Microbeam Facility Research Articles

Study on Single Event Upsets in a 28 nm Technology Static Random Access Memory Device Based on Micro-Beam Irradiation

As an important spaceborne electronic device, the static random access memory (SRAM) device is inevitably affected by the radiation of high-energy particles in space during its space mission. To reveal the single event effect (SEE) mechanism of 28 nm technology SRAM caused by high-energy particles, the sensitive area positioning of single event upsets (SEUs) and the distribution characteristics of multi-cell upsets (MCUs) were studied based on the pinhole heavy ion micro-beam facility. The results show that the actual range of SEUs caused by micro-beam irradiation is 4.8 μm × 7.8 μm. By moving the device platform in small steps (1 μm each step), a one-dimensional positioning method for locating the sensitive area of SEUs was established, which can reduce the dependence of localization accuracy on beam spot size, and the positioning accuracy can be improved to 1 μm. The MCU test indicates that the upset pattern is closely related to the spacing of sensitive areas within adjacent SRAM cells, and the probability of MCUs is reduced by well contacts and bit interleaving.

The Role of PIXE and XRF in Heritage Science: The INFN-CHNet LABEC Experience

Analytical techniques play a fundamental role in heritage science. Among them, Particle Induced X-ray Emission (PIXE) and X-ray Fluorescence (XRF) techniques are widely used in many laboratories for elemental composition analysis. Although they are well-established, a strong effort is put on their upgrade, making them suitable for more and more applications. Over the years, at the INFN-LABEC (the laboratory of nuclear techniques for the environment and cultural heritage of the Italian National Institute of Nuclear Physics), the INFN-CHNet group, the network devoted to cultural heritage, has carried out many technological improvements to the PIXE and XRF set-ups for the analysis of works of art and archaeological finds. Among the many, we recall here the scanning external microbeam facility at the TANDEM accelerator and the MA-XRF scanner. The two instruments have shown complementary features: the former permits quantitative analysis of elements heavier than sodium, which is not possible with the latter in most of the case studies. On the contrary, the scanner has the undeniable advantage of portability, allowing it to work in situ. In this framework of technological developments in heritage science, INFN, CERN, and OPD are jointly carrying on the MACHINA (Movable Accelerator for Cultural Heritage In-situ Non-destructive Analysis) project for on-site Ion Beam Analysis (IBA) studies on cultural heritage.

Modification of spray-deposited CdO thin films by 1.5 MeV proton irradiation

Thin films of cadmium oxide (CdO) with different thicknesses in the range of 78–250 nm were prepared and deposited on glass substrates by using a spray pyrolysis technique. A microbeam facility (Lund Ion Beam Analysis facility) was used to irradiate the prepared CdO thin films with a 1.5 MeV proton beam for fluence in the range of 2 × 1012–2 × 1014 ions/cm2. The surface morphology of the CdO films was measured by atomic force microscopy, and it was observed that the grain size and surface roughness were increased as a function of ion fluence. A UV spectrophotometer was used to study the optical properties of the samples, and the results revealed that the absorbance and optical band gaps increased with an increase in the proton fluence and CdO film’s thickness. This work explores the possibility of CdO material modification using low-energy proton irradiation.

Cytoplasmic Radiation Induced Radio-Adaptive Response in Human Lung Fibroblast WI-38 Cells.

It has been reported that in cells exposed to low-dose radiation, radio-adaptive responses can be induced which make irradiated cells refractory to subsequent high-dose irradiation. However, whether adaptive responses are possible when only the cytoplasm, not the nucleus, of the cell is exposed to radiation is still unclear. In this study, using the proton microbeam facility at the National Institute of Radiological Sciences (Japan), we found that cytoplasmic irradiation activates radio-adaptive responses in normal human lung fibroblast WI-38 cells. Our results showed that when cells received cytoplasmic irradiation with 500 protons prior to 2 Gy or 6 Gy X-ray broad-beam irradiation, the DNA double-strand break levels were significantly reduced. In contrast, at cytoplasmic irradiation with less than 100 protons, the radio-adaptive response was not detected. Moreover, the time interval between cytoplasmic irradiation and whole-cell X-ray irradiation should be longer than 6 h for the induction of adaptive responses. In addition, cytoplasmic irradiation elevated the level of cellular mitochondrial superoxide, which enhanced the phosphorylation of extracellular signal-regulated kinases 1/2 (ERK 1/2) and its mediated nuclear accumulation of nuclear factor (erythroid-derived 2)-like 2 (NRF2). This signaling pathway contributed to cytoplasmic irradiation-induced adaptive response as supported by the observations that treatment with the mitochondrial superoxide scavenger mito-tempol, ERK 1/2 inhibitor U0126 or NRF2 inhibitor ML385 could repress the adaptive response. Overall, we showed that cytoplasmic irradiation induces radio-adaptive responses and that mitochondrial superoxide/ERK 1/2/NRF2 signaling is a mechanism. Our results provide new information on the biological effects induced by cytoplasm-targeted irradiation.

