more consistent with (thermal) X-ray observations, and provide valuable information by mapping the thermal plasma from ～0.3 to ～30 MK. Such improvement is a key step in understanding the nature of individual X-ray sources, and particularly important for studies of ?are initiation.
关键词： magnetic reconnection,methods: data analysis,Sun: X-rays, gamma rays,Sun: ?ares,Sun: corona,Sun: UV radiation
更新于2025-09-23 15:23:52
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Optimization of thin n-in-p planar pixel modules for the ATLAS upgrade at HL-LHC
摘要： The ATLAS experiment will undergo around the year 2025 a replacement of the tracker system in view of the high luminosity phase of the LHC (HL-LHC) with a new 5-layer pixel system. Thin planar pixel sensors are promising candidates to instrument the innermost region of the new pixel system, thanks to the reduced contribution to the material budget and their high charge collection efficiency after irradiation. The sensors of 50-150 μm thickness, interconnected to FE-I4 read-out chips, have been characterized with radioactive sources and beam tests. In particular active edge sensors have been investigated. The performance of two different versions of edge designs are compared: the first with a bias ring, and the second one where only a floating guard ring has been implemented. The hit efficiency at the edge has also been studied after irradiation at a fluence of 1015 neq/cm2. Highly segmented sensors will represent a challenge for the tracking in the forward region of the pixel system at HL-LHC. In order to reproduce the performance of 50x50 μm2 pixels at high pseudo-rapidity values, FE-I4 compatible planar pixel sensors have been studied before and after irradiation in beam tests at high incidence angles with respect to the short pixel direction. Results on the hit efficiency in this configuration are discussed for different sensor thicknesses.
关键词： Hybrid detectors,Radiation-hard detectors,Particle tracking detectors
更新于2025-09-23 15:23:52
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Testbeam results of irradiated ams H18 HV-CMOS pixel sensor prototypes
摘要： HV-CMOS pixel sensors are a promising option for the tracker upgrade of the ATLAS experiment at the LHC, as well as for other future tracking applications in which large areas are to be instrumented with radiation-tolerant silicon pixel sensors. We present results of testbeam characterisations of the 4th generation of Capacitively Coupled Pixel Detectors (CCPDv4) produced with the ams H18 HV-CMOS process that have been irradiated with different particles (reactor neutrons and 18 MeV protons) to fluences between 1 × 10^14 and 5 × 10^15 1-MeV- neq/cm^2. The sensors were glued to ATLAS FE-I4 pixel readout chips and measured at the CERN SPS H8 beamline using the FE-I4 beam telescope. Results for all fluences are very encouraging with all hit efficiencies being better than 97% for bias voltages of 85 V. The sample irradiated to a fluence of 1 × 10^15 neq/cm^2 — a relevant value for a large volume of the upgraded tracker — exhibited 99.7% average hit efficiency. The results give strong evidence for the radiation tolerance of HV-CMOS sensors and their suitability as sensors for the experimental HL-LHC upgrades and future large-area silicon-based tracking detectors in high-radiation environments.
关键词： Particle tracking detectors (Solid-state detectors),Solid state detectors,Radiation-hard detectors,Electronic detector readout concepts (solid-state)
更新于2025-09-23 15:23:52
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Resonant Enhancement of THz Radiation Through Vertically Aligned Carbon Nanotubes Array by Applying Wiggler Magnetic Field
摘要： The present analysis develops a novel theory of terahertz radiation generation by beating of two laser beams, incident obliquely on the array of vertically aligned carbon nanotubes (CNTs) in the presence of an external wiggler magnetic field. The array of CNTs behaves as nanoantenna to generate THz radiations. The incident lasers exert a ponderomotive force on the electrons of the CNTs to produce nonlinear oscillatory velocity, which beats with the applied wiggler magnetic field. This beating produces a nonlinear current at (ω2 ? ω1, k2 ? k1 + k0) which acts as an antenna to produce the THz radiation. We observe that when the beat frequency (ω2 ? ω1) lies near the effective plasmon frequency of the CNTs, strong THz radiation is produced due to a resonant interaction of the laser with CNT electrons. The externally applied wiggler magnetic field enhances the efficiency of THz radiation of nanoantenna by providing the necessary momentum to the generated THz radiation. We explore the impact of radius and length of nanotubes on the efficiency of THz generation. The generated THz power is enhanced at an optimum angle of incidence of lasers with an array of CNTs.
