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Research of X-ray induced single event soft errors in 45 nm SRAM
摘要： As the feature size of the device decreases, the critical charge decreases gradually and the influence of radiation particles becomes more and more serious, especially the single event upset (SEU). Some previously unknown radiation damage began to appear as the size of the device decreased. Low energy protons undergoing direct ionization can induce SEU in 65 nm static random access memories (SRAM), and muons can induce errors as a function of incident muon energy. In this work, the radiation damage caused by X-ray to the 45 nm SRAM is studied through experiments. The sensitive volume of SRAM is constructed using Monte Carlo radiation transport code Geant4 to analyze the effects of critical charge and metal interconnect overlayers of different materials. The experimental results suggested that under the low power state, the secondary electrons produced by the X-ray can induce upsets, lower the voltage, and increase the number of errors. Monte Carlo simulation shows that as the critical charge decreased, SEU becomes more severe. At the same time, photons interact with high atomic number materials in the metal interconnect overlayers, which could generate more secondary electrons resulting in the SEU cross section rising to a higher value.
关键词： SRAM,single event upset,radiation damage,metal interconnect overlayers,X-ray,critical charge
更新于2025-09-10 09:29:36
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Charging of electron beam irradiated amorphous carbon thin films at liquid nitrogen temperature
摘要： We studied the charging behavior of an amorphous carbon thin film kept at liquid-nitrogen temperature under focused electron-beam irradiation. Negative charging of the thin film is observed. The charging is attributed to a local change in the work function of the thin film induced by electron-stimulated desorption similar to the working principle of the hole free phase plate in its Volta potential implementation at elevated temperature. The negative bias of the irradiated film arises from the electron beam induced desorption of water molecules from the carbon film surface. The lack of positive charging, which is expected for non-conductive materials, is explained by a sufficient electrical conductivity of the carbon thin film even at liquid-nitrogen temperature as proven by multi-probe scanning tunneling microscopy and spectroscopy measurements.
关键词： Thin film,Radiation damage,Phase plate,Electron-beam induced charging,Hole free phase plate,Transmission electron microscope,Volta phase plate
更新于2025-09-10 09:29:36
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The influence of stopping power and temperature on latent track formation in YAP and YAG
摘要： Transmission electron microscopy techniques were used to analyse the effect of swift heavy ion irradiation on both yttrium aluminium perovskite (YAP) YAlO3, and yttrium aluminium garnet (YAG) Y3Al5O12 single crystals. The crystals were irradiated with Kr, Xe and Bi ions with energies ranging from 107 to 1030 MeV. These ions have electronic stopping powers in the range from 11 to 41 keV/nm. The ion fluences were all within the non-overlapping regime for latent ion tracks i.e. 1011–1012 cm?2. A number of crystals were also irradiated at different temperatures of 80, 300 and 1000 K at a fixed stopping power. Latent ion tracks with an amorphous core were observed in all samples. The track diameters were seen to increase with increasing stopping power. Track diameters only increase by a significant amount as a result of irradiation temperature at 1000 K, whereas the diameters at 80 and 300 K differ only slightly. Ion tracks in YAG were also found to be larger than those in YAP at comparable stopping powers. It was found that on average 10 keV/nm of extra energy input is required to produce ion tracks in YAP with diameters similar to those in YAG. The results also suggest that the complexity of the crystal structure plays a significant role in the formation of ion tracks in these crystals.
关键词： YAG,Radiation damage,YAP,Latent track,TEM,Swift heavy ion
更新于2025-09-10 09:29:36
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Radiation damage effects caused by soft X-rays in silicon pad detectors
摘要： We present the results of a systematic investigation of X-ray induced radiation damage in silicon pad sensors for total ionising doses up to 320 Gy (SiO2). The radiation induced degradation of energy spectra as well as of critical sensor parameters, capacitance and leakage current, have been measured vs total dose. Detailed analysis of the measured energy resolution shows that degradation of energy resolution can be explained by degradation of the sensor parameters. Additional radiation e?ects related to charge division have been observed.