Characterization of a pixelated silicon microdosimeter in micro-beams of light ions

The monolithic silicon telescope technology allows to produce solid state microdosimeters. A detector constituted by a matrix of pixels (2 μm in thickness) coupled with a deeper stage (about 500 μm in thickness) was designed, developed and characterized by comparing its response against Tissue Equivalent Proportional Counters (TEPCs) in different irradiation fields, showing promising results. Each pixel of the ΔE stage is a thin diode of 9 μm in diameter delimited by a guard ring of 14 μm in diameter.The aim of this work is the study of the charge collection efficiency of the single pixel of the silicon microdosimeter by irradiating a prototype at the micro-beam facility of the Ion Beam Center - IBC of the University of Surrey. Different light ions were exploited (protons, lithium ions and carbon ions) and scanned on different positions on and around a single pixel of the detector.The results show that the charge generated by events on the sensitive region of the ΔE stage is completely collected, while a charge collection efficiency lower than one characterizes the region between the central pixel and its guard ring. The guard ring delimits properly the sensitive region: no signals arise from events outside the 14 μm in diameter ring.Nevertheless, the microdosimetric distributions of the different charged particles highlight a minor distortion in terms of the absorbed dose. This latter result justifies the good agreement with TEPCs in terms of microdosimetric distributions in different hadrons beams described in previous works.

A new SiPM-based positron annihilation lifetime spectrometer using LYSO and LFS-3 scintillators

Positron annihilation lifetime (PAL) spectroscopy is a unique technique to characterize atomic-scaled microstructure of materials, especially the vacancy-type defects. Compared to photomultiplier tube, silicon photomultiplier (SiPM) has a higher quantum efficiency, a more compact size, and a much lower price. Considering the evident advantages of SiPM, we developed a SiPM-based PAL (SiPM-PAL) spectrometer by using LFS-3 and LYSO scintillators in the sizes of 3×3×l mm3. The performance of the SiPM-PAL spectrometer was studied with four different scintillator lengths (l) of 5.0, 9.5, 13.8, and 20.0 mm. Under the same experimental conditions, with LFS-3 scintillator length decreasing from 20.0 to 5.0 mm, the time resolution (in FWHM) of SiPM-PAL spectrometer was significantly improved from 174.9 to 135.9 ps. While for the SiPM-PAL spectrometer with LYSO scintillators, the time resolution improved from 181.9 to 137.0 ps with scintillator length decreasing from 20.0 to 5.0 mm. Compared to conventional PAL spectrometer using photomultiplier tubes, a novel, small size, and low cost PAL spectrometer is successfully constructed by using SiPMs. Easy customization and superiority in time resolution and small size of SiPM-based scintillation detectors guarantee high flexibility and adaptability to the SiPM-PAL spectrometers, positron micro-beam facilities, and angular correlation of positron annihilation radiation measurements.

Publisher's Note: "Performance and application of heavy ion nuclear microbeam facility at the Nuclear Physics Institute in Řež, Czech Republic" [Rev. Sci. Instrum. 90, 013701 (2019)

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From Energy Deposition of Ionizing Radiation to Cell Damage Signaling: Benchmarking Simulations by Measured Yields of Initial DNA Damage after Ion Microbeam Irradiation.

