Irradiation Tests Research Articles

Research on single event effects and hardening design of LDMOS transistors

In this paper, an N-type Lateral Diffused Metal Oxide Semiconductor (LDMOS) device was designed using a heavily doped P+ well and drain N-type buffer layer structure in the BCD process. The hardened mechanism of heavily doped P+ well and drain N-type buffer layer structures was simulated and analyzed using a TCAD device simulator. To verify the anti-SEE performance of the LDMOS, the irradiation test was conducted using Ta ion (LET = 79.2 MeV·cm−2 mg−1). The results show that increasing P+ well doping concentration and using buffer layer structure can increase the single event burnout (SEB) voltage of high-voltage LDMOS devices. SEB did not occur within the full operation voltage range.

Superconductor based, tomographic, neutron diagnostics for fusion power monitoring.

We propose a scalable system of compact, superconducting neutron monitors, which can be embedded in any existing cryogenic infrastructure of a fusion system. The pixel-based nature of the detectors allows them to be placed at intervals following the circumference of a cooled zone, e.g., a field coil, thus allowing for a tomographic measurement of the neutron flux surrounding the plasma. An early stage prototype of the superconducting bolometer is described, and the key results of a previous feasibility study of this prototype performed with cold neutrons are summarized. The bolometer can be adapted for use with fast neutrons by altering the composition and geometry of the neutron-to-heat conversion layer. This paper describes the initial feasibility considerations for implementation in a superconducting tokamak. The sensor is based on a high-temperature superconductor, making it possible to select the operation temperature in the range 1-90K. Neutron flux numbers were found using the ITER MCNP reference model, and these were embedded in a TOPAS model to find the expected signal measured by the bolometer at the position of a toroidal field coil. The results at the coil position indicate suitable operation levels in terms of the magnitude of the measured signal, with a measurable signal of several ohm, which is much smaller than the saturation energy of the detector. Radiation hardness is estimated and found to be on the order of at least 40 years for the relevant radiation levels. The upcoming investigation activities of the project are described for both radiation testing and analytical modeling.

Enhancement of System Observability During System-Level Radiation Testing Through Total Current Consumption Monitoring

Enhancement of System Observability During System-Level Radiation Testing Through Total Current Consumption Monitoring

X-ray Computed Tomography of Tristructural Isotropic (TRISO) Fuel from the AGR-5/6/7 Irradiation Tests

X-ray Computed Tomography of Tristructural Isotropic (TRISO) Fuel from the AGR-5/6/7 Irradiation Tests

Measurement of cross-section of the 6Li(d,α)4He, 6Li(d,p)7Li, 6Li(d,p)7Li*, 7Li(d,α)5He, and 7Li(d,nα)4He reactions at the deuteron energies from 0.3 MeV to 2.2 MeV

The interaction of a deuteron beam with lithium is characterized by a high yield of neutrons, high energy of neutrons and a large variety of reactions. The reliable data of the reactions cross-sections are important for many applications, including radiation testing of advanced materials and equipment. The experimental data on the cross-sections differ greatly from one author to another; for a number of reactions there is no data on the cross-section in the databases. Measurements of the reactions cross-sections were carried out at the accelerator-based neutron source VITA at Budker Institute of Nuclear Physics (Novosibirsk, Russia) using an α-spectrometer. The 6Li(d,α)4He, 6Li(d,p)7Li, 6Li(d,p)7Li*, 7Li(d,α)5He, and 7Li(d,nα)4He reactions cross-sections at deuteron energies from 0.3 MeV to 2.2 MeV have been measured. The obtained data are presented tabular form.

Irradiation effects on GEM detectors operated at RUN1 and RUN2 at the LHCb experiment

Triple-GEM detectors with pad readout have been employed to equip the innermost region (R1) of the first station (M1) within the Muon system of the LHCb experiment. The GEM detectors have been operated with an Ar/CO2/CF4 = 45/15/40 gas mixture at a gas gain of about 4000 with an average particle flux of about 250 kHz/cm2. Throughout RUN1 and RUN2, spanning approximately 440 days of colliding beams, the GEM detectors accumulated a charge of up to 0.5 C/cm2. This paper presents a comparative analysis between a global irradiation test of GEM detectors at the Calliope facility (ENEA-Casaccia, 1.25 MeV γ ray flux from a 60Co source) and the GEMs operated at LHCb, focusing on the impacts of a CF4-based gas mixture. In both instances, the detectors were opened and the GEM foils were examined by the EN-MME-MM CERN group with a Field Emission Gun Scanning Electron Microscope (FEG-SEM) for a magnified image analysis and an X-Max Energy Dispersive X-ray Spectroscopy (EDS) for the chemical one.

