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Sample records for ion-beam irradiation effects

  1. New Ion Beam Materials Laboratory for Materials Modification and Irradiation Effects Research

    SciTech Connect

    Zhang, Yanwen; Crespillo, Miguel L; Xue, Haizhou; Jin, Ke; Chen, Chien-Hung; Fontana, Cristiano L; Graham, Dr. Joseph T.; Weber, William J

    2014-11-01

    A new multifunctional ion beam materials laboratory (IBML) has been established at the University of Tennessee, in partnership with Oak Ridge National Laboratory. The IBML is currently equipped with two ion sources, a 3 MV tandem accelerator, three beamlines and three endstations. The IBML is primarily dedicated to fundamental research on ion-solid interaction, ion beam analysis, ion beam modification, and other basic and applied research on irradiation effects in a wide range of materials. An overview of the IBML facility is provided, and experimental results are reported to demonstrate the specific capabilities.

  2. New ion beam materials laboratory for materials modification and irradiation effects research

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Crespillo, M. L.; Xue, H.; Jin, K.; Chen, C. H.; Fontana, C. L.; Graham, J. T.; Weber, W. J.

    2014-11-01

    A new multifunctional ion beam materials laboratory (IBML) has been established at the University of Tennessee, in partnership with Oak Ridge National Laboratory. The IBML is currently equipped with two ion sources, a 3 MV tandem accelerator, three beamlines and three endstations. The IBML is primarily dedicated to fundamental research on ion-solid interaction, ion beam analysis, ion beam modification, and other basic and applied research on irradiation effects in a wide range of materials. An overview of the IBML facility is provided, and experimental results are reported to demonstrate the specific capabilities.

  3. Protective effects of shikonin on brain injury induced by carbon ion beam irradiation in mice.

    PubMed

    Gan, Lu; Wang, Zhen Hua; Zhang, Hong; Zhou, Rong; Sun, Chao; Liu, Yang; Si, Jing; Liu, Yuan Yuan; Wang, Zhen Guo

    2015-02-01

    Radiation encephalopathy is the main complication of cranial radiotherapy. It can cause necrosis of brain tissue and cognitive dysfunction. Our previous work had proved that a natural antioxidant shikonin possessed protective effect on cerebral ischemic injury. Here we investigated the effects of shikonin on carbon ion beam induced radiation brain injury in mice. Pretreatment with shikonin significantly increased the SOD and CAT activities and the ratio of GSH/GSSG in mouse brain tissues compared with irradiated group (P<0.01), while obviously reduced the MDA and PCO contents and the ROS levels derived from of the brain mitochondria. The shikonin also noticeably improved the spatial memory deficits caused by carbon ion beam irradiation. All results demonstrated that shikonin could improve the irradiated brain injury which might resulted from its modulation effects on the oxidative stress induced by the 12C6+ ion beam. PMID:25716567

  4. Effects of Ga ion-beam irradiation on monolayer graphene

    SciTech Connect

    Wang, Quan; Mao, Wei; Zhang, Yanmin; Shao, Ying; Ren, Naifei; Ge, Daohan

    2013-08-12

    The effects of Ga ion on the single layer graphene (SLG) have been studied by Raman spectroscopy (RS), SEM, and field-effect characterization. Under vacuum conditions, Ga ion-irradiation can induce disorders and cause red shift of 2D band of RS, rather than lattice damage in high quality SLG. The compressive strain induced by Ga ion decreases the crystalline size in SLG, which is responsible for the variation of Raman scattering and electrical properties. Nonlinear out-put characteristic and resistance increased are also found in the I-V measurement. The results have important implications during CVD graphene characterization and related device fabrication.

  5. Effects of Ga ion-beam irradiation on monolayer graphene

    NASA Astrophysics Data System (ADS)

    Wang, Quan; Mao, Wei; Ge, Daohan; Zhang, Yanmin; Shao, Ying; Ren, Naifei

    2013-08-01

    The effects of Ga ion on the single layer graphene (SLG) have been studied by Raman spectroscopy (RS), SEM, and field-effect characterization. Under vacuum conditions, Ga ion-irradiation can induce disorders and cause red shift of 2D band of RS, rather than lattice damage in high quality SLG. The compressive strain induced by Ga ion decreases the crystalline size in SLG, which is responsible for the variation of Raman scattering and electrical properties. Nonlinear out-put characteristic and resistance increased are also found in the I-V measurement. The results have important implications during CVD graphene characterization and related device fabrication.

  6. Low energy Ar+ ion beam irradiation effects on Si ripple pattern.

    PubMed

    Pahlovy, Shahjada A; Yanagimoto, Kazuma; Miyamoto, Iwao

    2011-02-01

    Etching of surfaces by ion beam sputtering is widely used to pattern surfaces. Recent studies using the high-spatial-resolution capability of the scanning tunneling microscope, atomic force microscope and SEM (Scanning Electron Microscopy) disclose in fact that ion bombardment creates repetitive structures at micro-nanometre scale, waves (ripples), checkerboards or pyramids. The phenomenon is related to the interaction between ion erosion and diffusion of adatoms (vacancies), which causes surface re-organization. In this paper we investigated the ripple pattern formation on Si substrates by low energy Ar+ ion bombardment and the dose effect on ripple size. We also briefly discussed the irradiation effects (at normal incidence) on ripple pattern for different irradiation time. Finally, based on Bradley and Harper (BH) theory we proposed a model to understand the mechanism of ripple pattern change due to Ar+ ion beam irradiation. PMID:21456140

  7. Investigation of the effect of low energy ion beam irradiation on mono-layer graphene

    SciTech Connect

    Xu, Yijun; II. Physikalisches Institut, Universität Göttingen, Friedrich- Hund- Platz 1, 37077 Göttingen; State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050 ; Zhang, Kun; Brüsewitz, Christoph; Hofsäss, Hans Christian; Wu, Xuemei; State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050

    2013-07-15

    In this paper, the effect of low energy irradiation on mono-layer graphene was studied. Mono-layer graphene films were irradiated with B, N and F ions at different energy and fluence. X-ray photoelectron spectroscopy indicates that foreign ions implanted at ion energies below 35 eV could dope into the graphene lattice and form new chemical bonds with carbon atoms. The results of Raman measurement indicate that ion beam irradiation causes defects and disorder to the graphene crystal structure, and the level of defects increases with increasing of ion energy and fluence. Surface morphology images also prove that ion beam irradiation creates damages to graphene film. The experiment results suggest that low-energy irradiation with energies of about 30 eV and fluences up to 5·10{sup 14} cm{sup −2} could realize small amount of doping, while introducing weak damage to graphene. Low energy ion beam irradiation, provides a promising approach for controlled doping of graphene.

  8. Focused helium-ion beam irradiation effects on electrical properties of multi-layer WSe2

    NASA Astrophysics Data System (ADS)

    Pudasaini, Pushpa Raj; Stanford, Michael; Cross, Nick; Duscher, Gerd; Mandrus, David; Rack, Philip

    Atomically thin transition metal dichalcogenides (TMDs) are currently receiving great attention due to their excellent opto-electronic properties. Tuning optical and electrical properties of mono and few layers TMDs, such as Tungsten diselenide (WSe2), by controlling the defects, is an intriguing opportunity to fabricate the next generation opto-electronic devices. Here, we report the effects of focused helium ion beam irradiation on structural, optical and electrical properties of few layer WSe2, via high resolution scanning transmission electron microscopy, Raman spectroscopy and electrical measurements. By controlling the ion irradiation dose, we selectively introduced precise defects in few layer WSe2 thereby locally tuning the electrically resistivity of the material. Hole transport in the few layer WSe2 is severely affected compared to electron transport for the same dose of helium ion beam irradiation studied. Furthermore, by selectively exposing the ion beams, we demonstrate the lateral p-n junction in few layer WSe2 flakes, which constitute an important advance towards two dimensional opto-electronic devices. Materials Science and Technology Division, ORNL, Oak Ridge, TN 37831, USA.

  9. Mutagenic effects of carbon ion beam irradiations on dry Lotus japonicus seeds

    NASA Astrophysics Data System (ADS)

    Luo, Shanwei; Zhou, Libin; Li, Wenjian; Du, Yan; Yu, Lixia; Feng, Hui; Mu, Jinhu; Chen, Yuze

    2016-09-01

    Carbon ion beam irradiation is a powerful method for creating mutants and has been used in crop breeding more and more. To investigate the effects of carbon ion beams on Lotus japonicus, dry seeds were irradiated by 80 MeV/u carbon ion beam at dosages of 0, 100, 200, 300, 400, 500 and 600 Gy. The germination rate, survival rate and root length of M1 populations were explored and the dose of 400 Gy was selected as the median lethal dose (LD50) for a large-scale mutant screening. Among 2472 M2 plants, 127 morphological mutants including leaf, stem, flower and fruit phenotypic variation were found, and the mutation frequency was approximately 5.14%. Inter simple sequence repeat (ISSR) assays were utilized to investigate the DNA polymorphism between seven mutants and eight plants without phenotypic variation from M2 populations. No remarkable differences were detected between these two groups, and the total polymorphic rate was 0.567%.

  10. Effect of cumulated dose on hydrogen emission from polyethylene irradiated under oxidative atmosphere using gamma rays and ion beams

    NASA Astrophysics Data System (ADS)

    Ferry, M.; Pellizzi, E.; Boughattas, I.; Fromentin, E.; Dauvois, V.; de Combarieu, G.; Coignet, P.; Cochin, F.; Ngono-Ravache, Y.; Balanzat, E.; Esnouf, S.

    2016-01-01

    This work reports the effect of very high doses, up to 10 MGy, on the H2 emission from high density polyethylene (HDPE) irradiated with gamma rays and ion beams, in the presence of oxygen. This was obtained through a two-step procedure. First, HDPE films were pre-aged, at different doses, using either gamma rays or ion beams. In the second step, the pre-aged samples were irradiated in closed glass ampoules for gas quantification, using the same beam type as for pre-ageing. The hydrogen emission rate decreases when dose increases for both gamma rays and ion beams. However, the decreasing rate appears higher under gamma rays than under ion beam irradiations and this is assigned to a lesser oxidation level under the latter. Herein, we show the effectiveness of the radiation-induced defects scavenging effect under oxidative atmosphere, under low and high excitation densities.

  11. Effects of ion beam irradiation on adventitious shoot regeneration from in vitro leaf explants of Saintpaulia ionahta

    NASA Astrophysics Data System (ADS)

    Zhou, L. B.; Li, W. J.; Ma, S.; Dong, X. C.; Yu, L. X.; Li, Q.; Zhou, G. M.; Gao, Q. X.

    2006-03-01

    The effects of 960 MeV carbon ion beam and 8 MeV X-ray irradiation on adventitious shoots from in vitro leaf explants of two different Saintpaulia ionahta (Mauve and Indikon) cultivars were studied with regard to tissue increase, shoots differentiation and morphology changes in the shoots. The experimental results showed that the survival fraction of shoot formation for the Mauve and Indikon irradiated with the carbon ion beam at 20 Gy were 0.715 and 0.600, respectively, while those for both the cultivars exposed to the X-ray irradiation at the same dose were 1.000. Relative biological effectiveness (RBE) of Mauve with respect to X-ray was about two. Secondly, the percentage of regenerating explants with malformed shoots in all Mauve regenerating explants irradiated with carbon ion beam at 20 Gy accounted for 49.6%, while that irradiated with the same dose of X-ray irradiation was only 4.7%; as for Saintpaulia ionahta Indikon irradiated with 20 Gy carbon ion beam, the percentage was 43.3%, which was higher than that of X-ray irradiation. Last, many chlorophyll deficient and other varieties of mutants were obtained in this study. Based on the results above, it can be concluded that the effect of mutation induction by carbon ion beam irradiation on the leaf explants of Saintpaulia ionahta is better than that by X-ray irradiation; and the optimal mutagenic dose varies from 20 Gy to 25 Gy for carbon ion beam irradiation.

  12. Crystallization effects and diamond formation in amorphous carbon films under low energy ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Patsalas, P.; Logothetidis, S.

    2001-05-01

    The crystallization effects occurring in various types of amorphous carbon (a-C) thin films with different structure and bonding induced by post-growth low energy (<1.5 keV) Ar + ion beam irradiation are presented. Detailed X-ray diffraction (XRD) measurements were used to identify several allotropic forms of carbon such as graphite and diamond as well as SiC detected in a-C films after ion irradiation. The diamond and SiC nucleation occurs close to the a-C/Si interface, beyond the ion penetration depth suggesting a non-direct nucleation mechanism. The relative content, grain size, distribution and orientation of each particular crystalline phase in the films depend strongly on the microstructural characteristics of the as-grown films. We also consider the effects of ion energy and fluence and substrate material on the crystallization process in an effort to get a deeper insight of the fundamental mechanisms occurring during the interaction of various carbon materials with low energy ion beams.

  13. Effects of carbon ion beam irradiation on the shoot regeneration from in vitro axillary bud explants of the Impatiens hawkeri

    NASA Astrophysics Data System (ADS)

    Zhou, Libin; Zhou, Libin; Li, Wenjian; Li, Ping; Dong, Xicun; Qu, Ying; Ma, Shuang; Li, Qiang

    Accelerated ion beams is an excellent mutagen in plant breeding which can induce higher mutation frequencies and wider mutation spectrum than those of low linear energy transfer (LET) irradiations, such as X-rays (Okamura et al. 2003, Yamaguchi et al. 2003). Mutation breeding operation of two Saintpaulia ionahta cultivars using the method combining plant tissue culture technique and carbon ion beam irradiations were set out at Institute of Modern Physics from 2005 (Zhou et al. 2006). The effects of 960 MeV carbon ion beam and 8 MeV X-ray irradiations on regenerated shoots of Impatiens hawkeri from another kind of explants named in vitro axillary buds explants were studied recently. The biology endpoints in this study included relative number of roots (RNR), relative length of roots (RLR), relative height of shoots (RHS), relative number of nodes (RNN), survival fraction (SF) and morphology changes in the regenerated shoots. The experimental results showed that carbon ion beams inhibited the root and stem developments of axillary bud explants more severely than X-rays did. And the 50% lethal dose (LD50 ) is about 23.3 Gy for the carbon ion beam and 49.1 Gy for the X-rays, respectively. Relative biological effectiveness (RBE) of Impatiens hawkeri with respect to X-rays according to 50% SF was about two. Secondly, the percentage of shoots regenerated with malformed shoots including curliness, carnification, nicks in all Impatiens hawkeri axillary bud explants irradiated with carbon ion beam at 20 Gy accounted for 55.6%, while the highest number for the 40 Gy X-ray irradiation was 40%. Last, many regenerated shoots whose vascular bundle fused together were obtained only from explants irradiated with carbon ion beams. Based on the results above, it can be concluded that the effect of mutation induction by carbon ion beam irradiation on the axillary explants of Impatiens hawkeri is better than that by X-ray irradiation; and the optimal mutagenic dose varies from 20 Gy

  14. Effects of Prenatal Irradiation with an Accelerated Heavy-Ion Beam on Postnatal Development in Rats

    NASA Astrophysics Data System (ADS)

    Wang, B.; Murakami, M.; Eguchi-Kasai, K.; Nojima, K.; Shang, Y.; Tanaka, K.; Fujita, K.; Coffigny, H.; Hayata, I.

    Effects on postnatal neurophysiological development in offspring were studied following exposure of pregnant Wistar rats to accelerated neon-ion beams with a LET value of about 30 keV mu m at a dose range from 0 1 Gy to 2 0Gy on the 15th day of gestation The age at which four physiologic markers appeared and five reflexes were acquired was examined prior to weaning Gain in body weight was monitored until the offspring were 3 months old Male offspring were evaluated as young adults using two behavioral tests The effects of X-rays at 200 kVp measured for the same biological end points were studied for comparison Our previous study on carbon-ion beams with a LET value of about 13 keV mu m was also cited to elucidate a possible LET-related effect For most of the endpoints at early age significant alteration was even observed in offspring prenatally received 0 1 Gy of accelerated neon ions while neither X rays nor carbon-ions under the same dose resulted in such a significant alteration compared to that from the sham-irradiated dams All offspring whose mothers received 2 0 Gy died prior to weaning Offspring from dams irradiated with accelerated neon ions generally showed higher incidences of prenatal death and preweaning mortality markedly delayed accomplishment in their physiological markers and reflexes and gain in body weight compared to those exposed to X-rays or carbon ions at doses of 0 1 to 1 5 Gy Significantly reduced ratios of main organ weight to body weight at postnatal ages of 30 60 and 90 days were also observed

  15. Mutation induced with ion beam irradiation in rose

    NASA Astrophysics Data System (ADS)

    Yamaguchi, H.; Nagatomi, S.; Morishita, T.; Degi, K.; Tanaka, A.; Shikazono, N.; Hase, Y.

    2003-05-01

    The effects of mutation induction by ion beam irradiation on axillary buds in rose were investigated. Axillary buds were irradiated with carbon and helium ion beams, and the solid mutants emerged after irradiation by repeated cutting back. In helium ion irradiation, mutations were observed in plants derived from 9 buds among 56 irradiated buds in 'Orange Rosamini' and in plants derived from 10 buds among 61 irradiated buds in 'Red Minimo'. In carbon ion, mutations were observed in plants derived from 12 buds among 88 irradiated buds in 'Orange Rosamini'. Mutations were induced not only in higher doses but also in lower doses, with which physiological effect by irradiation was hardly observed. Irradiation with both ion beams induced mutants in the number of petals, in flower size, in flower shape and in flower color in each cultivar.

  16. Effect of swift heavy ion beam irradiation on the dielectric and ferroelectric properties of pure and cobalt doped TGS crystals

    NASA Astrophysics Data System (ADS)

    Bajpai, P. K.; Shah, Deepak; Kumar, Ravi

    2012-01-01

    Effect of swift heavy ion (100 MeV O 7+ ion) beam irradiation on the temperature and frequency dependence of real ( ɛ') and imaginary ( ɛ″) parts of dielectric permittivity in pure and Co 2+ doped TGS crystals are analyzed. Irradiation with swift heavy ion beam changes the dielectric response considerably. Observed dielectric peak in irradiated crystals shifts towards lower temperature and broadens up; the reduction in peak value, shift in temperature and broadening changes systematically with fluence. The most interesting results of SHI irradiation are (i) the dielectric loss peak value ( emax″) in all crystals is invariably less in comparison to the value in unirradiated crystals (ii) the minimum value of dielectric loss peak ( emax″) occurs at different fluence in different crystals, and (iii) a second loss peak is observed below Tc in CTGS10 especially at higher fluence. It seems that irradiation creates/strengthens internal field in the crystals by orienting the domains through some mechanism that is not clear at present. The observed results could be explained if one presumes that irradiation annihilate the defects already present in the crystals by creating local charges and thermal gradient resulting into internal bias field. Ferroelectric hysteresis loops demonstrate the internal bias field developing in the SHI irradiated crystals. It is argued that SHI irradiation is a better alternate in comparison to cobalt doping in inhibiting dipolar switching in TGS crystal.

  17. Irradiation effect on PET surface using low energy argon ion beam

    NASA Astrophysics Data System (ADS)

    Soliman, Barakat A.; Abdelrahman, Moustafa M.; Abdelsalam, Fatama W.; Aly, Kamal A.

    2013-01-01

    A study of various physical properties of a PET film irradiated with an Ar beam is reported. SEM images and UV-VIS and FTIR spectra were obtained for a number of ionic fluxes and three irradiation times. Small changes in the energy gap of degradated samples were found, and the SEM images indicate that the optimum homogeneity and roughness are reached after 30 min of irradiation. These results may well be of practical interest. A modified saddle field ion source was used as a preparation tool of the surface of polyethylene terephthalate PET polymer substrate to be ready for coating or thin film deposition. Argon ion beam was used for this purpose, where the scanning electron microscope (SEM) shows that, the best sample is the one which was irradiated to 30 min, where this sample is more homogenous and roughness than other irradiated samples. Also the (UV-VIS) spectrum tells us that, there is small change on energy gap and this is meaning that, the change on electric properties is small also. In this case the sample is more homogenous and of higher roughness than other irradiated samples.

  18. Silicon ion irradiation effects on the magnetic properties of ion beam synthesized CoPt phase

    SciTech Connect

    Balaji, S.; Amirthapandian, S.; Panigrahi, B. K.; Mangamma, G.; Kalavathi, S.; Gupta, Ajay; Nair, K. G. M.

    2012-06-05

    Ion beam mixing of Pt/Co bilayers using self ion (Pt{sup +}) beam results in formation of CoPt phase. Upon ion beam annealing the ion mixed samples using 4 MeV Si{sup +} ions at 300 deg. C, diffusion of Co towards the Pt/Co interface is observed. The Si{sup +} ion beam rotates the magnetization of the CoPt phase from in plane to out of plane of the film.

  19. Area-selective formation of Si nanocrystals by assisted ion-beam irradiation during dual-ion-beam deposition

    SciTech Connect

    Kim, Jae Kwon; Cha, Kyu Man; Kang, Jung Hyun; Kim, Yong; Yi, Jae-Yel; Chung, Tae Hun; Bark, Hong Jun

    2004-08-30

    We investigate the effect of Ar-ion-beam irradiation during the deposition of SiO{sub x} films by dual-ion-beam deposition system. Ion-beam irradiation effectively increases the oxygen content, x, in SiO{sub x} films indicative of the preferential sputtering of Si phase as compared to SiO{sub 2} phase in SiO{sub x} films. We observe the intense photoluminescence from nonirradiated sample after postdeposition annealing at 1100 deg. C indicating the formation of Si nanocrystals as shown by a cross-sectional transmission electron microscope. However, the increased oxygen content in ion-beam-irradiated sample results in small optical volume of small Si nanocrystals not sufficient for yielding appreciable photoluminescence intensity after postdeposition annealing. The property is utilized for achieving the area-selective formation of Si nanocrytals by inserting a shadow mask in assist ion beam during deposition.

  20. Role of isolated and clustered DNA damage and the post-irradiating repair process in the effects of heavy ion beam irradiation.

    PubMed

    Tokuyama, Yuka; Furusawa, Yoshiya; Ide, Hiroshi; Yasui, Akira; Terato, Hiroaki

    2015-05-01

    Clustered DNA damage is a specific type of DNA damage induced by ionizing radiation. Any type of ionizing radiation traverses the target DNA molecule as a beam, inducing damage along its track. Our previous study showed that clustered DNA damage yields decreased with increased linear energy transfer (LET), leading us to investigate the importance of clustered DNA damage in the biological effects of heavy ion beam radiation. In this study, we analyzed the yield of clustered base damage (comprising multiple base lesions) in cultured cells irradiated with various heavy ion beams, and investigated isolated base damage and the repair process in post-irradiation cultured cells. Chinese hamster ovary (CHO) cells were irradiated by carbon, silicon, argon and iron ion beams with LETs of 13, 55, 90 and 200 keV µm(-1), respectively. Agarose gel electrophoresis of the cells with enzymatic treatments indicated that clustered base damage yields decreased as the LET increased. The aldehyde reactive probe procedure showed that isolated base damage yields in the irradiated cells followed the same pattern. To analyze the cellular base damage process, clustered DNA damage repair was investigated using DNA repair mutant cells. DNA double-strand breaks accumulated in CHO mutant cells lacking Xrcc1 after irradiation, and the cell viability decreased. On the other hand, mouse embryonic fibroblast (Mef) cells lacking both Nth1 and Ogg1 became more resistant than the wild type Mef. Thus, clustered base damage seems to be involved in the expression of heavy ion beam biological effects via the repair process. PMID:25717060

  1. Carbon-Ion Beam Irradiation Effectively Suppresses Migration and Invasion of Human Non-Small-Cell Lung Cancer Cells

    SciTech Connect

    Akino, Yuichi; Teshima, Teruki Kihara, Ayaka; Kodera-Suzumoto, Yuko; Inaoka, Miho; Higashiyama, Shigeki; Furusawa, Yoshiya; Matsuura, Nariaki

    2009-10-01

    Purpose: Control of cancer metastasis is one of the most important issues in cancer treatment. We previously demonstrated that carbon particle irradiation suppresses the metastatic potential of cancer cells, and many studies have reported that photon irradiation promotes it. The purpose of this study was to investigate the effect of carbon beam on non-small-cell lung cancer (NSCLC) cell aggressiveness and gene expression. Methods and Materials: A549 (lung adenocarcinoma) and EBC-1 (lung squamous cell carcinoma) cells were treated with 290 MeV/nucleon carbon ion beam at the Heavy Ion Medical Accelerator in Chiba or with 4-MV X-ray at Osaka University. We tested proliferative, migratory, and invasive activities by cell proliferation assay, Boyden chamber assay, and Matrigel chemoinvasion assay, respectively. cDNA microarray and reverse transcription polymerase chain reaction were also performed to assess mRNA expression alteration. Results: X-irradiation increased cell proliferation of A549 cells at 0.5 Gy, whereas high-dose X-ray reduced migration and invasion of A549 cells. By contrast, carbon beam irradiation did not enhance proliferation, and it reduced the migration and invasion capabilities of both A549 and EBC-1 cells more effectively than did X-irradiation. Carbon beam irradiation induced alteration of various gene expression profiles differently from X-ray irradiation. mRNA expression of ANLN, a homologue of anillin, was suppressed to 60% levels of basal expression in carbon beam-irradiated A549 cells after 12 h. Conclusion: Carbon beam effectively suppresses the metastatic potential of A549 and EBC-1 cells. Carbon beam also has different effects on gene expressions, and downregulation of ANLN was induced only by carbon beam irradiation.

  2. Effect of Hydrogen ion beam irradiation onto the FIR reflectivity of pulsed laser deposited mirror like Tungsten films

    NASA Astrophysics Data System (ADS)

    Mostako, A. T. T.; Khare, Alika; Rao, C. V. S.; Raole, Prakash M.; Vala, Sudhirsinh; Jakhar, Shrichand; Basu, T. K.; Abhangi, Mitul; Makwana, Rajinikant J.

    2012-04-01

    The optical quality of the First Mirrors (FMs) of a fusion device (burning plasma experiments, ITER) deteriorates due to the erosion by charge exchange neutrals, re-deposition of the eroded material and the lattice damage by the bombardment of the high energetic particles. This degradation of the optical quality of the plasma facing components in such a harsh environment is a serious concern for the reliability of the spectroscopic based optical diagnostics using FM of a fusion device. In this paper, the effect of 8 keV Hydrogen ion beam irradiation onto the FIR reflectivity of Tungsten thin film mirror is presented. The Tungsten thin films were prepared via Pulsed Laser Deposition (PLD) technique. The Tungsten mirrors were subjected to X-ray Diffraction (XRD), Energy Dispersive X-ray (EDX), Scanning Electron Microscope (SEM) and Atomic Force Microscope (AFM) for characterization. The specular reflectivities of the Tungsten mirrors before and after exposure to ion beam were recorded with Fourier Transform of Infra-Red (FTIR) technique. The ion penetration depth and straggle into Tungsten thin film and stainless steel (SS) substrate were estimated by Transport of Ions in Matter (TIRM) simulation code. The changes in post exposure IR reflectivity were interpreted in terms of these parameters.

  3. Radiosensitizing effect of carboplatin and paclitaxel to carbon-ion beam irradiation in the non-small-cell lung cancer cell line H460.

    PubMed

    Kubo, Nobuteru; Noda, Shin-ei; Takahashi, Akihisa; Yoshida, Yukari; Oike, Takahiro; Murata, Kazutoshi; Musha, Atsushi; Suzuki, Yoshiyuki; Ohno, Tatsuya; Takahashi, Takeo; Nakano, Takashi

    2015-03-01

    The present study investigated the ability of carboplatin and paclitaxel to sensitize human non-small-cell lung cancer (NSCLC) cells to carbon-ion beam irradiation. NSCLC H460 cells treated with carboplatin or paclitaxel were irradiated with X-rays or carbon-ion beams, and radiosensitivity was evaluated by clonogenic survival assay. Cell proliferation was determined by counting the number of viable cells using Trypan blue. Apoptosis and senescence were evaluated by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) staining and senescence-associated β-galactosidase (SA-β-gal) staining, respectively. The expression of cleaved caspase-3, Bax, p53 and p21 was analyzed by western blotting. Clonogenic survival assays demonstrated a synergistic radiosensitizing effect of carboplatin and paclitaxel with carbon-ion beams; the sensitizer enhancement ratios (SERs) at the dose giving a 10% survival fraction (D10) were 1.21 and 1.22, respectively. Similarly, carboplatin and paclitaxel showed a radiosensitizing effect with X-rays; the SERs were 1.41 and 1.29, respectively. Cell proliferation assays validated the radiosensitizing effect of carboplatin and paclitaxel with both carbon-ion beam and X-ray irradiation. Carboplatin and paclitaxel treatment combined with carbon-ion beams increased TUNEL-positive cells and the expression of cleaved caspase-3 and Bax, indicating the enhancement of apoptosis. The combined treatment also increased SA-β-gal-positive cells and the expression of p53 and p21, indicating the enhancement of senescence. In summary, carboplatin and paclitaxel radiosensitized H460 cells to carbon-ion beam irradiation by enhancing irradiation-induced apoptosis and senescence. PMID:25599995

  4. Effect of low energy oxygen ion beam irradiation on ionic conductivity of solid polymer electrolyte

    SciTech Connect

    Manjunatha, H. Kumaraswamy, G. N.; Damle, R.

    2014-04-24

    Over the past three decades, solid polymer electrolytes (SPEs) have drawn significant attention of researchers due to their prospective commercial applications in high energy-density batteries, electrochemical sensors and super-capacitors. The optimum conductivity required for such applications is about 10{sup −2} – 10{sup −4} S/cm, which is hard to achieve in these systems. It is known that the increase in the concentration of salt in the host polymer results in a continuous increase in the ionic conductivity. However, there is a critical concentration of the salt beyond which the conductivity decreases due to formation of ion pairs with no net charge. In the present study, an attempt is made to identify the concentration at which ion pair formation occurs in PEO: RbBr. We have attempted to modify microstructure of the host polymer matrix by low energy ion (Oxygen ion, O{sup +1} with energy 100 keV) irradiation. Ionic conductivity measurements in these systems were carried out using Impedance Spectroscopy before and after irradiation to different fluencies of the oxygen ion. It is observed that the conductivity increases by one order in magnitude. The increase in ionic conductivity may be attributed to the enhanced segmental motion of the polymer chains. The study reveals the importance of ion irradiation as an effective tool to enhance conductivity in SPEs.

  5. Silver ion beam irradiation effects on poly(lactide-co-glycolide) (PLGA)/clay nanocomposites

    NASA Astrophysics Data System (ADS)

    Kaur, Manpreet; Singh, Surinder; Mehta, Rajeev

    2014-12-01

    Swift heavy ions induced modification of thin films of blends of poly(lactide-co-glycolide) (PLGA) (50:50) with organically modified nanoclay (Cloisite® 30B) has been studied, using optical, structural and surface morphological analysis. Presence of nanoclay is found to enhance the properties of this degradable copolymer by reducing the rate of degradation even at high irradiation fluence. Optical and structural analysis of the polymer nanocomposites suggests that both the cross-linking and chain scission phenomenon are caused by swift heavy ion irradiation. XRD measurements show intercalation of PLGA in the clay galleries. Surface morphology of a nanocomposite indicates significant changes after irradiation at various fluences.

  6. Temperature measurements during high flux ion beam irradiations.

    PubMed

    Crespillo, M L; Graham, J T; Zhang, Y; Weber, W J

    2016-02-01

    A systematic study of the ion beam heating effect was performed in a temperature range of -170 to 900 °C using a 10 MeV Au(3+) ion beam and a Yttria stabilized Zirconia (YSZ) sample at a flux of 5.5 × 10(12) cm(-2) s(-1). Different geometric configurations of beam, sample, thermocouple positioning, and sample holder were compared to understand the heat/charge transport mechanisms responsible for the observed temperature increase. The beam heating exhibited a strong dependence on the background (initial) sample temperature with the largest temperature increases occurring at cryogenic temperatures and decreasing with increasing temperature. Comparison with numerical calculations suggests that the observed heating effect is, in reality, a predominantly electronic effect and the true temperature rise is small. A simple model was developed to explain this electronic effect in terms of an electrostatic potential that forms during ion irradiation. Such an artificial beam heating effect is potentially problematic in thermostated ion irradiation and ion beam analysis apparatus, as the operation of temperature feedback systems can be significantly distorted by this effect. PMID:26931879

  7. Temperature measurements during high flux ion beam irradiations

    NASA Astrophysics Data System (ADS)

    Crespillo, M. L.; Graham, J. T.; Zhang, Y.; Weber, W. J.

    2016-02-01

    A systematic study of the ion beam heating effect was performed in a temperature range of -170 to 900 °C using a 10 MeV Au3+ ion beam and a Yttria stabilized Zirconia (YSZ) sample at a flux of 5.5 × 1012 cm-2 s-1. Different geometric configurations of beam, sample, thermocouple positioning, and sample holder were compared to understand the heat/charge transport mechanisms responsible for the observed temperature increase. The beam heating exhibited a strong dependence on the background (initial) sample temperature with the largest temperature increases occurring at cryogenic temperatures and decreasing with increasing temperature. Comparison with numerical calculations suggests that the observed heating effect is, in reality, a predominantly electronic effect and the true temperature rise is small. A simple model was developed to explain this electronic effect in terms of an electrostatic potential that forms during ion irradiation. Such an artificial beam heating effect is potentially problematic in thermostated ion irradiation and ion beam analysis apparatus, as the operation of temperature feedback systems can be significantly distorted by this effect.

  8. Effects of carbon ion beam irradiation on lung injury and pulmonary fibrosis in mice

    PubMed Central

    WU, ZHENHUA; WANG, XINYU; YANG, RONG; LIU, YANG; ZHAO, WEIPING; SI, JIN; MA, XIAOFEI; SUN, CHAO; LIU, YUANYUAN; TAN, YONG; LIU, WEI; ZHANG, XIN; DI, CUIXIA; WANG, ZHENHUA; ZHANG, HONG; ZHANG, ZHONGXIANG

    2013-01-01

    Radiation-induced lung injury is a well-described complication of nuclear accidents, marrow-transplant pretreatment and thoracic radiotherapy. The mechanism is complex and no special therapy for it is available at present. To study radiation pulmonary injury following heavy ion radiotherapy for thoracic tumors, Kunming mice were randomly divided into 4 groups: normal control and 2, 4 and 6 Gy irradiation groups which underwent whole-body exposure to 235 MeV/u 12C6+ administered at the Heavy Ion Research Facility in Lanzhou (HIRFL). The pathological changes were observed by hematoxylin and eosin staining and the hydroxyproline (HP) content was assessed by spectrophotometry at months 1, 2, 3, 4, 5 and 6 after radiation exposure. In addition, the expression of tumor necrosis factor (TNF)-α and transforming growth factor (TGF)-β in the lung tissues was measured. The results showed that, compared with the control group, the lung tissue HP content was increased following irradiation but did not statistically significantly change after 4 months in the 4- and 6-Gy-treated groups. However, in the 2-Gy-treated group, the HP content was markedly increased between months 1 and 4 and decreased after month 4. The extent of the lung injury was significantly increased by the higher radiation dosages but was relieved in the 2 Gy group as the time since irradiation increased. The results also revealed that the levels of TNF-α were upregulated and reached a maximum at month 2, but decreased noticeably 2 months later in the experimental groups. The expression of TGF-β increased markedly in month 4 and was altered little in the 4- and 6-Gy-treated groups but decreased sharply in the 2 Gy irradiation group after month 4. These findings suggest that heavy ion radiotherapy for chest tumors causes lung injury to a certain extent, while there is likely to be little injury to lungs treated with <2 Gy, which provides scientific evidence for the use of heavy ion therapy for thoracic tumors

  9. University of Wisconsin Ion Beam Laboratory: A facility for irradiated materials and ion beam analysis

    SciTech Connect

    Field, K. G.; Wetteland, C. J.; Cao, G.; Maier, B. R.; Gerczak, T. J.; Kriewaldt, K.; Sridharan, K.; Allen, T. R.; Dickerson, C.; Field, C. R.

    2013-04-19

    The University of Wisconsin Ion Beam Laboratory (UW-IBL) has recently undergone significant infrastructure upgrades to facilitate graduate level research in irradiated materials phenomena and ion beam analysis. A National Electrostatics Corp. (NEC) Torodial Volume Ion Source (TORVIS), the keystone upgrade for the facility, can produce currents of hydrogen ions and helium ions up to {approx}200 {mu}A and {approx}5 {mu}A, respectively. Recent upgrades also include RBS analysis packages, end station developments for irradiation of relevant material systems, and the development of an in-house touch screen based graphical user interface for ion beam monitoring. Key research facilitated by these upgrades includes irradiation of nuclear fuels, studies of interfacial phenomena under irradiation, and clustering dynamics of irradiated oxide dispersion strengthened steels. The UW-IBL has also partnered with the Advanced Test Reactor National Scientific User Facility (ATR-NSUF) to provide access to the irradiation facilities housed at the UW-IBL as well as access to post irradiation facilities housed at the UW Characterization Laboratory for Irradiated Materials (CLIM) and other ATR-NSUF partner facilities. Partnering allows for rapid turnaround from proposed research to finalized results through the ATR-NSUF rapid turnaround proposal system. An overview of the UW-IBL including CLIM and relevant research is summarized.

  10. Effects of prenatal irradiation with accelerated heavy-ion beams on postnatal development in rats: III. Testicular development and breeding activity

    NASA Astrophysics Data System (ADS)

    Wang, B.; Murakami, M.; Eguchi-Kasai, K.; Nojima, K.; Shang, Y.; Tanaka, K.; Watanabe, K.; Fujita, K.; Moreno, S. G.; Coffigny, H.; Hayata, I.

    With a significant increase in human activities dealing with space missions, potential teratogenic effects on the mammalian reproductive system from prenatal exposure to space radiation have become a hot topic that needs to be addressed. However, even for the ground experiments, such effects from exposure to high LET ionizing radiation are not as well studied as those for low LET ionizing radiations such as X-rays. Using the Heavy-Ion Medical Accelerator in Chiba (HIMAC) and Wistar rats, effects on gonads in prenatal male fetuses, on postnatal testicular development and on breeding activity of male offspring were studied following exposure of the pregnant animals to either accelerated carbon-ion beams with a LET value of about 13 keV/μm or neon-ion beams with a LET value of about 30 keV/μm at a dose range from 0.1 to 2.0 Gy on gestation day 15. The effects of X-rays at 200 kVp estimated for the same biological end points were studied for comparison. A significantly dose-dependent increase of apoptosis in gonocytes appeared 6 h after irradiations with a dose of 0.5 Gy or more. Measured delayed testis descent and malformed testicular seminiferous tubules were observed to be significantly different from the control animals at a dose of 0.5 Gy. These effects are observed to be dose- and LET-dependent. Markedly reduced testicular weight and testicular weight to body weight ratio were scored at postnatal day 30 even in the offspring that were prenatally irradiated with neon-ions at a dose of 0.1 Gy. A dose of 0.5 Gy from neon-ion beams induced a marked decrease in breeding activity in the prenatally irradiated male rats, while for the carbon-ion beams or X-rays, the significantly reduced breeding activity was observed only when the prenatal dose was at 1.0 Gy or more. These findings indicated that prenatal irradiations with heavy-ion beams on gestation day 15 generally induced markedly detrimental effects on prenatal gonads, postnatal testicular development and male

  11. ION BEAM ETCHING EFFECTS IN BIOLOGICAL MICROANALYSIS

    EPA Science Inventory

    Oxygen ion beam sputter etching used in SIMS has been shown to produce morphologic effects which have similarities and differences in comparison to rf plasma etching of biological specimens. Sputter yield variations resulting from structural microheterogeneity are illustrated (e....