关键词： Si microstrip and pad detectors,X-ray detectors,Radiation damage evaluation methods
更新于2025-09-09 09:28:46
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O12 scintillator
摘要： The characteristics of a Gd3Al2Ga3O12 crystal scintillator doped with cerium and co-doped with magnesium and titanium have been studied, mainly in view of using it for the Phase II upgrade of the LHCb electromagnetic calorimeter. Samples of the scintillator were irradiated with γ (60Co) to 2 kGy and with 24 GeV protons to 900 kGy. The proton fluence value was ～3·1015 cm?2. It was found that γ-irradiation did not produce any change in the optical transmission of the crystals in the spectral range of the scintillation light, whereas a degradation after the proton irradiation was measurable. For the 1 cm thick sample, a loss of transmission of 3.6% was measured at the wavelength of maximum scintillation (520 nm), and the measured induced absorption coefficient at this wavelength was ～3.6 m?1. The formation of radioisotopes in the crystal at proton irradiation has been analyzed. The formation of isotopes was also simulated with the help of the FLUKA package. The simulation was found to be in a good agreement with experimental results. The results have been used to estimate the expected intensity of parasitic radio-luminescence at high-luminosity operation in a GAGG/W sampling electromagnetic calorimeter.
关键词： Electromagnetic calorimetry,radiation damage,gadolinium-aluminum-gallium garnet,optical transmission,scintillation crystal
更新于2025-09-09 09:28:46
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Gallium Oxide || Radiation damage in Ga2O3
摘要： β-Ga2O3 has a large bandgap of approximately 4.9 eV and an estimated critical electric field (EC) strength of 8 MV/cm. The large bandgap of β-Ga2O3 allows high-temperature device operation and this large critical field allows high-voltage operation (relative to maximum breakdown) and the most common device structure reported to date has been Schottky rectifiers. This material also has potential in devices with low power loss during high-frequency switching in the GHz regime. Similarly, Ga2O3-based photodetectors are attracting interest for their promise as truly solar-blind deep ultraviolet (UV) photodetectors exhibiting cut-off wavelengths below 280 nm. These would have applications in detection of UV wavelengths for military applications, air purification, space communication, ozone-layer monitoring, and flame sensing.
关键词： β-Ga2O3,photodetectors,radiation damage,Schottky rectifiers,wide bandgap semiconductors
更新于2025-09-09 09:28:46
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Latent tracks in bulk yttrium-iron garnet crystals irradiated with low and high velocity krypton and xenon ions
摘要： Bulk yttrium-iron garnet (YIG) single crystals have been irradiated with swift Kr and Xe ions having energies from 0.4 to 22.8 MeV/u and electronic stopping powers from 8.9 to 28.9 keV/nm near the irradiated surface. Transmission electron microscopy (TEM) has been used for direct observation of non-overlapping amorphous latent tracks in the near surface region of the irradiated bulk YIG crystals. The amorphous track radii observed in this work have been compared with previously reported data from direct and indirect measurements. It was found that the thickness of the sample subjected to swift heavy ion irradiation does not significantly affect the resulting amorphous track size observed by TEM in YIG. The results also support previously observed consistency between direct TEM and indirect Rutherford backscattering in channelling mode (RBS/C) and Mossbauer spectroscopy (MS) methods for amorphous track evaluation in YIG when electronic stopping power is greater than ～13 keV/nm, which is sufficient to create cylindrical amorphous tracks by high velocity ions (E > 10 MeV/u). Indirect methods provide underestimated values compared to TEM when the electronic stopping power is below ～13 keV/nm, for which discrete amorphous tracks are supposed to be formed by high velocity ions.