Advances in accelerator technology, which have enabled conforming radiotherapy with charged hadronic species, have brought benefits as well as potential new risks to patients. To better understand the effects of ionizing radiation on tumor and surrounding tissue, it is important to investigate and quantify the relationship between energy deposition at the nanometric scale and the initial biological events. Monte Carlo track structure simulation codes provide a powerful tool for investigating this relationship; however, their success and reliability are dependent on their improvement and development accordingly to the dedicated biological data to which they are challenged. For this aim, a microbeam facility that allows for fluence control, down to one ion per cell nucleus, was used to evaluate relative frequencies of DNA damage after interaction between the incoming ion and DNA according to radiation quality. Primary human cells were exposed to alpha particles of three different energies with respective linear energy transfers (LETs) of approximately 36, 85 or 170 keV·µm-1 at the cells' center position, or to protons (19 keV·µm-1). Statistical evaluation of nuclear foci formation (53BP1/γ-H2AX), observed using immunofluorescence and related to a particle traversal, was undertaken in a large population of cell nuclei. The biological results were adjusted to consider the factors that drive the experimental uncertainties, then challenged with results using Geant4-DNA code modeling of the ionizing particle interactions on a virtual phantom of the cell nucleus with the same mean geometry and DNA density as the cells used in our experiments. Both results showed an increase of relative frequencies of foci (or simulated DNA damage) in cell nuclei as a function of increasing LET of the traversing particles, reaching a quasi-plateau when the LET exceeded 80-90 keV·µm-1. For the LET of an alpha particle ranging from 80-90 to 170 keV·µm-1, 10-30% of the particle hits did not lead to DNA damage inducing 53BP1 or γ-H2AX foci formation.

Nuclear factor (erythroid-derived 2)-like 2 antioxidative response mitigates cytoplasmic radiation-induced DNA double-strand breaks.

It has been reported that DNA double‐strand breaks (DSB) can be induced by cytoplasm irradiation, and that both reactive free radicals and mitochondria are involved in DSB formation. However, the cellular antioxidative responses that are stimulated and the biological consequences of cytoplasmic irradiation remain unknown. Using the Single Particle Irradiation system to Cell (SPICE) proton microbeam facility at the National Institute of Radiological Sciences ([NIRS] Japan), the response of nuclear factor (erythroid‐derived 2)‐like 2 (NRF2) antioxidative signaling to cytoplasmic irradiation was studied in normal human lung fibroblast WI‐38 cells. Cytoplasmic irradiation stimulated the localization of NRF2 to the nucleus and the expression of its target protein, heme oxygenase 1. Activation of NRF2 by tert‐butylhydroquinone mitigated the levels of DSB induced by cytoplasmic irradiation. Mitochondrial fragmentation was also promoted by cytoplasmic irradiation, and treatment with mitochondrial division inhibitor 1 (Mdivi‐1) suppressed cytoplasmic irradiation‐induced NRF2 activation and aggravated DSB formation. Furthermore, p53 contributed to the induction of mitochondrial fragmentation and activation of NRF2, although the expression of p53 was significantly downregulated by cytoplasmic irradiation. Finally, mitochondrial superoxide (MitoSOX) production was enhanced under cytoplasmic irradiation, and use of the MitoSOX scavenger mitoTEMPOL indicated that MitoSOX caused alterations in p53 expression, mitochondrial dynamics, and NRF2 activation. Overall, NRF2 antioxidative response is suggested to play a key role against genomic DNA damage under cytoplasmic irradiation. Additionally, the upstream regulators of NRF2 provide new clues on cytoplasmic irradiation‐induced biological processes and prevention of radiation risks.

Performance and application of heavy ion nuclear microbeam facility at the Nuclear Physics Institute in Řež, Czech Republic

The Tandetron Laboratory of the Nuclear Physics Institute of the Czech Academy of Sciences is equipped with five beam lines associated with a 3 MV tandem electrostatic accelerator model 4130 MC from High Voltage Engineering Europa B.V. This accelerator is coupled with two duoplasmatron sources and a single sputter ion source and provides ions from hydrogen to gold. One of these lines is a nuclear microbeam facility, utilizing ion beams of micro- and sub-micro sizes for materials research by use of particle induced x-ray emission spectroscopy, particle induced gamma emission, Rutherford back-scattering spectroscopy, and scanning transmission ion microscopy methods as well as for ion beam writing. The major advantage of the presented microprobe is a possibility of 3D structure creation not only in polymer materials using light ions but also in other materials such as glass, ceramics, etc. by use of heavy ions. The focusing system allows focusing of charged particles with a maximum rigidity of 11 MeV amu/q2. The usual resolution in high and low current modes is 2 × 3 µm2 for a 100 pA and 0.3 × 0.5 µm2 for the 2000 ions/s of 2 MeV protons, respectively. A detailed facility description is given in the paper. The applications of focused beams of heavy ions as well as examples of light ions utilizing are also presented in the article.