  12. Temperature measurements during high flux ion beam irradiations

    DOE PAGESBeta

    Crespillo, Miguel L.; Graham, Joseph T.; Zhang, Yanwen; Weber, William J.

    2016-02-16

    A systematic study of the ion beam heating effect was performed in a temperature range of –170 to 900 °C using a 10 MeV Au3+ ion beam and a Yttria stabilized Zirconia (YSZ) sample at a flux of 5.5 × 1012 cm–2 s–1. Different geometric configurations of beam, sample, thermocouple positioning, and sample holder were compared to understand the heat/charge transport mechanisms responsible for the observed temperature increase. The beam heating exhibited a strong dependence on the background (initial) sample temperature with the largest temperature increases occurring at cryogenic temperatures and decreasing with increasing temperature. Comparison with numerical calculations suggestsmore » that the observed heating effect is, in reality, a predominantly electronic effect and the true temperature rise is small. Furthermore, a simple model was developed to explain this electronic effect in terms of an electrostatic potential that forms during ion irradiation. Such an artificial beam heating effect is potentially problematic in thermostated ion irradiation and ion beamanalysis apparatus, as the operation of temperature feedback systems can be significantly distorted by this effect.« less

  13. Focused helium-ion beam irradiation effects on electrical transport properties of few-layer WSe2: enabling nanoscale direct write homo-junctions

    PubMed Central

    Stanford, Michael G.; Pudasaini, Pushpa Raj; Belianinov, Alex; Cross, Nicholas; Noh, Joo Hyon; Koehler, Michael R.; Mandrus, David G.; Duscher, Gerd; Rondinone, Adam J.; Ivanov, Ilia N.; Ward, T. Zac; Rack, Philip D.

    2016-01-01

    Atomically thin transition metal dichalcogenides (TMDs) are currently receiving significant attention due to their promising opto-electronic properties. Tuning optical and electrical properties of mono and few-layer TMDs, such as tungsten diselenide (WSe2), by controlling the defects, is an intriguing opportunity to synthesize next generation two dimensional material opto-electronic devices. Here, we report the effects of focused helium ion beam irradiation on the structural, optical and electrical properties of few-layer WSe2, via high resolution scanning transmission electron microscopy, Raman spectroscopy, and electrical transport measurements. By controlling the ion irradiation dose, we selectively introduce precise defects in few-layer WSe2 thereby locally tuning the resistivity and transport properties of the material. Hole transport in the few layer WSe2 is degraded more severely relative to electron transport after helium ion irradiation. Furthermore, by selectively exposing material with the ion beam, we demonstrate a simple yet highly tunable method to create lateral homo-junctions in few layer WSe2 flakes, which constitutes an important advance towards two dimensional opto-electronic devices. PMID:27263472

  14. Focused helium-ion beam irradiation effects on electrical transport properties of few-layer WSe2: enabling nanoscale direct write homo-junctions

    NASA Astrophysics Data System (ADS)

    Stanford, Michael G.; Pudasaini, Pushpa Raj; Belianinov, Alex; Cross, Nicholas; Noh, Joo Hyon; Koehler, Michael R.; Mandrus, David G.; Duscher, Gerd; Rondinone, Adam J.; Ivanov, Ilia N.; Ward, T. Zac; Rack, Philip D.

    2016-06-01

    Atomically thin transition metal dichalcogenides (TMDs) are currently receiving significant attention due to their promising opto-electronic properties. Tuning optical and electrical properties of mono and few-layer TMDs, such as tungsten diselenide (WSe2), by controlling the defects, is an intriguing opportunity to synthesize next generation two dimensional material opto-electronic devices. Here, we report the effects of focused helium ion beam irradiation on the structural, optical and electrical properties of few-layer WSe2, via high resolution scanning transmission electron microscopy, Raman spectroscopy, and electrical transport measurements. By controlling the ion irradiation dose, we selectively introduce precise defects in few-layer WSe2 thereby locally tuning the resistivity and transport properties of the material. Hole transport in the few layer WSe2 is degraded more severely relative to electron transport after helium ion irradiation. Furthermore, by selectively exposing material with the ion beam, we demonstrate a simple yet highly tunable method to create lateral homo-junctions in few layer WSe2 flakes, which constitutes an important advance towards two dimensional opto-electronic devices.

  15. Focused helium-ion beam irradiation effects on electrical transport properties of few-layer WSe2: enabling nanoscale direct write homo-junctions.

    PubMed

    Stanford, Michael G; Pudasaini, Pushpa Raj; Belianinov, Alex; Cross, Nicholas; Noh, Joo Hyon; Koehler, Michael R; Mandrus, David G; Duscher, Gerd; Rondinone, Adam J; Ivanov, Ilia N; Ward, T Zac; Rack, Philip D

    2016-01-01

    Atomically thin transition metal dichalcogenides (TMDs) are currently receiving significant attention due to their promising opto-electronic properties. Tuning optical and electrical properties of mono and few-layer TMDs, such as tungsten diselenide (WSe2), by controlling the defects, is an intriguing opportunity to synthesize next generation two dimensional material opto-electronic devices. Here, we report the effects of focused helium ion beam irradiation on the structural, optical and electrical properties of few-layer WSe2, via high resolution scanning transmission electron microscopy, Raman spectroscopy, and electrical transport measurements. By controlling the ion irradiation dose, we selectively introduce precise defects in few-layer WSe2 thereby locally tuning the resistivity and transport properties of the material. Hole transport in the few layer WSe2 is degraded more severely relative to electron transport after helium ion irradiation. Furthermore, by selectively exposing material with the ion beam, we demonstrate a simple yet highly tunable method to create lateral homo-junctions in few layer WSe2 flakes, which constitutes an important advance towards two dimensional opto-electronic devices. PMID:27263472

  16. Focused helium-ion beam irradiation effects on electrical transport properties of few-layer WSe2: Enabling nanoscale direct write homo-junctions

    DOE PAGESBeta

    Stanford, Michael; Noh, Joo Hyon; Koehler, Michael R.; Mandrus, David G.; Duscher, Gerd; Rondinone, Adam Justin; Ivanov, Ilia N.; Ward, Thomas Zac; Rack, Philip D.; Pudasaini, Pushpa Raj; et al

    2016-06-06

    Atomically thin transition metal dichalcogenides (TMDs) are currently receiving significant attention due to their promising opto-electronic properties. Tuning optical and electrical properties of mono and few-layer TMDs, such as tungsten diselenide (WSe2), by controlling the defects, is an intriguing opportunity to synthesize next generation two dimensional material opto-electronic devices. Here, we report the effects of focused helium ion beam irradiation on the structural, optical and electrical properties of few-layer WSe2, via high resolution scanning transmission electron microscopy, Raman spectroscopy, and electrical transport measurements. By controlling the ion irradiation dose, we selectively introduce precise defects in few-layer WSe2 thereby locally tuningmore » the resistivity and transport properties of the material. Hole transport in the few layer WSe2 is degraded more severely relative to electron transport after helium ion irradiation. Moreover, by selectively exposing material with the ion beam, we demonstrate a simple yet highly tunable method to create lateral homo-junctions in few layer WSe2 flakes, which constitutes an important advance towards two dimensional opto-electronic devices.« less

  17. Characterisation of dual ion beam irradiated yttria-stabilised zirconia by specific analytical techniques

    NASA Astrophysics Data System (ADS)

    Zhang, Yanwen; Wang, Xu; Liu, Shiyi; Tang, Meixiong; Zhao, Ziqiang

    2015-01-01

    The combined effect of dual ion beam irradiated yttria-stabilized zirconia was investigated through Rutherford backscattering spectrometry/channeling (RBS/C), high resolution X-ray diffraction (HRXRD), atomic force microscopy (AFM) and transmission electron microscopy (TEM). Compared with other experimental results of single ion beam irradiation, a multistep damage accumulation model can also explain the irradiation effects of dual ion beam. Irradiation damage created by Ar + He ions are simply additive and no synergy effect has been observed. The variation trends of step height and displacement damage are similar. The synergic effects of displacement damage between heavy recoil atoms and α-particle in nuclear waste matrices will not cause more serious damage than the sum of two kinds of ions. The two experimental damage peaks are consistent with those calculated using stopping and range of ions in matter (SRIM). Phase stability and irradiation resistance is further confirmed by high resolution transmission electron microscopy (HRTEM).

  18. In vivo 3D analysis of systemic effects after local heavy-ion beam irradiation in an animal model

    PubMed Central

    Nagata, Kento; Hashimoto, Chika; Watanabe-Asaka, Tomomi; Itoh, Kazusa; Yasuda, Takako; Ohta, Kousaku; Oonishi, Hisako; Igarashi, Kento; Suzuki, Michiyo; Funayama, Tomoo; Kobayashi, Yasuhiko; Nishimaki, Toshiyuki; Katsumura, Takafumi; Oota, Hiroki; Ogawa, Motoyuki; Oga, Atsunori; Ikemoto, Kenzo; Itoh, Hiroshi; Kutsuna, Natsumaro; Oda, Shoji; Mitani, Hiroshi

    2016-01-01

    Radiotherapy is widely used in cancer treatment. In addition to inducing effects in the irradiated area, irradiation may induce effects on tissues close to and distant from the irradiated area. Japanese medaka, Oryzias latipes, is a small teleost fish and a model organism for evaluating the environmental effects of radiation. In this study, we applied low-energy carbon-ion (26.7 MeV/u) irradiation to adult medaka to a depth of approximately 2.2 mm from the body surface using an irradiation system at the National Institutes for Quantum and Radiological Science and Technology. We histologically evaluated the systemic alterations induced by irradiation using serial sections of the whole body, and conducted a heart rate analysis. Tissues from the irradiated side showed signs of serious injury that corresponded with the radiation dose. A 3D reconstruction analysis of the kidney sections showed reductions in the kidney volume and blood cell mass along the irradiated area, reflecting the precise localization of the injuries caused by carbon-beam irradiation. Capillary aneurysms were observed in the gill in both ventrally and dorsally irradiated fish, suggesting systemic irradiation effects. The present study provides an in vivo model for further investigation of the effects of irradiation beyond the locally irradiated area. PMID:27345436

  19. In vivo 3D analysis of systemic effects after local heavy-ion beam irradiation in an animal model.

    PubMed

    Nagata, Kento; Hashimoto, Chika; Watanabe-Asaka, Tomomi; Itoh, Kazusa; Yasuda, Takako; Ohta, Kousaku; Oonishi, Hisako; Igarashi, Kento; Suzuki, Michiyo; Funayama, Tomoo; Kobayashi, Yasuhiko; Nishimaki, Toshiyuki; Katsumura, Takafumi; Oota, Hiroki; Ogawa, Motoyuki; Oga, Atsunori; Ikemoto, Kenzo; Itoh, Hiroshi; Kutsuna, Natsumaro; Oda, Shoji; Mitani, Hiroshi

    2016-01-01

    Radiotherapy is widely used in cancer treatment. In addition to inducing effects in the irradiated area, irradiation may induce effects on tissues close to and distant from the irradiated area. Japanese medaka, Oryzias latipes, is a small teleost fish and a model organism for evaluating the environmental effects of radiation. In this study, we applied low-energy carbon-ion (26.7 MeV/u) irradiation to adult medaka to a depth of approximately 2.2 mm from the body surface using an irradiation system at the National Institutes for Quantum and Radiological Science and Technology. We histologically evaluated the systemic alterations induced by irradiation using serial sections of the whole body, and conducted a heart rate analysis. Tissues from the irradiated side showed signs of serious injury that corresponded with the radiation dose. A 3D reconstruction analysis of the kidney sections showed reductions in the kidney volume and blood cell mass along the irradiated area, reflecting the precise localization of the injuries caused by carbon-beam irradiation. Capillary aneurysms were observed in the gill in both ventrally and dorsally irradiated fish, suggesting systemic irradiation effects. The present study provides an in vivo model for further investigation of the effects of irradiation beyond the locally irradiated area. PMID:27345436

  20. Correlation between surface phonon mode and luminescence in nanocrystalline CdS thin films: An effect of ion beam irradiation

    SciTech Connect

    Kumar, Pragati Agarwal, Avinash; Saxena, Nupur; Singh, Fouran; Gupta, Vinay

    2014-07-28

    The influence of swift heavy ion irradiation (SHII) on surface phonon mode (SPM) and green emission in nanocrystalline CdS thin films grown by chemical bath deposition is studied. The SHII of nanocrystalline CdS thin films is carried out using 70 MeV Ni ions. The micro Raman analysis shows that asymmetry and broadening in fundamental longitudinal optical (LO) phonon mode increases systematically with increasing ion fluence. To analyze the role of phonon confinement, spatial correlation model (SCM) is fitted to the experimental data. The observed deviation of SCM to the experimental data is further investigated by fitting the micro Raman spectra using two Lorentzian line shapes. It is found that two Lorentzian functions (LFs) provide better fitting than SCM fitting and facilitate to identify the contribution of SPM in the observed distortion of LO mode. The behavior of SPM as a function of ion fluence is studied to correlate the observed asymmetry (Γ{sub a}/Γ{sub b}) and full width at half maximum of LO phonon mode and to understand the SHII induced enhancement of SPM. The ion beam induced interstitial and surface state defects in thin films, as observed by photoluminescence (PL) spectroscopy studies, may be the underlying reason for enhancement in SPM. PL studies also show enhancement in green luminescence with increase in ion fluence. PL analysis reveals that the variation in population density of surface state defects after SHII is similar to that of SPM. The correlation between SPM and luminescence and their dependence on ion irradiation fluence is explained with the help of thermal spike model.

  1. Secondary particle tracks generated by ion beam irradiation

    NASA Astrophysics Data System (ADS)

    García, Gustavo

    2015-05-01

    The Low Energy Particle Track Simulation (LEPTS) procedure is a powerful complementary tool to include the effect of low energy electrons and positrons in medical applications of radiation. In particular, for ion-beam cancer treatments provides a detailed description of the role of the secondary electrons abundantly generated around the Bragg peak as well as the possibility of using transmuted positron emitters (C11, O15) as a complement for ion-beam dosimetry. In this study we present interaction probability data derived from IAM-SCAR corrective factors for liquid environments. Using these data, single electron and positron tracks in liquid water and pyrimidine have been simulated providing information about energy deposition as well as the number and type of interactions taking place in any selected ``nanovolume'' of the irradiated area. In collaboration with Francisco Blanco, Universidad Complutense de Madrid; Antonio Mu noz, Centro de Investigaciones Energéticas Medioambientales y Tecnológicas and Diogo Almeida, Filipe Ferreira da Silva, Paulo Lim ao-Vieira, Universidade Nova de Lisboa. Supported by the Spanish and Portuguese governments.

  2. Molecular dynamics simulations of electron and ion beam irradiation of multiwalled carbon nanotubes: The effects on failure by inner tube sliding

    SciTech Connect

    Pregler, Sharon K.; Sinnott, Susan B.

    2006-06-01

    Irradiation of nanotube structures with electron and ion beams has been used to produce functionalized nanotubes and fundamentally new structures, including junctions. Here, we build on previous studies to investigate the low-energy electron and ion (Ar and CF{sub 3}) beam irradiation of triple-walled carbon nanotubes that consist entirely of either chiral or armchair tubes. Effective incident energies of 50 eV/ion and 50 keV/electron are considered. The approach is classical molecular dynamic simulations using reactive empirical bond-order potentials and the primary knock-on atom approach to model the effects of electron irradiation. The results indicate that these various irradiation processes produce local damage to the nanotubes that includes crosslinking, that the degree of damage depends to some degree on the chirality of the nanotubes, and that the radial distribution of crosslinks depends significantly on the irradiating particle. Importantly, the effect of these crosslinks, and their radial distribution along the circumference of the nanotube, on the tendency of multiwalled nanotubes to fail by the sword-in-sheath mechanism is examined.

  3. Morphological and biochemical responses of Oryza sativa L. (cultivar MR219) to ion beam irradiation*

    PubMed Central

    Ling, Anna Pick Kiong; Ung, Ying Chian; Hussein, Sobri; Harun, Abdul Rahim; Tanaka, Atsushi; Yoshihiro, Hase

    2013-01-01

    Objective: Heavy ion beam, which has emerged as a new mutagen in the mutation breeding of crops and ornamental plants, is expected to result in the induction of novel mutations. This study investigates the morphological and biochemical responses of Oryza sativa toward different doses of carbon ion beam irradiation. Methods: In this study, the dry seeds of O. sativa were irradiated at 0, 20, 40, 60, 80, 100, and 120 Gy, followed by in-vitro germination under controlled conditions. Morphological and biochemical studies were conducted to investigate the morphological and physiological responses of O. sativa towards ion beam irradiation. Results: The study demonstrated that low doses (10 Gy) of ion beam have a stimulating effect on the height, root length, and fresh weight of the plantlets but not on the number of leaves. Meanwhile, doses higher than 10 Gy caused reductions in all the morphological parameters studied as compared to the control samples. The highest total soluble protein content [(2.11±0.47) mg/g FW] was observed in plantlets irradiated at 20 Gy. All irradiated plantlets were found to have 0.85% to 58.32% higher specific activity of peroxidase as compared to the control samples. The present study also revealed that low doses of ion beam (10 and 20 Gy) had negligible effect on the total chlorophyll content of O. sativa plantlets while 40 Gy had a stimulating effect on the chlorophyll content. Plantlets irradiated between 40 to 120 Gy were shown to be 0.38% to 9.98% higher in total soluble nitrogen content which, however, was not significantly different from the control samples. Conclusions: Carbon ion beam irradiation administered at low to moderate doses of 10 to 40 Gy may induce O. sativa mutants with superior characteristics. PMID:24302713

  4. Efficient modification of floral traits by heavy-ion beam irradiation on transgenic Torenia.

    PubMed

    Ohtsubo, Norihiro; Sasaki, Katsutomo; Aida, Ryutaro; Ryuto, Hiromichi; Ichida, Hiroyuki; Hayashi, Yoriko; Abe, Tomoko

    2012-01-01

    While heavy-ion beam irradiation is becoming popular technology for mutation breeding in Japan, the combination with genetic manipulation makes it more convenient to create greater variation in plant phenotypes. We have succeeded in producing over 200 varieties of transgenic torenia (Torenia fournieri Lind.) from over 2,400 regenerated plants by this procedure in only 2 years. Mutant phenotypes were observed mainly in flowers and showed wide variation in colour and shape. Higher mutation rates in the transgenics compared to those in wild type indicate the synergistic effect of genetic manipulation and heavy-ion beam irradiation, which might be advantageous to create greater variation in floral traits. PMID:22351017

  5. MeV single-ion beam irradiation of mammalian cells using the Surrey vertical nanobeam, compared with broad proton beam and X-ray irradiations

    NASA Astrophysics Data System (ADS)

    Prakrajang, K.; Jeynes, J. C. G.; Merchant, M. J.; Kirkby, K.; Kirkby, N.; Thopan, P.; Yu, L. D.

    2013-07-01

    As a part of a systematic study on mechanisms involved in physical cancer therapies, this work investigated response of mammalian cells to ultra-low-dose ion beam irradiation. The ion beam irradiation was performed using the recently completed nanobeam facility at the Surrey Ion Beam Centre. A scanning focused vertical ion nano-beam was applied to irradiate Chinese hamster V79 cells. The V79 cells were irradiated in two different beam modes, namely, focused single ion beam and defocused scanning broad ion beam of 3.8-MeV protons. The single ion beam was capable of irradiating a single cell with a precisely controlled number of the ions to extremely low doses. After irradiation and cell incubation, the number of surviving colonies as a function of the number of the irradiating ions was measured for the cell survival fraction curve. A lower survival for the single ion beam irradiation than that of the broad beam case implied the hypersensitivity and bystander effect. The ion-beam-induced cell survival curves were compared with that from 300-kV X-ray irradiation. Theoretical studies indicated that the cell death in single ion irradiation mainly occurred in the cell cycle phases of cell division and intervals between the cell division and the DNA replication. The success in the experiment demonstrated the Surrey vertical nanobeam successfully completed.

  6. Combined effects of nuclear and electronic energy losses in solids irradiated with a dual-ion beam

    NASA Astrophysics Data System (ADS)

    Thomé, Lionel; Debelle, Aurélien; Garrido, Frédérico; Trocellier, Patrick; Serruys, Yves; Velisa, Gihan; Miro, Sandrine

    2013-04-01

    Single and dual-beam irradiations of oxide (c-ZrO2, MgO, Gd2Ti2O7) and carbide (SiC) single crystals were performed to study combined effects of nuclear (Sn) and electronic (Se) energy losses. Rutherford backscattering experiments in channeling conditions show that the Sn/Se cooperation induces a strong decrease of the irradiation-induced damage in SiC and MgO and almost no effects in c-ZrO2 and Gd2Ti2O7. The healing process is ascribed to electronic excitations arising from the electronic energy loss of swift ions. These results present a strong interest for both fundamental understanding of the ion-solid interactions and technological applications in the nuclear industry where expected cooperative Sn/Se effects may lead to the preservation of the integrity of nuclear devices.

  7. A study on the effect of low energy ion beam irradiation on Au/TiO2 system for its application in photoelectrochemical splitting of water

    NASA Astrophysics Data System (ADS)

    Verma, Anuradha; Srivastav, Anupam; Sharma, Dipika; Banerjee, Anamika; Sharma, Shailja; Satsangi, Vibha Rani; Shrivastav, Rohit; Avasthi, Devesh Kumar; Dass, Sahab

    2016-07-01

    Nanostructured TiO2 thin films were deposited on indium tin oxide (ITO) substrate via sol-gel technique and were modified by plasmonic Au layer. The plasmonic Au modified TiO2 (Au/TiO2) thin films were then irradiated with 500 keV Ar2+ ion beam at different ion fluences viz. 1 × 1016, 3 × 1016 and 1 × 1017 to study the effect of nuclear energy deposition on the morphology, crystallinity, band gap, surface plasmon resonance (SPR) peak exhibited by Au particles and photoelectrochemical properties of the system. Prepared thin films were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), Rutherford backscattering spectrometry (RBS) measurements and UV-visible spectroscopy. The photoelectrochemical measurements revealed that both Au/TiO2 and Au/TiO2 thin film irradiated at 1 × 1016 fluence exhibits enhanced photoelectrochemical response in comparison to pristine TiO2. The film irradiated at 1 × 1016 fluence offered maximum applied bias photon-to-current efficiency (ABPE) and shows 6 times increment in photocurrent density which was attributed to more negative flat band potential, maximum decrease in band gap, high open circuit voltage (Voc) and reduced charge transfer resistance.

  8. High electronic excitations and ion beam mixing effects in high energy ion irradiated Fe/Si multilayers

    SciTech Connect

    Bauer, P.; Dufour, C.; Jaouen, C.; Marchal, G.; Pacaud, J.; Grilhe, J.; Jousset, J.C.

    1997-01-01

    M{umlt o}ssbauer spectroscopy ({sup 57}Fe) shows evidence for mixing effects induced by electronic energy deposition in nanoscale Fe/Si multilayers irradiated with swift heavy ions. A decrease in the mixing efficiency with electronic stopping power is reported; a threshold is found, under which iron environment modifications no longer occur. The kinetics of Fe{endash}Si phase formation after irradiation suggests the existence of three regimes: (i) for high excitation levels, a magnetic amorphous phase is formed directly in the wake of the incoming ion and an almost complete mixing is reached at low fluence (10{sup 13} U/cm{sup 2}); (ii) for low excitation levels, a paramagnetic Si-rich amorphous phase is favored at the interface while crystalline iron subsists at high fluences; (iii) for intermediate excitation levels, saturation effects are observed and the formation rate of both magnetic and paramagnetic phases points to direct mixing in the ion wake but with a reduced track length in comparison to U irradiation. The measured interfacial mixing cross section induced by electronic energy deposition suggests that a thermal diffusion process is mainly involved in addition to damage creation. {copyright} {ital 1997 American Institute of Physics.}

  9. Effects of prenatal irradiation with an accelerated heavy-ion beam on postnatal development in rats: II. Further study on neurophysiologic alterations

    NASA Astrophysics Data System (ADS)

    Wang, B.; Murakami, M.; Eguchi-Kasai, K.; Nojima, K.; Shang, Y.; Tanaka, K.; Watanabe, K.; Fujita, K.; Moreno, S. G.; Coffigny, H.; Hayata, I.

    Organogenesis is a highly radiosensitive period, study of prenatal exposure to high LET heavy ion beams on postnatal development is important for clarifying the radiation risk in space and promoting the evidence-based mechanism research. The effects from heavy ion irradiations are not well studied as those for low LET radiations such as X-rays in this field, even the ground-based investigations remain to be addressed. Using the Heavy Ion Medical Accelerator in Chiba (HIMAC) and Wistar rats, postnatal neurophysiological development in offspring was investigated following exposure of pregnant rats to accelerated neon-ion beams with a LET value of about 30 keV/μm at a dose range from 0.1 to 2.0 Gy on the 15th day of gestation. The age for appearance of four physiologic markers and attainment of five neonatal reflexes, and gain in body weight were monitored. Male offspring were evaluated as young adults using two behavioral tests including open field and hole-board dipping tests. The effects of X-rays at 200 kVp measured for the same biological end points were studied for comparison. For most of the endpoints at early age, significant neurophysiological alteration was observed even in offspring receiving 0.1 Gy of accelerated neon ions but not X-rays. All offspring receiving 2.0 Gy of accelerated neon ions died prior to weaning. Offspring prenatally irradiated with neon ions generally showed higher incidences of prenatal death, increased preweaning mortality, markedly delayed accomplishment in physiological markers and reflexes, significantly lower body weight and reduced ratios of main organ weight to body weight, and altered behavior compared to those exposed to X-rays at doses of 0.1 1.5 Gy. These findings indicate that irradiations with neon ions at 0.1 1.5 Gy on day 15 of gestation caused varied developmental alterations in offspring, and efficient dose leading to the detrimental effects seemed to be lower than that of X-rays.

  10. Comprehensive identification of mutations induced by heavy-ion beam irradiation in Arabidopsis thaliana.

    PubMed

    Hirano, Tomonari; Kazama, Yusuke; Ishii, Kotaro; Ohbu, Sumie; Shirakawa, Yuki; Abe, Tomoko

    2015-04-01

    Heavy-ion beams are widely used for mutation breeding and molecular biology. Although the mutagenic effects of heavy-ion beam irradiation have been characterized by sequence analysis of some restricted chromosomal regions or loci, there have been no evaluations at the whole-genome level or of the detailed genomic rearrangements in the mutant genomes. In this study, using array comparative genomic hybridization (array-CGH) and resequencing, we comprehensively characterized the mutations in Arabidopsis thaliana genomes irradiated with Ar or Fe ions. We subsequently used this information to investigate the mutagenic effects of the heavy-ion beams. Array-CGH demonstrated that the average number of deleted areas per genome were 1.9 and 3.7 following Ar-ion and Fe-ion irradiation, respectively, with deletion sizes ranging from 149 to 602,180 bp; 81% of the deletions were accompanied by genomic rearrangements. To provide a further detailed analysis, the genomes of the mutants induced by Ar-ion beam irradiation were resequenced, and total mutations, including base substitutions, duplications, in/dels, inversions, and translocations, were detected using three algorithms. All three resequenced mutants had genomic rearrangements. Of the 22 DNA fragments that contributed to the rearrangements, 19 fragments were responsible for the intrachromosomal rearrangements, and multiple rearrangements were formed in the localized regions of the chromosomes. The interchromosomal rearrangements were detected in the multiply rearranged regions. These results indicate that the heavy-ion beams led to clustered DNA damage in the chromosome, and that they have great potential to induce complicated intrachromosomal rearrangements. Heavy-ion beams will prove useful as unique mutagens for plant breeding and the establishment of mutant lines. PMID:25690092

  11. Combined effects of nuclear and electronic energy losses in solids irradiated with a dual-ion beam

    SciTech Connect

    Thome, Lionel; Debelle, Aurelien; Garrido, Frederico; Trocellier, Patrick; Serruys, Yves; Miro, Sandrine

    2013-04-08

    Single and dual-beam irradiations of oxide (c-ZrO{sub 2}, MgO, Gd{sub 2}Ti{sub 2}O{sub 7}) and carbide (SiC) single crystals were performed to study combined effects of nuclear (S{sub n}) and electronic (S{sub e}) energy losses. Rutherford backscattering experiments in channeling conditions show that the S{sub n}/S{sub e} cooperation induces a strong decrease of the irradiation-induced damage in SiC and MgO and almost no effects in c-ZrO{sub 2} and Gd{sub 2}Ti{sub 2}O{sub 7}. The healing process is ascribed to electronic excitations arising from the electronic energy loss of swift ions. These results present a strong interest for both fundamental understanding of the ion-solid interactions and technological applications in the nuclear industry where expected cooperative S{sub n}/S{sub e} effects may lead to the preservation of the integrity of nuclear devices.

  12. Studies on PAN-based carbon fibers irradiated by Ar+ ion beams.

    PubMed

    Park, Soo-Jin; Seo, Min-Kang; Kim, Hak-Yong; Lee, Douk-Rae

    2003-05-15

    In this work, the effects of Ar+ ion beam irradiation on carbon fibers were studied using tensile and surface analytical techniques. The single-fiber pull-out test was executed in order to characterize the fiber/epoxy matrix interfacial adhesion. The Ar+ ion beam was irradiated using an ion-assisted reaction (IAR) method in reactive gas conditions under an oxygen environment with 1 x 10(16) ions/cm(2) Ar+ ion dose (ID), 6 sccm blown gas flow rate, and different ion beam energy intensities. From the experimental results, both the interfacial shear strength (IFSS) and fracture toughness (Gi) were found to increase with increasing Ar+ ion irradiation intensity. This was probably due to the fact that Ar+ ion beam irradiation on carbon fibers was effective in altering their surface physical chemistry and structural morphology, resulting in improved interfacial adhesion in the fiber/epoxy matrix. The reliability of single-fiber pull-out test data could be improved by statistical analysis using the Weibull distribution, which served to predict the variation of the mechanical interfacial properties in a composite system. PMID:16256547

  13. 200 MeV Ag15+ ion beam irradiation effects on spray deposited 5 wt% `Li' doped V2O5 thin film

    NASA Astrophysics Data System (ADS)

    Kovendhan, M.; Joseph, D. Paul; Manimuthu, P.; Sendilkumar, A.; Asokan, K.; Venkateswaran, C.; Mohan, R.

    2016-05-01

    Lithium 5 wt% doped V2O5 thin film was deposited onto ITO substrate by spray pyrolysis technique. The substrate temperature was kept at 450 °C. 200 MeV Ag15+ ion beams at a fluence of 5×1012 ions/cm2 was irradiated on 5 wt% `Li' doped V2O5 film of thickness 1367 nm. The XRD pattern confirms that the pristine film is non stoichiometry with orthorhombic structure and upon irradiation the crystallinity decreased and an obvious textured growth along (020) plane is induced. Raman peak observed at 917 cm-1 is due to oxygen deficiency. Upon irradiation, the optical transparency and band gap of the film decreased. Electrical transport property study shows that the resistivity increased by one order for the irradiated film.

  14. Tailoring the properties of copper nanowires by ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Kumar, Narinder; Kumar, Rajesh; Kumar, Sushil; Chakarvarti, S. K.

    2016-02-01

    In the present paper, we investigated the change in the properties of copper nanowires under the irradiance of 80 MeV Si7+ ion beam. The nanowires were electrodeposited in the cylindrical pores of the track-etched polycarbonate membranes. The phase, morphology and optical absorbance of the fabricated nanowires were characterized by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and UV-visible spectroscopy, respectively. The XRD study showed a face centered cubic crystal structure of copper nanowires. Further measurements with FESEM revealed that nanowires were continuous, aligned with uniform diameter having high aspect ratio. The XRD spectra of irradiated nanowires indicated an improved crystalinity at low ion fluences while it declines at higher ion fluences. The optical absorbance properties of the irradiated copper nanowires were also examined. The absorption spectra exhibited a peak at 568 nm which was attributed to the surface plasmon resonance. A significant increase in absorbance after irradiation accounts for the possibility of defects formation. The electrical properties measured from I-V characteristics showed an increase in resistivity of irradiated nanowires.

  15. The response of the pyrochlore structure-type to ion-beam irradiation

    NASA Astrophysics Data System (ADS)

    Lian, Jie

    Pyrochlore with the general formula of A3+2B4+2O7 (Fd3m; Z = 8) has been proposed as the candidate waste form for the immobilization of actinides, particularly plutonium from dismantled nuclear weapons. Because actinides decay by alpha-decay events, radiation effects on the waste form are a concern. The effects of radiation on different pyrochlore compositions, A2B2O7 (A = La ˜ Lu, and Y; B = Ti, Sn, and Zr), have been investigated by 50 KeV He+, 600 KeV Ar+, 1.0 MeV Kr+, and 1.5 MeV Xe+ ion irradiations. Titanate pyrochlores are generally sensitive to ion beam damage and can be amorphized at a low damage level (˜0.2 dpa). The critical amorphization temperature, Tc, increases from ˜480 to ˜1120 K with increasing A-site cation size. A dramatically increasing radiation "resistance" to ion beam induced-amorphization has been observed with increasing Zr-content in the Gd2Ti2-xZrxO7 system. The pure end-member, Gd2Zr2O7, cannot be amorphized, even at doses as high as ˜100 dpa. Although zirconate pyrochlores are generally considered to be radiation "resistant", ion beam-induced amorphization occurs for La2Zr2O7 at a dose of ˜5.5 dpa at room temperature. Stannate pyrochlores A2Sn 2O7 (A = La, Nd, Gd) are readily amorphized by ion beam damage at a relatively low dose (˜1 dpa) at room temperature; while no evidence of amorphization has been observed in A2Sn2O7 (A = Er, Y, Lu) irradiated with 1 MeV Kr+ ions at a dose of ˜6 dpa at 25 K. The factors that influence the response of different pyrochlore compositions to ion irradiation-induced amorphization are discussed in terms of cation radius ratio, defect formation energies, and the tendency of the pyrochlore structure-type to undergo an order-disorder transition to the defect-fluorite structure. The "resistance" of the pyrochlore structure to ion beam-induced amorphization is not only affected by the relative sizes of the A- and B-site cations, but also the cation electronic configurations. Pyrochlore compositions

  16. Crystal-amorphous-silicon interface kinetics under ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Priolo, F.; La Ferla, A.; Spinella, C.; Rimini, E.; Campisano, S. U.; Ferla, G.

    1990-01-01

    Our recent work on ion-beam-assisted epitaxial growth of amorphous Si layers on single crystal substrates is reviewed. The crystallization was induced by a 600 keV Kr2+ beam at a dose rate of 1×1012/cm2 · s. During irradiations the samples were mounted on a resistively heated copper block whose temperature was maintained constant in the range 250-450°C. The planar motion of the crystal-amorphous interface was monitored in situ by dynamic reflectivity measurements. This technique allows the ion-induced growth rate to be measured with a very high precision. We have observed that this growth rate scales linearly with the energy deposited into elastic collisions at the crystal-amorphous interface by the impinging ions. Moreover, the rate shows an Arrhenius temperature dependence with a well defined activation energy of 0.32±0.05 eV. The dependence of this process on substrate orientation and on impurities either dissolved in the amorphous layer or present at very high concentration at the crystal-amorphous interface is also discussed.

  17. Crystal-amorphous-silicon interface kinetics under ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Priolo, F.; La Ferla, A.; Spinella, C.; Rimini, E.; Campisano, S. U.; Ferla, G.

    1989-11-01

    Our recent work on ion-beam-assisted epitaxial growth of amorphous Si layers on single crystal substrates is reviewed. The crystallization was induced by a 600 keV Kr 2+ beam at a dose rate of 1×10 12/cm 2 · s. During irradiations the samples were mounted on a resistively heated copper block whose temperature was maintained constant in the range 250-450°C. The planar motion of the crystal-amorphous interface was monitored in situ by dynamic reflectivity measurements. This technique allows the ion-induced growth rate to be measured with a very high precision. We have observed that this growth rate scales linearly with the energy deposited into elastic collisions at the crystal-amorphous interface by the impinging ions. Moreover, the rate shows an Arrhenius temperature dependence with a well defined activation energy of 0.32±0.05 eV. The dependence of this process on substrate orientation and on impurities either dissolved in the amorphous layer or present at very high concentration at the crystal-amorphous interface is also discussed.

  18. Formation of long-range ordered quantum dots arrays in amorphous matrix by ion beam irradiation

    SciTech Connect

    Buljan, M.; Bogdanovic-Radovic, I.; Karlusic, M.; Desnica, U. V.; Radic, N.; Dubcek, P.; Drazic, G.; Salamon, K.; Bernstorff, S.; Holy, V.

    2009-08-10

    We demonstrate the production of a well ordered three-dimensional array of Ge quantum dots in amorphous silica matrix. The ordering is achieved by ion beam irradiation and annealing of a multilayer film. Structural analysis shows that quantum dots nucleate along the direction of the ion beam used for irradiation, while the mutual distance of the quantum dots is determined by the diffusion properties of the multilayer material rather than the distances between traces of ions that are used for irradiation.

  19. Effect of O{sub 2}{sup +}, H{sub 2}{sup +}+ O{sub 2}{sup +}, and N{sub 2}{sup +}+ O{sub 2}{sup +} ion-beam irradiation on the field emission properties of carbon nanotubes

    SciTech Connect

    Acuna, J. J. S.; Alvarez, F.; Escobar, M.; Goyanes, S. N.; Candal, R. J.; Zanatta, A. R.

    2011-06-01

    The effect of O{sub 2}{sup +}, H{sub 2}{sup +}+ O{sub 2}{sup +}, and N{sub 2}{sup +}+ O{sub 2}{sup +} ion-beam irradiation of carbon nanotubes (CNTs) films on the chemical and electronic properties of the material is reported. The CNTs were grown by the chemical vapor deposition technique (CVD) on silicon TiN coated substrates previously decorated with Ni particles. The Ni decoration and TiN coating were successively deposited by ion-beam assisted deposition (IBAD) and afterwards the nanotubes were grown. The whole deposition procedure was performed in situ as well as the study of the effect of ion-beam irradiation on the CNTs by x-ray photoelectron spectroscopy (XPS). Raman scattering, field-effect emission gun scanning electron microscopy (FEG-SEM), and field emission (FE) measurements were performed ex situ. The experimental data show that: (a) the presence of either H{sub 2}{sup +} or N{sub 2}{sup +} ions in the irradiation beam determines the oxygen concentration remaining in the samples as well as the studied structural characteristics; (b) due to the experimental conditions used in the study, no morphological changes have been observed after irradiation of the CNTs; (c) the FE experiments indicate that the electron emission from the CNTs follows the Fowler-Nordheim model, and it is dependent on the oxygen concentration remaining in the samples; and (d) in association with FE results, the XPS data suggest that the formation of terminal quinone groups decreases the CNTs work function of the material.

  20. Effect of high-energy electron-beam irradiation on the optical properties of ion-beam-sputtered silicon oxynitride thin films.