The study of interaction of the high energetic plasma and electron pulses with multicomponent alloy surface

This paper investigates the impact of high-energy sources, namely, high-energy plasma pulses and high-energy electron beam pulses, on materials in the form of layer through separate and combined exposures. Experimental setups utilizing a Rod Plasma Injector (RPI) and an electron gun were employed for irradiation tests. The studies involved pre- and post-treatment analysis of morphology, chemical, and phase composition using scanning electron microscopy and x-ray diffraction measurements. Surface modifications under different exposure conditions were characterized, revealing that both sources induced significant alterations in surface composition and crystal structure. These interactions result in a more uniform chemical composition, reduced surface roughness, and a shift from an amorphous phase to a nanocrystalline or amorphous-nanocrystalline state. The results underscore the potential of high-energy sources for efficient surface engineering, offering opportunities for customized material surface modifications through meticulous adjustment of these generation parameters.

Cell Therapies for Acute Radiation Syndrome.

The risks of severe ionizing radiation exposure are increasing due to the involvement of nuclear powers in combat operations, the increasing use of nuclear power, and the existence of terrorist threats. Exposure to a whole-body radiation dose above about 0.7 Gy results in H-ARS (hematopoietic acute radiation syndrome), which is characterized by damage to the hematopoietic system; higher doses result in further damage to the gastrointestinal and nervous systems. Only a few medical countermeasures for ARS are currently available and approved for use, although others are in development. Cell therapies (cells or products produced by cells) are complex therapeutics that show promise for the treatment of radiation injury and have been shown to reduce mortality and morbidity in animal models. Since clinical trials for ARS cannot be ethically conducted, animal testing is extremely important. Here, we describe cell therapies that have been tested in animal models. Both cells and cell products appear to promote survival and lessen tissue damage after whole-body irradiation, although the mechanisms are not clear. Because radiation exposure often occurs in conjunction with other traumatic injuries, animal models of combined injury involving radiation and future countermeasure testing for these complex medical problems are also discussed.

Rheological aspects of solid-to-liquid phase transitions in paraffin wax/bitumen blends for thermal energy storage applications

This paper correlates the evolution of the rheological and thermal properties with microstructure during the phase change of a blend of bitumen with a selected paraffin wax, having a melting point centred around 60 °C, for the development of bituminous based membranes for thermal energy storage applications. For this purpose, temperature sweep tests within the linear viscoelastic range, stationary state flow curves, Differential Scanning Calorimetry (DSC), polarised optical microscopy observations and solar irradiation tests were performed. The reported rheological results clearly point out a gel-like behaviour for both paraffin and paraffin/bitumen blend that is preserved almost up to the end of the phase change interval. This is consequence of the development of a network of interconnected crystals of paraffin wax which progressively disappear as temperature increases. Interestingly, a weak gel structure is kept even at low crystallinity levels since only a few junctions among structures are necessary to build a spanning network. Finally, the large degree of crystallinity of paraffin wax retained in the bitumen/paraffin wax is behind its thermoregulation ability, as was corroborated by solar irradiation tests. Therefore, results indicated the great potential of these formulations for thermal energy storage and related applications.

On the theory of nucleation of coherent inclusions in irradiated crystals

Based on a critical analysis of the existing model for the effect of excess vacancies and interstitials on the nucleation of coherent particles under irradiation, a new nucleation model is developed that uses the Brailsford-Bullough model for the steady state occupation probabilities of vacancies and interstitials at the particle interface, recently refined by the author. It is shown that, depending on the surface tension γ of a coherent particle, the nucleation mechanism can be qualitatively different. In the case of a relatively small γ, an instability can arise in the irradiated solid solution leading to the barrier-free nucleation of coherent precipitates. In the opposite case of a relatively large γ, the classical one-dimensional theory of homogeneous nucleation is applicable. In order to eliminate the uncertainty in the magnitude of surface tension (from the literature) and to better understand the underlying mechanisms of coherent particle nucleation in irradiation tests, additional atomistic studies are recommended.