Preliminary single event effect distribution investigation on 28 nm SoC using heavy ion microbeam

The SEE susceptibility on 28 nm Xilinx Zynq-7020 All Programmable SoC was investigated at heavy ion microbeam facilities in Institute of Modern Physics (IMP). The sensitive SEE spots distribution in entire PS area was obtained by running the on chip memory (OCM) test program. The extracted chip bottom modules layout information indicated that the SEE sensitive events occurred in the OCM area, central data processing area, and interfaces controlling buffer registers elements area, accounting for 19.6%, 32.6% and 47.8%, respectively. The results showed it was possible that the SEE events in other areas appeared more serious than in the target block located area. Meanwhile, the partial cross section was gotten in the test and it was (5.75 ± 0.85) × 10−5 cm2.

Raman imaging as a new approach to identification of the mayenite group minerals

The mayenite group includes minerals with common formula Ca12Al14O32−x(OH)3x[W6−3x], where W = F, Cl, OH, H2O and x = 0–2. This distinction in the composition is associated with W site which may remain unoccupied or be occupied by negatively charged ions: OH−, F−, Cl−, as well as neutral molecules like H2O. However, there is no experimental approach to easily detect or differentiate mineral species within the mayenite group. Electron micro-beam facilities with energy- or wavelength-dispersive X-ray detectors, as most common tools in mineralogy, appear to be insufficient and do not provide a definite identification, especially, of hydroxylated or hydrated phases. Some solution provides typical Raman analysis ensuring identification of minerals and 3D Raman imaging as an innovative approach to distinguish various co-existing minerals of the mayenite group within a small area of the rock sample. Raman spectroscopy has also been successfully used for a determination of water type incorporated into the mineral structure as well as for a spatial distribution of phases by cluster approach analysis and/or integrated intensity analysis of bands in the hydroxyl region. In this study, Raman technique was for the first time used to reconstruct a 3D model of mayenite group mineral zonation, as well as to determine a way of water incorporation in the structure of these minerals. Moreover, for the first time, Raman data were correlated with alterations during the mineral-forming processes and used for reconstruction of the thermal history of studied rock. As a result, the influence of combustion gases has been proposed as a crucial factor responsible for the transformation between fluormayenite and fluorkyuygenite.

Determination of the active volumes of solid-state photon-beam dosimetry detectors using the PTB proton microbeam.

This study aims at the experimental determination of the diameters and thicknesses of the active volumes of solid-state photon-beam detectors for clinical dosimetry. The 10MeV proton microbeam of the PTB (Physikalisch-Technische Bundesanstalt, Braunschweig) was used to examine two synthetic diamond detectors, type microDiamond (PTW Freiburg, Germany), and the silicon detectors Diode E (PTW Freiburg, Germany) and Razor Diode (Iba Dosimetry, Germany). The knowledge of the dimensions of their active volumes is essential for their Monte Carlo simulation and their applications in small-field photon-beam dosimetry. The diameter of the active detector volume was determined from the detector current profile recorded by radially scanning the proton microbeam across the detector. The thickness of the active detector volume was determined from the detector's electrical current, the number of protons incident per time interval and their mean stopping power in the active volume. The mean energy of the protons entering this volume was assessed by comparing the measured and the simulated influence of the thickness of a stack of aluminum preabsorber foils on the detector signal. For all detector types investigated, the diameters measured for the active volume closely agreed with the manufacturers' data. For the silicon Diode E detector, the thickness determined for the active volume agreed with the manufacturer's data, while for the microDiamond detectors and the Razor Diode, the thicknesses measured slightly exceeded those stated by the manufacturers. The PTB microbeam facility was used to analyze the diameters and thicknesses of the active volumes of photon dosimetry detectors for the first time. A new method of determining the thickness values with an uncertainty of ±10% was applied. The results appear useful for further consolidating detailed geometrical knowledge of the solid-state detectors investigated, which are used in clinical small-field photon-beam dosimetry.