    PubMed

    Karanth, Shivaprasad; Shanbhogue, Ganesh H; Nagendra, C L

    2005-10-10

    Silicon oxynitride thin films are prepared by ion-beam sputtering, and the optical properties and surface chemical composition are studied by spectrophotometric and x-ray photoelectron spectroscopy, respectively. It is seen that the films sputtered by use of nitrogen alone as the sputtering species from a silicon nitride target are completely transparent (k < 0.005) and have a refractive-index dispersion from 1.85 to 1.71 over the visible and near-infrared spectral regions, and the films show distinct spectral lines that are due to silicon, Si(2s), nitrogen, N(1s), and oxygen, O(1s). Sputter deposition of argon and of argon and nitrogen produces silicon-rich silicon oxynitride films that are absorbent and have high refractive indices. These films have a direct electronic transition, with a threshold energy of 1.75 eV. Electron irradiation transforms optically transparent silicon oxynitride films into silicon-rich silicon oxynitride films that have higher refractive indices and are optically absorbing owing to the presence of nonsaturated silicon in the irradiated films. The degradation in current responsivity of silicon photodetectors, under electron irradiation, is within 3% over the wavelength region from 450 to 750 nm, which is entirely due to the degradation of optical properties of silicon oxynitride antireflection coatings. PMID:16237933

  1. Characterization of polymeric films subjected to lithium ion beam irradiation

    SciTech Connect

    Gary S. Groenewold; W. Roger Cannon; Paul A. Lessing; Recep Avci; Muhammedin Deliorman; Mark Wolfenden; Doug W. Akers; J. Keith Jewell

    2013-02-01

    Two different polymeric materials that are candidate materials for use as binders for mixed uranium–plutonium oxide nuclear fuel pellets were subjected to Li ion beam irradiation, in order to simulate intense alpha irradiation. The materials (a polyethylene glycol 8000 and a microcrystalline wax) were then analyzed using a combination of mass spectrometry (MS) approaches and X-ray photoelectron spectroscopy (XPS). Samples of the irradiated PEG materials were dissolved in H2O and then analyzed using electrospray ionization-MS, which showed the formation of a series of small oligomers in addition to intact large PEG oligomers. The small oligomers were likely formed by radiation-induced homolytic scissions of the C–O and C–C bonds, which furnish radical intermediates that react by radical recombination with Hradical dot and OHradical dot. Surface analysis using SIMS revealed a heterogeneous surface that contained not only PEG-derived polymers, but also hydrocarbon-based entities that are likely surface contaminants. XPS of the irradiated PEG samples indicated the emergence of different carbon species, with peak shifts suggesting the presence of sp2 carbon atoms. Analysis of the paraffinic film using XPS showed the emergence of oxygen on the surface of the sample, and also a broadening and shifting of the C1s peak, demonstrating a change in the chemistry on the surface. The paraffinic film did not dissolve in either H2O or a H2O–methanol solution, and hence the bulk of the material could not be analyzed using electrospray. However a series of oligomers was leached from the bulk material that produced ion series in the ESI-MS analyses that were identified octylphenyl ethoxylate oligomers. Upon Li ion bombardment, these shifted to a lower average molecular weight, but more importantly showed the emergence of three new ion series that are being formed as a result of radiation damage. Surface analysis of the paraffinic polymers using SIMS produced spectra that were

  2. Characterization of polymeric films subjected to lithium ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Groenewold, Gary S.; Cannon, W. Roger; Lessing, Paul A.; Avci, Recep; Deliorman, Muhammedin; Wolfenden, Mark; Akers, Doug W.; Jewell, J. Keith; Zuck, Larry D.

    2013-02-01

    Two different polymeric materials that are candidate materials for use as binders for mixed uranium-plutonium oxide nuclear fuel pellets were subjected to Li ion beam irradiation, in order to simulate intense alpha irradiation. The materials (a polyethylene glycol 8000 and a microcrystalline wax) were then analyzed using a combination of mass spectrometry (MS) approaches and X-ray photoelectron spectroscopy (XPS). Samples of the irradiated PEG materials were dissolved in H2O and then analyzed using electrospray ionization-MS, which showed the formation of a series of small oligomers in addition to intact large PEG oligomers. The small oligomers were likely formed by radiation-induced homolytic scissions of the C-O and C-C bonds, which furnish radical intermediates that react by radical recombination with Hrad and OHrad . Surface analysis using SIMS revealed a heterogeneous surface that contained not only PEG-derived polymers, but also hydrocarbon-based entities that are likely surface contaminants. XPS of the irradiated PEG samples indicated the emergence of different carbon species, with peak shifts suggesting the presence of sp2 carbon atoms. Analysis of the paraffinic film using XPS showed the emergence of oxygen on the surface of the sample, and also a broadening and shifting of the C1s peak, demonstrating a change in the chemistry on the surface. The paraffinic film did not dissolve in either H2O or a H2O-methanol solution, and hence the bulk of the material could not be analyzed using electrospray. However a series of oligomers was leached from the bulk material that produced ion series in the ESI-MS analyses that were identified octylphenyl ethoxylate oligomers. Upon Li ion bombardment, these shifted to a lower average molecular weight, but more importantly showed the emergence of three new ion series that are being formed as a result of radiation damage. Surface analysis of the paraffinic polymers using SIMS produced spectra that were wholly dominated by

  3. Study of phase transitions in NbN ultrathin films under composite ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Prikhodko, K.; Gurovich, B.; Dement'eva, M.

    2016-04-01

    This work demonstrates implementation of Selective Displacement of Atoms (SDA) technique to change the crystal structure and atomic composition of thin superconductive film of NbN under low dose composite ion beam irradiation. All structure investigations were performed using High Resolution Transmission Electron Microscopy (HRTEM) technique by the analysis of Fourier transformation of bright field HRTEM images. It was found that composite ion beam irradiation induces the formation of niobium oxynitrides phases.

  4. A reorbiter for large GEO debris objects using ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Kitamura, Shoji; Hayakawa, Yukio; Kawamoto, Satomi

    2014-02-01

    In recent years, space debris problems have become very serious. The worst case occurs in the low Earth orbit (LEO) region, where debris-to-debris collisions generate new debris. The situation in the geostationary orbit (GEO) region is not as bad as that in the LEO. The debris problem in the GEO region, however, should not be left as it is because the GEO is unique and has few debris-cleansing modes. Thus, we proposed a concept for a reorbiter to reorbit large GEO debris objects such as satellites and rocket upper stages left in orbit after the ends of their missions. This concept is based on the idea of thrusting a debris object by irradiating it with an ion beam. The reorbiter, equipped with two ion engines, approaches a debris object, and the ion beam exhausted from one of the ion engines irradiates and thrusts it to change its orbit. The other engine on the opposite side is operated so that the reorbiter follows the debris object. Their orbits are raised in a spiral to a disposal orbit approximately 300 km higher. After that, the reorbiter returns to GEO to approach another debris object. This system can operate without catching debris objects; thus, it can be applied to a wide range of debris objects without regard to their shapes or rotations. A mission scenario was made to conduct efficient maneuvers. In the GEO region, a number of debris objects are distributed on orbit planes close to each other, and they can be reorbited one after another using a single reorbiter. For a typical model mission, the mission time and the total impulse of the ion engines were calculated. The results show that six debris objects can be reorbited in 170 days. The reorbiter has a targeted launch mass of 2500 kg and 6.9 kW of total power. The ion beam convergence, the effects of ion beam irradiation, and non-cooperative rendezvous were recognized as the critical issues of this system. A highly converged beam is required to make efficient debris irradiation. Numerical calculations

  5. Wide variety of flower-color and -shape mutants regenerated from leaf cultures irradiated with ion beams

    NASA Astrophysics Data System (ADS)

    Okamura, M.; Yasuno, N.; Ohtsuka, M.; Tanaka, A.; Shikazono, N.; Hase, Y.

    2003-05-01

    The efficiency of ion-beam irradiation combined with tissue culture in obtaining floral mutants was investigated and compared with those of gamma rays and X-rays in carnation. Leaf segments of carnation plants in vitro were irradiated with the 220 MeV carbon ions, and cultured till the shoot regenerated. The carbon ion had the highest effect in reducing the regeneration frequency, and the RBE value with respect to gamma-rays was four. The higher mutation frequency and the wider mutation spectrum were obtained in plants irradiated with the carbon ions than low LET radiations. Three new carnation varieties developed by ion-beam irradiation were applied for the registration of the Japanese Ministry of Agriculture, Forestry and Fisheries. The results indicate that ion beam irradiation could induce wide variety of flower-color and -shape mutants, and that the combined method of ion-beam irradiation with tissue culture is useful to obtain the commercial varieties in a short time.

  6. Magnetic modification at sub-surface of FeRh bulk by energetic ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Koide, T.; Uno, H.; Sakane, H.; Sakamaki, M.; Amemiya, K.; Iwase, A.; Matsui, T.

    2015-05-01

    Ferromagnetic layered structure has been made at sub-surface of the antiferromagnetic FeRh bulk samples by high energy He ion beam irradiation. In accordance with the Transport of Ions in Matter simulation, such ion beam can effectively deposit the elastic collision energy in several μm regions in the depth from the surface. Measurement with a superconducting quantum interference device reveals the irradiated samples to be ferromagnetic. Assuming that only the part the energy deposited can be modified to be ferromagnetic, the corresponding irradiation induced magnetization is consistent with the data that we previously reported. On the other hand, the X-ray magnetic circular dichroism (XMCD) spectra for the irradiated samples are totally unchanged as those for the unirradiated samples. Since XMCD signal in total emission yield method is considered to be surface sensitive with a typical probing depth of several nm, the surface magnetic state is maintained to be antiferromagnetic. By utilizing these phenomena, three-dimensional magnetic patterning of FeRh can be realized, which may potentially be used for future magnetic exchange device application such as nano-scale sensors and memories.

  7. Magnetic modification at sub-surface of FeRh bulk by energetic ion beam irradiation

    SciTech Connect

    Koide, T.; Iwase, A.; Uno, H.; Sakane, H.; Sakamaki, M.; Amemiya, K.; Matsui, T.

    2015-05-07

    Ferromagnetic layered structure has been made at sub-surface of the antiferromagnetic FeRh bulk samples by high energy He ion beam irradiation. In accordance with the Transport of Ions in Matter simulation, such ion beam can effectively deposit the elastic collision energy in several μm regions in the depth from the surface. Measurement with a superconducting quantum interference device reveals the irradiated samples to be ferromagnetic. Assuming that only the part the energy deposited can be modified to be ferromagnetic, the corresponding irradiation induced magnetization is consistent with the data that we previously reported. On the other hand, the X-ray magnetic circular dichroism (XMCD) spectra for the irradiated samples are totally unchanged as those for the unirradiated samples. Since XMCD signal in total emission yield method is considered to be surface sensitive with a typical probing depth of several nm, the surface magnetic state is maintained to be antiferromagnetic. By utilizing these phenomena, three-dimensional magnetic patterning of FeRh can be realized, which may potentially be used for future magnetic exchange device application such as nano-scale sensors and memories.

  8. Electron-Cloud Effects on Heavy-Ion Beams

    SciTech Connect

    Azevedo, T; Friedman, A; Cohen, R; Vay, J

    2004-03-29

    Stray electrons can be introduced in positive-charge accelerators for heavy ion fusion (or other applications) as a result of ionization of ambient gas or gas released from walls due to halo-ion impact, or as a result of secondary-electron emission. We are developing a capability for self-consistent simulation of ion beams with the electron clouds they produce. We report on an ingredient in this capability, the effect of specified electron cloud distributions on the dynamics of a coasting ion beam. We consider here electron distributions with axially varying density, centroid location, or radial shape, and examine both random and sinusoidally varying perturbations. We find that amplitude variations are most effective in spoiling ion beam quality, though for sinusoidal variations which match the natural ion beam centroid oscillation or breathing mode frequencies, the centroid and shape perturbations can also be effective. We identify a possible instability associated with resonance with the beam-envelope ''breathing'' mode. One conclusion from this study is that heavy-ion beams are surprisingly robust to electron clouds, compared to a priori expectations.

  9. Structural Modification of Single Wall and Multiwalled Carbon Nanotubes under Carbon, Nickel and Gold Ion Beam Irradiation

    SciTech Connect

    Jeet, Kiran; Jindal, V. K.; Dharamvir, Keya; Bharadwaj, L. M.

    2011-12-12

    Thin film samples of carbon nanotubes were irradiated with ion beam of carbon, nickel and gold. The irradiation results were characterized using Raman Spectroscopy. Modifications of the disorder mode (D mode) and the tangential mode (G mode) under different irradiation fluences were studied in detail. Raman results of carbon ion beam indicate the interesting phenomenon of ordering of the system under irradiation. Under the effect of nickel and gold ion irradiation, the structural evolution of CNTs occurs in three different stages. At lower fluences the process of healing occurs; at intermediate fluences damages on the surface of CNTs occurs and finally at very high fluences of the order of 1x10{sup 14} ions/cm{sup 2} the system gets amorphised.

  10. Large scale silver nanowires network fabricated by MeV hydrogen (H+) ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Honey, S.; Naseem, S.; Ishaq, A.; Maaza, M.; Bhatti, M. T.; Wan, D.

    2016-04-01

    A random two-dimensional large scale nano-network of silver nanowires (Ag-NWs) is fabricated by MeV hydrogen (H+) ion beam irradiation. Ag-NWs are irradiated under H+ ion beam at different ion fluences at room temperature. The Ag-NW network is fabricated by H+ ion beam-induced welding of Ag-NWs at intersecting positions. H+ ion beam induced welding is confirmed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Moreover, the structure of Ag NWs remains stable under H+ ion beam, and networks are optically transparent. Morphology also remains stable under H+ ion beam irradiation. No slicings or cuttings of Ag-NWs are observed under MeV H+ ion beam irradiation. The results exhibit that the formation of Ag-NW network proceeds through three steps: ion beam induced thermal spikes lead to the local heating of Ag-NWs, the formation of simple junctions on small scale, and the formation of a large scale network. This observation is useful for using Ag-NWs based devices in upper space where protons are abandoned in an energy range from MeV to GeV. This high-quality Ag-NW network can also be used as a transparent electrode for optoelectronics devices. Project supported by the National Research Foundation of South Africa (NRF), the French Centre National pour la Recherche Scientifique, iThemba-LABS, the UNESCO-UNISA Africa Chair in Nanosciences & Nanotechnology, the Third World Academy of Science (TWAS), Organization of Women in Science for the Developing World (OWSDW), the Abdus Salam ICTP via the Nanosciences African Network (NANOAFNET), and the Higher Education Commission (HEC) of Pakistan.

  11. Producing metastable nanophase with sharp interface by means of focused ion beam irradiation

    SciTech Connect

    Barna, Arpad; Kotis, Laszlo; Labar, Janos; Osvath, Zoltan; Toth, Attila L.; Menyhard, Miklos; Zalar, Anton; Panjan, Peter

    2009-02-15

    Amorphous carbon/nickel double layers were irradiated by 30 keV Ga{sup +} ions via focused ion beam. The effect of irradiation on the concentration distribution of all constituents was studied by Auger electron spectroscopy depth profiling and cross sectional transmission electron microscopy, while the morphology change of the sample was determined by atomic force microscopy. The Ga{sup +} ion irradiation results in the formation of metastable Ni{sub 3}C layer with a uniform thickness. The C/Ni{sub 3}C and Ni{sub 3}C/Ni interfaces were found to be sharp up to a fluence of 200 Ga{sup +} ions/nm{sup 2}.

  12. Effects of electron irradiation on the ferroelectric 180 deg. in-plane nanostripe domain structure in a thin film prepared from a bulk single crystal of BaTiO{sub 3} by focused ion beam

    SciTech Connect

    Matsumoto, Takao; Okamoto, Masakuni

    2011-01-01

    Effects of electron irradiation on the ferroelectric 180 deg. in-plane nanostripe domain structure in a thin film prepared from a bulk single crystal of BaTiO{sub 3} by focused ion beam were studied. The domain structure transformed into a characteristic 90 deg. in-plane nanostripe domain structure under intense electron irradiation. In particular, an unconventional triangular 90 deg. in-plane nanostripe domain structure was observed. Polarization analysis suggests the existence of an incomplete or half tetradomain vortex at the boundary of the triangular domain structure. Together with the help of phase-field simulations using time-dependent Ginzburg-Landau equations, it is suggested that such a domain structure is created by an anisotropic in-plane electric field, which is plausibly induced by an anisotropic interaction of the incident electron beam with the ferroelectric material.

  13. Development of an Ion Beam Irradiation System for Liquid Crystal Alignment Layer Production

    SciTech Connect

    Matsumoto, Takeshi; Kinoshita, Yuko; Tanii, Masahiro; Tatemichi, Junichi; Konishi, Masashi; Naito, Masao

    2008-11-03

    Ion beam irradiation was employed to produce alignment layers for liquid crystal (LC) displays. The alignment characteristics were compared with those by the conventional rubbing method. Ion incident angle to the films played an important role in LC sample optical qualities. A new ion irradiation method to realize a multi-domain structure for a wide viewing angle was demonstrated.

  14. Linear Energy Transfer-Dependent Change in Rice Gene Expression Profile after Heavy-Ion Beam Irradiation.

    PubMed

    Ishii, Kotaro; Kazama, Yusuke; Morita, Ryouhei; Hirano, Tomonari; Ikeda, Tokihiro; Usuda, Sachiko; Hayashi, Yoriko; Ohbu, Sumie; Motoyama, Ritsuko; Nagamura, Yoshiaki; Abe, Tomoko

    2016-01-01

    A heavy-ion beam has been recognized as an effective mutagen for plant breeding and applied to the many kinds of crops including rice. In contrast with X-ray or γ-ray, the heavy-ion beam is characterized by a high linear energy transfer (LET). LET is an important factor affecting several aspects of the irradiation effect, e.g. cell survival and mutation frequency, making the heavy-ion beam an effective mutagen. To study the mechanisms behind LET-dependent effects, expression profiling was performed after heavy-ion beam irradiation of imbibed rice seeds. Array-based experiments at three time points (0.5, 1, 2 h after the irradiation) revealed that the number of up- or down-regulated genes was highest 2 h after irradiation. Array-based experiments with four different LETs at 2 h after irradiation identified LET-independent regulated genes that were up/down-regulated regardless of the value of LET; LET-dependent regulated genes, whose expression level increased with the rise of LET value, were also identified. Gene ontology (GO) analysis of LET-independent up-regulated genes showed that some GO terms were commonly enriched, both 2 hours and 3 weeks after irradiation. GO terms enriched in LET-dependent regulated genes implied that some factor regulates genes that have kinase activity or DNA-binding activity in cooperation with the ATM gene. Of the LET-dependent up-regulated genes, OsPARP3 and OsPCNA were identified, which are involved in DNA repair pathways. This indicates that the Ku-independent alternative non-homologous end-joining pathway may contribute to repairing complex DNA legions induced by high-LET irradiation. These findings may clarify various LET-dependent responses in rice. PMID:27462908

  15. Linear Energy Transfer-Dependent Change in Rice Gene Expression Profile after Heavy-Ion Beam Irradiation

    PubMed Central

    Ishii, Kotaro; Kazama, Yusuke; Morita, Ryouhei; Hirano, Tomonari; Ikeda, Tokihiro; Usuda, Sachiko; Hayashi, Yoriko; Ohbu, Sumie; Motoyama, Ritsuko; Nagamura, Yoshiaki; Abe, Tomoko

    2016-01-01

    A heavy-ion beam has been recognized as an effective mutagen for plant breeding and applied to the many kinds of crops including rice. In contrast with X-ray or γ-ray, the heavy-ion beam is characterized by a high linear energy transfer (LET). LET is an important factor affecting several aspects of the irradiation effect, e.g. cell survival and mutation frequency, making the heavy-ion beam an effective mutagen. To study the mechanisms behind LET-dependent effects, expression profiling was performed after heavy-ion beam irradiation of imbibed rice seeds. Array-based experiments at three time points (0.5, 1, 2 h after the irradiation) revealed that the number of up- or down-regulated genes was highest 2 h after irradiation. Array-based experiments with four different LETs at 2 h after irradiation identified LET-independent regulated genes that were up/down-regulated regardless of the value of LET; LET–dependent regulated genes, whose expression level increased with the rise of LET value, were also identified. Gene ontology (GO) analysis of LET-independent up-regulated genes showed that some GO terms were commonly enriched, both 2 hours and 3 weeks after irradiation. GO terms enriched in LET-dependent regulated genes implied that some factor regulates genes that have kinase activity or DNA-binding activity in cooperation with the ATM gene. Of the LET-dependent up-regulated genes, OsPARP3 and OsPCNA were identified, which are involved in DNA repair pathways. This indicates that the Ku-independent alternative non-homologous end-joining pathway may contribute to repairing complex DNA legions induced by high-LET irradiation. These findings may clarify various LET-dependent responses in rice. PMID:27462908

  16. Application of ion beam irradiated ePTFE to repair small vessel injuries

    NASA Astrophysics Data System (ADS)

    Takahashi, N.; Suzuki, Y.; Ujiie, H.; Hori, T.; Iwaki, M.; Yamada, T.

    2007-04-01

    In surgery, bleeding from small injured vessels often requires prompt hemostasis without occlusion. This study evaluated the usefulness of 0.06 mm thick ion beam irradiated ePTFE sheets to repair small holes in vessels. Both surfaces of ePTFE sheets were irradiated with a 150 keV-Ar+ beam with fluences of 5 × 1014 ions/cm2. A small hole up to 2 mm in diameter was created in the common carotid artery of a rabbit. The defect was wrapped with an ion beam irradiated or non-irradiated ePTFE sheet. Fibrin glue was used to fix the ePTFE sheets to the common carotid artery. Hemostasis was instantly obtained with ion beam irradiated ePTFE but was rather difficult when using a non-irradiated ePTFE sheet. Three weeks after implantation, no occlusion was observed. Histological examination showed that the ePTFE sheets functioned as a scaffold for vessel wall regeneration. Thin ion beam irradiated ePTFE would be useful in vascular surgery.

  17. Fabricating high-density magnetic storage elements by low-dose ion beam irradiation

    SciTech Connect

    Neb, R.; Sebastian, T.; Pirro, P.; Hillebrands, B.; Pofahl, S.; Schaefer, R.; Reuscher, B.

    2012-09-10

    We fabricate magnetic storage elements by irradiating an antiferromagnetically coupled ferromagnetic/nonmagnetic/ferromagnetic trilayer by a low-dose ion beam. The irradiated areas become ferromagnetically coupled and are capable of storing information if their size is small enough. We employ Fe/Cr/Fe trilayers and a 30 keV focused Ga{sup +}-ion beam to demonstrate the working principle for a storage array with a bit density of 7 Gbit/in.{sup 2}. Micromagnetic simulations suggest that bit densities of at least two magnitudes of order larger should be possible.

  18. Recovery effects due to the interaction between nuclear and electronic energy losses in SiC irradiated with a dual-ion beam

    NASA Astrophysics Data System (ADS)

    Thomé, Lionel; Velisa, Gihan; Miro, Sandrine; Debelle, Aurélien; Garrido, Frédérico; Sattonnay, Gaël; Mylonas, Stamatis; Trocellier, Patrick; Serruys, Yves

    2015-03-01

    Single and dual-beam ion irradiations of silicon carbide (SiC) were performed to study possible Synergetic effects between Nuclear (Sn) and Electronic (Se) Energy Losses. Results obtained combining Rutherford backscattering in channeling conditions, Raman spectroscopy, and transmission electron microscopy techniques show that dual-beam irradiation of SiC induces a dramatic change in the final sample microstructure with a substantial decrease of radiation damage as compared to single-beam irradiation. Actually, a defective layer containing dislocations is formed upon dual-beam irradiation (Sn&Se), whereas single low-energy irradiation (Sn alone) or even sequential (Sn + Se) irradiations lead to full amorphization. The healing process is ascribed to the electronic excitation arising from the electronic energy loss of swift ions. These results shed new light on the long-standing puzzling problem of the existence of a possible synergy between Sn and Se in ion-irradiation experiments. This work is interesting for both fundamental understanding of the ion-solid interactions and technological applications in the nuclear industry where recovery Sn/Se effects may preserve the integrity of nuclear devices.

  19. Dual ion beam irradiation of polymeric materials for the modification of optical properties with improved adhesion

    NASA Astrophysics Data System (ADS)

    Park, Jae-Won; Lee, Eal H.; Lee, Jae-Sang; Lee, Byung-hoon; Kim, Min-kyu; Lee, Chan-Young; Kim, Hyung-jin; Choi, Byung-Ho

    2012-06-01

    Metallic (chromium) coating has often been applied on the surface of polymeric components, mainly to improve their appearance with a metallic luster and to protect from degradation under UV and visible light. However, the toxic nature of hexavalent chromium and delamination problems are an increasing concern in the plating industry. A similar metallic luster and the UV-visible light protection can be achieved by treating the surface of polymers by ion beams. However, a degradation by weathering including cracks, loss of glossiness, blistering, and eventual delamination have been problematic for ion beam processed polymers, particularly with a single ion beam irradiation. The main cause of adhesion failure is the abrupt change in material properties at the interface between coating and polymer or ion beam treated surface and the underlying untreated bulk polymer. In this work, therefore, a method is developed that improves adhesion by producing a graded interface by employing a dual ion beam processing. For demonstration purposes in this work, polycarbonate/acrylonitrile butadiene styrene blends were irradiated first with nitrogen ions followed by helium ions, achieving the desired metallic luster with improved adhesion. The experimental findings are explained in light of the stopping range of ions in materials and their interaction mechanisms with polymeric materials.

  20. Modifications of optical properties of PC/ABS by dual ions beam irradiation

    NASA Astrophysics Data System (ADS)

    Park, Jae-Won; Lee, Jae-Sang; Lee, Byung-hoon; Kim, Min-kyu; Moon, Byung-Sik; Lee, Chan-Young; Choi, Byung-Ho

    2013-03-01

    Polycarbonate (PC)/acrylonitrile butadien styrene (ABS) blends used in the inner parts of automobiles require a glossy and metallic colored optical property. Such a surface can be produced by ion beam irradiation, but the surface treated by a single ion species irradiation tends to be degraded upon a long term exposure under UV and visible lights, which includes the loss of glossiness and the delamination of the irradiated layer. Such degradations can be prevented or greatly reduced by a combined irradiation of heavy and light ions such as N and He ions. This may be attributable to a graded interface between the irradiation affected layer and the base materials by overlapping penetration depths of the heavy and light ions. This work is motivated by an effort to substitute the conventional Cr plating process with the ion beam process in the automobile industry.

  1. Focused Ion Beam Induced Effects on MOS Transistor Parameters

    SciTech Connect

    Abramo, Marsha T.; Antoniou, Nicholas; Campbell, Ann N.; Fleetwood, Daniel M.; Hembree, Charles E.; Jessing, Jeffrey R.; Soden, Jerry M.; Swanson, Scot E.; Tangyunyong, Paiboon; Vanderlinde, William E.

    1999-07-28

    We report on recent studies of the effects of 50 keV focused ion beam (FIB) exposure on MOS transistors. We demonstrate that the changes in value of transistor parameters (such as threshold voltage, V{sub t}) are essentially the same for exposure to a Ga+ ion beam at 30 and 50 keV under the same exposure conditions. We characterize the effects of FIB exposure on test transistors fabricated in both 0.5 {micro}m and 0.225 {micro}m technologies from two different vendors. We report on the effectiveness of overlying metal layers in screening MOS transistors from FIB-induced damage and examine the importance of ion dose rate and the physical dimensions of the exposed area.

  2. Emulation of reactor irradiation damage using ion beams

    DOE PAGESBeta

    Was, G. S.; Jiao, Z.; Getto, E.; Sun, K.; Monterrosa, A. M.; Maloy, S. A.; Anderoglu, O.; Sencer, B. H.; Hackett, M.

    2014-06-14

    The continued operation of existing light water nuclear reactors and the development of advanced nuclear reactor depend heavily on understanding how damage by radiation to levels degrades materials that serve as the structural components in reactor cores. The first high dose ion irradiation experiments on a ferritic-martensitic steel showing that ion irradiation closely emulates the full radiation damage microstructure created in-reactor are described. Ferritic-martensitic alloy HT9 (heat 84425) in the form of a hexagonal fuel bundle duct (ACO-3) accumulated 155 dpa at an average temperature of 443°C in the Fast Flux Test Facility (FFTF). Using invariance theory as a guide,more » irradiation of the same heat was conducted using self-ions (Fe++) at 5 MeV at a temperature of 460°C and to a dose of 188 displacements per atom. The void swelling was nearly identical between the two irradiation and the size and density of precipitates and loops following ion irradiation are within a factor of two of those for neutron irradiation. The level of agreement across all of the principal microstructure changes between ion and reactor irradiation establishes the capability of tailoring ion irradiation to emulate the reactor-irradiated microstructure.« less

  3. Emulation of reactor irradiation damage using ion beams

    SciTech Connect

    Was, G. S.; Jiao, Z.; Getto, E.; Sun, K.; Monterrosa, A. M.; Maloy, S. A.; Anderoglu, O.; Sencer, B. H.; Hackett, M.

    2014-06-14

    The continued operation of existing light water nuclear reactors and the development of advanced nuclear reactor depend heavily on understanding how damage by radiation to levels degrades materials that serve as the structural components in reactor cores. The first high dose ion irradiation experiments on a ferritic-martensitic steel showing that ion irradiation closely emulates the full radiation damage microstructure created in-reactor are described. Ferritic-martensitic alloy HT9 (heat 84425) in the form of a hexagonal fuel bundle duct (ACO-3) accumulated 155 dpa at an average temperature of 443°C in the Fast Flux Test Facility (FFTF). Using invariance theory as a guide, irradiation of the same heat was conducted using self-ions (Fe++) at 5 MeV at a temperature of 460°C and to a dose of 188 displacements per atom. The void swelling was nearly identical between the two irradiation and the size and density of precipitates and loops following ion irradiation are within a factor of two of those for neutron irradiation. The level of agreement across all of the principal microstructure changes between ion and reactor irradiation establishes the capability of tailoring ion irradiation to emulate the reactor-irradiated microstructure.

  4. Zenithal alignment of liquid crystal on homeotropic polyimide film irradiated by ion beam.

    PubMed

    Choi, Yoonseuk; Yoon, Tae-Hoon; Kwon, Jin Hyuk; Yi, Jonghoon; Gwag, Jin Seog

    2012-01-01

    We investigate the pretilt characteristics of a nematic liquid crystal [LC] in terms of ion beam exposure conditions on the homeotropic polyimide alignment layer. The pretilt angle of LCs in the case of high-energy ion beam treatment was decreased considerably almost the same to that of the homogenous alignment layer though we used homeotropic polyimide film at first. Increasing irradiating energy, we could control the pretilt from 90° to 1° with several steps. We believe that this is because the side chain with hydrophobicity in the used polyimide is broken by ion beam exposure. To confirm it, contact angle measurement was carried out. With this result, we can easily control the LC pretilt in the pixel with appropriate exposure conditions which is critical to achieve excellent electrooptic characteristics and good image quality. PMID:22221956

  5. Zenithal alignment of liquid crystal on homeotropic polyimide film irradiated by ion beam

    PubMed Central

    2012-01-01

    We investigate the pretilt characteristics of a nematic liquid crystal [LC] in terms of ion beam exposure conditions on the homeotropic polyimide alignment layer. The pretilt angle of LCs in the case of high-energy ion beam treatment was decreased considerably almost the same to that of the homogenous alignment layer though we used homeotropic polyimide film at first. Increasing irradiating energy, we could control the pretilt from 90° to 1° with several steps. We believe that this is because the side chain with hydrophobicity in the used polyimide is broken by ion beam exposure. To confirm it, contact angle measurement was carried out. With this result, we can easily control the LC pretilt in the pixel with appropriate exposure conditions which is critical to achieve excellent electrooptic characteristics and good image quality. PMID:22221956

  6. Zenithal alignment of liquid crystal on homeotropic polyimide film irradiated by ion beam

    NASA Astrophysics Data System (ADS)

    Choi, Yoonseuk; Yoon, Tae-Hoon; Kwon, Jin Hyuk; Yi, Jonghoon; Gwag, Jin Seog

    2012-01-01

    We investigate the pretilt characteristics of a nematic liquid crystal [LC] in terms of ion beam exposure conditions on the homeotropic polyimide alignment layer. The pretilt angle of LCs in the case of high-energy ion beam treatment was decreased considerably almost the same to that of the homogenous alignment layer though we used homeotropic polyimide film at first. Increasing irradiating energy, we could control the pretilt from 90° to 1° with several steps. We believe that this is because the side chain with hydrophobicity in the used polyimide is broken by ion beam exposure. To confirm it, contact angle measurement was carried out. With this result, we can easily control the LC pretilt in the pixel with appropriate exposure conditions which is critical to achieve excellent electrooptic characteristics and good image quality.

  7. Production of a thermal stress resistant mutant Euglena gracilis strain using Fe-ion beam irradiation.

    PubMed

    Yamada, Koji; Kazama, Yusuke; Mitra, Sharbanee; Marukawa, Yuka; Arashida, Ryo; Abe, Tomoko; Ishikawa, Takahiro; Suzuki, Kengo

    2016-08-01

    Euglena gracilis is a common phytoplankton species, which also has motile flagellate characteristics. Recent research and development has enabled the industrial use of E. gracilis and selective breeding of this species is expected to further expand its application. However, the production of E. gracilis nuclear mutants is difficult because of the robustness of its genome. To establish an efficient mutation induction procedure for E. gracilis, we employed Fe-ion beam irradiation in the RIKEN RI beam factory. A decrease in the survival rate was observed with the increase in irradiation dose, and the upper limit used for E. gracilis selective breeding was around 50 Gy. For a practical trial of Fe-ion irradiation, we conducted a screening to isolate high-temperature-tolerant mutants. The screening yielded mutants that proliferated faster than the wild-type strain at 32 °C. Our results demonstrate the effectiveness of heavy-ion irradiation on E. gracilis selective breeding. PMID:27075598

  8. Nanopatterning of metal-coated silicon surfaces via ion beam irradiation: Real time x-ray studies reveal the effect of silicide bonding

    SciTech Connect

    El-Atwani, Osman; Gonderman, Sean; Suslova, Anastassiya; Fowler, Justin; El-Atwani, Mohamad; DeMasi, Alexander; Ludwig, Karl; Paul Allain, Jean

    2013-03-28

    We investigated the effect of silicide formation on ion-induced nanopatterning of silicon with various ultrathin metal coatings. Silicon substrates coated with 10 nm Ni, Fe, and Cu were irradiated with 200 eV argon ions at normal incidence. Real time grazing incidence small angle x-ray scattering (GISAXS) and x-ray fluorescence (XRF) were performed during the irradiation process and real time measurements revealed threshold conditions for nanopatterning of silicon at normal incidence irradiation. Three main stages of the nanopatterning process were identified. The real time GISAXS intensity of the correlated peaks in conjunction with XRF revealed that the nanostructures remain for a time period after the removal of the all the metal atoms from the sample depending on the binding energy of the metal silicides formed. Ex-situ XPS confirmed the removal of all metal impurities. In-situ XPS during the irradiation of Ni, Fe, and Cu coated silicon substrates at normal incidence demonstrated phase separation and the formation of different silicide phases that occur upon metal-silicon mixing. Silicide formation leads to nanostructure formation due the preferential erosion of the non-silicide regions and the weakening of the ion induced mass redistribution.

  9. Nanoindentation creep study on an ion beam irradiated oxide dispersion strengthened alloy

    NASA Astrophysics Data System (ADS)

    Huang, Zijing; Harris, Adrian; Maloy, Stuart A.; Hosemann, Peter

    2014-08-01

    Oxide dispersion strengthened (ODS) alloys are considered advanced structural materials for nuclear application due to their radiation tolerance and creep resistance. Ion beam irradiation is used to study the property changes due to displacement damage. In this work 1 dpa displacement damage in an ODS was produced followed by a nanoindentation creep study at temperatures up to 600 °C to evaluate the changes in mechanical properties due to irradiation. Converted yield strength (YS) and creep related parameters are reported.

  10. Magnetic properties of Fe{sub 7}Co{sub 3} films with gas cluster ion beam irradiations

    SciTech Connect

    Toyoda, Noriaki; Fujimoto, Akihiro; Yamada, Isao

    2013-05-07

    Gas cluster ion beam (GCIB) irradiation was performed on Fe{sub 7}Co{sub 3} films to examine the magnetic properties. After Ar ion beam etching, the coercive force (H{sub c}) increased from the initial value; this may have been caused by irradiation damage from high-energy Ar ions. H{sub c} decreased after Ar-GCIB irradiation (acceleration voltage (V{sub a}): 20 kV, ion fluence (F): 1 Multiplication-Sign 10{sup 15} ions/cm{sup 2}). Since GCIB is an equivalent low-energy (several eV/atom) ion beam, it shows a damage-recovery effect. When the ionization electron voltage (V{sub e}) was reduced from 200 to 60 V, H{sub c} was observed to further decrease. Since the fraction of multiply charged Ar-GCIB decreased with decreasing V{sub e}, severe damage of Fe{sub 7}Co{sub 3} films can be minimized by employing low V{sub e}.

  11. Variation in the electrical properties of ion beam irradiated cadmium selenate nanowires

    NASA Astrophysics Data System (ADS)

    Chauhan, R. P.; Narula, Chetna; Panchal, Suresh

    2016-05-01

    The key feature of nanowires consists in the pronounced change in properties induced by the low dimensionality and high surface to volume ratio. The study of electrical transport properties of nanowires is important for electronic device applications. Energetic ions create changes, which may be structural or chemical, in a material along their track and these changes might alter the material's properties. The demand of the modern technology is to understand the effect of radiation on the different properties of the material for its further applications. The present study is on the high-energy Nickel ion beam (160 MeV Ni+12) induced modifications in the electrical and structural properties of the cadmium selenate nanowires. An enhancement in the electrical conductivity of irradiated wires was observed as the ion fluence was increased especially in the forward I-V characteristics. The creation of defects by ion irradiation and the synergy of the ions during their passage in the sample with the intrinsic charge carriers may be responsible for the variation in the transport properties of the irradiated nanowires.

  12. Change in Ion Beam Induced Current from Si Metal-Oxide-Semiconductor Capacitors after Gamma-Ray Irradiation

    SciTech Connect

    Ohshima, T.; Onoda, S.; Hirao, T.; Takahashi, Y.; Vizkelethy, G.; Doyle, B. L.

    2009-03-10

    To investigate the effects of gamma-ray irradiation on transient current induced in MOS capacitors by heavy ion incidence, Si MOS capacitors were irradiated with gamma-rays up to 60.9 kGy(SiO2). The change in Transient Ion Beam Induced Current (TIBIC) signals due to gamma-ray irradiation was investigated using 15 MeV-oxygen ion microbeams. After gamma-ray irradiation, the peak current of the TIBIC signal vs. bias voltage curve shifted toward negative voltages. This shift can be interpreted in terms of the charge trapped in the oxide. In this dose range, no significant effects of the interface traps induced by gamma-ray irradiation on the TIBIC signals were observed.

  13. Virus inactivation studies using ion beams, electron and gamma irradiation

    NASA Astrophysics Data System (ADS)

    Smolko, Eduardo E.; Lombardo, Jorge H.