Optical responsive asphalt coating with temperature-sensitive TiO2 quantum dots: Formula and temperature adaptability

The application of conventional asphalt contributes to extremely high pavement temperature in hot season as its black color entails large solar absorption. In this study, optical responsive asphalt is proposed to control pavement temperature, which is developed by introducing temperature-sensitive TiO2 quantum dots (TiO2 QDs) into traditional asphalt. Temperature-sensitive TiO2 QDs are prepared by blending thermochromic polymer and TiO2 quantum dots with varied concentrations. Optical characterizations on temperature-sensitive TiO2 QDs have demonstrated that peak value of solar absorption in temperature-sensitive TiO2 QDs at 45 °C is 14.29 %–22.86 % higher than that at 15 °C; the maximum fluorescent intensity of temperature-sensitive TiO2 QDs at 45 °C is 8.5 % higher than that at 15 °C. The results from optical characterizations on temperature-sensitive TiO2 QDs modified asphalt show that the incorporation of temperature-sensitive TiO2 quantum dots endows asphalt low solar reflectance at high temperature and high solar absorption at low temperature. Fluorescent intensity of modified asphalt at 45 °C is increased by 21.6 %, 10.2 % and 5.7 % than that at 15 °C for asphalt containing 5 %, 10 %, and 20 % temperature-sensitive TiO2 QDs, respectively. Indoor solar radiation simulation tests have revealed that compared with traditional asphalt, temperature-sensitive TiO2 QDs modified asphalt coating could yield cooling effectiveness of 6.4 °C at high temperature. Meanwhile, outdoor solar radiation test indicates TiO2 QDs modified asphalt coating could realize warming effectiveness of 0.7 °C at low temperature. The outcomes on temperature-sensitive TiO2 QDs modified asphalt with temperature-adaptability properties makes an advancement in functional pavement.

Effect of Microwave Irradiation on Mechanical Properties and Microstructures of Minerals

Microwave-assisted rock breaking is a new and promising technology for the tunneling and drilling industry. Minerals in rocks have an important influence on the effect of microwave-assisted rock breaking. In this paper, common minerals in rocks such as potash feldspar (hereafter referred to as K-feldspar), calcite and pyroxene were selected as samples, and a lot of microwave irradiation tests were carried out by using a hamilab-v1500 microwave oven. The mass, strength and microstructure of the rock samples were tested before and after microwave irradiation. The change law of the mineral mass, strength and microstructure with regard to temperature was analyzed, and the influence mechanism was discussed. The results show that the strength of K-feldspar increases from 20 °C to 400 °C but decreases significantly when it is higher than 400 °C; the strength of pyroxene increases from 20 °C to 600 °C but decreases when it is higher than 600 °C; the strength of calcite decreases with the increase in temperature. As for the weakening pattern, pyroxene shows drawstring, step and flow with the increase in temperature, but K-feldspar and calcite show that failure occurs along the cleavage plane of the crystal structure. The higher the temperature of microwave irradiation, the finer the pattern at the fractured zone is, and the more fragmented it becomes; the loss of mineral mass increases with the increase in the temperature of microwave irradiation.

Space radiation testing and thermal cycling of functionally coated Alexandrite laser crystals

We present a space environmental test campaign of functionally coated, high-quality Alexandrite laser crystals developed in the course of the Horizon 2020 project GALACTIC. The campaign comprises gamma and proton irradiation as well as thermal cycling tests. As the result of a detailed qualification procedure consisting of transmittance measurements, LIDT, tape-lift, and functional laser tests in a diode-pumped configuration before and after environmental testing, their suitability for space applications could be demonstrated.