Toward the use of single crystal diamond based detector for ion-beam therapy microdosimetry

In this work, the fabrication and characterization of a microdosimeter based on a synthetic single crystal diamond is reported. The microdosimeter is realized by means of both standard photolithography and selective chemical vapor deposition techniques to accurately define its micrometric sensitive volume.Experimental measurements were carried out at the Ruđer Bošković Institute microbeam facility using different particles such as proton, helium, lithium, carbon and oxygen. Ion beam induced charge (IBIC) technique was performed to characterize the microdosimeter response in terms of its charge collection properties. The experimental data were also analyzed by means of Geant4 Monte Carlo simulations.Diamond based microdosimeter shows a well-defined active volume. Homogeneity of the response was estimated at about 7% and linked to structural defects of the diamond surface as deduced by AFM inspection. The detector response shows a good linear behavior for ions of different kind and energy, indicating that the detector is suitable for measuring a wide range of particles and LET i.e. 100 ÷ 3000 keV/μm. Finally, microdosimetric capabilities of the diamond based microdosimeter were preliminarily tested in low LET radiation fields (i.e. protons beam).

Evidence of Pulse Quenching in AND and OR Gates by Experimental Probing of Full Single-Event Transient Waveforms

We present experimental results obtained from full-waveform measurements of single-event transients (SETs) occurring in the conventional two-input AND and OR gates under focused heavy-ion radiation. Chips with test circuits were fabricated in a 65-nm bulk CMOS technology, and were irradiated in a microbeam facility using 197Au and 48Ca species. The resulting SETs were sensed using a dedicated on-chip analog multiplexer circuit. The obtained position-dependent ion hit responses were analyzed, and the strong evidence of charge-sharing-induced pulse quenching was observed. For SETs that propagated through the inverting stage of AND and OR circuits, a significant degradation of measured SET pulse widths and heights was seen. These observations are in good accordance with earlier published simulation and experimental results based on inverter chains. Test circuits also exhibited distinct SET responses depending on their logic state, making the AND gate a better candidate for exploiting the pulse quenching effect when circuits are placed in a triple well.

Development of single-event-effects analysis system at the IMP microbeam facility

Single-event-effects (SEEs) in integrated circuits (ICs) caused by galactic single ions are the major cause of anomalies for a spacecraft. The main strategies to decrease radiation failures for spacecraft are using SEEs less-sensitive devices and design radiation hardened ICs. High energy ion microbeam is one of the powerful tools to obtain spatial information of SEEs in ICs and to guide the radiation hardening design. The microbeam facility in the Institute of Modern Physics (IMP), Chinese Academy of Science (CAS) can meet both the liner energy transfer (LET) and ion range requirements for SEEs simulation experiments on ground. In order to study SEEs characteristics of ICs at this microbeam platform, a SEEs analysis system was developed. This system can target and irradiate ICs with single ions in micrometer-scale accuracy, meanwhile it acquires multi-channel SEE signals and maps the SEE sensitive regions online. A 4-Mbit NOR Flash memory was tested with this system using 2.2GeVKr ions, the radiation sensitive peripheral circuit regions for SEEs of 1 to 0 and 0 to 1 upset, multi-bit-upset and single event latchup have been obtained.

Influence of the environment and phototoxicity of the live cell imaging system at IMP microbeam facility

To investigate the spatiotemporal dynamics of DNA damage and repair after the ion irradiation, an online live cell imaging system has been established based on the microbeam facility at Institute of Modern Physics (IMP). The system could provide a sterile and physiological environment by making use of heating plate and live cell imaging solution. The phototoxicity was investigated through the evaluation of DNA repair protein XRCC1 foci formed in HT1080-RFP cells during the imaging exposure. The intensity of the foci induced by phototoxicity was much lower compared with that of the foci induced by heavy ion hits. The results showed that although spontaneous foci were formed due to RFP exposure during live cell imaging, they had little impact on the analysis of the recruitment kinetics of XRCC1 in the foci induced by the ion irradiation.

A preclinical microbeam facility with a conventional x-ray tube.