    2005-07-01

    Known methods of virus inactivation are based on the chemical action of some substances such as acetylethylenimine, betapropiolactone, glycidalaldehyde, formaldehyde, etc. In such a process, the viral suspension should be kept at room or higher temperatures for 24-48 h. Under these conditions, physical and chemical agents act to degrade the virus antigenic proteins. On the contrary with ionizing radiations at low temperatures, the treatment does not cause such degradation allowing the study of different viral functions. In this work, particle (α, d and ß) and γ irradiations were used for partial and total inactivation of Foot and Mouth Disease Virus (FMDV), Rauscher Leukemia Virus (RLV) and Herpes Simplex Virus (HSV). Obtention of the D37 dose from survival curves and the application of the target theory, permitted the determination of molecular weight of the nucleic acid genomes, EBR values and useful information for vaccine preparation. For RLV virus, a two target model of the RNA genome was deduced in accordance with biological information while from data from the literature and our own work on the structure of the scrapie prion, considering the molecular weight obtained by application of the theory, a new model for prion replication is presented, based on a trimer molecule.

  14. Change in magnetic and structural properties of FeRh thin films by gold cluster ion beam irradiation with the energy of 1.67 MeV/atom

    NASA Astrophysics Data System (ADS)

    Koide, T.; Saitoh, Y.; Sakamaki, M.; Amemiya, K.; Iwase, A.; Matsui, T.

    2014-05-01

    The effect of energetic cluster ion beam irradiation on magnetic and structural properties of FeRh thin films have been investigated. The cluster ions used in the present studies consist of a few gold atoms with the energy of 1.67 MeV/gold atom. Saturation magnetization of the sample irradiated with Au3 cluster ion beam (280 emu/cc) is larger than that for the irradiated sample with Au1 ion beam (240 emu/cc) for the same irradiation ion fluence. These results can also be confirmed by the X-ray magnetic circular dichroism (XMCD) measurement; the XMCD signal for Au3 cluster ion irradiation is larger than that for Au1 ion irradiation. Since the ion beam irradiation induced magnetization of FeRh is significantly correlated with the amount of the lattice defects in the samples, cluster ion beam irradiation can be considered to effectively introduce the lattice defects in B2-type FeRh rather than the single ion beam. Consequently, cluster ion irradiation is better than single ion irradiation for the viewpoint of saturation magnetization, even if the same irradiation energy is deposited in the samples.

  15. Simulating Electron Cloud Effects in Heavy-Ion Beams

    SciTech Connect

    Cohen, R.H.; Friedman, A.; Lund, S.W.; Molvik, A.W.; Azevedo, T.; Vay, J.-L.; Stoltz, P.; Veitzer, S.

    2004-08-04

    Stray electrons can be introduced in heavy ion fusion accelerators as a result of ionization of ambient gas or gas released from walls due to halo-ion impact, or as a result of secondary-electron emission. We summarize here results from several studies of electron-cloud accumulation and effects: (1) Calculation of the electron cloud produced by electron desorption from computed beam ion loss; the importance of ion scattering is shown; (2) Simulation of the effect of specified electron cloud distributions on ion beam dynamics. We find electron cloud variations that are resonant with the breathing mode of the beam have the biggest impact on the beam (larger than other resonant and random variations), and that the ion beam is surprisingly robust, with an electron density several percent of the beam density required to produce significant beam degradation in a 200-quadrupole system. We identify a possible instability associated with desorption and resonance with the breathing mode. (3) Preliminary investigations of a long-timestep algorithm for electron dynamics in arbitrary magnetic fields.

  16. Morphological change of self-organized protrusions of fluoropolymer surface by ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Kitamura (Ogawa), Akane; Kobayashi, Tomohiro; Satoh, Takahiro; Koka, Masashi; Kamiya, Tomihiro; Suzuki, Akihiro; Terai, Takayuki

    2013-07-01

    Polytetrafluoroethylene (PTFE) and fluorinated ethylene propylene (FEP) are typical fluoropolymers displaying several desirable technological properties such as electrical insulation and high chemical resistance. When their surfaces are irradiated with ion beams, dense micro-protrusions formed after the emergence and spread of micropores across the entire irradiated area, allowing culture cells to spread on the top of the protrusions. In this study, we investigate the morphological changes introduced in the fluoropolymer surfaces by ion beams as the energy of the beams is increased. When an FEP sample was irradiated with a nitrogen ion beam with an energy of less than 350 keV at 1.0 μA/cm2, protrusions were formed with a density between 2 × 107/cm2 and 2 × 108/cm2. However, at energies higher than 350 keV, the protrusions became sparse, and the density dropped to 5 × 102/cm2. Protrusions appeared sporadically during irradiation at high energies, and the top of the protrusions appeared as spots inside the sample, which were difficult to etch and became elongated as the erosion of the surface progressed. Erosion was caused by sputtering of FEP molecules and evaporation at notably elevated temperatures on the surface. Analysis based on attenuated total reflectance/Fourier transform infrared spectroscopy showed the presence of Cdbnd C bonds as well as -COOH, -Cdbnd O, and -OH bonds on all irradiated samples. Their concentration on the surface densely covered with micro-protrusions was higher than that on the surface with sparse protrusions after irradiation at energies exceeding 350 keV. Thus, we determined a suitable range for the ion energy for creating FEP surfaces densely covered with protrusions.

  17. Ion beam induced luminescence analysis of defect evolution in lithium fluoride under proton irradiation

    NASA Astrophysics Data System (ADS)

    Quaranta, A.; Valotto, G.; Piccinini, M.; Montereali, R. M.

    2015-11-01

    Ion beam induced luminescence (IBIL) spectra of pure LiF under irradiation by a 2 MeV proton beam were analyzed as a function of the dose in order to deepen the kinetic mechanisms underlying the formation of luminescent point defects. The intensity evolution with dose at several emission wavelengths has been studied within a wide spectral interval, from ultraviolet (UV) to near infrared (NIR), and their different change rates have been correlated to the electronic defect formation processes. The intensity at few selected wavelengths was analyzed with a multiple linear regression (MLR) method in order to demonstrate that a linear calibration curve can be obtained and that an on-line optical dose monitor for ion beams can be realized.

  18. Grain growth kinetics during ion beam irradiation of chemical vapor deposited amorphous silicon

    SciTech Connect

    Spinella, C.; Lombardo, S. ); Campisano, S.U. )

    1990-08-06

    The amorphous to polycrystal transition during Kr ion beam irradiation of chemical vapor deposited silicon layers has been studied in the temperature range 320--480 {degree}C. At each irradiation temperature the average grain diameter increases linearly with the Kr dose, while the grain density remains constant within the experimental accuracy. The growth rate follows a complex behavior which can be described by dynamic defect generation and annihilation. The absolute value of the grain growth rate is equal to that of the ion-assisted epitaxial layer by layer crystallization in the silicon (111) orientation. This result can be related to the crystal grain structure and morphology.

  19. Synergistic Effect of Triple Ion Beams on Radiation Damage in CLAM Steel

    NASA Astrophysics Data System (ADS)

    Yuan, Da-Qing; Zheng, Yong-Nan; Zuo, Yi; Fan, Ping; Zhou, Dong-Mei; Zhang, Qiao-Li; Ma, Xiao-Qiang; Cui, Bao-Qun; Chen, Li-Hua; Jiang, Wei-Sheng; Wu, Yi-Can; Huang, Qun-Ying; Peng, Lei; Cao, Xing-Zhong; Wang, Bao-Yi; Wei, Long; Zhu, Sheng-Yun

    2014-04-01

    The synergistic effect of triple ion beams is investigated by simultaneous and sequential irradiations of gold, hydrogen and helium ions on the low activation martensitic steel (CLAM) developed in China. The depth profile measurements of the positron annihilation Doppler broadening S parameter are carried out as a function of slow-positron beam energy to examine the produced radiation damage. The synergistic effect of displacement damage and hydrogen and helium on the formation of radiation damage is clearly observed. In the preset case, this effect suppresses the radiation damage in the CLAM steel due to the helium and/or hydrogen filling of vacancy clusters.

  20. Surface reformation and electro-optical characteristics of liquid crystal alignment layers using ion beam irradiation

    SciTech Connect

    Oh, Byeong-Yun; Lee, Kang-Min; Kim, Byoung-Yong; Kim, Young-Hwan; Han, Jin-Woo; Han, Jeong-Min; Lee, Sang-Keuk; Seo, Dae-Shik

    2008-09-15

    The surface modification characteristics of liquid crystal (LC) alignment layers irradiated with various argon (Ar) ion beam (IB) energies were investigated as a substitute for rubbing technology. Various pretilt angles were created on the IB-irradiated polyimide (PI) surfaces after IB irradiation, but the Ar ions did not alter the morphology on the PI surface, indicating that the pretilt angle was not due to microgrooves. The chemical bonding states of the IB-irradiated PI surfaces were analyzed in detail by x-ray photoelectron spectroscopy to verify the compositional behavior for the LC alignment. Chemical structure analysis showed that the alignment ability of LCs was due to the preferential reorientation of the carbon network due to the breaking of C=O double bonds in the imide ring parallel to the incident IB direction. The potential of applying nonrubbing technology to display devices was further supported by the superior electro-optical characteristics compared to rubbed PI.

  1. Selective liquid crystal molecule orientation on ion beam irradiated tantalum oxide ultrathin films

    SciTech Connect

    Lim, Ji-Hun; Oh, Byeong-Yun; Lee, Won-Kyu; Lee, Kang-Min; Na, Hyun-Jae; Kim, Byoung-Yong; Seo, Dae-Shik; Han, Jeong-Min; Hwang, Jeong-Yeon

    2009-09-21

    We recently achieved the homogeneous alignment of liquid crystal (LC) on amorphous Ta{sub 2}O{sub 5} layers. This study demonstrates that LC layers could be aligned either homogeneously or vertically by increasing the growth temperature of rf magnetron sputtering device and the irradiation time of the DuoPIGatron type Ar ion beam device causing uniform and dense plasma. We attained two LC orientations by observing Ta 4f and O 1s peak shifts with x-ray photoelectron spectroscopy. Moreover, the decreased thickness of layers with high-k dielectric constants helped to decrease driving LC voltages and in turn to achieve low power consumption.

  2. Enhanced annealing of damage in ion-implanted 4H-SiC by MeV ion-beam irradiation

    NASA Astrophysics Data System (ADS)

    Kinomura, A.; Chayahara, A.; Mokuno, Y.; Tsubouchi, N.; Horino, Y.

    2005-05-01

    The effect of ion-beam annealing for implantation-induced damage in single-crystalline 4H silicon carbide has been studied. Four sets of samples, implanted with two types of ions (C or Si) and two different damage levels (complete or incomplete amorphization), were prepared to investigate the influence of damaging conditions. The damaged samples were irradiated with a 3-MeV Ge ion beam at 600 °C in the range of 1×1015-2×1016cm-2 to induce the ion-beam annealing. Some of the damaged samples were thermally annealed without the Ge irradiation to evaluate pure thermal effects. Rutherford backscattering/channeling for these samples revealed substantial enhancements of damage annealing under the MeV ion-beam irradiation. The enhanced annealing effect was stronger for the incompletely amorphized samples than for the completely amorphized samples. For both cases, the annealing effects almost saturated with increasing ion fluence. The results suggest the competition between the annealing and damaging effects induced by the annealing beam, at least, for the incompletely amorphized samples.

  3. Enhanced annealing of damage in ion-implanted 4H-SiC by MeV ion-beam irradiation

    SciTech Connect

    Kinomura, A.; Chayahara, A.; Mokuno, Y.; Tsubouchi, N.; Horino, Y.

    2005-05-15

    The effect of ion-beam annealing for implantation-induced damage in single-crystalline 4H silicon carbide has been studied. Four sets of samples, implanted with two types of ions (C or Si) and two different damage levels (complete or incomplete amorphization), were prepared to investigate the influence of damaging conditions. The damaged samples were irradiated with a 3-MeV Ge ion beam at 600 deg. C in the range of 1x10{sup 15}-2x10{sup 16} cm{sup -2} to induce the ion-beam annealing. Some of the damaged samples were thermally annealed without the Ge irradiation to evaluate pure thermal effects. Rutherford backscattering/channeling for these samples revealed substantial enhancements of damage annealing under the MeV ion-beam irradiation. The enhanced annealing effect was stronger for the incompletely amorphized samples than for the completely amorphized samples. For both cases, the annealing effects almost saturated with increasing ion fluence. The results suggest the competition between the annealing and damaging effects induced by the annealing beam, at least, for the incompletely amorphized samples.

  4. Development of an ion beam alignment system for real-time scanning tunneling microscope observation of dopant-ion irradiation

    SciTech Connect

    Kamioka, Takefumi; Sato, Kou; Kazama, Yutaka; Watanabe, Takanobu; Ohdomari, Iwao

    2008-07-15

    An ion beam alignment system has been developed in order to realize real-time scanning tunneling microscope (STM) observation of 'dopant-ion' irradiation that has been difficult due to the low emission intensity of the liquid-metal-ion-source (LMIS) containing dopant atoms. The alignment system is installed in our original ion gun and STM combined system (IG/STM) which is used for in situ STM observation during ion irradiation. By using an absorbed electron image unit and a dummy sample, ion beam alignment operation is drastically simplified and accurized. We demonstrate that sequential STM images during phosphorus-ion irradiation are successfully obtained for sample surfaces of Si(111)-7x7 at room temperature and a high temperature of 500 deg. C. The LMIS-IG/STM equipped with the developed ion beam alignment system would be a powerful tool for microscopic investigation of the dynamic processes of ion irradiation.

  5. Surface modifications of hydrogen storage alloy by heavy ion beams with keV to MeV irradiation energies

    NASA Astrophysics Data System (ADS)

    Abe, Hiroshi; Tokuhira, Shinnosuke; Uchida, Hirohisa; Ohshima, Takeshi

    2015-12-01

    This study deals with the effect of surface modifications induced from keV to MeV heavy ion beams on the initial reaction rate of a hydrogen storage alloy (AB5) in electrochemical process. The rare earth based alloys like this sample alloy are widely used as a negative electrode of Ni-MH (Nickel-Metal Hydride) battery. We aimed to improve the initial reaction rate of hydrogen absorption by effective induction of defects such as vacancies, dislocations, micro-cracks or by addition of atoms into the surface region of the metal alloys. Since defective layer near the surface can easily be oxidized, the conductive oxide layer is formed on the sample surface by O+ beams irradiation, and the conductive oxide layer might cause the improvement of initial reaction rate of hydriding. This paper demonstrates an effective surface treatment of heavy ion irradiation, which induces catalytic activities of rare earth oxides in the alloy surface.

  6. Evaluation of surface damage on organic materials irradiated with Ar cluster ion beam

    SciTech Connect

    Yamamoto, Y.; Ichiki, K.; Ninomiya, S.; Matsuo, J.; Seki, T.; Aoki, T.

    2011-01-07

    The sputtering yields of organic materials under large cluster ion bombardment are much higher than those under conventional monomer ion bombardment. The sputtering rate of arginine remains constant with fluence for an Ar cluster ion beam, but decreases with fluence for Ar monomer. Additionally, because Ar cluster etching induces little damage, Ar cluster ion can be used to achieve molecular depth profiling of organic materials. In this study, we evaluated the damage to poly methyl methacrylate (PMMA) and arginine samples irradiated with Ar atomic and Ar cluster ion beams. Arginine samples were analyzed by secondary ion mass spectrometry (SIMS) and PMMA samples were analyzed by X-ray photoelectron spectroscopy (XPS). The chemical structure of organic materials remained unchanged after Ar cluster irradiation, but was seriously damaged. These results indicated that bombardment with Ar cluster ions induced less surface damage than bombardment with Ar atomic ion. The damage layer thickness with 5 keV Ar cluster ion bombardment was less than 1 nm.

  7. Surface morphology and resistivity of aluminum oxide films prepared by plasma CVD combined with ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Nakai, H.; Shinohara, J.; Sassa, T.; Ikegami, Y.

    1997-01-01

    Plasma CVD combined with simultaneous ion beams has been developed in order to prepare ceramic insulating films which have strong force of adhesion and higher electric resistivity at high temperatures. Aluminum oxide (Al 2O 3) films were deposited on nickel based superalloy (Inconel 718) by thermal CVD, plasma CVD and ion beam assisted plasma CVD at the several substrate temperatures. The surface morphology of these films was analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was confirmed that, by ion beam irradiation, the extent of crystallization was enhanced at lower substrate temperature and grain size became smaller. The electric resistivity was measured in the temperature range of RT to 800°C. The film, deposited by ion beam assisted plasma CVD at 800°C, had higher electric resistivity than the films by conventional CVD.

  8. The damaging effects of nitrogen ion beam implantation on upland cotton ( Gossypium hirsutum L.) pollen grains

    NASA Astrophysics Data System (ADS)

    Yu, Yanjie; Wu, Lijun; Wu, Yuejin; Wang, Qingya; Tang, Canming

    2008-09-01

    With the aim to study the effects of an ion beam on plant cells, upland cotton (Gossypium hirsutum L.) cultivar "Sumian 22" pollen grains were irradiated in vacuum (7.8 × 10-3 Pa) by low-energy nitrogen ions with an energy of 20 keV at various fluences ranging from 0.26 × 1016 to 0.78 × 1016 N+/cm2. The irradiation effects on pollen grains were tested, considering the ultrastructural changes in the exine and interior walls of pollen grains, their germination rate, the growth speed of the pollen tubes in the style, fertilization and boll development after the pistils were pollinated by the pollen grains which had been implanted with nitrogen ions. Nitrogen ions entered the pollen grains by etching and penetrating the exine and interior walls and destroying cell structures. A greater percentage of the pollen grains were destroyed as the fluence of N+ ions increased. Obviously, the nitrogen ion beam penetrated the exine and interior walls of the pollen grains and produced holes of different sizes. As the ion fluence increased, the amount and the density of pollen grain inclusions decreased and the size of the lacuna and starch granules increased. Pollen grain germination rates decreased with increasing ion fluence. The number of pollen tubes in the style declined with increased ion implantation into pollen grains, but the growth speed of the tubes did not change. All of the pollen tubes reached the end of the style at 13 h after pollination. This result was consistent with that of the control. Also, the weight and the diameter of the ovary decreased and shortened with increased ion beam implantation fluence. No evident change in the fecundation time of the ovule was observed. These results indicate that nitrogen ions can enter pollen grains and cause a series of biological changes in pollen grains of upland cotton.

  9. Surface composition, microstructure and corrosion resistance of AZ31 magnesium alloy irradiated by high-intensity pulsed ion beam

    SciTech Connect

    Li, P.; Lei, M.K.; Zhu, X.P.

    2011-06-15

    High-intensity pulsed ion beam (HIPIB) irradiation of AZ31 magnesium alloy is performed and electrochemical corrosion experiment of irradiated samples is carried out by using potentiodynamic polarization technology in order to explore the effect of HIPIB irradiation on corrosion resistance of magnesium alloy. The surface composition, cross-sectional morphology and microstructure are characterized by using electron probe microanalyzer, optical microscope and transmission electron microscope, respectively. The results indicated that HIPIB irradiation leads to a significant improvement in corrosion resistance of magnesium alloy, in terms of the considerable increase in both corrosion potential and pitting breakdown potential. The microstructural refinement and surface purification induced by HIPIB irradiation are responsible for the improved corrosion resistance. - Research Highlights: {yields} A modified layer about 30 {mu}m thick is obtained by HIPIB irradiation. {yields} Selective ablation of element/impurity phase having lower melting point is observed. {yields} More importantly, microstructural refinement occurred on the irradiated surface. {yields} The modified layer exhibited a significantly improved corrosion resistance. {yields} Improved corrosion resistance is ascribed to the combined effect induced by HIPIB.

  10. Liquid Crystal Alignment on Solution Derived Zinc Oxide Films via Ion Beam Irradiation.

    PubMed

    Park, Hong-Gyu; Han, Jae-Jun; Seo, Dae-Shik

    2016-03-01

    A 75-nm-thick ZnO film was deposited by a sol-gel method on indium-tin oxide (ITO)-coated glass. This film served as a liquid crystal (LC) alignment layer. We report the fabrication and characteristics of this film after ion-beam (IB) irradiation. Uniform LC alignment was achieved at an IB incident energy above 2400 eV. The IB-treated ZnO surface was analyzed by X-ray photoelectron spectroscopy (XPS), monitoring the intensity of the Zn 2p and O 1s peaks as a function of IB-irradiation energy density. The electro-optical (EO) characteristics of a twisted nematic-liquid crystal display (TN-LCD) were comparable to rubbed polyimide. PMID:27455726

  11. Superior optical properties of homogeneous liquid crystal alignment on a tin (IV) oxide surface sequentially modulated via ion beam irradiation.

    PubMed

    Kang, Young-Gu; Park, Hong-Gyu; Kim, Hyung-Jun; Kim, Young-Hwan; Oh, Byeong-Yun; Kim, Byoung-Yong; Kim, Dai-Hyun; Seo, Dae-Shik

    2010-10-11

    We first investigated the alignment characteristics of tin (IV) oxide (SnO(2)) thin films deposited by radio-frequency (RF) magnetron sputtering. This study demonstrates that liquid crystal (LC) molecules could be aligned homogeneously by controlling the Ion Beam (IB) irradiation energy densities. We also show that the pretilt angle of the LC molecules has a close relation with the surface energy. X-ray photoelectron spectroscopy (XPS) indicates that a non-stoichiometric SnO(2-x) surface converted by ion beam irradiation can horizontally align the LC molecules. The measured electro-optical (EO) characteristics showed high performance, comparable with those of rubbed and ion-beam irradiated polyimide (PI) layers. PMID:20941057

  12. In-situ XMCD evaluation of ferromagnetic state at FeRh thin film surface induced by 1 keV Ar ion beam irradiation and annealing

    NASA Astrophysics Data System (ADS)

    Matsui, T.; Aikoh, K.; Sakamaki, M.; Amemiya, K.; Iwase, A.

    2015-12-01

    Surface ferromagnetic state of FeRh thin films irradiated with 1 keV Ar ion-beam has been investigated by using soft X-ray Magnetic Circular Dichroism (XMCD). It was revealed that the Fe atoms of the samples were strongly spin-polarized after Ar ion-beam irradiation. Due to its small penetration depth, 1 keV Ar ion-beam irradiation can modify the magnetic state at subsurface of the samples. In accordance with the XMCD sum rule analysis, the main component of the irradiation induced ferromagnetism at the FeRh film surface was to be effective spin magnetic moment, and not to be orbital moment. We also confirmed that the surface ferromagnetic state could be produced by thermal annealing of the excessively ion irradiated paramagnetic subsurface of the FeRh thin films. This novel magnetic modification technique by using ion irradiation and subsequent annealing can be a potential tool to control the surface magnetic state of FeRh thin films.

  13. Thermal effects on the Ga+ ion beam induced structural modification of a-SiC:H

    NASA Astrophysics Data System (ADS)

    Tsvetkova, T.; Wright, C. D.; Craciun, M. F.; Bischoff, L.; Angelov, O.; Dimova-Malinovska, D.

    2012-12-01

    The effects of implantation temperature and post-implantation thermal annealing on the Ga+ ion beam induced optical contrast formation in hydrogenated silicon-carbon alloy (a-SiC:H) films and underlying structural modifications have been studied. The optical contrast formed (between implanted and unimplanted regions of the film material) has been made use of in the form of optical pattern formation by computer-operated Ga+-focused ion beam. Possible applications of this effect in the area of submicron lithography and high-density optical data storage have been suggested with regard to the most widely spread focused micro-beam systems based on Ga+ liquid metal ion sources. The implanted samples were structurally analysed using vibrational spectroscopies, like Raman and infra-red (IR) spectroscopy, to define optimum implantation conditions. The precise role of implantation temperature effects, i.e. the target temperature during Ga+ ion irradiation, on the structural modification obtainable has been therefore a key part of this study. Appropriate post-implantation annealing treatments were also studied, since these are expected to offer further benefits in reducing the required ion dose and enhancing the optical contrast, thus increasing the cost-effectiveness of the method.

  14. Multivariate analysis of Ion Beam Induced Luminescence spectra of irradiated silver ion-exchanged silicate glasses

    NASA Astrophysics Data System (ADS)

    Valotto, Gabrio; Quaranta, Alberto; Cattaruzza, Elti; Gonella, Francesco; Rampazzo, Giancarlo

    A multivariate analysis is used for the identification of the spectral features in Ion Beam Induced Luminescence (IBIL) spectra of soda-lime silicate glasses doped with silver by Ag+-Na+ ion exchange. Both Principal Component Analysis and multivariate analysis were used to characterize time-evolving IBIL spectra of Ag-doped glasses, by means of the identification of the number and of the wavelength positions of the main luminescent features and the study of their evolution during irradiation. This method helps to identify the spectral features of the samples spectra, even when partially overlapped or less intense. This analysis procedure does not require additional input such as the number of peaks.

  15. Multivariate analysis of Ion Beam Induced Luminescence spectra of irradiated silver ion-exchanged silicate glasses.

    PubMed

    Valotto, Gabrio; Quaranta, Alberto; Cattaruzza, Elti; Gonella, Francesco; Rampazzo, Giancarlo

    2012-09-01

    A multivariate analysis is used for the identification of the spectral features in Ion Beam Induced Luminescence (IBIL) spectra of soda-lime silicate glasses doped with silver by Ag(+)-Na(+) ion exchange. Both Principal Component Analysis and multivariate analysis were used to characterize time-evolving IBIL spectra of Ag-doped glasses, by means of the identification of the number and of the wavelength positions of the main luminescent features and the study of their evolution during irradiation. This method helps to identify the spectral features of the samples spectra, even when partially overlapped or less intense. This analysis procedure does not require additional input such as the number of peaks. PMID:22571943

  16. A prototype compton camera for in-vivo dosimetry of ion beam cancer irradiation

    SciTech Connect

    Kormoll, T.; Fiedler, F.; Golnik, C.; Heidel, K.; Kempe, M.; Schoene, S.; Sobiella, M.; Zuber, K.; Enghardt, W.

    2011-07-01

    Three-dimensional in-vivo dose monitoring of ion beam cancer irradiation can improve the quality of treatment. For this purpose we investigate the feasibility of imaging the single photon emissions due to nuclear reactions of projectiles with target nuclei (in-beam SPECT). A suitable imaging technique in the energy range of the emitted gamma rays is the Compton camera. A prototype based on prior simulations is currently under construction. Te system comprises two CdZnTe cross-strip detectors with steering grid and depth-of-interaction capability and one segmented LSO scintillator crystal with modified Anger light readout. We present the concept of the system including the front-end and DAQ electronics as well as first measurements. (authors)

  17. In-situ Study of Nanostructure and Electrical Resistance of Nanocluster Films Irradiated with Ion Beams

    SciTech Connect

    Jiang, Weilin; Sundararajan, Jennifer A.; Varga, Tamas; Bowden, Mark E.; Qiang, You; McCloy, John S.; Henager, Charles H.; Montgomery, Robert O.

    2014-08-11

    An in-situ study is reported on the structural evolution in nanocluster films under He+ ion irradiation using an advanced helium ion microscope. The films consist of loosely interconnected nanoclusters of magnetite or iron-magnetite (Fe-Fe3O4) core-shells. The nanostructure is observed to undergo dramatic changes under ion-beam irradiation, featuring grain growth, phase transition, particle aggregation, and formation of nanowire-like network and nano-pores. Studies based on ion irradiation, thermal annealing and election irradiation have indicated that the major structural evolution is activated by elastic nuclear collisions, while both electronic and thermal processes can play a significant role once the evolution starts. The electrical resistance of the Fe-Fe3O4 films measured in situ exhibits a super-exponential decay with dose. The behavior suggests that the nanocluster films possess an intrinsic merit for development of an advanced online monitor for neutron radiation with both high detection sensitivity and long-term applicability, which can enhance safety measures in many nuclear operations.

  18. Dose response and mutation induction by ion beam irradiation in buckwheat

    NASA Astrophysics Data System (ADS)

    Morishita, T.; Yamaguchi, H.; Degi, K.; Shikazono, N.; Hase, Y.; Tanaka, A.; Abe, T.

    2003-05-01

    The biological effects of ion beams were investigated to pursue the development of a method for breeding by mutation in buckwheat. Common buckwheat (Botansoba, Bot) and tartary buckwheat (Rotundatiem, Rot) seeds were exposed to various ions in linear energy transfer (LET) at 9-630 keV/μm. The lethal dose 50 (LD 50) of ion beams were 10-300 Gy (Bot) and 30-500 Gy (Rot). It was indicated that a penetrating depth in excess of 1.7 mm is necessary to thoroughly saturate the target, and ions with a penetrating depth of less than 2.2 mm were affected by the presence of hulls. The maximum values of the relative biological effectiveness were 17.7 (Rot) and 22.5 (Bot) at 305 keV/μm. The effective cross sections increased with the LET, and the maximum values were 2.7 (Rot) and 3.0 μm 2 (Bot). The mutation induction effects of He and C ions were higher than those of gamma rays.

  19. Harmonic analysis of irradiation asymmetry for cylindrical implosions driven by high-frequency rotating ion beams.

    PubMed

    Bret, A; Piriz, A R; Tahir, N

    2012-03-01

    Cylindrical implosions driven by intense heavy ion beams should be instrumental in the near future for study of high-energy-density matter. By rotating the beam by means of a high-frequency wobbler, it should be possible to deposit energy in the outer layers of a cylinder, compressing the material deposited in its core. The beam's temporal profile should, however, generate an inevitable irradiation asymmetry likely to feed the Rayleigh-Taylor instability (RTI) during the implosion phase. In this paper, we compute the Fourier components of the target irradiation in order to make the connection with previous works on the RTI performed in this setting. Implementing one- and two-dimensional beam models, we find that these components can be expressed exactly in terms of the Fourier transform of the temporal beam profile. If T is the beam duration and Ω its rotation frequency, "magic products" ΩT can be identified which cancel the first harmonic of the deposited density, resulting in an improved irradiation symmetry. PMID:22587191

  20. Local control of magnetic damping in ferromagnetic/non-magnetic bilayers by interfacial intermixing induced by focused ion-beam irradiation

    SciTech Connect

    King, J. A.; Burn, D. M.; Sallabank, E. A.; Hindmarch, A. T.; Atkinson, D. E-mail: abarman@bose.res.in; Ganguly, A.; Pal, S.; Barman, A. E-mail: abarman@bose.res.in; Hase, T. P. A.

    2014-06-16

    The influence of interfacial intermixing on the picosecond magnetization dynamics of ferromagnetic/non-magnetic thin-film bilayers was studied. Low-dose focused-ion-beam irradiation was used to induce intermixing across the interface between a 10 nm Ni{sub 81}Fe{sub 19} layer and a 2–3 nm capping layer of either Au or Cr. Time-resolved magneto-optical Kerr effect was used to study magnetization dynamics as a function of ion-beam dose. With an Au cap, the damping of the un-irradiated bilayer was comparable with native Ni{sub 81}Fe{sub 19} and increased with increasing ion dose. In contrast, for Ni{sub 81}Fe{sub 19}/Cr the damping was higher than that for native Ni{sub 81}Fe{sub 19}, but the damping decreased with increasing dose.

  1. Site-selective local fluorination of graphene induced by focused ion beam irradiation

    PubMed Central

    Li, Hu; Daukiya, Lakshya; Haldar, Soumyajyoti; Lindblad, Andreas; Sanyal, Biplab; Eriksson, Olle; Aubel, Dominique; Hajjar-Garreau, Samar; Simon, Laurent; Leifer, Klaus

    2016-01-01

    The functionalization of graphene remains an important challenge for numerous applications expected by this fascinating material. To keep advantageous properties of graphene after modification or functionalization of its structure, local approaches are a promising road. A novel technique is reported here that allows precise site-selective fluorination of graphene. The basic idea of this approach consists in the local radicalization of graphene by focused ion beam (FIB) irradiation and simultaneous introduction of XeF2 gas. A systematic series of experiments were carried out to outline the relation between inserted defect creation and the fluorination process. Based on a subsequent X-ray photoelectron spectroscopy (XPS) analysis, a 6-fold increase of the fluorine concentration on graphene under simultaneous irradiation was observed when compared to fluorination under normal conditions. The fluorine atoms are predominately localized at the defects as indicated from scanning tunneling microscopy (STM). The experimental findings are confirmed by density functional theory which predicts a strong increase of the binding energy of fluorine atoms when bound to the defect sites. The developed technique allows for local fluorination of graphene without using resists and has potential to be a general enabler of site-selective functionalization of graphene using a wide range of gases. PMID:26822900

  2. A Comparison of the Effects of RF Plasma Discharge and Ion Beam Supply on the Growth of Cubic Boron Nitride Films Formed by Laser Physical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Kaneda, Kayo; Shibata, Kimihiro

    1994-01-01

    This paper presents a comparison of the effects of RF plasma discharge and ion beam supply on the growth of cubic boron nitride films formed by excimer laser physical vapor deposition (laser PVD). The film structure was analyzed by fourier transformation infrared region (FT-IR) spectroscopy and thin-film X-ray diffraction analysis. The structure of the film deposited with an RF plasma discharge provided between the substrate and target was hexagonal BN. On the other hand, that of the film deposited by irradiating the substrate directly with an ion beam was hexagonal BN (hBN) and cubic BN (cBN). It is thought that direct irradiation of the vapor generated from the target by accelerated ions increased the activation energy of the vapor, with the result that the film structure was changed. Besides irradiating the substrate directly with the ion beam resulted primarily in the etching of hBN while cBN remained.

  3. Radiation-induced ICAM-1 expression via TGF-β1 pathway on human umbilical vein endothelial cells; comparison between X-ray and carbon-ion beam irradiation.

    PubMed

    Kiyohara, Hiroki; Ishizaki, Yasuki; Suzuki, Yoshiyuki; Katoh, Hiroyuki; Hamada, Nobuyuki; Ohno, Tatsuya; Takahashi, Takeo; Kobayashi, Yasuhiko; Nakano, Takashi

    2011-01-01

    Adhesion of inflammatory cells to endothelial cells is considered to be involved in the process of radiation-induced damage and fibrosis. Intercellular adhesion molecule-1 (ICAM-1) and transforming growth factor-beta1 (TGF-β1) are thought to play important roles in this process. In this study, radiation-induced ICAM-1 expression on endothelial cells was investigated with the use of an inhibitor of TGF-β1 receptor kinase (SB431542) and the effects of X-ray and carbon-ion beam were compared. Cell cultures of human umbilical vein endothelial cells (HUVE cells) were incubated with TGF-β1 and irradiated with 140 KV X-ray. Next, HUVE cells were irradiated with X-ray and 220 MeV carbon-ion beam with or without SB431542. Immunofluorescence analysis was used to quantify ICAM-1 expression. The expression of ICAM-1 on HUVE cells was significantly increased by the stimulation with TGF-β1. Expression of ICAM-1 was increased by X-ray and carbon-ion beam irradiation and decreased significantly with SB431542 after both irradiations. The expression of ICAM-1 by 2 Gy of carbon-ion beam irradiation was 6.7 fold higher than that of non-irradiated cells, while 5 Gy of X-ray irradiation increased the expression of ICAM-1 by 2.5 fold. According to ICAM-1 expression, the effect of carbon-ion beam irradiation was about 2.2, 4.4 and 5.0 times greater than that of the same doses of X-ray irradiation (1, 2 and 5 Gy, respectively). The present results suggested that radiation-induced ICAM-1 expression on HUVE cells was, at least partially, regulated by TGF-β1. Carbon-ion beam induced significantly higher ICAM-1 expression than X-ray. PMID:21343678

  4. Persistent ion beam induced conductivity in zinc oxide nanowires

    SciTech Connect

    Johannes, Andreas; Niepelt, Raphael; Gnauck, Martin; Ronning, Carsten

    2011-12-19

    We report persistently increased conduction in ZnO nanowires irradiated by ion beam with various ion energies and species. This effect is shown to be related to the already known persistent photo conduction in ZnO and dubbed persistent ion beam induced conduction. Both effects show similar excitation efficiency, decay rates, and chemical sensitivity. Persistent ion beam induced conduction will potentially allow countable (i.e., single dopant) implantation in ZnO nanostructures and other materials showing persistent photo conduction.

  5. Extended calibration range for prompt photon emission in ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Bellini, F.; Boehlen, T. T.; Chin, M. P. W.; Collamati, F.; De Lucia, E.; Faccini, R.; Ferrari, A.; Lanza, L.; Mancini-Terracciano, C.; Marafini, M.; Mattei, I.; Morganti, S.; Ortega, P. G.; Patera, V.; Piersanti, L.; Russomando, A.; Sala, P. R.; Sarti, A.; Sciubba, A.; Solfaroli Camillocci, E.; Voena, C.

    2014-05-01

    Monitoring the dose delivered during proton and carbon ion therapy is still a matter of research. Among the possible solutions, several exploit the measurement of the single photon emission from nuclear decays induced by the irradiation. To fully characterize such emission the detectors need development, since the energy spectrum spans the range above the MeV that is not traditionally used in medical applications. On the other hand, a deeper understanding of the reactions involving gamma production is needed in order to improve the physic models of Monte Carlo codes, relevant for an accurate prediction of the prompt-gamma energy spectrum. This paper describes a calibration technique tailored for the range of energy of interest and reanalyzes the data of the interaction of a 80 MeV/u fully stripped carbon ion beam with a Poly-methyl methacrylate target. By adopting the FLUKA simulation with the appropriate calibration and resolution a significant improvement in the agreement between data and simulation is reported.

  6. Matrix effects in biological SIMS using cluster ion beams of different chemical composition.

    PubMed

    Alnajeebi, Afnan M; Vickerman, John C; Lockyer, Nicholas P

    2016-06-01

    The influence of the matrix effect on secondary ion yield presents a very significant challenge in quantitative secondary ion mass spectrometry (SIMS) analysis, for example, in determining the relative concentrations of metabolites that characterize normal biological activities or disease progression. Not only the sample itself but also the choice of primary ion beam may influence the extent of ionization suppression/enhancement due to the local chemical environment. In this study, an assessment of ionization matrix effects was carried out on model systems using C60 (+), Arn (+), and (H2O)n (+) cluster ion beams. The analytes are pure and binary mixtures of amino acids arginine and histidine biological standards. Ion beams of 20 keV were compared with a range of cluster sizes n = 1000-10 000. The component secondary ion yields were assessed for matrix effects using different primary ion beams and sample composition. The presence of water in the cluster beam is associated with a reduction in the observed matrix effects, suggesting that chemically reactive ion beams may provide a route to more quantitative SIMS analysis of complex biological systems. PMID:26825287

  7. The influence of electron irradiation on electron holography of focused ion beam milled GaAs p-n junctions

    SciTech Connect

    Cooper, David; Twitchett-Harrison, Alison C.; Midgley, Paul A.; Dunin-Borkowski, Rafal E.

    2007-05-01

    Electron beam irradiation is shown to significantly influence phase images recorded from focused ion beam milled GaAs p-n junction specimens examined using off-axis electron holography in the transmission electron microscope. Our results show that the use of improved electrical connections to the specimen overcomes this problem, and may allow the correct built in potential across the junction to be recovered.

  8. Ultra-low-energy (<10 eV/u) ion beam bombardment effect on naked DNA

    NASA Astrophysics Data System (ADS)

    Thopan, P.; Thongkumkoon, P.; Prakrajang, K.; Suwannakachorn, D.; Yu, L. D.