Purification and investigation of bio-glycerol as heat transfer fluid and as coolant in automobile radiators

Glycerol is a key by product of the biodiesel extraction process. The rapid growth of biodiesel establishments will continue to result in glycerol oversupply. Purified glycerol can be used as an antifreeze in automotive radiators since it has a freezing point of −30 °C and a boiling temperature of 160 °C. Heat transfer by automotive radiators is important in optimizing engine fuel economy. The goal of this research is to employ purified bio glycerol as a heat transfer fluid and a coolant in vehicle radiators. The proposed water mixed bio glycerol convective heat transfer rate is experimentally compared to standard ethylene glycol. The rate of heat transfer by bio glycerol is determined by passing the fluid through an automobile radiator test apparatus. For this objective, an Automobile Radiator test rig is devised and built. Experiments with distilled water blended bio-glycerol in volume ratios of 50:50, 70:30, and 60:40 were carried out, and the test findings revealed that the 70:30 water bio glycerol volume ratio created a higher heat transfer rate when compared to the water ethylene glycol mixture.

Localized Stress Effects on the Single Event Effects Sensitivity of Microelectronics

Understanding the single event effects (SEE) sensitivity of microelectronic devices and circuits is essential for long-term mission success in ionizing radiation environments. SEEs occur when a single ionizing particle strikes a device with enough energy to cause anomalous malfunction or even a catastrophic failure event. It is conventionally viewed as an electrical phenomenon, whereas this study investigates the possible role of multi-physics. Specifically, we show that localized mechanical stress in electronic devices significantly impacts the degree of SEE sensitivity. We present a technique that indirectly maps both electrical and mechanical field localization to spatially map SEE sensitivity without any need for radiation test sources. It is demonstrated on the operational amplifier LM124 under both pristine and stressed conditions. To validate our hypothesis, our experimental results are compared with those obtained from the well-established pulsed laser SEE technique. Excellent agreement between these results supports our hypothesis that SEE susceptibility may have fundamental roots in both electrical and mechanical fields. Therefore, the ability to map the localizations in these fields may indirectly map the SEE sensitivity of large area electronics, which is very expensive in time and resources.

Proton irradiation of FPGA-embedded hadron fluence sensors

Hadron fluence monitors based on static random access memories (SRAMs) are in use at particle accelerators for the protection of electronics and at proton-therapy facilities for measuring secondary neutrons. One shortcoming of current solutions is that they necessitate SRAMs to detect radiation-induced single event upsets and require additional components to transfer the counts from the radiation area. This approach limits the practicality of the sensors due to their power requirements, increased board complexity, larger physical footprint and reduced total ionizing dose tolerance. In this work, we present proton irradiation test results of a novel proton and neutron fluence sensor we designed. The sensor is fully embedded in a SRAM-based field programmable gate array (FPGA) solving the abovementioned limitations of the state of the art. The FPGA configuration SRAM is used as a sensitive element, while the Joint Test Action Group interface is leveraged as a read out circuitry. We irradiated six sensor units by means of a variable-energy proton beam at the Trento Institute for Fundamental Physics and Applications (TIFPA, Trento, Italy). We discuss our results in terms of proton to upset cross section as a function of the proton energy in the range from 70 to 228 MeV, also parameterized with respect to the power supply voltage. We evaluate the variability of the cross section in the set of irradiated samples. Moreover, we show how we used the device to image the proton beam and measure beam profiles for aligning the configuration RAM and beam centers. We also suggest alternate reading modes to measure the fluence on the device by measuring the drawn current, rather than counting upsets.

Radiation hardness and quality validation of the on-detector electronics for the CMS Drift Tubes upgrade