Purpose:Microbeam radiation therapy is an innovative treatment approach in radiation therapy that uses arrays of a few tens of micrometer wide and a few hundreds of micrometer spaced planar x‐ray beams as treatment fields. In preclinical studies these fields efficiently eradicated tumors while normal tissue could effectively be spared. However, development and clinical application of microbeam radiation therapy is impeded by a lack of suitable small scale sources. Until now, only large synchrotrons provide appropriate beam properties for the production of microbeams.Methods:In this work, a conventional x‐ray tube with a small focal spot and a specially designed collimator are used to produce microbeams for preclinical research. The applicability of the developed source is demonstrated in a pilot in vitro experiment. The properties of the produced radiation field are characterized by radiochromic film dosimetry.Results:50 μm wide and 400 μm spaced microbeams were produced in a 20 × 20 mm2 sized microbeam field. The peak to valley dose ratio ranged from 15.5 to 30, which is comparable to values obtained at synchrotrons. A dose rate of up to 300 mGy/s was achieved in the microbeam peaks. Analysis of DNA double strand repair and cell cycle distribution after in vitro exposures of pancreatic cancer cells (Panc1) at the x‐ray tube and the European Synchrotron leads to similar results. In particular, a reduced G2 cell cycle arrest is observed in cells in the microbeam peak region.Conclusions:At its current stage, the source is restricted to in vitro applications. However, moderate modifications of the setup may soon allow in vivo research in mice and rats.

Live cell imaging combined with high-energy single-ion microbeam.

DNA strand breaks can lead to cell carcinogenesis or cell death if not repaired rapidly and efficiently. An online live cell imaging system was established at the high energy microbeam facility at the Institute of Modern Physics to study early and fast cellular response to DNA damage after high linear energy transfer ion radiation. The HT1080 cells expressing XRCC1-RFP were irradiated with single high energy nickel ions, and time-lapse images of the irradiated cells were obtained online. The live cell imaging analysis shows that strand-break repair protein XRCC1 was recruited to the ion hit position within 20 s in the cells and formed bright foci in the cell nucleus. The fast recruitment of XRCC1 at the ion hits reached a maximum at about 200 s post-irradiation and then was followed by a slower release into the nucleoplasm. The measured dual-exponential kinetics of XRCC1 protein are consistent with the proposed consecutive reaction model, and the measurements obtained that the reaction rate constant of the XRCC1 recruitment to DNA strand break is 1.2 × 10(-3) s(-1) and the reaction rate constant of the XRCC1 release from the break-XRCC1 complex is 1.2 × 10(-2) s(-1).

Spectroscopic properties and radiation damage investigation of a diamond based Schottky diode for ion-beam therapy microdosimetry

In this work, a detailed analysis of the properties of a novel microdosimeter based on a synthetic single crystal diamond is reported. Focused ion microbeams were used to investigate the device spectropscopic properties as well as the induced radiation damage effects. A diamond based Schottky diode was fabricated by chemical vapor deposition with a very thin detecting region, about 400 nm thick (approximately 1.4 μm water equivalent thickness), corresponding to the typical size in microdosimetric measurements. A 200 × 200 μm2 square metallic contact was patterned on the diamond surface by standard photolithography to define the sensitive area. Experimental measurements were carried out at the Ruder Boškovic′ Institute microbeam facility using 4 MeV carbon and 5 MeV silicon ions. Ion beam induced charge maps were employed to characterize the microdosimeter response in terms of its charge collection properties. A stable response with no evidence of polarization or memory effects was observed up to the maximum investigated ion beam flux of about 1.7 × 109 ions·cm−2·s−1. A homogeneity of the response about 6% was found over the sensitive region with a well-defined confinement of the response within the active area. Tests of the radiation damage effect were performed by selectively irradiating small areas of the device with different ion fluences, up to about 1012 ions/cm2. An exponential decrease of the charge collection efficiency was observed with a characteristic decay constant of about 4.8 MGy and 1 MGy for C and Si ions, respectively. The experimental data were analyzed by means of GEANT4 Monte Carlo simulations. A direct correlation between the diamond damaging effect and the Non Ionizing Energy Loss (NIEL) fraction was found. In particular, an exponential decay of the charge collection efficiency with an exponential decay as a function of NIEL is observed, with a characteristic constant of about 9.3 kGy-NIEL for both carbon and silicon ions.