    2014-05-01

    Since ion energy deposition in the ion-bombarded materials dominantly occurs in the low-energy range, it is very interesting to know effects from ultra-low-energy ion interaction with DNA for understanding ion-beam-induced genetic mutation. Tens-keV Ar- and N-ion beams were decelerated to ultra-low energy ranging from 20 to 100 eV, or only a few to 10 eV/u, to bombard naked plasmid DNA. The bombarded DNA was analyzed using gel electrophoresis for DNA form changes. The original DNA supercoiled form was found to change to relaxed and linear forms, indicating single or double strand breaks after bombarded by tens-eV ion beam. N-ion beam was found more effective in inducing DNA change and mutation than Ar-ion beam. The study demonstrated that the ion bombardment with energy as low as several-tens eV was able to break DNA strands and thus potentially to cause genetic modification of biological cells. The experimental results were discussed in terms of direct atomic collision between the ions and DNA atoms.

  9. Ion beam mixing by focused ion beam

    SciTech Connect

    Barna, Arpad; Kotis, Laszlo; Labar, Janos L.; Osvath, Zoltan; Toth, Attila L.; Menyhard, Miklos; Zalar, Anton; Panjan, Peter

    2007-09-01

    Si amorphous (41 nm)/Cr polycrystalline (46 nm) multilayer structure was irradiated by 30 keV Ga{sup +} ions with fluences in the range of 25-820 ions/nm{sup 2} using a focused ion beam. The effect of irradiation on the concentration distribution was studied by Auger electron spectroscopy depth profiling, cross-sectional transmission electron microscopy, and atomic force microscopy. The ion irradiation did not result in roughening on the free surface. On the other hand, the Ga{sup +} irradiation produced a strongly mixed region around the first Si/Cr interface. The thickness of mixed region depends on the Ga{sup +} fluence and it is joined to the pure Cr matrix with an unusual sharp interface. With increasing fluence the width of the mixed region increases but the interface between the mixed layer and pure Cr remains sharp. TRIDYN simulation failed to reproduce this behavior. Assuming that the Ga{sup +} irradiation induces asymmetric mixing, that is during the mixing process the Cr can enter the Si layer, but the Si cannot enter the Cr layer, the experimental findings can qualitatively be explained.

  10. Neutralization of Space Charge Effects for Low Energy Ion Beams Using Field Emitters

    SciTech Connect

    Nicolaescu, D.; Sakai, S.; Matsuda, K.; Gotoh, Y.; Ishikawa, J.

    2008-11-03

    The paper presents models and computations for neutralization of space charge effects using electrons provided by field emitter arrays. Different ion species ({sup 11}B{sup +},{sup 31}P{sup +},{sup 75}As{sup +}) with energy in the range E{sub ion} = 200 eV-1 keV have been considered. The ion beam divergence is studied as a function of electron beam geometry and physical parameters (electron and ion energy, electron/ion current ratio I{sub el}/I{sub ion}). The electron beam geometry takes into account electron source positions and initial launching angles. It is shown that optimal ion beam neutralization occurs for low energy electrons emitted parallel to the ion beam.

  11. Selective Improvement of NO2 Gas Sensing Behavior in SnO2 Nanowires by Ion-Beam Irradiation.

    PubMed

    Kwon, Yong Jung; Kang, Sung Yong; Wu, Ping; Peng, Yuan; Kim, Sang Sub; Kim, Hyoun Woo

    2016-06-01

    We irradiated SnO2 nanowires with He ions (45 MeV) with different ion fluences. Structure and morphology of the SnO2 nanowires did not undergo noticeable changes upon ion-beam irradiation. Chemical equilibrium in SnO2/gas systems was calculated from thermodynamic principles, which were used to study the sensing selectivity of the tested gases, demonstrating the selective sensitivity of the SnO2 surface to NO2 gas. Being different from other gases, including H2, ethanol, acetone, SO2, and NH3, the sensor response to NO2 gas significantly increases as the ion fluence increases, showing a maximum under an ion fluence of 1 × 10(16) ions/cm(2). Photoluminescence analysis shows that the relative intensity of the peak at 2.1 eV to the peak at 2.5 eV increases upon ion-beam irradiation, suggesting that structural defects and/or tin interstitials have been generated. X-ray photoelectron spectroscopy indicated that the ionic ratio of Sn(2+/)Sn(4+) increases by the ion-beam irradiation, supporting the formation of surface Sn interstitials. Using thermodynamic calculations, we explained the observed selective sensing behavior. A molecular level model was also established for the adsorption of NO2 on ion-irradiated SnO2 (110) surfaces. We propose that the adsorption of NO2-related species is considerably enhanced by the generation of surface defects that are comprised of Sn interstitials. PMID:27167241

  12. Comparison of Biological Effectiveness of Carbon-Ion Beams in Japan and Germany

    SciTech Connect

    Uzawa, Akiko; Ando, Koichi Koike, Sachiko; Furusawa, Yoshiya; Matsumoto, Yoshitaka; Takai, Nobuhiko; Hirayama, Ryoichi; Watanabe, Masahiko; Scholz, Michael; Elsaesser, Thilo; Peschke, Peter

    2009-04-01

    Purpose: To compare the biological effectiveness of 290 MeV/amu carbon-ion beams in Chiba, Japan and in Darmstadt, Germany, given that different methods for beam delivery are used for each. Methods and Materials: Murine small intestine and human salivary gland tumor (HSG) cells exponentially growing in vitro were irradiated with 6-cm width of spread-out Bragg peaks (SOBPs) adjusted to achieve nearly identical beam depth-dose profiles at the Heavy-Ion Medical Accelerator in Chiba, and the SchwerIonen Synchrotron in Darmstadt. Cell kill efficiencies of carbon ions were measured by colony formation for HSG cells and jejunum crypts survival in mice. Cobalt-60 {gamma} rays were used as the reference radiation. Isoeffective doses at given survivals were used for relative biological effectiveness (RBE) calculations and interinstitutional comparisons. Results: Isoeffective D{sub 10} doses (mean {+-} standard deviation) of HSG cells ranged from 2.37 {+-} 0.14 Gy to 3.47 {+-} 0.19 Gy for Chiba and from 2.31 {+-} 0.11 Gy to 3.66 {+-} 0.17 Gy for Darmstadt. Isoeffective D{sub 10} doses of gut crypts after single doses ranged from 8.25 {+-} 0.17 Gy to 10.32 {+-} 0.14 Gy for Chiba and from 8.27 {+-} 0.10 Gy to 10.27 {+-} 0.27 Gy for Darmstadt, whereas isoeffective D{sub 30} doses after three fractionated doses were 9.89 {+-} 0.17 Gy through 13.70 {+-} 0.54 Gy and 10.14 {+-} 0.20 Gy through 13.30 {+-} 0.41 Gy for Chiba and Darmstadt, respectively. Overall difference of RBE between the two facilities was 0-5% or 3-7% for gut crypt survival or HSG cell kill, respectively. Conclusion: The carbon-ion beams at the National Institute of Radiological Sciences in Chiba, Japan and the Gesellschaft fuer Schwerionenforschung in Darmstadt, Germany are biologically identical after single and daily fractionated irradiation.

  13. Electro-optical characteristics of ZrO2 nanoparticle doped liquid crystal on ion-beam irradiated polyimide layer.

    PubMed

    Park, Hong-Gyu; Kim, Hyung-Jun; Kim, Myoung-Seong; Lee, Il-Hwan; Seo, Dae-Shik

    2012-07-01

    It is well known that doping liquid crystals (LCs) with nanoparticles can readily change the physical and electro-optical properties of LC mixture. In this paper, we report on how the electro-optical properties and thermal stability of an LC system were enhanced by dispersing zirconia (ZrO2) nanoparticles in nematic LCs on ion-beam irradiated polyimide layers. Homogeneous LC alignment was achieved and ZrO2/LC mixture was applied in twisted-nematic (TN) mode. The addition of ZrO2 nanoparticles contributed to improvement of electro-optical properties in the TN LC cell by lowering voltage operation and decreasing response time. The TN LC cells with a ZrO2 nanoparticle concentration of 2.0 wt% showed the lowest threshold voltage of 2.0 V and the fastest response time of 15.3 ms. This enhanced electro-optical performance was likely due to van-der waals interactions and the screening effect of the ZrO2 nanoparticles in the LC medium. The thermal stability of the ZrO2/LC mixture was also improved compared to a pristine LC system. PMID:22966615

  14. Ion beam induced effects on the ferromagnetism in Pd nanoparticles

    SciTech Connect

    Kulriya, P. K.; Mehta, B. R.; Agarwal, D. C.; Agarwal, Kanika; Kumar, Praveen; Shivaprasad, S. M.; Avasthi, D. K.

    2012-06-05

    Present study demonstrates the role of metal-insulator interface and ion irradiation induced defects on the ferromagnetic properties of the non-magnetic materials. Magnetic properties of the Pd nanoparticles(NPs) embedded in the a-silica matrix synthesized using atom beam sputtering technique, were determined using SQUID magnetometry measurements which showed that ferromagnetic response of Pd increased by 3.5 times on swift heavy ion(SHI) irradiation. The ferromagnetic behavior of the as-deposited Pd NPs is due to strain induced by the surrounding matrix and modification in the electronic structure at the Pd-silica interface as revealed by insitu XRD and XPS investigations, respectively. The defects created by the SHI bombardment are responsible for enhancement of the magnetization in the Pd NPs.

  15. The acquisition of Clostridium tyrobutyricum mutants with improved bioproduction under acidic conditions after two rounds of heavy-ion beam irradiation

    PubMed Central

    Zhou, Xiang; Yang, Zhen; Jiang, Ting-Ting; Wang, Shu-Yang; Liang, Jian-Ping; Lu, Xi-Hong; Wang, Liang

    2016-01-01

    End-product inhibition is a key factor limiting the production of organic acid during fermentation. Two rounds of heavy-ion beam irradiation may be an inexpensive, indispensable and reliable approach to increase the production of butyric acid during industrial fermentation processes. However, studies of the application of heavy ion radiation for butyric acid fermentation engineering are lacking. In this study, a second 12C6+ heavy-ion irradiation-response curve is used to describe the effect of exposure to a given dose of heavy ions on mutant strains of Clostridium tyrobutyricum. Versatile statistical elements are introduced to characterize the mechanism and factors contributing to improved butyric acid production and enhanced acid tolerance in adapted mutant strains harvested from the fermentations. We characterized the physiological properties of the strains over a large pH value gradient, which revealed that the mutant strains obtained after a second round of radiation exposure were most resistant to harsh external pH values and were better able to tolerate external pH values between 4.5 and 5.0. A customized second round of heavy-ion beam irradiation may be invaluable in process engineering. PMID:27426447

  16. Formation of multi-charged ion beams by focusing effect of mid-electrode on electron cyclotron resonance ion source

    SciTech Connect

    Imai, Youta Kimura, Daiju; Kurisu, Yosuke; Nozaki, Dai; Yano, Keisuke; Kumakura, Sho; Sato, Fuminobu; Kato, Yushi; Iida, Toshiyuki

    2014-02-15

    We are constructing a tandem type electron cyclotron resonance ion source (ECRIS) and a beam line for extracting ion beams. The ion beam is extracted from the second stage by an accel-decel extraction system with a single-hole and the ion beam current on each electrode is measured. The total ion beam current is measured by a faraday cup downstream the extraction electrodes. We measure these currents as a function of the mid-electrode potential. We also change the gap length between electrodes and perform similar measurement. The behaviors of these currents obtained experimentally against the mid-electrode potential show qualitatively good agreement with a simple theoretical consideration including sheath potential effects. The effect of mid-electrode potential is very useful for decreasing the beam loss for enhancing ion beam current extracted from ECRIS.

  17. Effect of Ar Ion Beam Pre-Treatment of Poly(ethylene terephthalate) Substrate on the Mechanical and Electrical Stability of Flexible InSnO Films Grown by Roll-to-Roll Sputtering System

    NASA Astrophysics Data System (ADS)

    Choi, Kwang-Hyuk; Kim, Han-Ki

    2013-10-01

    We investigated the effects of Ar ion beam irradiation on a flexible poly(ethylene terephthalate) (PET) substrate as surface pre-treatment method in the roll-to-roll (R2R) sputtering system and its contribution to the electrical durability of flexible InSnO (ITO) electrode upon that the flexible PET substrate under repeated mechanical stresses. It was found that the Ar ion beam irradiation of the flexible PET surface could improve an adhesion between R2R sputter-grown ITO film and the PET substrate. X-ray photoelectron spectroscopy results showed that the Ar ion beam irradiation lead to an increase of hydrophilic functional groups when the working pressure, Ar ion beam power, and exposure time increases. Repetitive bending stresses for the flexible ITO/PET film which fabricated through the surface pre-treatment by Ar ion beam irradiation showed more stable electrical durability than those of ITO films on the wet-cleaned PET substrate due to enhanced interfacial adhesion between the ITO film and PET surface. This suggests that the Ar ion beam pre-treatment before sputtering of ITO film in R2R sputtering system is an effective technique to improve the adhesion between ITO film and PET substrate.

  18. Physical and biological properties of the ion beam irradiated PMMA-based composite films

    NASA Astrophysics Data System (ADS)

    Shanthini, G. M.; Martin, Catherine Ann; Sakthivel, N.; Veerla, Sarath Chandra; Elayaraja, K.; Lakshmi, B. S.; Asokan, K.; Kanjilal, D.; Kalkura, S. Narayana

    2015-02-01

    Polymethyl methacrylate (PMMA) and PMMA-hydroxyapatite (PMMA-HAp) composite films, prepared by the solvent evaporation method were irradiated with 100 MeV Si7+ ions. Crystallographic, morphological and the functional groups of the pristine and irradiated samples were studied using glancing incident X-ray diffraction (GIXRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) respectively. SEM reveals the creation of pores, along with an increase in porosity and cluster size on irradiation. Decrease in crystalline nature and crystallite size with an increase in ion fluence was observed from GIXRD patterns. The surface roughness and the wettability of the material were also enhanced, which could favour the cell-material interaction. The irradiated samples adsorbed significantly greater amount of proteins than pristine. Also, irradiation does not produce any toxic byproducts or leachants, and maintains the viability of 3T3 cells. The response of the irradiated samples towards biomedical applications was demonstrated by the improved antimicrobial activity, haemocompatibility and cytocompatibility. Swift heavy ion irradiation (SHI) could be an effective tool to modify and engineer the surface properties of the polymers to enhance the biocompatibility.

  19. High performance twisted nematic liquid crystal display with solution-derived YZO surface modification via ion-beam irradiation.

    PubMed

    Lee, Jae-Won; Park, Hong-Gyu; Jeong, Hae-Chang; Jang, Sang-Bok; Park, Tae-Kyu; Seo, Dae-Shik

    2014-12-15

    Solution-derived YZO films were investigated as liquid crystal (LC) alignment layers modified by ion beam (IB) irradiation. Solution processing was adopted in place of the sputtering method for the deposition of YZO films as LC alignment layers. Uniform and homogeneous LC alignment was achieved to produce a high performance LC system. X-ray photoelectron spectroscopy analysis showed that surface reformation of YZO films by annealing and IB irradiation affects the uniformity of the LC alignment. Superior electro-optical characteristics of twisted nematic LC cells constructed from IB-irradiated YZO films were observed, which indicates that the proposed solution-derived YZO films have strong potential for use in the production of advanced LC displays. PMID:25607088

  20. Effect of hydrogen ion beam treatment on Si nanocrystal/SiO2 superlattice-based memory devices

    NASA Astrophysics Data System (ADS)

    Fu, Sheng-Wen; Chen, Hui-Ju; Wu, Hsuan-Ta; Chuang, Bing-Ru; Shih, Chuan-Feng

    2016-03-01

    This study presents a novel route for synthesizing silicon-rich oxide (SRO)/SiO2 superlattice-based memory devices with an improved memory window and retention properties. The SiO2 and SRO superlattices are deposited by reactive sputtering. Specifically, the hydrogen ion beam is used to irradiate the SRO layer immediately after its deposition in the vacuum chamber. The use of the hydrogen ion beam was determined to increase oxygen content and the density of the Si nanocrystals. The memory window increased from 16 to 25.6 V, and the leakage current decreased significantly by two orders, to under ±20 V, for the hydrogen ion beam-prepared devices. This study investigates the mechanism into how hydrogen ion beam treatment alters SRO films and influences memory properties.

  1. Effect of powerful pulsed and continuous ion beams on the Al- Cu-Mg alloy structure

    NASA Astrophysics Data System (ADS)

    Gushchina, N. V.; Makhin'ko, F. F.; Ovchinnikov, V. V.; Gusel'nikov, V. I.; Remnev, G. E.

    2016-02-01

    The paper considers the results of an electron microscopy study of the VD1 alloy of the Al-Cu-Mg system after cold working and subsequent irradiation with a powerful pulsed ion beam (70% C+ + 30% H+, E = 180 keV) in the pulsed-periodic mode (t = 80 ns, f = 0.1 Hz, j = 200 A/cm2, F = 1-1014 cm-2) and under the conditions of the generation of only one pulse (t = 180 ns, j = 100 A/cm2, F = 2-1015 cm-2). It is established that this irradiation noticeably affects the microstructure of the cold-worked 3 mm thick sheets of VD1 alloy. The initial cellular dislocation structure transforms into a subgrain one. The intensity of structural transformations in the alloy increases with ion current density of a pulse. A similar transformation of a dislocation structure over the entire thickness of the sample is observed under irradiation with continuous Ar+ ion beams (E = 20-40 keV) with not high fluences (1015-1016 cm-2).

  2. Ion Beam Energy Dependant Study of Nanopore Sculpting

    NASA Astrophysics Data System (ADS)

    Ledden, Brad

    2005-03-01

    Experiments show that ion beams of various energies (1keV, 3keV, and 5keV) can be used to controllably ``sculpt'' nanoscale features in silicon nitride films using a feedback controlled ion beam sculpting apparatus. We report on nanopore ion beam sculpting effects that depend on inert gas ion beam energy. We show that: (1) all ion beam energies enable single nanometer control of structural dimensions in nanopores; (2) the ion beam energies above show similar ion beam flux dependence of nanopore formation; (3) the thickness of nanopores differs depending on ion beam energy. Computer simulations (with SRIM and TRIM) and an ``adatom'' surface diffusion model are employed to explain the dynamics of nanoscale dimension change by competing sputtering and surface mass transport processes induced by different ion beam irradiation. These experiments and theoretical work reveal the surface atomic transport phenomena in a quantitative way that allows the extraction of parameters such as the adatom surface diffusion coefficients and average travel distances.

  3. Annealing of TiO2 Films Deposited on Si by Irradiating Nitrogen Ion Beams

    SciTech Connect

    Yokota, Katsuhiro; Yano, Yoshinori; Miyashita, Fumiyoshi

    2006-11-13

    Thin TiO2 films were deposited on Si at a temperature of 600 deg. C by an ion beam assisted deposition (IBAD) method. The TiO2 films were annealed for 30 min in Ar at temperatures below 700 deg. C. The as-deposited TiO2 films had high permittivities such 200 {epsilon}o and consisted of crystallites that were not preferentially oriented to the c-axis but had an expanded c-axis. On the annealed TiO2 films, permittivities became lower with increasing annealing temperature, and crystallites were oriented preferentially to the (110) plane.

  4. A novel algorithm for the calculation of physical and biological irradiation quantities in scanned ion beam therapy: the beamlet superposition approach

    NASA Astrophysics Data System (ADS)

    Russo, G.; Attili, A.; Battistoni, G.; Bertrand, D.; Bourhaleb, F.; Cappucci, F.; Ciocca, M.; Mairani, A.; Milian, F. M.; Molinelli, S.; Morone, M. C.; Muraro, S.; Orts, T.; Patera, V.; Sala, P.; Schmitt, E.; Vivaldo, G.; Marchetto, F.

    2016-01-01

    The calculation algorithm of a modern treatment planning system for ion-beam radiotherapy should ideally be able to deal with different ion species (e.g. protons and carbon ions), to provide relative biological effectiveness (RBE) evaluations and to describe different beam lines. In this work we propose a new approach for ion irradiation outcomes computations, the beamlet superposition (BS) model, which satisfies these requirements. This model applies and extends the concepts of previous fluence-weighted pencil-beam algorithms to quantities of radiobiological interest other than dose, i.e. RBE- and LET-related quantities. It describes an ion beam through a beam-line specific, weighted superposition of universal beamlets. The universal physical and radiobiological irradiation effect of the beamlets on a representative set of water-like tissues is evaluated once, coupling the per-track information derived from FLUKA Monte Carlo simulations with the radiobiological effectiveness provided by the microdosimetric kinetic model and the local effect model. Thanks to an extension of the superposition concept, the beamlet irradiation action superposition is applicable for the evaluation of dose, RBE and LET distributions. The weight function for the beamlets superposition is derived from the beam phase space density at the patient entrance. A general beam model commissioning procedure is proposed, which has successfully been tested on the CNAO beam line. The BS model provides the evaluation of different irradiation quantities for different ions, the adaptability permitted by weight functions and the evaluation speed of analitical approaches. Benchmarking plans in simple geometries and clinical plans are shown to demonstrate the model capabilities.

  5. Effects of ion beam mixing on the formation of SiGe nanocrystals by ion implantation

    SciTech Connect

    Zhu, J.G.; White, C.W.; Budai, J.D.; Withrow, S.P.; Henderson, D.O.

    1996-06-01

    Nanocrystals of SiGe alloy have been formed inside a SiO{sub 2} matrix by the ion implantation technique. It is demonstrated that the sequence of implantation of Si and Ge ions affects the nanocrystal formation significantly. This is explained by the ion beam mixing effect during sequential implantation. The size distributions of the SiGe nanocrystals can also be controlled by annealing conditions.

  6. Ion-beam irradiation, gene identification, and marker-assisted breeding in the development of low-cadmium rice.

    PubMed

    Ishikawa, Satoru; Ishimaru, Yasuhiro; Igura, Masato; Kuramata, Masato; Abe, Tadashi; Senoura, Takeshi; Hase, Yoshihiro; Arao, Tomohito; Nishizawa, Naoko K; Nakanishi, Hiromi

    2012-11-20

    Rice (Oryza sativa L.) grain is a major dietary source of cadmium (Cd), which is toxic to humans, but no practical technique exists to substantially reduce Cd contamination. Carbon ion-beam irradiation produced three rice mutants with <0.05 mg Cd⋅kg(-1) in the grain compared with a mean of 1.73 mg Cd⋅kg(-1) in the parent, Koshihikari. We identified the gene responsible for reduced Cd uptake and developed a strategy for marker-assisted selection of low-Cd cultivars. Sequence analysis revealed that these mutants have different mutations of the same gene (OsNRAMP5), which encodes a natural resistance-associated macrophage protein. Functional analysis revealed that the defective transporter protein encoded by the mutant osnramp5 greatly decreases Cd uptake by roots, resulting in decreased Cd in the straw and grain. In addition, we developed DNA markers to facilitate marker-assisted selection of cultivars carrying osnramp5. When grown in Cd-contaminated paddy fields, the mutants have nearly undetectable Cd in their grains and exhibit no agriculturally or economically adverse traits. Because mutants produced by ion-beam radiation are not transgenic plants, they are likely to be accepted by consumers and thus represent a practical choice for rice production worldwide. PMID:23132948

  7. Irradiation With Carbon Ion Beams Induces Apoptosis, Autophagy, and Cellular Senescence in a Human Glioma-Derived Cell Line

    SciTech Connect

    Jinno-Oue, Atsushi; Shimizu, Nobuaki; Hamada, Nobuyuki; Wada, Seiichi; Tanaka, Atsushi; Shinagawa, Masahiko; Ohtsuki, Takahiro; Mori, Takahisa; Saha, Manujendra N.; Hoque, Ariful S.; Islam, Salequl; Kogure, Kimitaka; Funayama, Tomoo; Kobayashi, Yasuhiko

    2010-01-15

    Purpose: We examined biological responses of human glioma cells to irradiation with carbon ion beams (C-ions). Methods and Materials: A human glioma-derived cell line, NP-2, was irradiated with C-ions. Apoptotic cell nuclei were stained with Hoechst 33342. Induction of autophagy was examined either by staining cells with monodansylcadaverine (MDC) or by Western blotting to detect conversion of microtuble-associated protein light chain 3 (MAP-LC3) (LC3-I) to the membrane-bound form (LC3-II). Cellular senescence markers including induction of senescence-associated beta-galactosidase (SA-beta-gal) were examined. The mean telomere length of irradiated cells was determined by Southern blot hybridization. Expression of tumor suppressor p53 and cyclin/cyclin-dependent kinase inhibitor p21{sup WAF1/CIP1} in the irradiated cells was analyzed by Western blotting. Results: When NP-2 cells were irradiated with C-ions at 6 Gy, the major population of the cells died of apoptosis and autophagy. The residual fraction of attached cells (<1% of initially irradiated cells) could not form a colony: however, they showed a morphological phenotype consistent with cellular senescence, that is, enlarged and flattened appearance. The senescent nature of these attached cells was further indicated by staining for SA-beta-gal. The mean telomere length was not changed after irradiation with C-ions. Phosphorylation of p53 at serine 15 as well as the expression of p21{sup WAF1/CIP1} was induced in NP-2 cells after irradiation. Furthermore, we found that irradiation with C-ions induced cellular senescence in a human glioma cell line lacking functional p53. Conclusions: Irradiation with C-ions induced apoptosis, autophagy, and cellular senescence in human glioma cells.

  8. Effect of ion beam parameters on engineering of nanoscale voids and their stability under post-growth annealing

    NASA Astrophysics Data System (ADS)

    Hooda, Sonu; Khan, S. A.; Satpati, B.; Stange, D.; Buca, D.; Bala, M.; Pannu, C.; Kanjilal, D.; Kabiraj, Debdulal

    2016-03-01

    Swift heavy ion (SHI) irradiation of damaged germanium (d-Ge) layer results in porous structure with voids aligned along ion trajectory due to local melting and resolidification during high electronic energy deposition. The present study focuses on the irradiation temperature- and incident angle-dependent growth dynamics and shape evolution of these voids due to 100 MeV Ag ions irradiation. The d-Ge layers were prepared by multiple low-energy Ar ion implantations in single crystalline Ge with damage formation of ~7 displacements per atom. Further, these d-Ge layers were irradiated using 100 MeV Ag ions at two different temperatures (77 and 300 K) and three different angles (7°, 30° and 45°). After SHI irradiation, substantial volume expansion of d-Ge layer is detected which is due to formation of nanoscale voids. The volume expansion is observed to be more in the samples irradiated at 77 K as compared to 300 K at a given irradiation fluence. It is observed that the voids are of spherical shape at low ion irradiation fluence. The voids grow in size and change their shape from spherical to prolate spheroid with increasing ion fluence. The major axis of spheroid is observed to be aligned approximately along the ion beam direction which has been confirmed by irradiation at three different angles. The change in shape is a consequence of combination of compressive strain and plastic flow developed due to thermal spike generated along ion track. Post-SHI irradiation annealing shows increase in size of voids and reversal of shape from prolate spheroid towards spherical through strain relaxation. The stability of voids was studied with the effect of post-growth annealing.

  9. Influence of the ion irradiation on the properties of β-FeSi 2 layers prepared by ion beam assisted deposition

    NASA Astrophysics Data System (ADS)

    Barradas, N. P.; Panknin, D.; Wieser, E.; Schmidt, B.; Betzl, M.; Mücklich, A.; Skorupa, W.

    1997-05-01

    β-FeSi 2 layers on Si substrates were produced by ion beam assisted deposition (IBAD). The influence of the deposition parameters on the structure was studied by Rutherford backscattering, X-ray diffraction, cross-section transmission electron microscopy, and scanning electron microscopy. The layers grow in a columnar way with pin-holes and their surface is rough. An IBAD process with low Ar energy ( EAr = 200 eV) and low Ar ion to Fe atom ratio ( {I Ar}/{A Fe} = 0.15 ) improves the layer structure in comparison to samples prepared without Ar irradiation. Less pin-holes are formed, and the roughness shows a minimum. The roughness increases for larger values of EAr or {I Ar}/{A Fe}. All samples are polycrystalline but with a pronounced texture. The preferential orientation FeSi 2(110,101)∥Si(001), with a few degrees misorientation, is found. This preferred grain orientation is also enhanced by the IBAD process. Hall effect measurements were done and the I-V characteristics of the samples were measured. The results are discussed in relation with the influence of the ion beam.

  10. Vertical Liquid Crystal Orientation on Amorphous Tantalum Pentoxide Surfaces Depending on Anisotropic Dipole-Dipole Interaction via Ion Beam Irradiation

    NASA Astrophysics Data System (ADS)

    Lee, Jong-Jin; Kim, Hyung-Jun; Kang, Young-Gu; Kim, Young-Hwan; Park, Hong-Gyu; Kim, Byoung-Yong; Seo, Dae-Shik

    2011-03-01

    We achieved vertically aligned (VA) liquid crystals (LCs) on amorphous tantalum pentoxide (Ta2O5) alignment films deposited by radio frequency (rf) magnetron sputtering using ion beam (IB) irradiation. By analyzing measurements by X-ray photoelectron spectroscopy (XPS), we confirmed the bond breaking, as detected from the O 1s spectra, which caused an isotropic dipole-dipole interaction between the LC molecules and the Ta2O5 alignment film to uniformly align the vertical LC molecular orientation as a function of IB energy density. Moreover, by examining the electro-optical (EO) characteristics of the Ta2O5 surfaces compared with those of the polyimide (PI) alignment layer, we confirmed that Ta2O5 has a low threshold voltage and a low power consumption when used as an LC alignment layer.

  11. Ion beam degradation analysis of poly(3-hexylthiophene) (P3HT): can cryo-FIB minimize irradiation damage?

    PubMed

    Sezen, Meltem; Plank, Harald; Nellen, Philipp M; Meier, Stephan; Chernev, Boril; Grogger, Werner; Fisslthaler, Evelin; List, Emil J W; Scherf, Ullrich; Poelt, Peter

    2009-07-01

    In this study, to assess the influence of the temperature on the ion beam degradation, irradiation experiments on organic semiconductor materials were performed for both cryogenic and room temperature conditions. Thin P3HT films on silicon substrates were exposed to increasing ion doses in dual beam FIB. The degradation behaviour by means of a decrease in the C[double bond, length as m-dash]C band which corresponds to a loss of conjugation was investigated by means of Raman spectroscopy. In addition, atomic force microscopy (AFM) and Kelvin probe force microscopy (KPFM) were used for a characterization of morphology and surface potential which provide information on temperature and ion dose dependent degradation behaviour. PMID:19562145

  12. Biaxial texturing of inorganic photovoltaic thin films using low energy ion beam irradiation during growth

    SciTech Connect

    Groves, James R; De Paula, Raymond F; Hayes, Garrett H; Li, Joel B; Hammond, Robert H; Salleo, Alberto; Clemens, Bruce M

    2010-05-07

    We describe our efforts to control the grain boundary alignment in polycrystalline thin films of silicon by using a biaxially textured template layer of CaF{sub 2} for photovoltaic device applications. We have chosen CaF{sub 2} as a candidate material due to its close lattice match with silicon and its suitability as an ion beam assisted deposition (mAD) material. We show that the CaF{sub 2} aligns biaxially at a thickness of {approx}10 nm and, with the addition of an epitaxial CaF{sub 2} layer, has an in-plane texture of {approx}15{sup o}. Deposition of a subsequent layer of Si aligns on the template layer with an in-plane texture of 10.8{sup o}. The additional improvement of in-plane texture is similar to the behavior observed in more fully characterized IBAD materials systems. A germanium buffer layer is used to assist in the epitaxial deposition of Si on CaF{sub 2} template layers and single crystal substrates. These experiments confirm that an mAD template can be used to biaxially orient polycrystalline Si.

  13. Carbon ion beam focusing using laser irradiated heated diamond hemispherical shells

    SciTech Connect

    Offermann, Dustin T; Flippo, Kirk A; Gaillard, Sandrine A

    2009-01-01

    Experiments preformed at the Los Alamos National Laboratory's Trident Laser Facility were conducted to observe the acceleration and focusing of carbon ions via the TNSA mechanism using hemispherical diamond targets. Trident is a 200TW class laser system with 80J of 1 {micro}m, short-pulse light delivered in 0.5ps, with a peak intensity of 5 x 10{sup 20} W/cm{sup 2}. Targets where Chemical Vapor Deposition (CVD) diamonds formed into hemispheres with a radius of curvature of 400{micro}m and a thickness of 5{micro}m. The accelerated ions from the hemisphere were diagnosed by imaging the shadow of a witness copper mesh grid located 2mm behind the target onto a film pack located 5cm behind the target. Ray tracing was used to determine the location of the ion focal spot. The TNSA mechanism favorably accelerates hydrogen found in and on the targets. To make the carbon beam detectable, targets were first heated to several hundred degrees Celsius using a CW, 532nm, 8W laser. Imaging of the carbon beam was accomplished via an auto-radiograph of a nuclear activated lithium fluoride window in the first layer of the film pack. The focus of the carbon ion beam was determined to be located 630 {+-} 110 {micro}m from the vertex of the hemisphere.

  14. Channeling effect in polycrystalline deuterium-saturated CVD diamond target bombarded by deuterium ion beam

    NASA Astrophysics Data System (ADS)

    Bagulya, A. V.; Dalkarov, O. D.; Negodaev, M. A.; Rusetskii, A. S.; Chubenko, A. P.; Ralchenko, V. G.; Bolshakov, A. P.

    2015-07-01

    At the ion accelerator HELIS at LPI, the neutron yield is investigated in DD reactions within a strongly textured polycrystalline deuterium-saturated CVD diamond under irradiation by a deuterium ion beam with the energy of less than 30 keV. The measurements of the neutron flux in the beam direction are performed using a multichannel detector based on 3He counters, in dependence on the target angle, β, with respect to the beam axis. A significant anisotropy in the neutron yield is observed. At β = 0° the yield is higher by a factor of 3 as compared to that at β = ±45°. The possible reasons for the anisotropy, including ion channeling, are discussed.

  15. Effects of coating material on the fabrication accuracy of focused ion beam machining of insulators

    NASA Astrophysics Data System (ADS)

    Joe, Hang-Eun; Park, Jae-Hyeong; Kim, Seong Hyeon; Kim, Gyuho; Jun, Martin B. G.; Min, Byung-Kwon

    2015-09-01

    Focused ion beam (FIB) machining of insulators is a crucial process in the rapid prototyping of nanodevices for optical applications. A conductive material is generally coated on the insulator prior to FIB machining to achieve high fabrication accuracy. In this paper, we report on the effects on machining accuracy of four coating materials: Pt, Ni, Ag, and Co. The dimensional accuracy at channel sidewalls was improved by selecting a coating material that induces charge-carrier generation in a small range. The geometric and electrical characteristics of the FIB-machined surfaces were evaluated to elucidate the association between the fabrication accuracy and the range of charge-carrier distribution.

  16. Effects of polycrystallinity in nano patterning by ion-beam sputtering

    SciTech Connect

    Yoon, Sun Mi; Kim, J.-S.; Yoon, D.; Cheong, H.; Kim, Y.; Lee, H. H.

    2014-07-14

    Employing graphites with distinctly different mean grain sizes, we study the effects of polycrystallinity on the pattern formation by ion-beam sputtering. The grains influence the growth of the ripples in a highly anisotropic fashion; both the mean uninterrupted ripple length along the ridges and the surface width depend on the mean size of the grains, which is attributed to the large sputter yield at the grain boundary compared with that on the terrace. In contrast, the ripple wavelength does not depend on the mean size of the grains, indicating that the mass transport across the grain boundaries should efficiently proceed by both thermal diffusion and ion-induced processes.

  17. Effect of reactive ion beam etching on the photoluminescence of CdTe epitaxial layers

    SciTech Connect

    Martinez-Pastor, J.; Fuster, D.; Abellan, M.; Anguita, J.; Sochinskii, N. V.

    2008-03-01

    We demonstrated the effect of reactive ion beam etching (RIBE) process on the PL properties of CdTe/sapphire metal organic vapor phase epitaxy layers. At optimum conditions, the RIBE attack does not make significant morphological changes but it results in an increase of the concentration of acceptor impurities. This was revealed by an increase of the overall photoluminescence (PL) intensity and, simultaneously, a decrease of the PL decay time, more important on the low energy side of PL spectrum due to the recombination of carriers in acceptor pairs.

  18. Optimal conditions for high current proton irradiations at the university of Wisconsin's ion beam laboratory

    SciTech Connect

    Wetteland, C. J.; Field, K. G.; Gerczak, T. J.; Eiden, T. J.; Maier, B. R.; Albakri, O.; Sridharan, K.; Allen, T. R.

    2013-04-19

    The National Electrostatics Corporation's (NEC) Toroidal Volume Ion Source (TORVIS) source is known for exceptionally high proton currents with minimal service downtime as compared to traditional sputter sources. It has been possible to obtain over 150{mu}A of proton current from the source, with over 70{mu}A on the target stage. However, beam fluxes above {approx}1 Multiplication-Sign 10{sup 17}/m2-s may have many undesirable effects, especially for insulators. This may include high temperature gradients at the surface, sputtering, surface discharge, cracking or even disintegration of the sample. A series of experiments were conducted to examine the role of high current fluxes in a suite of ceramics and insulating materials. Results will show the optimal proton irradiation conditions and target mounting strategies needed to minimize unwanted macro-scale damage, while developing a procedure for conducting preliminary radiation experiments.

  19. Characterization of ion beam irradiated 304 stainless steel utilizing nanoindentation and Laue microdiffraction

    NASA Astrophysics Data System (ADS)

    Lupinacci, A.; Chen, K.; Li, Y.; Kunz, M.; Jiao, Z.; Was, G. S.; Abad, M. D.; Minor, A. M.; Hosemann, P.

    2015-03-01

    Characterizing irradiation damage in materials utilized in light water reactors is critical for both material development and application reliability. Here we use both nanoindentation and Laue microdiffraction to characterize both the mechanical response and microstructure evolution due to irradiation. Two different irradiation conditions were considered in 304 stainless steel: 1 dpa and 10 dpa. In addition, an annealed condition of the 10 dpa specimen for 1 h at 500 °C was evaluated. Nanoindentation revealed an increase in hardness due to irradiation and also revealed that hardness saturated in the 10 dpa case. Broadening using Laue microdiffraction peaks indicates a significant plastic deformation in the irradiated area that is in good agreement with both the SRIM calculations and the nanoindentation results.

  20. Development of ion beams for space effects testing using an ECR ion source

    SciTech Connect

    Benitez, Janilee; Hodgkinson, Adrian; Johnson, Mike; Loew, Tim; Lyneis, Claude; Phair, Larry

    2013-04-19

    At LBNL's 88-Inch Cyclotron and Berkeley Accelerator Space Effects (BASE) Facility, a range of ion beams at energies from 1 to 55 MeV/nucleon are used for radiation space effects testing. By bombarding a component with ion beams the radiation component of the space environment can be simulated and single event effects (SEEs) determined. The performance of electronic components used in space flight and high altitude aircraft can then be evaluated. The 88- Inch Cyclotron is coupled to the three electron cyclotron resonance ion sources (ECR, AECR-U, VENUS). These ion sources provide a variety of ion species, ranging from protons to heavy ions such as bismuth, for these tests. In particular the ion sources have been developed to provide {sup c}ocktails{sup ,} a mixture of ions of similar mass-to-charge ratio, which can be simultaneously injected into the cyclotron, but selectively extracted from it. The ions differ in both their linear energy transfer (LET) deposited to the part and in their penetration depth into the tested part. The current heavy ion cocktails available are the 4.5, 10, 16, and 30 MeV per nucleon.