In view of the High Luminosity LHC upgrade, the so-called Phase 2 upgrade, the electronics of the Drift Tubes (DT) subdetector of CMS will undergo a complete innovation. The requirements in terms of trigger rate will exceed the capabilities of the present electronics. Thus, all the on-detector electronics together with the associated back-end need to be replaced. Phase-2 on-detector electronics for DT consist of about 800 FPGAs (Field Programmable Gate Array) based boards called OBDT (On-detector Board for Drift Tubes). These boards are sub-divided in two different categories: 600 OBDT ϕ and 200 OBDT θ, targeting respectively the readout of DT wires parallel and normal to the LHC beams. Each OBDT ϕ is able to time-digitize 240 channels with sub-nanosecond resolution and upstream to the back end using multiple high-speed optical links running at 10.24 Gb/s. The choice of components known to have good resistance to radiation was a requirement in the design of the OBDT. The main component, the FPGA, is a flash-based PolarFire from Microsemi, already qualified in different facilities for radiation hardness tests. As a validation step, a campaign of radiation tests was carried out at the INFN-TIFPA Protontherapy Centre in Trento, Italy, using proton beams. The behavior of an OBDT ϕ board was evaluated during radiation exposure with a total dose much higher than expected to be integrated during 10 years of HL-LHC, which is 0.5 Gy.

Thermal Tests of Type B Radioactive Transport Package: Experimental Description and Heat Flux Analysis

ABSTRACTThe design of Type B radioactive transport package should be able to withstand the fire accident scenario in transportation accident conditions. For the simulation of the fire scenario, there are mainly three methods: pool fire test, furnace test and thermal radiation test. This paper tried to carry out the fire test with the furnace method that the conditions in the furnace can be more carefully controlled. The paper described the requirements of fire test, test conditions and measurement test methods and analysed the temperature change of fire site and the heat flux data of the surface of the package during the fire test. The test results seemed that the fire test method could provide satisfactory thermal environment for fire test of Type B radioactive transport package.

Systematic testing, verification and validation of laser treatments for unglazed earthenware affected by lichens and fungi biodeterioration

In recent years, there has been a growing interest in exploring environmentally friendly and healthy alternatives to conventional solvent cleaning and biocides in the conservation of stone artworks. Here, we focus on the potential of laser-based photonic methods for treating biodeteriorated earthenware artefacts. The investigation was conducted on Roman dolia (jars) of the International Museum of Ceramics, Faenza, Italy. Three removal methods were tested and compared: (i) brushing using a soft-bristled electric brush and water, referred to as brush cleaning; (ii) a combination of brushing and laser ablation; and (iii) biocide and brushing. Four laser systems with different wavelengths and optimized pulse durations in nanosecond or microsecond regimes were used in the tests. Systematic irradiation tests were conducted to determine the damage thresholds and define safe laser irradiation levels. The characterizations of the surfaces under treatment were carried out pre- and post-laser irradiation using optical microscopy, 3D photogrammetry, and Pulse-Amplitude-Modulated Chlorophyll-Fluorometry. Furthermore, spectroscopic methods based on FTIR, Raman, and LIBS techniques were used to assess the effectiveness of the removal process and the composition of uncovered surfaces. Results have indicated that gentle brushing and water is the most effective approach for safely removing around 60% of the bio-colonization weakly anchored to the substrate over the area under treatment. This comprised viable species, whereas the remaining 40% of the area included endolithic species, mostly thalli of Verrucaria nigrescens and rock-dwelling fungi. The eradication of the latter was the real conservation concern requiring attention. Following the experimentation, the optimal method for safely uncovering the earthenware surface was a combination of water-assisted brushing and 1064 nm laser irradiation as a finishing treatment.

Radiation tests of a CubeSat OBC

Nano-satellites, which are following the CubeSat standard have established for demanding industrial and scientific applications with critical requirements on reliability and radiation tolerance. The employment of commercial off-the-shelf components enables a state-of-the-art performance but requires extensive testing to avoid and mitigate malefunctions due to the space environment. The CubeSat mission CLIMB is representative for future missions with a complex payload, a high power budget and a harsh radiation exposure. For this reason, a comprehensive irradiation study of its on-board-computer was done. The total ionizing dose damage of 50krad was evaluated at a 60Co source. As a consequence of this test, specific components were exchanged before performing single event effect studies at the synchrotron accelerator MedAustron. A board-level test revealed that the majority of effects concern the central micro controller wherefore was followed by a component-level test. Those irradiation tests make use of a pencil beam to map the device under test, which provides additional information to localize effects - by the timestamp - at the expense of an increased irradiation time compared to a homogeneous exposure. In this paper, we summarize the major findings of the test campaign and mitigation means and present a procedure for single event effect studies at medical accelerators.