关键词： THz radiation,Carbon nanotubes,Antenna theory,Wiggler magnetic field,Plasma,Nanotechnology
更新于2025-09-23 15:23:52
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[IEEE 2018 18th International Symposium on Antenna Technology and Applied Electromagnetics (ANTEM) - Waterloo, ON (2018.8.19-2018.8.22)] 2018 18th International Symposium on Antenna Technology and Applied Electromagnetics (ANTEM) - Excitation of Hyperbolic Plasmons and Transition Radiation in Phosphorene by a Swift Electron
摘要： We analyze the energy loss channels for a fast electron traversing a monolayer phosphorene under oblique incidence taking the retardation effects into account.
关键词： transition radiation,electron energy loss,retardation effects,Phosphorene,hyperbolic plasmon polariton
更新于2025-09-23 15:23:52
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[IEEE 2018 18th International Symposium on Antenna Technology and Applied Electromagnetics (ANTEM) - Waterloo, ON (2018.8.19-2018.8.22)] 2018 18th International Symposium on Antenna Technology and Applied Electromagnetics (ANTEM) - A Log-Periodic Monopole Array with Uniform Spacing
摘要： This paper presents a log-periodic monopole array antenna with end-fire radiation and vertical polarization. It consists of 13 monopole elements and a meandering microstrip line on the bottom as the feeding line. The adjacent monopoles are of uniform spacing instead of conventional logarithmic spacing. A prototype is fabricated and tested. Measured results show that an impedance bandwidth from 2 to 6 GHz (3:1) for VSWR < 2 and a realized gain better than 7.6 dBi over the same operating frequency band are obtained.
关键词： log-periodic antenna,End-fire radiation,monopole array,uniform spacing
更新于2025-09-23 15:23:52
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[IEEE 2018 18th International Symposium on Antenna Technology and Applied Electromagnetics (ANTEM) - Waterloo, ON (2018.8.19-2018.8.22)] 2018 18th International Symposium on Antenna Technology and Applied Electromagnetics (ANTEM) - Plasmon Excitation and Transition Radiation in Graphene Traversed by a Fast Charged Particle
摘要： A progress report is presented on recent theoretical investigations of the interaction of fast charged particles with single and multiple graphene layers. By adopting a fully relativistic formulation of the problem, special focus is placed on retardation effects in the energy loss of a charged particle due to electronic excitations in graphene, which include its plasmon polariton modes, as well as the energy that is emitted from graphene in the form of transition radiation. Using both empirical and ab initio models for the dynamic in-plane conductivity of graphene allows the exploration of energy losses at frequencies ranging from the terahertz to the ultraviolet.
关键词： transition radiation,electron energy loss,graphene,relativistic effects,plasmon polariton
更新于2025-09-23 15:23:52
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[IEEE 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - Honolulu, HI (2018.7.18-2018.7.21)] 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - Unveiling the Impact of Distinct Melanosome Arrangements on the Attenuation of Cancer-Inducing Ultraviolet Radiation
摘要： The exposure of human skin to ultraviolet radiation (UVR) can trigger a wide array of biological responses, including photocarcinogenesis. Melanin, either in colloidal form or encapsulated into melanosomes, is known to be the main UVR attenuation substance acting within the cutaneous tissues. Although many studies have addressed the protective role of this pigment against the harmful effects of UVR exposure, the impact of different melanosome arrangements on the mitigation of these effects remains to be quantitatively verified. The difficulties to resolve this open question can be mainly attributed to the intrinsic practical limitations of in vivo and in vitro experiments involving skin specimens. In this paper, we describe controlled in silico experiments that allowed us to overcome such limitations and provide quantitative evidence for the clarification of this question. Besides contributing to a more robust understanding of the physiological parameters associated with cutaneous UVR attenuation, our findings can be incorporated into the development of more effective strategies for the evaluation of individuals' susceptibility to UVR exposure. Such strategies are essential for the prevention of UVR-induced pathologies, particularly skin cancer.
关键词： melanosome,sieve and detour effects,ultraviolet radiation,melanin,predictive simulation,skin cancer
更新于2025-09-23 15:23:52