  1. Flux effect on the ion-beam nitriding of austenitic stainless-steel AISI 304L

    SciTech Connect

    Abrasonis, G.; Riviere, J.P.; Templier, C.; Pranevicius, L.; Barradas, N.P.

    2005-06-15

    The effect of flux and Ar pretreatment during ion-beam nitriding of austenitic stainless steel is investigated. The ion energy and temperature were 1.2 keV and 400 deg. C, respectively, the ion current densities were 0.5, 0.67, and 0.83 mA cm{sup -2}. The nitrogen distribution profiles were measured using nuclear reaction analysis. The obtained nitrogen distribution profiles were analyzed by the means of the nitrided layer thickness evolution due to sputtering and diffusion and the model of trapping-detrapping. Both approaches could fit well the experimental results, however, different diffusion coefficients have to be assumed for each current density. In addition, the diffusion coefficients are higher for higher current densities. On the other hand, it is shown that the pretreatment with Ar-ion beam at nitriding temperatures produces only a thermal effect without any other influence on the following nitrogen diffusion. The results are discussed in relation with surface and temperature effects and atomic transport mechanisms.

  2. Development of ion beams for space effects testing using an ECR ion source

    NASA Astrophysics Data System (ADS)

    Benitez, Janilee; Hodgkinson, Adrian; Johnson, Mike; Loew, Tim; Lyneis, Claude; Phair, Larry

    2013-04-01

    At LBNL's 88-Inch Cyclotron and Berkeley Accelerator Space Effects (BASE) Facility, a range of ion beams at energies from 1 to 55 MeV/nucleon are used for radiation space effects testing. By bombarding a component with ion beams the radiation component of the space environment can be simulated and single event effects (SEEs) determined. The performance of electronic components used in space flight and high altitude aircraft can then be evaluated. The 88- Inch Cyclotron is coupled to the three electron cyclotron resonance ion sources (ECR, AECR-U, VENUS). These ion sources provide a variety of ion species, ranging from protons to heavy ions such as bismuth, for these tests. In particular the ion sources have been developed to provide "cocktails", a mixture of ions of similar mass-to-charge ratio, which can be simultaneously injected into the cyclotron, but selectively extracted from it. The ions differ in both their linear energy transfer (LET) deposited to the part and in their penetration depth into the tested part. The current heavy ion cocktails available are the 4.5, 10, 16, and 30 MeV per nucleon.

  3. Atomic-scale effects behind structural instabilities in Si lamellae during ion beam thinning

    SciTech Connect

    Holmstroem, E.; Nordlund, K.; Kotakoski, J.; Lechner, L.; Kaiser, U.

    2012-03-15

    The rise of nanotechnology has created an ever-increasing need to probe structures on the atomic scale, to which transmission electron microscopy has largely been the answer. Currently, the only way to efficiently thin arbitrary bulk samples into thin lamellae in preparation for this technique is to use a focused ion beam (FIB). Unfortunately, the established FIB thinning method is limited to producing samples of thickness above {approx}20 nm. Using atomistic simulations alongside experiments, we show that this is due to effects from finite ion beam sharpness at low milling energies combined with atomic-scale effects at high energies which lead to shrinkage of the lamella. Specifically, we show that attaining thickness below 26 nm using a milling energy of 30 keV is fundamentally prevented by atomistic effects at the top edge of the lamella. Our results also explain the success of a recently proposed alternative FIB thinning method, which is free of the limitations of the conventional approach due to the absence of these physical processes.

  4. Radiation transport effects in heavy-ion beam--target interaction studies: Measurement of target opacity and beam conversion efficiency

    SciTech Connect

    Tahir, N. A.; Arnold, R. C.

    1989-07-01

    In this paper detailed simulations are presented of radiation-hydrodynamicresponse of gaseous cylindrical targets irradiated with heavy-ion beams thatwill be produced at the Gesellschaft f/umlt u/r Schwerionenforschung, Darmstadt,using a heavy-ion synchrotron (SIS) (/ital Heavy/ /ital Ion//usion/, AIP Conference Proceedings No. 152 (AIP, NewYork, 1986), p. 23). The purpose of this work is to explore material conditionsfor which the thermal radiation effects can be maximized. This is desirable inorder to study a number of interesting and important effects includingmaximization of conversion efficiency of the ion beam energy to thermalradiation and measurement of the target opacity in the SIS experiments. It isexpected that the SIS beams will produce a specific deposition power of 10 TW/g.The simulations in this paper show that a temperature of the order of 10 eVcould be achieved by the SIS beams using homogeneous, cylindrical Xe targets. Ithas been shown that with the help of these computer simulations one should beable to measure the target opacity in these experiments within a factor of 3.Also these calculations show that in the SIS experiments one should be able tohave a 50% conversion efficiency using a Xe target under optimum conditions. Ithas been found that the radiation effects will be optimized in the SISexperiments if the initial target density is of the order of 10/sup /minus/3/ g/cm/sup 3/.If the initial density is too high (of the order of 10/sup /minus/1/ g/cm/sup 3/ or more),hydrodynamic effects will dominate, while, on the other hand, if the initialdensity is too low (of the order of 10/sup /minus/4/ g/cm/sup 3/ or less), the electronthermal conductivity will take over.

  5. Homogeneously aligned liquid crystal molecules on reformed poly(methyl methacrylate) via ion-beam irradiation

    NASA Astrophysics Data System (ADS)

    Jeong, Hae-Chang; Park, Hong-Gyu; Lee, Ju Hwan; Jang, Sang Bok; Oh, Byeong-Yun; Han, Jeong-Min; Seo, Dae-Shik

    2016-04-01

    We demonstrated uniform LC alignment using IB-irradiated poly(methyl methacrylate) (PMMA) as an alignment layer. We confirmed the topographical changes on PMMA caused by IB irradiation. Moreover, the wettability and chemical modification of the PMMA surface were investigated as functions of incidence angle. The results show that PMMA irradiated with IB at an incidence angle of 30° had a higher molecular polarity than PMMA irradiated with IB at other incidence angles, resulting in strong van der Waals interactions between the surface and LC molecules. The LC cells containing PMMA irradiated with IB at an incidence angle of 30° exhibited good thermal stability (180°) compared with LC cells containing conventional rubbing PI (150°). In addition, LC molecules on PMMA irradiated with IB at an incidence angle of 30° were observed to switch faster than those on conventional rubbing PI. Therefore, PMMA irradiated with IB under the optimal conditions may allow for PMMA to be applied in advanced LC devices as an alternative alignment layer.

  6. Performance characteristics of HBC stripper foils irradiated by 650 keV H- and high intensity DC ion beams

    NASA Astrophysics Data System (ADS)

    Sugai, I.; Takagi, A.; Takeda, Y.; Irie, Y.; Oyaizu, M.; Kawakami, H.

    2014-06-01

    Newly developed Hybrid type Boron mixed Carbon (HBC) stripper foils are extensively used not only for the RCS of J-PARC and PSR of LANL, but also for other low energy, high intensity proton accelerators in medical applications. We had before tested HBC stripper foils with 3.2 MeV Ne+ and DC heavy ion beams. In order to further understand characteristics of HBC stripper foils, we measured the following parameters using the KEK-650 keV H- and light ion Cockcroft Walton DC accelerator: foil lifetime, thickness reduction, uniformity before and after beam irradiation, and foil deformation. Energy deposition in the present experiment was adjusted to a similar level to that of the HBC foil used in the RCS of J-PARC’. In addition, to understand the reason why the HBC stripper foils have high durability against high intensity beam irradiation, we investigated various physical properties, and compared them between the HBC foils and other tested carbon stripper foils. The sizes of the carbon particles in the HBC foil were found to play a vital role in the lifetime.

  7. Effects of evolving surface morphology on yield during focused ion beam milling of carbon.

    SciTech Connect

    Mayer, Thomas Michael; Adams, David Price; Archuleta, Kim M.; Vasile, Michael J.

    2005-07-01

    We investigate evolving surface morphology during focused ion beam bombardment of C and determine its effects on sputter yield over a large range of ion dose (10{sup 17}-10{sup 19} ions/cm{sup 2}) and incidence angles ({Theta} = 0-80{sup o}). Carbon bombarded by 20 keV Ga{sup +} either retains a smooth sputtered surface or develops one of two rough surface morphologies (sinusoidal ripples or steps/terraces) depending on the angle of ion incidence. For conditions that lead to smooth sputter-eroded surfaces there is no change in yield with ion dose after erosion of the solid commences. However, for all conditions that lead to surface roughening we observe coarsening of morphology with increased ion dose and a concomitant decrease in yield. A decrease in yield occurs as surface ripples increase wavelength and, for large {Theta}, as step/terrace morphologies evolve. The yield also decreases with dose as rippled surfaces transition to have steps and terraces at {Theta} = 75{sup o}. Similar trends of decreasing yield are found for H{sub 2}O-assisted focused ion beam milling. The effects of changing surface morphology on yield are explained by the varying incidence angles exposed to the high-energy beam.

  8. Localized dose delivering by ion beam irradiation for experimental trial of establishing brain necrosis model.

    PubMed

    Takata, Takushi; Kondo, Natsuko; Sakurai, Yoshinori; Tanaka, Hiroki; Hasegawa, Takashi; Kume, Kyo; Suzuki, Minoru

    2015-11-01

    Localized dose delivery techniques to establish a brain radiation necrosis model are described. An irradiation field was designed by using accelerated protons or helium ions with a spread-out Bragg peak. Measurement of the designed field confirmed that a high dose can be confined to a local volume of an animal brain. The irradiation techniques described here are very useful for establishing a necrosis model without existence of extraneous complications. PMID:26454176

  9. The influence of ion beam rastering on the swelling of self-ion irradiated pure iron at 450 °C

    NASA Astrophysics Data System (ADS)

    Gigax, Jonathan G.; Aydogan, Eda; Chen, Tianyi; Chen, Di; Shao, Lin; Wu, Y.; Lo, W. Y.; Yang, Y.; Garner, F. A.

    2015-10-01

    Ion beam scanning or "rastering" is a technique that is frequently used to uniformly cover a larger specimen area during ion irradiation. In this study, we addressed the effects of rastered and defocused beams, using 3.5 MeV iron ions to irradiate pure iron at 450 °C to peak doses of 50 and 150 dpa. We focused on a frequency range relevant to pulsed fusion devices and show its importance to ion irradiation experiments used for simulating neutron damage. The beam was scanned at 15.6, 1.94, and 0.244 Hz and the resulting microstructure was compared with that produced by a non-rastered, defocused beam. At 150 dpa, the defocused beam case resulted in the highest observed void swelling of ∼12% at a depth of ∼700 nm, a depth short of the peak dose position at 1000 nm. The swelling at the peak dose position was significantly reduced by the defect imbalance phenomenon. A maximum swelling rate of ∼0.12%/dpa was measured in this specimen at a depth of 600 nm below the ion-incident surface. Rastering led to much lower swelling levels achieved at significantly lower swelling rates, with the greatest rate of decrease occurring below ∼1 Hz. Furthermore, the impact of the defect imbalance arising from interstitial injection and spatial distribution difference of initial interstitial and vacancy defects was strongly pronounced in the non-rastered case with a lesser effect observed with decreasing raster frequency.

  10. Nanoscale patterning of CrPt3 magnetic thin films by using ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Suharyadi, Edi; Oshima, Daiki; Kato, Takeshi; Iwata, Satoshi

    We have successfully fabricated planar patterned CrPt3 ordered L12 alloy films by Kr+ ion irradiation. Planar-patterned CrPt3 nanodots with various bit sizes from 200 nm to 50 nm were successfully fabricated by 30 keV Kr+ ion irradiation at a dose of 2 × 1014 ions/cm2, where e-beam lithography was used for creating the resist mask. We have confirmed that the nanofabrication process didn't change the magnetic properties of CrPt3 ordered L12 alloy films. As-prepared film exhibited perpendicular hysteresis loop with the coercivity of 5.5 kOe. The typical perpendicular maze domain structure with the stripe structure was clearly seen in as-prepared CrPt3 film. Magnetic force microscopy (MFM) images of patterned CrPt3 nanodots indicated that each un-irradiated bit consists of localized perpendicular magnetic domain structures, which corresponds to perpendicular magnetization direction. Nanodots with bit size ⩽80 nm show either dark or bright contrast, suggesting single domain structure. No magnetic contrast in irradiated space is due to the suppressing of the magnetization by Kr+ ion irradiation.

  11. Dual and Triple Ion-Beam Irradiations of Fe, Fe(Cr) and Fe(Cr)-ODS Final Report: IAEA SMoRE CRP

    SciTech Connect

    Fluss, M J; Hsiung, L L; Marian, J

    2011-11-20

    Structures of nanoparticles in Fe-16Cr-4.5Al-0.3Ti-2W-0.37Y2O3 (K3) and Fe-20Cr-4.5Al-0.34Ti-0.5Y2O3 (MA956) oxide dispersion strengthened (ODS) ferritic steels produced by mechanical alloying (MA) and followed by hot extrusion have been studied using high-resolution transmission electron microscopy (HRTEM) techniques to gain insight about the formation mechanism of nanoparticles in MA/ODS steels. The observations of Y-Al-O complex-oxide nanoparticles in both ODS steels imply that decomposition of Y2O3 in association with internal oxidation of Al occurred during mechanical alloying. While the majority of oxide nanoparticles formed in both steels is Y4Al2O9, a few oxide particles of YAlO3 are also occasionally observed. These results reveal that Ti (0.3 wt %) plays an insignificant role in forming oxide nanoparticles in the presence of Al (4.5 wt %). HRTEM observations of crystalline nanoparticles larger than {approx}2 nm and amorphous or disordered cluster domains smaller than {approx}2 nm provide an insight into the formation mechanism of oxide nanoparticle in MA/ODS steels, which we believe from our observations involves a solid-state amorphous precursor followed by recrystallization. Dual ion-beam irradiations using He{sup +} + Fe{sup +8} ions were employed to gain more detailed insight about the role of nanoparticles in suppressing radiation-induced swelling. This is elaborated through TEM examinations of cavity distributions in ion-irradiated Fe-14Cr and K3-ODS ferritic steels. HRTEM observations of helium-filled cavities (helium bubbles) preferably trapped at nanoscale oxide particles and clusters in ion-irradiated K3-ODS are presented. Finally, we describe the results from triple ion-beam irradiations using H{sup +} + He{sup +} + Fe{sup +8} ions to emulate fusion first wall radiation effects. Preliminary work is reported that confirms the existence of significant hydrogen synergistic effects described earlier by Tanaka et al., for Fe(Cr) and by Wakai et al

  12. Investigation of effect of solenoid magnet on emittances of ion beam from laser ablation plasma.

    PubMed

    Ikeda, Shunsuke; Romanelli, Mark; Cinquegrani, David; Sekine, Megumi; Kumaki, Masafumi; Fuwa, Yasuhiro; Kanesue, Takeshi; Okamura, Masahiro; Horioka, Kazuhiko

    2014-02-01

    A magnetic field can increase an ion current of a laser ablation plasma and is expected to control the change of the plasma ion current. However, the magnetic field can also make some fluctuations of the plasma and the effect on the beam emittance and the emission surface is not clear. To investigate the effect of a magnetic field, we extracted the ion beams under three conditions where without magnetic field, with magnetic field, and without magnetic field with higher laser energy to measure the beam distribution in phase space. Then we compared the relations between the plasma ion current density into the extraction gap and the Twiss parameters with each condition. We observed the effect of the magnetic field on the emission surface. PMID:24593624

  13. Investigation of effect of solenoid magnet on emittances of ion beam from laser ablation plasma

    NASA Astrophysics Data System (ADS)

    Ikeda, Shunsuke; Romanelli, Mark; Cinquegrani, David; Sekine, Megumi; Kumaki, Masafumi; Fuwa, Yasuhiro; Kanesue, Takeshi; Okamura, Masahiro; Horioka, Kazuhiko

    2014-02-01

    A magnetic field can increase an ion current of a laser ablation plasma and is expected to control the change of the plasma ion current. However, the magnetic field can also make some fluctuations of the plasma and the effect on the beam emittance and the emission surface is not clear. To investigate the effect of a magnetic field, we extracted the ion beams under three conditions where without magnetic field, with magnetic field, and without magnetic field with higher laser energy to measure the beam distribution in phase space. Then we compared the relations between the plasma ion current density into the extraction gap and the Twiss parameters with each condition. We observed the effect of the magnetic field on the emission surface.

  14. Nanopore Sculpting with Low Energy Ion Beam of Noble Gases

    NASA Astrophysics Data System (ADS)

    Cai, Qun; Ledden, Brad; Krueger, Eric; Golovchenko, Jene; Li, Jiali

    2005-03-01

    Experiments show that 3keV Helium, Neon, Argon, Krypton, and Xenon ion beams can be used to controllably ``sculpt'' nanoscale features in silicon nitride films using a feedback controlled ion beam sculpting apparatus. Here we report nanopore ion beam sculpting effects that depend on the inert gas ion species. We demonstrate that: (1) all the noble gas ion beams enable single nanometer control of structural dimensions in nanopores; (2) every ion species above shows similar ion beam flux dependence of nanopore formation, (3) the thickness of nanopores sculpted with different inert gas ion beam is deferent. Computer simulations (with SRIM and TRIM) and an ``adatom'' surface diffusion model are employed to explain the dynamics of nanoscale dimension change by competing sputtering and surface mass transport processes induced by different ion beam irradiation. These experiments and theoretical work reveal the surface atomic transport phenomena in a quantitative way that allows the extraction of parameters such as the adatom surface diffusion coefficients and average travel distances.

  15. Introduction to Ion Beam Therapy

    SciTech Connect

    Martisikova, Maria

    2010-01-05

    Presently, ion beam therapy reaches an increasing interest within the field of radiation therapy, which is caused by the promising clinical results obtained in the last decades. Ion beams enable higher dose conformation to the tumor and increased sparing of the surrounding tissue in comparison to the standard therapy using high energy photons. Heavy ions, like carbon, offer in addition increased biological effectiveness, which makes them suitable for treatment of radioresistant tumors. This contribution gives an overview over the physical and biological properties of ion beams. Common fundamental principles of ion beam therapy are summarized and differences between standard therapy with high energy photons, proton and carbon ion therapy are discussed. The technologies used for the beam production and delivery are introduced, with emphasis to the differences between passive and active beam delivery systems. The last part concentrates on the quality assurance in ion therapy. Specialties of dosimetry in medical ion beams are discussed.

  16. AFM characterization of model nuclear fuel oxide multilayer structures modified by heavy ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Hawley, M. E.; Devlin, D. J.; Reichhardt, C. J.; Sickafus, K. E.; Usov, I. O.; Valdez, J. A.; Wang, Y. Q.

    2010-10-01

    This work explored a potential new model dispersion fuel form consisting of an actinide material embedded in a radiation tolerant matrix that captures fission products (FPs) and is easily separated chemically as waste from the fuel material. To understand the stability of this proposed dispersion fuel form design, an idealized model system composed of a multilayer film was studied. This system consisted of a tri-layer structure of an MgO layer sandwiched between two HfO 2 layers. HfO 2 served as a surrogate fissile material for UO 2 while MgO represented a stable, fissile product (FP) getter that is easily separated from the fissile material. This type of multilayer film structure allowed us to control the size of and spacing between each layer. The films were grown at room temperature by e-beam deposition on a Si(1 1 1) substrate and post-annealed annealing at a range of temperatures to crystallize the HfO 2 layers. The 550 °C annealed sample was subsequently irradiated with 10 MeV Au 3+ ions at a range of fluences from 5 × 10 13 to 3.74 × 10 16 ions/cm 2. Separate single layer constituent films and the substrate were also irradiated at 5 × 10 15 and 8 × 10 14 and 2 × 10 16, respectively. After annealing and irradiation, the samples were characterized using atomic force imaging techniques to determine local changes in microstructure and mechanical properties. All samples annealed above 550 °C cracked. From the AFM results we observed both crack healing and significant modification of the surface at higher fluences.

  17. Ion beam irradiation as a tool to improve the ionic conductivity in solid polymer electrolyte systems

    NASA Astrophysics Data System (ADS)

    Manjunatha, H.; Damle, R.; Kumaraswamy, G. N.

    2016-05-01

    Solid polymer electrolytes (SPEs) have potential applications in solid state electronic and energy devices. The optimum conductivity of SPEs required for such applications is about 10-1 - 10-3 Scm-1, which is hard to achieve in these systems. It is observed that ionic conductivity of SPEs continuously increase with increasing concentration of inorganic salt in the host polymer. However, there is a critical concentration of the salt beyond which the conductivity of SPEs decreases due to the formation of ion pairs. In the present study, solid polymer thin films based on poly (ethylene oxide) (PEO) complexed with NaBr salt with different concentrations have been prepared and the concentration at which ion pair formation occurs in PEOxNaBr is identified. The microstructure of the SPE with highest ionic conductivity is modified by irradiating it with low energy O+1 ion (100 keV) of different fluencies. It is observed that the ionic conductivity of irradiated SPEs increases by one order in magnitude. The increase in ionic conductivity may be attributed to the enhanced segmental motion of the polymer chains due to radiation induced micro structural modification.

  18. Polarity-inverted ScAlN film growth by ion beam irradiation and application to overtone acoustic wave (000-1)/(0001) film resonators

    SciTech Connect

    Suzuki, Masashi; Yanagitani, Takahiko; Odagawa, Hiroyuki

    2014-04-28

    Polarity inversion in wurtzite film is generally achieved by the epitaxial growth on a specific under-layer. We demonstrate polarity inversion of c-axis oriented ScAlN films by substrate ion beam irradiation without using buffer layer. Substrate ion beam irradiation was induced by either sputtering a small amount of oxide (as a negative ion source) onto the cathode or by applying a RF bias to the substrate. Polarity of the films was determined by a press test and nonlinear dielectric measurement. Second overtone thickness extensional mode acoustic resonance and suppression of fundamental mode resonance, indicating complete polarity inversion, were clearly observed in bilayer highly oriented (000-1)/(0001) ScAlN film.

  19. The effect of focused ion beam machining on residual stress and crack morphologies in alumina

    NASA Astrophysics Data System (ADS)

    Inkson, B. J.; Leclere, D.; Elfallagh, F.; Derby, B.

    2006-02-01

    Focused ion beams (FIB) are widely used to locally sputter away material from surfaces at the nanoscale, but the effect of localised geometry changes and surface damage generated by FIB processing on material stress states are poorly understood. Evolution of stress states has been investigated in alumina samples with high local residual stress concentrations around nanoindents and scratches. Crack morphologies under the nanoindents and scratches have been investigated with respect to the location and geometry of the 'cross-sectional' surface trenches machined by FIB. It is found that the density of cracks observed around the nanoindentation sites depends on the location and milling sequence of the cross-sectional FIB trenches which alter local stress states. Cr3+ fluorescence spectroscopy has additionally been used to map stresses around alumina scratch and FIB-machined surface trenches.

  20. Ion beam sputter etching of orthopedic implanted alloy MP35N and resulting effects on fatigue

    NASA Technical Reports Server (NTRS)

    Wintucky, E. G.; Christopher, M.; Bahnuik, E.; Wang, S.

    1981-01-01

    The effects of two types of argon ion sputter etched surface structures on the tensile stress fatigue properties of orthopedic implant alloy MP35N were investigated. One surface structure was a natural texture resulting from direct bombardment by 1 keV argon ions. The other structure was a pattern of square holes milled into the surface by a 1 keV argon ion beam through a Ni screen mask. The etched surfaces were subjected to tensile stress only in fatigue tests designed to simulate the cyclic load conditions experienced by the stems of artificial hip joint implants. Both types of sputter etched surface structures were found to reduce the fatigue strength below that of smooth surface MP35N.

  1. Ion-chain interaction in keV ion-beam-irradiated polystyrene

    SciTech Connect

    Calcagno, L.; Foti, G.; Licciardello, A.; Puglisi, O.

    1987-09-21

    Molecular weight distribution has been measured in monodisperse polystyrene film (MW = 9 000 amu) after ion bombardment, in the ion fluence range 10/sup 11/--10/sup 13/ ions/cm/sup 2/. The chosen beams are 100 keV He, 200 keV Ne, and 400 keV Ar. The experimental data have been interpreted in terms of a simple statistical model for cross-links. The chemical yield is found to be very high and equal to 0.30, about a factor of 10 higher than the values given in the literature for gamma irradiation (M. Dole, in The Radiation Chemistry of Macromolecules (Academic, New York, 1973), Vol. 2, Chap. 5, p. 57).

  2. Radiation chemical behavior of aqueous butanal oxime solutions irradiated with helium ion beams

    NASA Astrophysics Data System (ADS)

    Costagliola, A.; Venault, L.; Deroche, A.; Garaix, G.; Vermeulen, J.; Omnee, R.; Duval, F.; Blain, G.; Vandenborre, J.; Fattahi-Vanani, M.; Vigier, N.

    2016-02-01

    Samples of butanal oxime in aqueous solution have been irradiated with the helion (4He2+) beam of the ARRONAX (Nantes) and the CEMHTI (Orléans) cyclotrons. The consumption yield of butanal oxime has been measured by gas-chromatography coupled with mass spectrometry. Yields of gaseous products (mainly H2) have also been measured by micro-gas-chromatography. Butanal oxime can react with H• radicals by abstraction mechanism to enhance H2 production. Yields of liquid phase products (hydrogen peroxide and nitrite ion) have been measured by colorimetric methods. Butanal oxime acts as a scavenger of OH• radical to inhibit the production of H2O2. The observation of the radiolytic products allows then to discuss a degradation mechanism of butanal oxime in aqueous solutions.

  3. Electron Cloud Effects in Intense, Ion Beam Linacs Theory and Experimental Planning for HIF

    SciTech Connect

    Molvik, A W; Cohen, R H; Lund, S M; Bieniosek, F M; Lee, E P; Prost, L R; Seidl, P A; Vay, P-A

    2002-05-23

    Heavy-ion accelerators for heavy-ion inertial fusion energy (HIF) will operate at high aperture-fill factors with high beam current and long durations. (Injected currents of order 1 A and 20 {micro}s at a few MeV for each of {approx}100 beams, will be compressed to the order of 100 A and 0.2 {micro}s, reaching GeV energies in a power plant driver.) This will be accompanied by beam ions impacting walls, liberating gas molecules and secondary electrons. Without special preparation, the {approx}10% electron population predicted for driver-scale experiments will affect beam transport; but wall conditioning and other mitigation techniques should result in substantial reduction. Theory and particle-in-cell simulations suggest that electrons, from ionization of residual and desorbed gas and secondary electrons from vacuum walls, will be radially trapped in the {approx}4 kV ion beam potential. Trapped electrons can modify the beam space charge, vacuum pressure, ion transport dynamics, and halo generation, and can potentially cause ion-electron instabilities. Within quadrupole (and dipole) magnets, the longitudinal electron velocity is limited to drift velocities (E x B and {del}B) and the electron density can vary azimuthally, radially, and longitudinally. These variations can cause centroid misalignment, emittance growth and halo growth. Diagnostics are being developed to measure the energy and flux of electrons and gas evolved from walls, and the net charge and gas density within magnetic quadrupoles. We will also measure the depth of trapping of electrons, their axial and radial transport, and the effects of electrons on the ion beam.

  4. Effects of ion beams pretreatment on damage of UV-B radiation on seedlings of winter wheat (Triticum aestivum L.).

    PubMed

    Zhao, Shuaipeng; Huang, Qunce; Yang, Pengming; Zhang, Jiajia; Jia, Hongru; Jiao, Zhen

    2012-12-01

    The seeds of winter wheat were pretreated with three different doses of low-energy N(+) beams, and its seedlings were subjected to UV-B irradiation (10.08 kJ m(-2) day(-1)) at three-leaves stage. The growth characteristic of seeds, the oxidative damage to membrane system induced by UV-B radiation, and the alleviating effects of N(+) beams pretreatment to radiation damage were investigated. The results showed that the germination rate and seedling rate, respectively, increased 14.09 ± 1.03 and 13.91 ± 1.21 % compared with control (CK) at the dose of 4.0 × 10(16) ions/cm(2). When seedlings were exposed to UV-B radiation, the pretreatment method under the dose of 4.0 × 10(16) ions/cm(2) made the activity of peroxidase and superoxide dismutase increasing, the content of chlorophyll enhancing, but the content of malondialdehyde reducing significantly compared with that of the single UV-B radiation. Whereas, the activity of catalase irradiated by UV-B improved notably under the pretreatment dose of 8.0 × 10(16) ions/cm(2). In addition, after being irradiated with UV-B, the content of soluble protein and glutathione whose seeds were pretreated by the dose of 6.0 × 10(16) ions/cm(2) were higher than that of the single UV-B radiation. It was suggested that the suitable dose of low-energy ion beams pretreatment to wheat seeds could change its physiological characteristics at seedlings stage to alleviate the damage effects from UV-B radiation. PMID:23054823

  5. Triple ion-beam studies of radiation damage effects in a 316LN austenitic alloy for a high power spallation neutron source

    SciTech Connect

    Lee, E.H.; Rao, G.R.; Hunn, J.D.; Rice, P.M.; Lewis, M.B.; Cook, S.W.; Farrell, K.; Mansur, L.K.

    1997-09-01

    Austenitic 316LN alloy was ion-irradiated using the unique Triple Ion Beam Facility (TIF) at ORNL to investigate radiation damage effects relevant to spallation neutron sources. The TIF was used to simulate significant features of GeV proton irradiation effects in spallation neutron source target materials by producing displacement damage while simultaneously injecting helium and hydrogen at appropriately high gas/dpa ratios. Irradiations were carried out at 80, 200, and 350 C using 3.5 MeV Fe{sup ++}, 360 keV He{sup +}, and 180 keV H{sup +} to accumulate 50 dpa by Fe, 10,000 appm of He, and 50,000 appm of H. Irradiations were also carried out at 200 C in single and dual ion beam modes. The specific ion energies were chosen to maximize the damage and the gas accumulation at a depth of {approximately} 1 {micro}m. Variations in microstructure and hardness of irradiated specimens were studied using transmission electron microscopy (TEM) and a nanoindentation technique, respectively. TEM investigation yielded varying damage defect microstructures, comprising black dots, faulted and unfaulted loops, and a high number density of fine bubbles (typically less than 1 nm in diameter). With increasing temperature, faulted loops had a tendency to unfault, and bubble microstructure changed from a bimodal size distribution to a unimodal distribution. Triple ion irradiations at the three temperatures resulted in similar increases in hardness of approximately a factor of two. Individually, Fe and He ions resulted in a similar magnitude of hardness increase, whereas H ions showed only a very small effect. The present study has yielded microstructural information relevant to spallation neutron source conditions and indicates that the most important concern may be radiation induced hardening and associated ductility loss.

  6. Four-Dimensional Lung Treatment Planning in Layer-Stacking Carbon Ion Beam Treatment: Comparison of Layer-Stacking and Conventional Ungated/Gated Irradiation

    SciTech Connect

    Mori, Shinichiro; Kanematsu, Nobuyuki; Asakura, Hiroshi; Sharp, Gregory C.; Kumagai, Motoki; Dobashi, Suguru; Nakajima, Mio; Yamamoto, Naoyoshi; Kandatsu, Susumu; Baba, Masayuki

    2011-06-01

    Purpose: We compared four-dimensional (4D) layer-stacking and conventional carbon ion beam distribution in the treatment of lung cancer between ungated and gated respiratory strategies using 4DCT data sets. Methods and Materials: Twenty lung patients underwent 4DCT imaging under free-breathing conditions. Using planning target volumes (PTVs) at respective respiratory phases, two types of compensating bolus were designed, a full single respiratory cycle for the ungated strategy and an approximately 30% duty cycle for the exhalation-gated strategy. Beams were delivered to the PTVs for the ungated and gated strategies, PTV(ungated) and PTV(gated), respectively, which were calculated by combining the respective PTV(Tn)s by layer-stacking and conventional irradiation. Carbon ion beam dose distribution was calculated as a function of respiratory phase by applying a compensating bolus to 4DCT. Accumulated dose distributions were calculated by applying deformable registration. Results: With the ungated strategy, accumulated dose distributions were satisfactorily provided to the PTV, with D95 values for layer-stacking and conventional irradiation of 94.0% and 96.2%, respectively. V20 for the lung and Dmax for the spinal cord were lower with layer-stacking than with conventional irradiation, whereas Dmax for the skin (14.1 GyE) was significantly lower (21.9 GyE). In addition, dose conformation to the GTV/PTV with layer-stacking irradiation was better with the gated than with the ungated strategy. Conclusions: Gated layer-stacking irradiation allows the delivery of a carbon ion beam to a moving target without significant degradation of dose conformity or the development of hot spots.

  7. Preparation of ion-track membranes of poly( p-phenylene terephthalamide): Control of pore shape by irradiation with different ion beams

    NASA Astrophysics Data System (ADS)

    Suzuki, Yasuyuki; Yamaki, Tetsuya; Koshikawa, Hiroshi; Asano, Masaharu; Voss, Kay-Obbe; Neumann, Reinhard; Yoshida, Masaru

    2007-07-01

    The preparation of ion-track membranes of thermally stable poly( p-phenylene terephthalamide) (PPTA) was performed by ion beam irradiation followed by chemical etching with a sodium hypochlorite solution. Cylindrical pores were observed in the membrane irradiated with 197Au and 238U ions at an energy of 11.1 MeV/n. In contrast, funnel shape pores appeared in the membrane irradiated with 84Kr, 102Ru and 129Xe ion at energies of 6.2, 3.6 and 3.5 MeV/n, respectively. The 197Au and 238U ion irradiation was found to exhibit more than four times larger sensitivity to the track etching under the same etching conditions. Consequently, the pore shape can be controlled by the masses and energies of the irradiated ions, in close relation to the etching sensitivity of the track.

  8. Collective effects on the wakefield and stopping power of an ion beam pulse in plasmas

    SciTech Connect

    Zhang, Ling-yu; Zhao, Xiao-ying; Qi, Xin E-mail: duanws@nwnu.edu.cn Duan, Wen-shan E-mail: duanws@nwnu.edu.cn Xiao, Guo-qing; Yang, Lei E-mail: duanws@nwnu.edu.cn

    2015-05-15

    A two-dimensional (2D) particle-in-cell simulation is carried out to study the collective effects on the wakefield and stopping power for a hydrogen ion beam pulse propagation in hydrogen plasmas. The dependence of collective effects on the beam velocity and density is obtained and discussed. For the beam velocity, it is found that the collective effects have the strongest impact on the wakefield as well as the stopping power in the case of the intermediate beam velocities, in which the stopping power is also the largest. For the beam density, it is found that at low beam densities, the collective contribution to the stopping power increase linearly with the increase of the beam density, which corresponds well to the results calculated using the dielectric theory. However, at high beam densities, our results show that after reaching a maximum value, the collective contribution to the stopping power starts to decrease significantly with the increase of the beam density. Besides, at high beam densities, the wakefield loses typical V-shaped cone structures, and the wavelength of the oscillation wakefield increases as the beam density increases.

  9. Effects of focused ion beam milling on austenite stability in ferrous alloys

    SciTech Connect

    Knipling, K.E.; Rowenhorst, D.J.; Fonda, R.W.; Spanos, G.

    2010-01-15

    The susceptibility of fcc austenite to transform to bcc during focused ion beam milling was studied in three commercial stainless steels. The alloys investigated, in order of increasing austenite stability, were: (i) a model maraging steel, Sandvik 1RK91; (ii) an AISI 304 austenitic stainless steel; and (iii) AL-6XN, a super-austenitic stainless steel. Small trenches were milled across multiple austenite grains in each alloy using a 30 kV Ga{sup +} ion beam at normal incidence to the specimen surface. The ion beam dose was controlled by varying the trench depth and the beam current. The factors influencing the transformation of fcc austenite to bcc (listed in order of decreasing influence) were found to be: (i) alloy composition (i.e., austenite stability), (ii) ion beam dose (or trench depth), and (iii) crystallographic orientation of the austenite grains. The ion beam current had a negligible influence on the FIB-induced transformation of austenite in these alloys.

  10. Investigation of nonthermal particle effects on ionization dynamics in high current density ion beam transport experiments

    NASA Astrophysics Data System (ADS)

    Chung, H. K.; MacFarlane, J. J.; Wang, P.; Moses, G. A.; Bailey, J. E.; Olson, C. L.; Welch, D. R.

    1997-01-01

    Light ion inertial fusion experiments require the presence of a moderate density background gas in the transport region to provide charge and current neutralization for a high current density ion beam. In this article, we investigate the effects of nonthermal particles such as beam ions or non-Maxwellian electron distributions on the ionization dynamics of the background gas. In particular, we focus on the case of Li beams being transported in an argon gas. Nonthermal particles as well as thermal electrons are included in time-dependent collisional-radiative calculations to determine time-dependent atomic level populations and charge state distributions in a beam-produced plasma. We also briefly discuss the effects of beam ions and energetic electrons on the visible and vacuum ultraviolet (VUV) spectral regions. It is found that the mean charge state of the gas, and hence the electron density, is significantly increased by collisions with energetic particles. This higher ionization significantly impacts the VUV spectral region, where numerous resonance lines occur. On the other hand, the visible spectrum tends to be less affected because the closely spaced excited states are populated by lower energy thermal electrons.

  11. Effects of ion beam modification on absorption and transport of hydrogen in perovskite-type oxide ceramics

    NASA Astrophysics Data System (ADS)

    Tsuchiya, B.; Nagata, S.; Toh, K.; Shikama, T.

    2006-01-01

    Surface modification of proton conductive material (Yb-doped SrCeO3 perovskite-type ceramics) has been carried out by irradiation with 10 keV D2+ , He+ or Ar+ ions at room temperature. By exposure of Ar gas including H2O to the irradiated surface, the concentration of H in the projected range increased. The absorption of H is associated due to dissociation of H2O. The concentrations of the absorbed H by D+, He+ and Ar+ ion irradiations became about 2.0, 0.3 and 1.0 times, respectively, as much as the saturation concentration by H+ ion implantation. It was also found by isochronal annealing experiments that the thermal desorption rate of H retained in the irradiated surface was lower than that in the unirradiated one. These results show that the trapping and migration of hydrogen atoms in the proton conducting oxide ceramics are enhanced by ion beam modification.

  12. Effect of radial plasma transport at the magnetic throat on axial ion beam formation

    NASA Astrophysics Data System (ADS)

    Zhang, Yunchao; Charles, Christine; Boswell, Rod

    2016-08-01

    Correlation between radial plasma transport and formation of an axial ion beam has been investigated in a helicon plasma reactor implemented with a convergent-divergent magnetic nozzle. The plasma discharge is sustained under a high magnetic field mode and a low magnetic field mode for which the electron energy probability function, the plasma density, the plasma potential, and the electron temperature are measured at the magnetic throat, and the two field modes show different radial parametric behaviors. Although an axial potential drop occurs in the plasma source for both field modes, an ion beam is only observed in the high field mode while not in the low field mode. The transport of energetic ions is characterized downstream of the plasma source using the delimited ion current and nonlocal ion current. A decay of ion beam strength is also observed in the diffusion chamber.

  13. Plasma effects of active ion beam injections in the ionosphere at rocket altitudes

    NASA Technical Reports Server (NTRS)

    Arnoldy, R. L.; Cahill, L. J., Jr.; Kintner, P. M.; Moore, T. E.; Pollock, C. J.