关键词： Transmission electron microscopy,Latent tracks,Radiation damage,Yttrium-iron garnet,Swift heavy ions
更新于2025-09-09 09:28:46
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In Vivo Imaging of Microglia Turnover in the Mouse Retina After Ionizing Radiation and Dexamethasone Treatment
摘要： Gamma irradiation and bone marrow transplantation (BMT) are established clinical procedures for the treatment of hematologic malignancies. The radiation targets cells in the bone marrow, but injury to other tissues, including the central nervous system (CNS), have been reported. Here, we examine if anti-inflammatory treatment can mitigate the radiation-induced turnover of retinal microglia and the replacement by bone marrow–derived cells (BMDCs). Two-color chimeric mice were generated by lethal irradiation of heterozygous CX3CR1-GFP mice that express GFP in microglial cells and bone marrow transplantation from universal DsRed donor mice. Mice were treated with the corticosteroid dexamethasone; a control group received no dexamethasone treatment. The populations of resident microglia (GFP+) and BMDCs (DsRed+) were quantified by serial in vivo imaging for 10 weeks after irradiation with a confocal scanning laser ophthalmoscope that we custom-built specifically for multicolor imaging of the murine retina. Ionizing radiation resulted in loss of 75% of the resident retinal microglia population after 70 days. Recruitment of BMDCs was delayed with respect to the microglia loss, resulting in a transient depletion of the total immune cell number in the retina. With dexamethasone treatment, both the loss of the resident microglia and the infiltration of BMDCs were suppressed by at least 50%. Anti-inflammatory treatment with the corticosteroidal agent dexamethasone preserves resident microglia and minimizes recruitment of BMDCs after ionizing radiation exposure and BMT.
关键词： radiation damage,bone marrow–derived cells,microglia,anti-inflammatory agents,scanning laser ophthalmoscopy
更新于2025-09-09 09:28:46
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[IEEE 2018 International Semiconductor Conference (CAS) - Sinaia, Romania (2018.10.10-2018.10.12)] 2018 International Semiconductor Conference (CAS) - Numerical Simulations of Radiation Damage Effects in Active-Edge Silicon Pixel Sensors for High-Energy Physics Experiments
摘要： High-energy physics experiments at the future CERN High Luminosity LHC (Large Hadron Collider) require highly segmented pixelated sensors of increased geometrical efficiency and the ability of withstanding extremely high radiation damage. The performance of planar n-on-p sensors with active edges is simulated at very high fluences (2×1016 neq/cm2), using a recent three level trap model for p-type silicon material. Precise structural definition is achieved by investigating the doping pro(cid:191)le of the devices via the Secondary Ion Mass Spectrometry technique. The breakdown voltage, and hole density distribution are studied as a function of radiation fluences.
关键词： TCAD simulation,radiation damage,Active edge sensor
更新于2025-09-09 09:28:46
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SOI Thin Microdosimeter Detectors for Low Energy Ions and Radiation Damage Studies
摘要： The responses of two silicon on insulator (SOI) 3D microdosimeters developed by the Centre for Medical Radiation Physics (CMRP) were investigated with a range of different low energy ions, with high linear energy transfer (LET). The two microdosimeters n-SOI and p-SOI were able to measure the LET of different ions including 7Li, 12C, 16O and 48Ti with ranges below 350 μm in silicon. No plasma effects were seen in the SOI microdosimeters when irradiated with the high LET ions. A Monte Carlo simulation using Geant4 was compared to the experimental measurements, whereby some discrepancies were observed for heavier ions at lower energies. This discrepancy can be partly attributed to uncertainties in the thickness of the energy degraders and overlayers of the devices. The microdosimetric measurements of low energy 16O ions were obtained and compared to a therapeutic 16O ion beam. The radiation hardness of the two devices was studied using the Ion Beam Induced Charge Collection technique (IBIC). Both types of microdosimeters when biased had no essential changes in charge collection efficiency (CCE) in the SV after irradiation with low energy ions.
关键词： LET,radiation damage,SOI microdosimeters,Geant4 simulation,low energy ions,IBIC
更新于2025-09-04 15:30:14