    1992-01-01

    Data from ARCS rocket ion beam injection experiments are primarily discussed. There are three results from this series of active experiments that are of particular interest in space plasma physics. These are the transverse acceleration of ambient ions in the large beam volume, the scattering of beam ions near the release payload, and the possible acceleration of electrons very close to the plasma generator which produce intense high frequency waves. The ability of 100 ma ion beam injections into the upper E and F regions of the ionosphere to produce these phenomena appear to be related solely to the process by which the plasma release payload and the ion beam are neutralized. Since the electrons in the plasma release do not convect with the plasma ions, the neutralization of both the payload and beam must be accomplished by large field-aligned currents (milliamperes/square meter) which are very unstable to wave growth of various modes.

  14. Ion beam sputtering of fluoropolymers

    NASA Technical Reports Server (NTRS)

    Sovey, J. S.

    1978-01-01

    Etching and deposition of fluoropolymers are of considerable industrial interest for applications dealing with adhesion, chemical inertness, hydrophobicity, and dielectric properties. This paper describes ion beam sputter processing rates as well as pertinent characteristics of etched targets and films. An argon ion beam source was used to sputter etch and deposit the fluoropolymers PTFE, FEP, and CTFE. Ion beam energy, current density, and target temperature were varied to examine effects on etch and deposition rates. The ion etched fluoropolymers yield cone or spire-like surface structures which vary depending upon the type of polymer, ion beam power density, etch time, and target temperature. Also presented are sputter target and film characteristics which were documented by spectral transmittance measurements, X-ray diffraction, ESCA, and SEM photomicrographs.

  15. Ion beam analysis of MgAl{sub 2}O{sub 4} spinel irradiated with fast neutrons to 50-250 dpa

    SciTech Connect

    Yu, Ning; Maggiore, C.J.; Sickafus, K.E.

    1995-12-31

    Non-destructive ion beam analysis techniques have been employed to examine the radiation damage in MgAl{sub 2}O{sub 4} spinel single crystals irradiated with fast neutrons at 400 and 750{degrees}C to high fluences ({>=}5 x 10{sup 22} n/cm{sup 2}, E{sub n} > 0.1 MeV). Rutherford backscattering and ion channeling measurements using 1-4 MeV He ion beams revealed that the radiation damage saturated after irradiation at 400{degrees}C to 50 displacements per atom. The energy dependence of dechanneling indicated the dominant extended defects present in the highly irradiated spinel are in the form of dislocations. Channeling angular scans of particle induced x-ray emission further suggested that neutron irradiation tends to randomize cation distribution for Mg{sup 2+} and Al{sup 3+} cations on the lattice sites. These results are compared to the microstructure observations of Kinoshita, et al. and the neutron scattering results of Sickafus, et al.

  16. Ion Beam Modification of Materials

    SciTech Connect

    Averback, B; de la Rubia, T D; Felter, T E; Hamza, A V; Rehn, L E

    2005-10-10

    This volume contains the proceedings of the 14th International Conference on Ion Beam Modification of Materials, IBMM 2004, and is published by Elsevier-Science Publishers as a special issue of Nuclear Instruments and Methods B. The conference series is the major international forum to present and discuss recent research results and future directions in the field of ion beam modification, synthesis and characterization of materials. The first conference in the series was held in Budapest, Hungary, 1978, and subsequent conferences were held every two years at locations around the Globe, most recently in Japan, Brazil, and the Netherlands. The series brings together physicists, materials scientists, and ion beam specialists from all over the world. The official conference language is English. IBMM 2004 was held on September 5-10, 2004. The focus was on materials science involving both basic ion-solid interaction processes and property changes occurring either during or subsequent to ion bombardment and ion beam processing in relation to materials and device applications. Areas of research included Nanostructures, Multiscale Modeling, Patterning of Surfaces, Focused Ion Beams, Defects in Semiconductors, Insulators and Metals, Cluster Beams, Radiation Effects in Materials, Photonic Devices, Ion Implantation, Ion Beams in Biology and Medicine including New Materials, Imaging, and Treatment.

  17. Fabrication of a TEM sample of ion-irradiated material using focused ion beam microprocessing and low-energy Ar ion milling.

    PubMed

    Jin, Hyung-Ha; Shin, Chansun; Kwon, Junhyun

    2010-01-01

    Cross-section-view TEM samples of ion-irradiated material are successfully fabricated using a focused ion beam (FIB) system and low-energy Ar ion milling. Ga ion-induced damages in FIB processing are reduced remarkably by the means of low-energy Ar ion milling. There are optimized ion milling conditions for the reduction and removal of the secondary artifacts such as defects and ripples. Incident angles and accelerated voltages are especially more important factors on the preservation of a clean surface far from secondary defects and surface roughing due to Ga and Ar ion bombardment. PMID:20484144

  18. Focused Ion Beam Fabrication of Silicon-On Field-Effect Transistors.

    NASA Astrophysics Data System (ADS)

    Mattiussi, Greg Andrew

    N-channel metal-oxide-semiconductor field-effect transistors (MOSFET's) have been fabricated on silicon -on-insulator (SOI) substrates using a Focused Ion Beam (FIB) to pattern the gate and to dope the source and drains. Lightly -doped source (LDS) structures were implemented with the FIB to increase the drain-to-source voltage at which single transistor latch-up occurred. FIB exposure of two electron-beam resists was investigated for lithography of the transistor gate and the device mesas. Vertical resist profiles were achieved for linewidths down to 0.2 μm in width in the case of the negative-tone SAL-601 resist from Shipley Co. Openings in resist as narrow as 0.35 μm were made using the positive-tone P28 resist from OCG Microelectronic Materials. Optimal doses, pre- and post-exposure processing conditions were determined for both resists. Transistors with LDS structures showed higher latching voltages than those without. The magnitude of the increase in latching voltage due to the LDS was a function of body doping level, SOI thickness, and coded gate length. The largest increase was 5.1 V for a 0.8 μm MOSFET fabricated in a 125 nm thick SOI film with a body implant dose of 5.6times10^ {12} B cm^{-2}. Devices fabricated in SOI films of thickness 250 nm showed smaller increases in latching voltage with the LDS than those in 125 nm SOI films.

  19. Formation of plasmid DNA strand breaks induced by low-energy ion beam: indication of nuclear stopping effects.

    PubMed

    Chen, Y; Jiang, B; Chen, Y; Ding, X; Liu, X; Chen, C; Guo, X; Yin, G

    1998-07-01

    Plasmid pGEM 3zf(+) was irradiated by nitrogen ion beam with energies between 20 and 100 keV and the fluence kept as 1x10(12)ions/cm2. The irradiated plasmid was assayed by neutral electrophoresis and quantified by densitometry. The yields of DNA with single-strand and double-strand breaks first increased then decreased with increasing ion energy. There was a maximal yield value in the range of 20-100 keV. The relationship between DNA double-strand breaks (DSB) cross-section and linear energy transfer (LET) also showed a peak-shaped distribution. To understand the physical process during DNA strand breaks, a Monte Carlo calculation code known as TRIM (Transport of Ions in Matter) was used to simulate energy losses due to nuclear stopping and to electronic stopping. It can be assumed that nuclear stopping plays a more important role in DNA strand breaks than electronic stopping in this energy range. The physical mechanisms of DNA strand breaks induced by a low-energy ion beam are also discussed. PMID:9728742

  20. Pulsed-ion-beam nitriding and smoothing of titanium surface in a vacuum

    SciTech Connect

    Zhu, X.P.; Suematsu, Hisayuki; Jiang Weihua; Yatsui, Kiyoshi; Lei, M.K.

    2005-08-29

    Both nitriding and smoothing of titanium have been achieved under irradiation of intense pulsed ion beam in a vacuum of 2x10{sup -2} Pa. Applying a screening method, we find that medium ion-beam intensity and multi-shot irradiation are effective for the processing, where repetitive surface melting with limited ablation favored Ti nitride formation as well as surface smoothing. The present results demonstrate that ambient gas atoms/molecules can be efficiently incorporated in metal matrices to form compounds under the ion-beam irradiation. The finding is of great significance for extending application scope of the ion-beam technique in materials research and processing, combined with the recent success in introducing ambient gas into the processing chamber.

  1. Effect of the electrostatic plasma lens on the emittance of ahigh-current heavy ion beam

    SciTech Connect

    Chekh, Yu.; Goncharov, A.; Protsenko, I.; Brown, I.G.

    2004-01-10

    We describe measurements we have made of the emittance of a high-current, moderate-energy ion beam after transport through a permanent-magnet electrostatic plasma lens. The results indicate the absence of emittance growth due to the lens, when the lens is adjusted for optimal beam focusing. The measured emittance for a 16 keV Cu{sup 2+} ion beam formed by a vacuum arc ion source was about 0.4 {pi} {center_dot} mm {center_dot} mrad at a beam current of 50 mA rising more-or-less linearly to 1.5 {pi} {center_dot} mm {center_dot} mrad at 250 mA, and was conserved in beam transport through the lens. These results have significance for the application of high-current ion sources and the electrostatic plasma lens to particle accelerator injection.

  2. Effect of surface texture by ion beam sputtering on implant biocompatibility and soft tissue attachment

    NASA Technical Reports Server (NTRS)

    Gibbons, D. F.

    1977-01-01

    The objectives in this report were to use the ion beam sputtering technique to produce surface textures on polymers, metals, and ceramics. The morphology of the texture was altered by varying both the width and depth of the square pits which were formed by ion beam erosion. The width of the ribs separating the pits were defined by the mask used to produce the texture. The area of the surface containing pits varies as the width was changed. The biological parameters used to evaluate the biological response to the texture were: (1) fibrous capsule and inflammatory response in subcutaneous soft tissue; (2) strength of the mechanical attachment of the textured surface by the soft tissue; and (3) morphology of the epidermal layer interfacing the textured surface of percutaneous connectors. Because the sputter yield on teflon ribs was approximately an order of magnitude larger than any other material the majority of the measurements presented in the report were obtained with teflon.

  3. The effect of residual gas scattering on Ga ion beam patterning of graphene

    SciTech Connect

    Thissen, Nick F. W. E-mail: a.a.bol@tue.nl; Vervuurt, R. H. J.; Weber, J. W.; Kessels, W. M. M.; Bol, A. A. E-mail: a.a.bol@tue.nl; Mulders, J. J. L.

    2015-11-23

    The patterning of graphene by a 30 kV Ga{sup +} focused ion beam (FIB) is studied by in-situ and ex-situ Raman spectroscopy. It is found that the graphene surrounding the patterned target area can be damaged at remarkably large distances of more than 10 μm. We show that scattering of the Ga ions in the residual gas of the vacuum system is the main cause of the large range of lateral damage, as the size and shape of the tail of the ion beam were strongly dependent on the system background pressure. The range of the damage was therefore greatly reduced by working at low pressures and limiting the total amount of ions used. This makes FIB patterning a feasible alternative to electron beam lithography as long as residual gas scattering is taken into account.

  4. Effect of N 4+ and C 4+ ion beam bombardment on the optical and structural characteristics of ethylene-norbornene copolymer (TOPAS)

    NASA Astrophysics Data System (ADS)

    Šiljegović, M.; Kačarević-Popović, Z. M.; Krklješ, A. N.; Stojanović, Z.; Jovanović, Z. M.

    2011-04-01

    Ion bombardment is a suitable tool to modify the optical properties of polymers. In the present study the effect of ion bombardment on the optical absorption of ethylene-norbornene copolymer (TOPAS) was studied using ultraviolet-visible (UV-Vis) and Raman spectroscopy. Polymer samples were bombarded with 60 keV C 4+ and N 4+ ion beams to various fluences ranging from 1.0 × 10 13 to 1.0 × 10 16 cm -2. The indirect and direct band gaps have been determined. The values of direct band gaps have been found to be greater than the corresponding values of the indirect band gaps. Activation energy has been investigated as the function of ion fluences. The number of carbon atoms per conjugated length is determined according to modified Tauc's equation. The correlation between the optical band gap, activation energy for optical transition and the number of carbon atoms per conjugated length as well as chemical structure changes induced by ion beams irradiation have been discussed in the case of ethylene-norbornene copolymer.

  5. Vertically aligned liquid crystals on a {gamma}-Al{sub 2}O{sub 3} alignment film using ion-beam irradiation

    SciTech Connect

    Park, Hong-Gyu; Kim, Young-Hwan; Oh, Byeong-Yun; Lee, Won-Kyu; Kim, Byoung-Yong; Seo, Dae-Shik; Hwang, Jeong-Yeon

    2008-12-08

    Using ion-beam (IB) irradiation, liquid crystals (LCs) were vertically aligned (VA) on a {gamma}-Al{sub 2}O{sub 3} alignment film. Atomic-layer deposition was used to orient the LCs on high-quality {gamma}-Al{sub 2}O{sub 3} alignment films. The LC molecule orientation indicates the vertical direction of the atomic-layer-deposited {gamma}-Al{sub 2}O{sub 3} alignment films. X-ray photoelectron spectroscopy showed that IB irradiation changed the chemical structure, shifting the Al-O binding energy and altering the Al-O bonding intensity. The low-voltage transmittance characteristics of the VA LC displays on the {gamma}-Al{sub 2}O{sub 3} alignment films were also measured, showing reduced voltage and power requirements.

  6. Effects of focused ion beam milling on the nanomechanical behavior of a molybdenum-alloy single crystal

    SciTech Connect

    Bei, H.; Shim, S.; Miller, M. K.; Pharr, G. M.; George, E. P.

    2007-09-10

    Nanoindentation was performed on a Mo-alloy single crystal to investigate effects of focused ion beam (FIB) milling on mechanical behavior. On a non-FIB-milled surface, pop-ins were observed on all load-displacement curves corresponding to a transition from elastic to plastic deformation. Similar pop-ins were not detected on surfaces subjected to FIB milling. This difference indicates that FIB milling introduces damage that obviates the need for dislocation nucleation during subsequent deformation. A second effect of FIB milling is that it increased the surface hardness. Together, these effects could be the source of the size effects reported in the literature on micropillar tests.

  7. Medium-energy ion-beam simulation of the effect of ionizing radiation and displacement damage on SiO2-based memristive nanostructures

    NASA Astrophysics Data System (ADS)

    Belov, Alexey; Mikhaylov, Alexey; Korolev, Dmitry; Guseinov, Davud; Gryaznov, Eugeny; Okulich, Eugenia; Sergeev, Victor; Antonov, Ivan; Kasatkin, Alexandr; Gorshkov, Oleg; Tetelbaum, David; Kozlovski, Vitali

    2016-07-01

    The principles of ion-beam simulation of the effect of fast (fission) neutrons and high-energy protons based on medium-energy ion irradiation have been developed for the Au/Zr/SiO2/TiN/Ti capacitor-like memristive nanostructures demonstrating the repeatable resistive switching phenomenon. By using the Monte-Carlo approach, the irradiation fluences of H+, Si+ and O+ ions at the energy of 150 keV are determined that provide the ionization and displacement damage equivalent to the cases of space protons (15 MeV) and fission neutrons (1 MeV) irradiation. No significant change in the resistive switching parameters is observed under ion irradiation up to the fluences corresponding to the extreme fluence of 1017 cm-2 of space protons or fission neutrons. The high-level radiation tolerance of the memristive nanostructures is experimentally confirmed with the application of 15 MeV proton irradiation and is interpreted as related to the local nature of conducting filaments and high concentration of the initial field-induced defects in oxide film.

  8. Effect of the annealing temperature and ion-beam bombardment on the properties of solution-derived HfYGaO films as liquid crystal alignment layers

    SciTech Connect

    Park, Hong-Gyu; Lee, Yun-Gun; Jang, Sang Bok; Lee, Ju Hwan; Jeong, Hae-Chang; Seo, Dae-Shik; Oh, Byeong-Yun

    2015-11-15

    Hafnium yttrium gallium oxide (HfYGaO) films were applied to liquid crystal displays (LCDs) as liquid crystal (LC) alignment layers, replacing conventional polyimide (PI) layers. The HfYGaO alignment layers were prepared by fabricating solution-processed HfYGaO films, annealing them, and treating them with ion-beam (IB) irradiation. The authors studied the effects of annealing temperature and IB irradiation of the solution-derived HfYGaO films on the orientation of LC molecules. The LC molecules on the solution-derived HfYGaO films were homogeneously and uniformly aligned by IB irradiation, irrespective of the annealing temperature. Atomic force microscopy analyses revealed that the surface reformation of the HfYGaO films induced by IB irradiation strengthened the van der Waals force between the LC molecules and the HfYGaO films, leading to uniform LC alignment. Enhanced electro-optical characteristics were observed in the twisted-nematic (TN) LCDs based on IB-irradiated HfYGaO films compared with those of TN-LCDs based on PI layers, demonstrating the high application potential of the proposed solution-derived HfYGaO films as LC alignment layers.

  9. Extended phase-correlated rescanning irradiation to improve dose homogeneity in carbon-ion beam liver treatment

    NASA Astrophysics Data System (ADS)

    Ogata, Risa; Mori, Shinichiro; Yasuda, Shigeo

    2014-09-01

    We previously reported that an adequate number of simple layered phase-correlated rescanning (PCR) irradiations improve dose conformation to a moving target. However, if PCR is not completed within a single gating window due to the particular irradiation specifications selected in advance and/or layer size, the iso-energy layer is completed using next gating window, and the effect of rescanning is effectively nullified. To solve this problem, we developed extended PCR irradiation. Extended PCR is conceptually based on simple PCR. It differs in that the dose rate is adjusted to irradiate the number of rescans within multiple gating windows when simple PCR is not finished within a single gating window. This process is repeated until the total prescribed dose is given. Here, 4DCT imaging was performed under free-breathing conditions in 10 patients with hepatocellular carcinoma. 4D dose distributions for a single field approach were performed with simple PCR and extended PCR using 4DCT. A total dose of 11.25 Gy(RBE) was administered to the field-specific target volume. The number of rescans was changed from 1 to 10. Respiratory gating of a 30% duty cycle around exhalation was applied. Dose assessment metrics (CTV-D95, CTV-Dmin, CTV-Dmax) with PCR improved with an increasing number of rescans, and largely plateaued at five or more rescans. Minimum D95 and Dmin values, and maximum Dmax and HI values fluctuated at odd and even numbers of rescans. Extended PCR improved all dose assessment metrics whereas PCR did not. Values with extended PCR were mostly constant with three or more rescans, or in other words independent of the number of rescans. Extended PCR improved dose conformation to a moving target with greater efficacy than simple PCR when more than two gating windows were necessary. Extended PCR can be applied to irradiation machines having a low maximum dose rate.

  10. Study on the bias-dependent effects of proton-induced damage in CdZnTe radiation detectors using ion beam induced charge microscopy.

    PubMed

    Gu, Yaxu; Jie, Wanqi; Rong, Caicai; Xu, Lingyan; Xu, Yadong; Lv, Haoyan; Shen, Hao; Du, Guanghua; Guo, Na; Guo, Rongrong; Zha, Gangqiang; Wang, Tao; Xi, Shouzhi

    2016-09-01

    The influence of damage induced by 2MeV protons on CdZnTe radiation detectors is investigated using ion beam induced charge (IBIC) microscopy. Charge collection efficiency (CCE) in irradiated region is found to be degraded above a fluence of 3.3×10(11)p/cm(2) and the energy spectrum is severely deteriorated with increasing fluence. Moreover, CCE maps obtained under the applied biases from 50V to 400V suggests that local radiation damage results in significant degradation of CCE uniformity, especially under low bias, i. e., 50V and 100V. The CCE nonuniformity induced by local radiation damage, however, can be greatly improved by increasing the detector applied bias. This bias-dependent effect of 2MeV proton-induced radiation damage in CdZnTe detectors is attributed to the interaction of electron cloud and radiation-induced displacement defects. PMID:27399802

  11. A 4D dose computation method to investigate motion interplay effects in scanned ion beam prostate therapy

    NASA Astrophysics Data System (ADS)

    Ammazzalorso, F.; Jelen, U.

    2014-06-01

    In particle therapy, the interplay between beam scanning and target motion during treatment delivery may result in dose deterioration. Interplay effects have been studied for targets exhibiting periodic respiratory motion, however, they are not well understood for irregular motion patterns, such as those exhibited by the prostate. In this note, we propose and validate a 4D dose computation method, which enables estimation of effective dose delivered to the prostate by scanning ion beams in presence of intrafraction motion, as well as facilitates investigation of various motion interplay countermeasures.

  12. Formation of Carbonized Polystyrene Sphere/hemisphere Shell Arrays by Ion Beam Irradiation and Subsequent Annealing or Chloroform Treatment

    PubMed Central

    Song, Xianyin; Dai, Zhigao; Xiao, Xiangheng; Li, Wenqing; Zheng, Xudong; Shang, Xunzhong; Zhang, Xiaolei; Cai, Guangxu; Wu, Wei; Meng, Fanli; Jiang, Changzhong

    2015-01-01

    Heat-resistant two-dimensional (2D) sphere/hemisphere shell array is significant for the fabrication of novel nanostructures. Here large-area, well-ordered arrays of carbonized polystyrene (PS) hollow sphere/hemisphere with controlled size and morphology are prepared by combining the nanosphere self-assembly, kV Ag ion beam modification, and subsequent annealing or chloroform treatment. Potential mechanisms for the formation and evolution of the heat-resistant carbonized PS spherical shell with increasing ion fluence and energy are discussed. Combined with noble metal or semiconductor, these modified PS sphere arrays should open up new possibilities for high-performance nanoscale optical sensors or photoelectric devices. PMID:26640125

  13. Rapid and direct micro-machining/patterning of polymer materials by oxygen MeV ion beam irradiation through masks

    NASA Astrophysics Data System (ADS)

    Brun, S.; Guibert, G.; Meunier, C.; Guibert, E.; Keppner, H.; Mikhailov, S.

    2011-10-01

    PTFE (PolyTetraFluoroEthylene), often called Teflon, is a well-known polymer for being a non-stick material with good thermal properties. Moreover, PTFE is biocompatible and especially it is a cyto-compatible polymer. To enable bonding, a chemical etching based on sodium solutions is generally used to modify surfaces. In this paper we study the etching of PTFE using an oxygen ion beam in the MeV energy range. We present micro-patterning of PTFE through masks with two fluences of 5 × 1015 and 1 × 1016 ion cm-2. As is demonstrated the use of a mask allows structuring of large areas while maintaining a distance between the mask and sample makes industrial applications possible.

  14. Formation of Carbonized Polystyrene Sphere/hemisphere Shell Arrays by Ion Beam Irradiation and Subsequent Annealing or Chloroform Treatment

    NASA Astrophysics Data System (ADS)

    Song, Xianyin; Dai, Zhigao; Xiao, Xiangheng; Li, Wenqing; Zheng, Xudong; Shang, Xunzhong; Zhang, Xiaolei; Cai, Guangxu; Wu, Wei; Meng, Fanli; Jiang, Changzhong

    2015-12-01

    Heat-resistant two-dimensional (2D) sphere/hemisphere shell array is significant for the fabrication of novel nanostructures. Here large-area, well-ordered arrays of carbonized polystyrene (PS) hollow sphere/hemisphere with controlled size and morphology are prepared by combining the nanosphere self-assembly, kV Ag ion beam modification, and subsequent annealing or chloroform treatment. Potential mechanisms for the formation and evolution of the heat-resistant carbonized PS spherical shell with increasing ion fluence and energy are discussed. Combined with noble metal or semiconductor, these modified PS sphere arrays should open up new possibilities for high-performance nanoscale optical sensors or photoelectric devices.

  15. Formation of Carbonized Polystyrene Sphere/hemisphere Shell Arrays by Ion Beam Irradiation and Subsequent Annealing or Chloroform Treatment.

    PubMed

    Song, Xianyin; Dai, Zhigao; Xiao, Xiangheng; Li, Wenqing; Zheng, Xudong; Shang, Xunzhong; Zhang, Xiaolei; Cai, Guangxu; Wu, Wei; Meng, Fanli; Jiang, Changzhong

    2015-01-01

    Heat-resistant two-dimensional (2D) sphere/hemisphere shell array is significant for the fabrication of novel nanostructures. Here large-area, well-ordered arrays of carbonized polystyrene (PS) hollow sphere/hemisphere with controlled size and morphology are prepared by combining the nanosphere self-assembly, kV Ag ion beam modification, and subsequent annealing or chloroform treatment. Potential mechanisms for the formation and evolution of the heat-resistant carbonized PS spherical shell with increasing ion fluence and energy are discussed. Combined with noble metal or semiconductor, these modified PS sphere arrays should open up new possibilities for high-performance nanoscale optical sensors or photoelectric devices. PMID:26640125

  16. Focused Ion Beam Technology for Optoelectronic Devices

    NASA Astrophysics Data System (ADS)

    Reithmaier, J. P.; Bach, L.; Forchel, A.

    2003-08-01

    High-resolution proximity free lithography was developed using InP as anorganic resist for ion beam exposure. InP is very sensitive on ion beam irradiation and show a highly nonlinear dose dependence with a contrast function comparable to organic electron beam resists. In combination with implantation induced quantum well intermixing this new lithographic technique based on focused ion beams is used to realize high performance nano patterned optoelectronic devices like complex coupled distributed feedback (DFB) and distributed Bragg reflector (DBR) lasers.

  17. Investigations of the Zeeman effect of some 142Nd ionic levels, using collinear laser ion beam spectroscopy

    NASA Astrophysics Data System (ADS)

    Werbowy, S.; Hühnermann, H.; Kwela, J.; Windholz, L.

    2015-11-01

    By performing laser excitation from the even 4f45d lower levels to the odd 4f46p and 4f35d2 upper levels of the neodymium ion 142Nd+, we have observed Zeeman splitting in an external magnetic field up to 330 G. We applied the high resolution spectroscopic method of collinear laser ion beam spectroscopy (CLIBS). With this method (unconventional for studying the Zeeman effect) we recorded very well-resolved Zeeman structure patterns with line widths of order of 100 MHz, which is only sometimes the natural line width. The obtained experimental Landé factors are compared with earlier measurements and with theoretical calculations.

  18. Real time x-ray studies during nanostructure formation on silicon via low energy ion beam irradiation using ultrathin iron films

    SciTech Connect

    El-Atwani, Osman; Suslova, Anastassiya; Gonderman, Sean; Fowler, Justin; El-Atwani, Mohamad; DeMasi, Alexander; Ludwig, Karl; Paul Allain, Jean

    2012-12-24

    Real time grazing incidence small angle x-ray scattering and x-ray fluorescence (XRF) are used to elucidate nanodot formation on silicon surfaces during low energy ion beam irradiation of ultrathin iron-coated silicon substrates. Four surface modification stages were identified: (1) surface roughening due to film erosion, (2) surface smoothing and silicon-iron mixing, (3) structure formation, and (4) structure smoothing. The results conclude that 2.5 Multiplication-Sign 10{sup 15} iron atoms in a 50 nm depth triggers surface nanopatterning with a correlated nanodots distance of 25 nm. Moreover, there is a wide window in time where the surface can have correlated nanostructures even after the removal of all the iron atoms from the sample as confirmed by XRF and ex-situ x-ray photoelectron spectroscopy (XPS). In addition, in-situ XPS results indicated silicide formation, which plays a role in the structure formation mechanism.

  19. Size effect of large deformable nanopillar by focused-ion-beam chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Tanaka, H.; Shinkai, M.; Shibutani, Y.; Kogo, Y.

    2009-11-01

    Nanoscopic fabrication technique has been achieved by the direct deposition methods using focused-ion-beam chemical vapor deposition (FIB-CVD). The nanopillar fabricated by FIB-CVD consists of an outer amorphous carbon ring and a inner gallium core. We developed the original double-cantilever (DC) bending test using two pillars rigidly connected by the exposure of a focused electron beam in a scanning electron microscope. The obtained deflection curves suggest that nanopillars have the size dependence to the mechanical response. The pillar with the diameter over 180 nm exhibits a wide region of stiffness weakening after linear response and then becomes extremely hardened at a large deflection. Thus, the pillar intrinsically possesses much more flexibility for bending without any fracturing. The accuracy of a DC testing is also discussed by estimating the bending rigidities of nanopillars, comparing to those obtained by resonance frequency tests.

  20. Ion Beam Propulsion Study

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Ion Beam Propulsion Study was a joint high-level study between the Applied Physics Laboratory operated by NASA and ASRC Aerospace at Kennedy Space Center, Florida, and Berkeley Scientific, Berkeley, California. The results were promising and suggested that work should continue if future funding becomes available. The application of ion thrusters for spacecraft propulsion is limited to quite modest ion sources with similarly modest ion beam parameters because of the mass penalty associated with the ion source and its power supply system. Also, the ion source technology has not been able to provide very high-power ion beams. Small ion beam propulsion systems were used with considerable success. Ion propulsion systems brought into practice use an onboard ion source to form an energetic ion beam, typically Xe+ ions, as the propellant. Such systems were used for steering and correction of telecommunication satellites and as the main thruster for the Deep Space 1 demonstration mission. In recent years, "giant" ion sources were developed for the controlled-fusion research effort worldwide, with beam parameters many orders of magnitude greater than the tiny ones of conventional space thruster application. The advent of such huge ion beam sources and the need for advanced propulsion systems for exploration of the solar system suggest a fresh look at ion beam propulsion, now with the giant fusion sources in mind.

  1. Effects of carbon-ion beams on human pancreatic cancer cell lines that differ in genetic status.

    PubMed

    Matsui, Yoshifumi; Asano, Takehide; Kenmochi, Takashi; Iwakawa, Mayumi; Imai, Takashi; Ochiai, Takenori

    2004-02-01

    The relative biologic effectiveness (RBE) of carbon-ion beams at 3 different linear energy transfer (LET) values (13, 50, and 80 keV/microm) accelerated by the Heavy Ion Medical Accelerator in Chiba on human pancreatic cancer cell lines differing in genetic status was determined. The RBE values were calculated as D10, the dose (Gy) required to reduce the surviving fraction to 10%, relative to X-rays. We also investigated apoptosis and the relationship between D10 and the cell cycle checkpoint using morphologic examination and flow cytometry analysis, respectively. The RBE values calculated by the D10 values ranged from 1.16 to 1.77 for the 13-keV/microm beam and from 1.83 to 2.46 for the 80-keV/microm beam. A correlation between the D10 values of each cell line and intensity of G2/M arrest was observed. In contrast, LET values did not clearly correlate with induction of apoptosis. These results suggest that carbon-ion beam therapy is a promising modality. Elucidation of the mechanisms of G2/M arrest and apoptosis may provide clues to enhancing the effects of radiation on pancreatic cancer. PMID:14758129

  2. Electron cloud effects in intense, ion beam linacs theory and experimental planning for heavy-ion fusion

    SciTech Connect

    Molvik, A.W.; Cohen, R.H.; Lund, S.M.; Bieniosek, F.M.; Lee, E.P.; Prost, L.R.; Seidl, P.A.; Vay, Jean-Luc

    2002-05-21

    Heavy-ion accelerators for HIF will operate at high aperture-fill factors with high beam current and long pulses. This will lead to beam ions impacting walls: liberating gas molecules and secondary electrons. Without special preparation a large fractional electron population ({approx}>1%) is predicted in the High-Current Experiment (HCX), but wall conditioning and other mitigation techniques should result in substantial reduction. Theory and particle-in-cell simulations suggest that electrons, from ionization of residual and desorbed gas and secondary electrons from vacuum walls, will be radially trapped in the {approx}4 kV ion beam potential. Trapped electrons can modify the beam space charge, vacuum pressure, ion transport dynamics, and halo generation, and can potentially cause ion-electron instabilities. Within quadrupole (and dipole) magnets, the longitudinal electron flow is limited to drift velocities (E x B and {del}B) and the electron density can vary azimuthally, radially, and longitudinally. These variations can cause centroid misalignment, emittance growth and halo growth. Diagnostics are being developed to measure the energy and flux of electrons and gas evolved from walls, and the net charge and gas density within magnetic quadrupoles, as well as the their effect on the ion beam.

  3. Chromium Grain-boundary Segregation and Effect of Ion Beam Cleaning on Fe-Ni-Cr Alloys

    SciTech Connect

    Saraf, Laxmikant V.

    2011-04-01

    The grain boundaries play important role to control the mechanical strength of ternary alloys. From spacecrafts to naval vessels to nuclear reactors, stress corrosion cracking, brittleness, oxidation mostly originates at the grain boundaries and cause long term structural stability problems in most of the metallic structures [1]. Fe-Ni-Cr based ternary metal alloys have been widely studied for more than fifty years [2, 3]. Despite of vast amount of research, chromium diffusion in stainless steel or other Ni-Fe-Cr based ternary alloys is still an open scientific problem with challenges in structural stability and corrosion resistance [4]. Particularly, austenite Fe-Ni-Cr is looked upon favorably in space and jet engine industry for their improved resistance to stress corrosion cracking [5]. In solid oxide fuel cells (SOFC), Ni-alloys are frequently used as interconnects and seals [6]. In this communication, simultaneous energy dispersive spectroscopy (EDS) and electron backscatter diffraction (EBSD) mapping is utilized to study chemical and structural aspects of chromium segregation in Fe-Ni-Cr alloy. A focused Ga-ion beam is also utilized to study the effect of ion beam cleaning on EBSD image quality (IQ) and inverse pole figure (IPF) maps of Fe-Ni-Cr alloy.

  4. Efficient Performance of Electrostatic Spray-Deposited TiO2 Blocking Layers in Dye-Sensitized Solar Cells after Swift Heavy Ion Beam Irradiation

    PubMed Central

    2011-01-01

    A compact TiO2 layer (~1.1 μm) prepared by electrostatic spray deposition (ESD) and swift heavy ion beam (SHI) irradiation using oxygen ions onto a fluorinated tin oxide (FTO) conducting substrate showed enhancement of photovoltaic performance in dye-sensitized solar cells (DSSCs). The short circuit current density (Jsc = 12.2 mA cm-2) of DSSCs was found to increase significantly when an ESD technique was applied for fabrication of the TiO2 blocking layer, compared to a conventional spin-coated layer (Jsc = 8.9 mA cm-2). When SHI irradiation of oxygen ions of fluence 1 × 1013 ions/cm2 was carried out on the ESD TiO2, it was found that the energy conversion efficiency improved mainly due to the increase in open circuit voltage of DSSCs. This increased energy conversion efficiency seems to be associated with improved electronic energy transfer by increasing the densification of the blocking layer and improving the adhesion between the blocking layer and the FTO substrate. The adhesion results from instantaneous local melting of the TiO2 particles. An increase in the electron transport from the blocking layer may also retard the electron recombination process due to the oxidized species present in the electrolyte. These findings from novel treatments using ESD and SHI irradiation techniques may provide a new tool to improve the photovoltaic performance of DSSCs.

  5. Adenovirus-mediated FIR demonstrated TP53-independent cell-killing effect and enhanced antitumor activity of carbon-ion beams.

    PubMed

    Kano, M; Matsushita, K; Rahmutulla, B; Yamada, S; Shimada, H; Kubo, S; Hiwasa, T; Matsubara, H; Nomura, F

    2016-01-01

    Combination therapy of carbon-ion beam with the far upstream element-binding protein (FBP)-interacting repressor, FIR, which interferes with DNA damage repair proteins, was proposed as an approach for esophageal cancer treatment with low side effects regardless of TP53 status. In vivo therapeutic antitumor efficacy of replication-defective adenovirus (E1 and E3 deleted adenovirus serotype 5) encoding human FIR cDNA (Ad-FIR) was demonstrated in the tumor xenograft model of human esophageal squamous cancer cells, TE-2. Bleomycin (BLM) is an anticancer agent that introduces DNA breaks. The authors reported that Ad-FIR involved in the BLM-induced DNA damage repair response and thus applicable for other DNA damaging agents. To examine the effect of Ad-FIR on DNA damage repair, BLM, X-ray and carbon-ion irradiation were used as DNA damaging agents. The biological effects of high linear energy transfer (LET) radiotherapy used with carbon-ion irradiation are more expansive than low-LET conventional radiotherapy, such as X-rays or γ rays. High LET radiotherapy is suitable for the local control of tumors because of its high relative biological effectiveness. Ad-FIR enhanced BLM-induced DNA damage indicated by γH2AX in vitro. BLM treatment increased endogenous nuclear FIR expression in TE-2 cells, and P27Kip1 expression was suppressed by TP53 siRNA and BLM treatment. Further, Ad-FIRΔexon2, a dominant-negative form of FIR that lacks exon2 transcriptional repression domain, decreased Ku86 expression. The combination of Ad-FIR and BLM in TP53 siRNA increased DNA damage. Additionally, Ad-FIR showed synergistic cell toxicity with X-ray in vitro and significantly increased the antitumor efficacy of carbon-ion irradiation in the xenograft mouse model of TE-2 cells (P=0.03, Mann-Whitney's U-test) and was synergistic with the sensitization enhancement ratio (SER) value of 1.15. Therefore, Ad-FIR increased the cell-killing activity of the carbon-ion beam that avoids late

  6. Ion beam texturing

    NASA Technical Reports Server (NTRS)

    Hudson, W. R.

    1976-01-01

    A microscopic surface texture is created by sputter etching a surface while simultaneously sputter depositing a lower sputter yield material onto the surface. A xenon ion beam source has been used to perform this texturing process on samples as large as three centimeters in diameter. Ion beam textured surface structures have been characterized with SEM photomicrographs for a large number of materials including Cu, Al, Si, Ti, Ni, Fe, Stainless steel, Au, and Ag. Surfaces have been textured using a variety of low sputter yield materials - Ta, Mo, Nb, and Ti. The initial stages of the texture creation have been documented, and the technique of ion beam sputter removal of any remaining deposited material has been studied. A number of other texturing parameters have been studied such as the variation of the texture with ion beam power, surface temperature, and the rate of texture growth with sputter etching time.

  7. Pulsed ion beam source

    DOEpatents

    Greenly, John B.

    1997-01-01

    An improved pulsed ion beam source having a new biasing circuit for the fast magnetic field. This circuit provides for an initial negative bias for the field created by the fast coils in the ion beam source which pre-ionize the gas in the source, ionize the gas and deliver the gas to the proper position in the accelerating gap between the anode and cathode assemblies in the ion beam source. The initial negative bias improves the interaction between the location of the nulls in the composite magnetic field in the ion beam source and the position of the gas for pre-ionization and ionization into the plasma as well as final positioning of the plasma in the accelerating gap. Improvements to the construction of the flux excluders in the anode assembly are also accomplished by fabricating them as layered structures with a high melting point, low conductivity material on the outsides with a high conductivity material in the center.

  8. CRionScan: A stand-alone real time controller designed to perform ion beam imaging, dose controlled irradiation and proton beam writing

    NASA Astrophysics Data System (ADS)

    Daudin, L.; Barberet, Ph.; Serani, L.; Moretto, Ph.

    2013-07-01

    High resolution ion microbeams, usually used to perform elemental mapping, low dose targeted irradiation or ion beam lithography needs a very flexible beam control system. For this purpose, we have developed a dedicated system (called “CRionScan”), on the AIFIRA facility (Applications Interdisciplinaires des Faisceaux d'Ions en Région Aquitaine). It consists of a stand-alone real-time scanning and imaging instrument based on a Compact Reconfigurable Input/Output (Compact RIO) device from National Instruments™. It is based on a real-time controller, a Field Programmable Gate Array (FPGA), input/output modules and Ethernet connectivity. We have implemented a fast and deterministic beam scanning system interfaced with our commercial data acquisition system without any hardware development. CRionScan is built under LabVIEW™ and has been used on AIFIRA's nanobeam line since 2009 (Barberet et al., 2009, 2011) [1,2]. A Graphical User Interface (GUI) embedded in the Compact RIO as a web page is used to control the scanning parameters. In addition, a fast electrostatic beam blanking trigger has been included in the FPGA and high speed counters (15 MHz) have been implemented to perform dose controlled irradiation and on-line images on the GUI. Analog to Digital converters are used for the beam current measurement and in the near future for secondary electrons imaging. Other functionalities have been integrated in this controller like LED lighting using Pulse Width Modulation and a “NIM Wilkinson ADC” data acquisition.

  9. Reprint of localized dose delivering by ion beam irradiation for experimental trial of establishing brain necrosis model.

    PubMed

    Takata, Takushi; Kondo, Natsuko; Sakurai, Yoshinori; Tanaka, Hiroki; Hasegawa, Takashi; Kume, Kyo; Suzuki, Minoru

    2015-12-01

    Localized dose delivery techniques to establish a brain radiation necrosis model are described. An irradiation field was designed by using accelerated protons or helium ions with a spread-out Bragg peak. Measurement of the designed field confirmed that a high dose can be confined to a local volume of an animal brain. The irradiation techniques described here are very useful for establishing a necrosis model without existence of extraneous complications. PMID:26515136

  10. High-powered pulsed-ion-beam acceleration and transport

    SciTech Connect

    Humphries, S. Jr.; Lockner, T.R.

    1981-11-01

    The state of research on intense ion beam acceleration and transport is reviewed. The limitations imposed on ion beam transport by space charge effects and methods available for neutralization are summarized. The general problem of ion beam neutralization in regions free of applied electric fields is treated. The physics of acceleration gaps is described. Finally, experiments on multi-stage ion acceleration are summarized.

  11. Ion Beam Therapy in Europe

    NASA Astrophysics Data System (ADS)

    Kraft, Gerhard

    2009-03-01

    At present, seven facilities in Europe treat deep-seated tumors with particle beams, six with proton beams and one with carbon ions. Three of these facilities are in Moscow, St. Petersburg and Dubna, Russia. Other facilities include the TSL Uppsala, Sweden, CPO Orsay, France, and PSI Villigen, Switzerland, all for proton therapy, and GSI, Darmstadt, Germany, which utilizes carbon ions only. But only two of these facilities irradiate with scanned ion beams: the Paul Scherer Institute (PSI), Villigen (protons) and the Gesellschaft für Schwerionenforschung (GSI), Darmstadt. These two facilities are experimental units within physics laboratories and have developed the technique of intensity-modulated beam scanning in order to produce irradiation conforming to a 3-D target. There are three proton centers presently under construction in Munich, Essen and Orsay, and the proton facility at PSI has added a superconducting accelerator connected to an isocentric gantry in order to become independent of the accelerator shared with the physics research program. The excellent clinical results using carbon ions at National Institute of Radiological Science (NIRS) in Chiba and GSI have triggered the construction of four new heavy-ion therapy projects (carbon ions and protons), located in Heidelberg, Pavia, Marburg and Kiel. The projects in Heidelberg and Pavia will begin patient treatment in 2009, and the Marburg and Kiel projects will begin in 2010 and 2011, respectively. These centers use different accelerator designs but have the same kind of treatment planning system and use the same approach for the calculation of the biological effectiveness of the carbon ions as developed at GSI [1]. There are many other planned projects in the works. Do not replace the word "abstract," but do replace the rest of this text. If you must insert a hard line break, please use Shift+Enter rather than just tapping your "Enter" key. You may want to print this page and refer to it as a style

  12. Effect of substrate temperature on residual stress of ZnO thin films prepared by ion beam deposition

    NASA Astrophysics Data System (ADS)

    Jeon, Ju-Won; Kim, Myoung; Jang, Lee-Woon; Hoffman, J. L.; Kim, Nam Soo; Lee, In-Hwan

    2012-02-01

    We have investigated the effect of substrate temperature on micro-structural properties of ZnO thin films prepared by ion beam deposition technique. ZnO thin films were deposited on AlN-buffered Si (111) and sapphire (001) substrates at various substrate temperatures. The structural properties and surface morphologies were examined by high resolution X-ray diffraction (XRD) and field emission scanning electron microscopy, respectively. The RMS roughness was measured by atomic force microscopy. XRD measurements confirmed that the ZnO thin films were grown well on the AlN-buffered Si (111) and sapphire (001) substrates along the c-axis. Minimization of residual stress was carried out by tuning the substrate temperature. The structural properties were notably improved with increasing substrate temperature.

  13. Effects of Ion Beam on Nanoindentation Characteristics of Glassy Polymeric Carbon Surface

    SciTech Connect

    Rodrigues, M. G.; Da Cruz, N. C.; Rangel, E. C.; Zimmerman, R. L.; Ila, Dr. Daryush; Poker, David B; Hensley, Dale K

    2005-01-01

    Glassy polymeric carbon (GPC) is a useful material for medical applications due to its chemical inertness and biocompatible characteristics. Mitral and aortic and hydrocephalic valves are examples of GPC prosthetic devices that have been fabricated and commercialized in Brazil. In this work, ion beam was used to improve the mechanical characteristics of GPC surface and therefore to avoid the propagation of microcracks where the cardiac valves are more fragile. A control group of phenolic resin samples heat-treated at 300, 400, 700, 1000, 1500, and 2500 C was characterized by measuring their hardness and Young's reduced elastic modulus with the depth of indentation. The control group was compared to results obtained with samples heat-treated at 700, 1000, and 1500 C and bombarded with energetic ions of silicon, carbon, oxygen, and gold at energies of 5, 6, 8, and 10 MeV, respectively, with fluences between 1.0 x 10{sup 13} and 1.0 x 10{sup 16} ions/cm{sup 2}. GPC nonbombarded samples showed that hardness depends on the heat treatment temperature (HTT), with a maximum hardness for heat treatment at 1000 C. The comparison between the control group and bombarded group also showed that hardness, after bombardment, had a greater increase for samples prepared at 700 C than for samples prepared at higher temperatures. The Young's elastic modulus presents an exponential relationship with depth. The parameters obtained by fitting depend on the HTT and on the ion used in the bombardment more than on energy and fluence. The hardness results show clearly that bombardment can promote carbonization, increase the linkage between the chains of the polymeric material, and promote recombination of broken bonds in lateral groups that are more numerous for samples heat-treated at 700 C.

  14. ESR spin trapping of radicals in methanol solution irradiated by heavy ion beams. Dependence on specific energy and LET

    NASA Astrophysics Data System (ADS)

    Nakagawa, Seiko; Murakami, Takeshi

    2015-08-01

    Radicals produced by the heavy ion (He, C, Ne, Si, Ar, and Fe) irradiation of methanol were spin trapped with PBN. Three kinds of radicals, PBN-CH3O, PBN-CH2OH, and PBN-H, were observed similar to those by γ-irradiation. The relative radical yields, PBN-CH3O/PBN-CH2OH and (PBN-CH3O + PBN-CH2OH)/PBN-H, varied depending on the LET value, the specific energy and mass of ions.

  15. Effects of ion beam heating on Raman spectra of single-walled carbon nanotubes

    SciTech Connect

    Hulman, Martin; Skakalova, Viera; Krasheninnikov, A. V.; Roth, S.

    2009-02-16

    Free standing films of single-wall carbon nanotubes were irradiated with energetic N{sup +} and C{sup 4+} ions. The observed changes in the Raman line shape of the radial breathing mode and the G band of the C{sup 4+} irradiated samples were similar to those found for a thermally annealed sample. We ascribe these changes to thermal desorption of volatile dopants from the initially doped nanotubes. A simple geometry of the experiment allows us to estimate the temperature rise by one-dimensional heat conductance equation. The calculation indicates that irradiation-mediated increase in temperature may account for the observed Raman spectra changes.

  16. Obliquely incident ion beam figuring

    NASA Astrophysics Data System (ADS)

    Zhou, Lin; Dai, Yifan; Xie, Xuhui; Li, Shengyi

    2015-10-01

    A new ion beam figuring (IBF) technique, obliquely incident IBF (OI-IBF), is proposed. In OI-IBF, the ion beam bombards the optical surface obliquely with an invariable incident angle instead of perpendicularly as in the normal IBF. Due to the higher removal rate in oblique incidence, the process time in OI-IBF can be significantly shortened. The removal rates at different incident angles were first tested, and then a test mirror was processed by OI-IBF. Comparison shows that in the OI-IBF technique with a 30 deg incident angle, the process time was reduced by 56.8%, while keeping the same figure correcting ability. The experimental results indicate that the OI-IBF technique is feasible and effective to improve the surface correction process efficiency.

  17. Surface Treatment of Polymers by Ion Beam Irradiation to Control the Human Osteoblast Adhesion: Fluence and Current Density Study

    NASA Astrophysics Data System (ADS)

    Guibert, G.; Rossel, T.; Weder, G.; Betschart, B.; Meunier, C.; Mikhailov, S.

    2009-03-01

    In the biomaterial field, the modification of surfaces are used to create polymers with high performances, preserving their bulk properties and creating specific interactions between the designed surfaces and the cells or tissues. The polymers were irradiated with a 900 keV Helium beam to modify their surface properties. Cell cultivation on the samples was done using human osteoblasts cells (hFOB 1.19). For PTFE, PS and PEEK polymers, the cell adhesion occurs after reached some threshold values of fluences. For PET or PMMA polymers, the cells adhere on the non irradiated samples, however the fluence value modifies the cell density. For PMMA and PTFE both, the fluence and the current density influence the cell adhesion. By modifying the appropriate parameters on each material, the control of the cell adhesion is possible. Indeed the surface treatment must be selected and adapted according to the further application: for biosensors, tissue engineering, tissue regeneration, neural probes, drug delivery, bio-actuators etc.

  18. Surface Treatment of Polymers by Ion Beam Irradiation to Control the Human Osteoblast Adhesion: Fluence and Current Density Study

    SciTech Connect

    Guibert, G.; Mikhailov, S.; Rossel, T.; Weder, G.; Betschart, B.; Meunier, C.

    2009-03-10

    In the biomaterial field, the modification of surfaces are used to create polymers with high performances, preserving their bulk properties and creating specific interactions between the designed surfaces and the cells or tissues. The polymers were irradiated with a 900 keV Helium beam to modify their surface properties. Cell cultivation on the samples was done using human osteoblasts cells (hFOB 1.19). For PTFE, PS and PEEK polymers, the cell adhesion occurs after reached some threshold values of fluences. For PET or PMMA polymers, the cells adhere on the non irradiated samples, however the fluence value modifies the cell density. For PMMA and PTFE both, the fluence and the current density influence the cell adhesion. By modifying the appropriate parameters on each material, the control of the cell adhesion is possible. Indeed the surface treatment must be selected and adapted according to the further application: for biosensors, tissue engineering, tissue regeneration, neural probes, drug delivery, bio-actuators etc.

  19. Temperature and ion-mass dependence of amorphization dose for ion beam irradiated zircon (ZrSiO{sub 4})

    SciTech Connect

    Wang, L.M.; Ewing, R.C.; Weber, W.J.; Eby, R.K.

    1992-12-01

    The temperature dependence of amorphization dose for zircon under 1.5 MeV Kr ion irradiation has been investigated using the ANL HVEM-Tandem Facility. Three regimes were observed in the amorphization dose-temperature curve. In the first regime (15 to 300 K), the critical amorphization dose increased from 3.06 to 4.5 ions/nm{sup 2}. In the second regime (300 to 473 K), there is little change in the amorphizationdose. In the third regime (> 473 K), the amorphization dose increased exponentially to 8.3 ions/nm{sup 2} at 913 K. This temperature dependence of amorphization dose can be described by two processes with different activation energies (0.018 and 0.31 eV respectively) which are attributed to close pair recombination in the cascades at low temperatures and radiation-enhanced epitaxial recrystallization at higher temperatures. The upper temperature limit for amorphization of zircon is estimated to be 1100 K. The ion-mass dependence of the amorphization dose (in dpa) has also been discussed in terms of the energy to recoils based on data obtained from He, Ne, Ar, Kr, Xe irradiations and a {sup 238}Pu-doped sample.

  20. Temperature and ion-mass dependence of amorphization dose for ion beam irradiated zircon (ZrSiO[sub 4])

    SciTech Connect

    Wang, L.M.; Ewing, R.C. . Dept. of Geology); Weber, W.J. ); Eby, R.K. . Dept. of Geological Sciences)

    1992-12-01

    The temperature dependence of amorphization dose for zircon under 1.5 MeV Kr ion irradiation has been investigated using the ANL HVEM-Tandem Facility. Three regimes were observed in the amorphization dose-temperature curve. In the first regime (15 to 300 K), the critical amorphization dose increased from 3.06 to 4.5 ions/nm[sup 2]. In the second regime (300 to 473 K), there is little change in the amorphizationdose. In the third regime (> 473 K), the amorphization dose increased exponentially to 8.3 ions/nm[sup 2] at 913 K. This temperature dependence of amorphization dose can be described by two processes with different activation energies (0.018 and 0.31 eV respectively) which are attributed to close pair recombination in the cascades at low temperatures and radiation-enhanced epitaxial recrystallization at higher temperatures. The upper temperature limit for amorphization of zircon is estimated to be 1100 K. The ion-mass dependence of the amorphization dose (in dpa) has also been discussed in terms of the energy to recoils based on data obtained from He, Ne, Ar, Kr, Xe irradiations and a [sup 238]Pu-doped sample.

  1. Pulsed ion beam source

    DOEpatents

    Greenly, J.B.

    1997-08-12

    An improved pulsed ion beam source is disclosed having a new biasing circuit for the fast magnetic field. This circuit provides for an initial negative bias for the field created by the fast coils in the ion beam source which pre-ionize the gas in the source, ionize the gas and deliver the gas to the proper position in the accelerating gap between the anode and cathode assemblies in the ion beam source. The initial negative bias improves the interaction between the location of the nulls in the composite magnetic field in the ion beam source and the position of the gas for pre-ionization and ionization into the plasma as well as final positioning of the plasma in the accelerating gap. Improvements to the construction of the flux excluders in the anode assembly are also accomplished by fabricating them as layered structures with a high melting point, low conductivity material on the outsides with a high conductivity material in the center. 12 figs.

  2. Ion-beam technologies

    SciTech Connect

    Fenske, G.R.

    1993-01-01

    This compilation of figures and diagrams reviews processes for depositing diamond/diamond-like carbon films. Processes addressed are chemical vapor deposition (HFCVD, PACVD, etc.), plasma vapor deposition (plasma sputtering, ion beam sputtering, evaporation, etc.), low-energy ion implantation, and hybrid processes (biased sputtering, IBAD, biased HFCVD, etc.). The tribological performance of coatings produced by different means is discussed.

  3. Performance and Controllability of Pulsed Ion Beam Ablation Propulsion

    SciTech Connect

    Yazawa, Masaru; Buttapeng, Chainarong; Harada, Nobuhiro; Suematsu, Hisayuki; Jiang Weihua; Yatsui, Kiyoshi

    2006-05-02

    We propose novel propulsion driven by ablation plasma pressures produced by the irradiation of pulsed ion beams onto a propellant. The ion beam ablation propulsion demonstrates by a thin foil (50 {mu}mt), and the flyer velocity of 7.7 km/s at the ion beam energy density of 2 kJ/cm2 adopted by using the Time-of-flight method is observed numerically and experimentally. We estimate the performance of the ion beam ablation propulsion as specific impulse of 3600 s and impulse bit density of 1700 Ns/m2 obtained from the demonstration results. In the numerical analysis, a one-dimensional hydrodynamic model with ion beam energy depositions is used. The control of the ion beam kinetic energy is only improvement of the performance but also propellant consumption. The spacecraft driven by the ion beam ablation provides high performance efficiency with short-pulsed ion beam irradiation. The numerical results of the advanced model explained latent heat and real gas equation of state agreed well with experimental ones over a wide range of the incident ion beam energy density.

  4. Ion beam processing of advanced electronic materials

    SciTech Connect

    Cheung, N.W.; Marwick, A.D.; Roberto, J.B.; International Business Machines Corp., Yorktown Heights, NY . Thomas J. Watson Research Center; Oak Ridge National Lab., TN )

    1989-01-01

    This report contains research programs discussed at the materials research society symposia on ion beam processing of advanced electronic materials. Major topics include: shallow implantation and solid-phase epitaxy; damage effects; focused ion beams; MeV implantation; high-dose implantation; implantation in III-V materials and multilayers; and implantation in electronic materials. Individual projects are processed separately for the data bases. (CBS)

  5. Flyer Acceleration by Pulsed Ion Beam Ablation and Application for Space Propulsion

    SciTech Connect

    Harada, Nobuhiro; Buttapeng, Chainarong; Yazawa, Masaru; Kashine, Kenji; Jiang Weihua; Yatsui, Kiyoshi

    2004-02-04

    Flyer acceleration by ablation plasma pressure produced by irradiation of intense pulsed ion beam has been studied. Acceleration process including expansion of ablation plasma was simulated based on fluid model. And interaction between incident pulsed ion beam and a flyer target was considered as accounting stopping power of it. In experiments, we used ETIGO-II intense pulsed ion beam generator with two kinds of diodes; 1) Magnetically Insulated Diode (MID, power densities of <100 J/cm2) and 2) Spherical-focused Plasma Focus Diode (SPFD, power densities of up to 4.3 kJ/cm2). Numerical results of accelerated flyer velocity agreed well with measured one over wide range of incident ion beam energy density. Flyer velocity of 5.6 km/s and ablation plasma pressure of 15 GPa was demonstrated by the present experiments. Acceleration of double-layer target consists of gold/aluminum was studied. For adequate layer thickness, such a flyer target could be much more accelerated than a single layer. Effect of waveform of ion beam was also examined. Parabolic waveform could accelerate more efficiently than rectangular waveform. Applicability of ablation propulsion was discussed. Specific impulse of 7000{approx}8000 seconds and time averaged thrust of up to 5000{approx}6000N can be expected. Their values can be controllable by changing power density of incident ion beam and pulse duration.

  6. Negative Ion Beam Extraction and Emittance

    SciTech Connect

    Holmes, Andrew J. T.

    2007-08-10

    The use of magnetic fields to both aid the production of negative ions and suppress the co-extracted electrons causes the emittance and hence the divergence of the negative ion beam to increase significantly due to the plasma non-uniformity from jxB drift. This drift distorts the beam-plasma meniscus and experimental results of the beam emittance are presented, which show that non-uniformity causes the square of the emittance to be proportional to the 2/3 power of the extracted current density. This can cause the divergence of the negative ion beam to be significantly larger than its positive ion counterpart. By comparing results from positive and negative ion beam emittances from the same source, it is also possible to draw conclusions about their vulnerability to magnetic effects. Finally emittances of caesiated and un-caesiated negative ion beams are compared to show how the surface and volume modes of production interact.

  7. Reduce the matrix effect in biological tissue imaging using dynamic reactive ionization and gas cluster ion beams.

    PubMed

    Tian, Hua; Wucher, Andreas; Winograd, Nicholas

    2016-06-01

    In the context of a secondary ion mass spectrometry (SIMS) experiment, dynamic reactive ionization (DRI) involves introducing a reactive dopant, HCl, into an Ar gas cluster primary ion beam along with a source of water to enable dissociation of HCl to free protons. This concerted effect, precisely occurring at the impact site of the cluster beam, enhances the protonation of molecular species. Here, the authors apply this methodology to study the hippocampus and cerebellum region of a frozen-hydrated mouse brain section. To determine the degree of enhancement associated with DRI conditions, sequential tissue slices were arranged in a mirrored configuration so that comparable regions of the tissue could be explored. The results show that the protonated lipid species are increased by ∼10-fold, but that the normally prevalent salt adducts are virtually unaffected. This observation is discussed as a novel approach to minimizing SIMS matrix effects in complex materials. Moreover, the chemical images of protonated lipid ions exhibit clearer features in the cerebellum region as compared to images acquired with the pure Ar cluster beam. PMID:26856333

  8. The Relative Biological Effectiveness for Carbon and Oxygen Ion Beams Using the Raster-Scanning Technique in Hepatocellular Carcinoma Cell Lines

    PubMed Central

    Habermehl, Daniel; Ilicic, Katarina; Dehne, Sarah; Rieken, Stefan; Orschiedt, Lena; Brons, Stephan; Haberer, Thomas; Weber, Klaus-Josef; Debus, Jürgen; Combs, Stephanie E.

    2014-01-01

    Background Aim of this study was to evaluate the relative biological effectiveness (RBE) of carbon (12C) and oxygen ion (16O)-irradiation applied in the raster-scanning technique at the Heidelberg Ion beam Therapy center (HIT) based on clonogenic survival in hepatocellular carcinoma cell lines compared to photon irradiation. Methods Four human HCC lines Hep3B, PLC, HepG2 and HUH7 were irradiated with photons, 12C and 16O using a customized experimental setting at HIT for in-vitro trials. Cells were irradiated with increasing physical photon single doses of 0, 2, 4 and 6 Gy and heavy ionsingle doses of 0, 0.125, 0.5, 1, 2, 3 Gy (12C and 16O). SOBP-penetration depth and extension was 35 mm +/−4 mm and 36 mm +/−5 mm for carbon ions and oxygen ions respectively. Mean energy level and mean linear energy transfer (LET) were 130 MeV/u and 112 keV/um for 12C, and 154 MeV/u and 146 keV/um for 16O. Clonogenic survival was computated and realtive biological effectiveness (RBE) values were defined. Results For all cell lines and both particle modalities α- and β-values were determined. As expected, α-values were significantly higher for 12C and 16O than for photons, reflecting a steeper decline of the initial slope of the survival curves for high-LET beams. RBE-values were in the range of 2.1–3.3 and 1.9–3.1 for 12C and 16O, respectively. Conclusion Both irradiation with 12C and 16O using the rasterscanning technique leads to an enhanced RBE in HCC cell lines. No relevant differences between achieved RBE-values for 12C and 16O were found. Results of this work will further influence biological-adapted treatment planning for HCC patients that will undergo particle therapy with 12C or 16O. PMID:25460352

  9. Ion beam surface modification

    NASA Technical Reports Server (NTRS)

    Dwight, D. W.

    1982-01-01

    The essential details of a study on the practical applications and mechanisms of polymer sputtering via Argon ion impact are summarized. The potential to modify the properties of polymer surfaces to improve their adherence, durability, biocompatibility, or other desirable properties by ion beam sputtering was emphasized. Ion beam milling can be of benefit as an analytical tool to obtain composition versus depth information. Ion impact from a directed ion gun source specifically etches polymer structures according to their morphologies, therefore this technique may be useful to study unknown or new morphological features. Factors addressed were related to: (1) the texture that arises on a polymer target after ion impact; (2) the chemistry of the top surface after ion impact; (3) the chemistry of sputtered films of polymeric material deposited on substrates placed adjacent to targets during ion impact; and (4) practical properties of textured polymer targets, specifically the wettability and adhesive bonding properties.

  10. Focused ion beam system

    DOEpatents

    Leung, K.; Gough, R.A.; Ji, Q.; Lee, Y.Y.

    1999-08-31

    A focused ion beam (FIB) system produces a final beam spot size down to 0.1 {mu}m or less and an ion beam output current on the order of microamps. The FIB system increases ion source brightness by properly configuring the first (plasma) and second (extraction) electrodes. The first electrode is configured to have a high aperture diameter to electrode thickness aspect ratio. Additional accelerator and focusing electrodes are used to produce the final beam. As few as five electrodes can be used, providing a very compact FIB system with a length down to only 20 mm. Multibeamlet arrangements with a single ion source can be produced to increase throughput. The FIB system can be used for nanolithography and doping applications for fabrication of semiconductor devices with minimum feature sizes of 0.1 m or less. 13 figs.

  11. Focused ion beam system

    DOEpatents

    Leung, Ka-Ngo; Gough, Richard A.; Ji, Qing; Lee, Yung-Hee Yvette

    1999-01-01

    A focused ion beam (FIB) system produces a final beam spot size down to 0.1 .mu.m or less and an ion beam output current on the order of microamps. The FIB system increases ion source brightness by properly configuring the first (plasma) and second (extraction) electrodes. The first electrode is configured to have a high aperture diameter to electrode thickness aspect ratio. Additional accelerator and focusing electrodes are used to produce the final beam. As few as five electrodes can be used, providing a very compact FIB system with a length down to only 20 mm. Multibeamlet arrangements with a single ion source can be produced to increase throughput. The FIB system can be used for nanolithography and doping applications for fabrication of semiconductor devices with minimum feature sizes of 0.1 .mu.m or less.

  12. Ion beam generating apparatus

    DOEpatents

    Brown, Ian G.; Galvin, James

    1987-01-01

    An ion generating apparatus utilizing a vacuum chamber, a cathode and an anode in the chamber. A source of electrical power produces an arc or discharge between the cathode and anode. The arc is sufficient to vaporize a portion of the cathode to form a plasma. The plasma is directed to an extractor which separates the electrons from the plasma, and accelerates the ions to produce an ion beam.

  13. Intense ion beam generator

    DOEpatents

    Humphries, Jr., Stanley; Sudan, Ravindra N.

    1977-08-30

    Methods and apparatus for producing intense megavolt ion beams are disclosed. In one embodiment, a reflex triode-type pulsed ion accelerator is described which produces ion pulses of more than 5 kiloamperes current with a peak energy of 3 MeV. In other embodiments, the device is constructed so as to focus the beam of ions for high concentration and ease of extraction, and magnetic insulation is provided to increase the efficiency of operation.

  14. Ion Beam Simulator

    Energy Science and Technology Software Center (ESTSC)

    2005-11-08

    IBSimu(Ion Beam Simulator) is a computer program for making two and three dimensional ion optical simulations. The program can solve electrostatic field in a rectangular mesh using Poisson equation using Finite Difference method (FDM). The mesh can consist of a coarse and a fine part so that the calculation accuracy can be increased in critical areas of the geometry, while most of the calculation is done quickly using the coarse mesh. IBSimu can launch ionmore » beam trajectories into the simulation from an injection surface or fomo plasma. Ion beam space charge of time independent simulations can be taken in account using Viasov iteration. Plasma is calculated by compensating space charge with electrons having Boltzmann energy distribution. The simulation software can also be used to calculate time dependent cases if the space charge is not calculated. Software includes diagnostic tools for plotting the geometry, electric field, space charge map, ion beam trajectories, emittance data and beam profiles.« less

  15. Nonpropulsive applications of ion beams

    NASA Technical Reports Server (NTRS)

    Hudson, W. R.

    1976-01-01

    Eight centimeter ion beam sources utilizing xenon and argon have been developed that operate over a wide range of beam energies and currents. Three types of processes have been studied: sputter deposition, ion beam machining, and ion beam surface texturing. The broad range of source operating conditions allows optimum sputter deposition of various materials. An ion beam source was used to ion mill laser reflection holograms using photoresist patterns on silicon. Ion beam texturing was tried with many materials and has a multitude of potential applications.

  16. Effect of ion-beam treatment on structure and fracture resistance of 12Cr1MoV steel under static, cyclic and dynamic loading

    SciTech Connect

    Panin, S. V. Vlasov, I. V. Sergeev, V. P.; Maruschak, P. O.

    2015-10-27

    Features of the structure and properties modification of 12Cr1MoV steel subjected to irradiation by zirconium ion beam have been investigated with the use of optical and electron microscopy as well as microhardness measurement. It has been shown that upon treatment the structure modification occurred across the entire cross-section of specimens with the thickness of 1 mm. Changes in the mechanical properties of these specimens under static, cyclic and impact loading are interpreted in terms of identified structure changes.

  17. Ion beam sputter etching

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A.; Rutledge, Sharon K.

    1986-01-01

    An ion beam etching process which forms extremely high aspect ratio surface microstructures using thin sputter masks is utilized in the fabrication of integrated circuits. A carbon rich sputter mask together with unmasked portions of a substrate is bombarded with inert gas ions while simultaneous carbon deposition occurs. The arrival of the carbon deposit is adjusted to enable the sputter mask to have a near zero or even slightly positive increase in thickness with time while the unmasked portions have a high net sputter etch rate.

  18. Ion beam accelerator system

    NASA Technical Reports Server (NTRS)

    Aston, Graeme (Inventor)

    1984-01-01

    A system is described that combines geometrical and electrostatic focusing to provide high ion extraction efficiency and good focusing of an accelerated ion beam. The apparatus includes a pair of curved extraction grids (16, 18) with multiple pairs of aligned holes positioned to direct a group of beamlets (20) along converging paths. The extraction grids are closely spaced and maintained at a moderate potential to efficiently extract beamlets of ions and allow them to combine into a single beam (14). An accelerator electrode device (22) downstream from the extraction grids, is at a much lower potential than the grids to accelerate the combined beam.

  19. Ion beam accelerator system

    NASA Technical Reports Server (NTRS)

    Aston, G. (Inventor)

    1981-01-01

    A system is described that combines geometrical and electrostatic focusing to provide high ion extraction efficiency and good focusing of an accelerated ion beam. The apparatus includes a pair of curved extraction grids with multiple pairs of aligned holes positioned to direct a group of beamlets along converging paths. The extraction grids are closely spaced and maintained at a moderate potential to efficiently extract beamlets of ions and allow them to combine into a single beam. An accelerator electrode device downstream from the extraction grids is at a much lower potential than the grids to accelerate the combined beam. The application of the system to ion implantation is mentioned.

  20. Ion beam lithography system

    DOEpatents

    Leung, Ka-Ngo

    2005-08-02

    A maskless plasma-formed ion beam lithography tool provides for patterning of sub-50 nm features on large area flat or curved substrate surfaces. The system is very compact and does not require an accelerator column and electrostatic beam scanning components. The patterns are formed by switching beamlets on or off from a two electrode blanking system with the substrate being scanned mechanically in one dimension. This arrangement can provide a maskless nano-beam lithography tool for economic and high throughput processing.

  1. Effects of focused ion beam milling on electron backscatter diffraction patterns in strontium titanate and stabilized zirconia.

    PubMed

    Saowadee, N; Agersted, K; Bowen, J R

    2012-06-01

    This study investigates the effect of focused ion beam (FIB) current and accelerating voltage on electron backscatter diffraction pattern quality of yttria-stabilized zirconia (YSZ) and Nb-doped strontium titanate (STN) to optimize data quality and acquisition time for 3D-EBSD experiments by FIB serial sectioning. Band contrast and band slope were used to describe the pattern quality. The FIB probe currents investigated ranged from 100 to 5000 pA and the accelerating voltage was either 30 or 5 kV. The results show that 30 kV FIB milling induced a significant reduction of the pattern quality of STN samples compared to a mechanically polished surface but yielded a high pattern quality on YSZ. The difference between STN and YSZ pattern quality is thought to be caused by difference in the degree of ion damage as their backscatter coefficients and ion penetration depths are virtually identical. Reducing the FIB probe current from 5000 to 100 pA improved the pattern quality by 20% for STN but only showed a marginal improvement for YSZ. On STN, a conductive coating can help to improve the pattern quality and 5 kV polishing can lead to a 100% improvement of the pattern quality relatively to 30 kV FIB milling. For 3D-EBSD experiments of a material such as STN, it is recommended to combine a high kV FIB milling and low kV polishing for each slice in order to optimize the data quality and acquisition time. PMID:22582798

  2. The EGFR mutation status affects the relative biological effectiveness of carbon-ion beams in non-small cell lung carcinoma cells

    PubMed Central

    Amornwichet, Napapat; Oike, Takahiro; Shibata, Atsushi; Nirodi, Chaitanya S.; Ogiwara, Hideaki; Makino, Haruhiko; Kimura, Yuka; Hirota, Yuka; Isono, Mayu; Yoshida, Yukari; Ohno, Tatsuya; Kohno, Takashi; Nakano, Takashi

    2015-01-01

    Carbon-ion radiotherapy (CIRT) holds promise to treat inoperable locally-advanced non-small cell lung carcinoma (NSCLC), a disease poorly controlled by standard chemoradiotherapy using X-rays. Since CIRT is an extremely limited medical resource, selection of NSCLC patients likely to benefit from it is important; however, biological predictors of response to CIRT are ill-defined. The present study investigated the association between the mutational status of EGFR and KRAS, driver genes frequently mutated in NSCLC, and the relative biological effectiveness (RBE) of carbon-ion beams over X-rays. The assessment of 15 NSCLC lines of different EGFR/KRAS mutational status and that of isogenic NSCLC lines expressing wild-type or mutant EGFR revealed that EGFR-mutant NSCLC cells, but not KRAS-mutant cells, show low RBE. This was attributable to (i) the high X-ray sensitivity of EGFR-mutant cells, since EGFR mutation is associated with a defect in non-homologous end joining, a major pathway for DNA double-strand break (DSB) repair, and (ii) the strong cell-killing effect of carbon-ion beams due to poor repair of carbon-ion beam-induced DSBs regardless of EGFR mutation status. These data highlight the potential of EGFR mutation status as a predictor of response to CIRT, i.e., CIRT may show a high therapeutic index in EGFR mutation-negative NSCLC. PMID:26065573

  3. The EGFR mutation status affects the relative biological effectiveness of carbon-ion beams in non-small cell lung carcinoma cells.

    PubMed

    Amornwichet, Napapat; Oike, Takahiro; Shibata, Atsushi; Nirodi, Chaitanya S; Ogiwara, Hideaki; Makino, Haruhiko; Kimura, Yuka; Hirota, Yuka; Isono, Mayu; Yoshida, Yukari; Ohno, Tatsuya; Kohno, Takashi; Nakano, Takashi

    2015-01-01

    Carbon-ion radiotherapy (CIRT) holds promise to treat inoperable locally-advanced non-small cell lung carcinoma (NSCLC), a disease poorly controlled by standard chemoradiotherapy using X-rays. Since CIRT is an extremely limited medical resource, selection of NSCLC patients likely to benefit from it is important; however, biological predictors of response to CIRT are ill-defined. The present study investigated the association between the mutational status of EGFR and KRAS, driver genes frequently mutated in NSCLC, and the relative biological effectiveness (RBE) of carbon-ion beams over X-rays. The assessment of 15 NSCLC lines of different EGFR/KRAS mutational status and that of isogenic NSCLC lines expressing wild-type or mutant EGFR revealed that EGFR-mutant NSCLC cells, but not KRAS-mutant cells, show low RBE. This was attributable to (i) the high X-ray sensitivity of EGFR-mutant cells, since EGFR mutation is associated with a defect in non-homologous end joining, a major pathway for DNA double-strand break (DSB) repair, and (ii) the strong cell-killing effect of carbon-ion beams due to poor repair of carbon-ion beam-induced DSBs regardless of EGFR mutation status. These data highlight the potential of EGFR mutation status as a predictor of response to CIRT, i.e., CIRT may show a high therapeutic index in EGFR mutation-negative NSCLC. PMID:26065573

  4. Examination of Ion Beam Acceleration and Self-Bias Effect in the Modified MadHeX Plasma Source with Conducting and Insulating Upstream Boundary Conditions

    NASA Astrophysics Data System (ADS)

    Sung, Yung-Ta; Devinney, Michael; Scharer, John

    2013-10-01

    The MadHeX experiment consists of a Pyrex tube connected to a stainless steel magnetic field expansion chamber (expansion ratio RE = 4.5) has been upgraded with an axial magnetic mirror field and an additional magnet in the transition region. This configuration enhances electron temperature and ionization fraction and minimizes neutral reflux. A half-turn double-helix antenna is used to excite electrostatic or inductive regime waves in the source. An ion beam of energy, E = 160 eV at 500 W RF power, has been observed in a low pressure (0.3 mtorr) argon plasma formed in the expansion region with a 340 G magnetic field with a R = 1.4 nozzle. The effects of upstream end plate boundary conditions on the plasma self-bias and ion beam acceleration are discussed. The effect of lower flow rates and pressures, higher RF powers (500 W-8 kW) and magnetic field strength dependence on the ion beam acceleration, plasma potential, electron density and temperature are explored. The axial ion velocity distribution function and temperatures at higher powers are observed by argon 668 nm laser induced fluorescence with density measurements obtained by mm wave interferometry. The EEDF and non-Maxwellian tail are examined using optical emission spectroscopy. Research supported by the University of Wisconsin-Madison.

  5. Photonic guiding structures in lithium niobate crystals produced by energetic ion beams

    NASA Astrophysics Data System (ADS)

    Chen, Feng

    2009-10-01

    A range of ion beam techniques have been used to fabricate a variety of photonic guiding structures in the well-known lithium niobate (LiNbO3 or LN) crystals that are of great importance in integrated photonics/optics. This paper reviews the up-to-date research progress of ion-beam-processed LiNbO3 photonic structures and reports on their fabrication, characterization, and applications. Ion beams are being used with this material in a wide range of techniques, as exemplified by the following examples. Ion beam milling/etching can remove the selected surface regions of LiNbO3 crystals via the sputtering effects. Ion implantation and swift ion irradiation can form optical waveguide structures by modifying the surface refractive indices of the LiNbO3 wafers. Crystal ion slicing has been used to obtain bulk-quality LiNbO3 single-crystalline thin films or membranes by exfoliating the implanted layer from the original substrate. Focused ion beams can either generate small structures of micron or submicron dimensions, to realize photonic bandgap crystals in LiNbO3, or directly write surface waveguides or other guiding devices in the crystal. Ion beam-enhanced etching has been extensively applied for micro- or nanostructuring of LiNbO3 surfaces. Methods developed to fabricate a range of photonic guiding structures in LiNbO3 are introduced. Modifications of LiNbO3 through the use of various energetic ion beams, including changes in refractive index and properties related to the photonic guiding structures as well as to the materials (i.e., electro-optic, nonlinear optic, luminescent, and photorefractive features), are overviewed in detail. The application of these LiNbO3 photonic guiding structures in both micro- and nanophotonics are briefly summarized.

  6. Intense non-relativistic cesium ion beam

    SciTech Connect

    Lampel, M.C.

    1984-02-01

    The Heavy Ion Fusion group at Lawrence Berkeley Laboratory has constructed the One Ampere Cesium Injector as a proof of principle source to supply an induction linac with a high charge density and high brightness ion beam. This is studied here. An electron beam probe was developed as the major diagnostic tool for characterizing ion beam space charge. Electron beam probe data inversion is accomplished with the EBEAM code and a parametrically adjusted model radial charge distribution. The longitudinal charge distribution was not derived, although it is possible to do so. The radial charge distribution that is derived reveals an unexpected halo of trapped electrons surrounding the ion beam. A charge fluid theory of the effect of finite electron temperature on the focusing of neutralized ion beams (Nucl. Fus. 21, 529 (1981)) is applied to the problem of the Cesium beam final focus at the end of the injector. It is shown that the theory's predictions and assumptions are consistent with the experimental data, and that it accounts for the observed ion beam radius of approx. 5 cm, and the electron halo, including the determination of an electron Debye length of approx. 10 cm.

  7. Spacecraft charging during ion beam emissions in sunlight

    NASA Technical Reports Server (NTRS)

    Lai, S. T.; Mcneil, W. J.; Aggson, T. L.

    1990-01-01

    During ion beam emissions from the SCATHA satellite, the potential of the negatively charged satellite body shows a sinusoidal oscillation frequency of once-per-spin of the satellite. The minimum occurs when the ion beam is sunward. The processes that may be responsible for the voltage modulation are considered. Neutralization of ion beam space charge by photoelectrons is examined. The photoelectrons are accelerated by the negative potential of the satellite. Effects of electron impact ionization, excitation of metastable states, and photoionization of xenon neutral atoms in the ion beam are studied in detail. Critical ionization velocity interaction is unlikely under the condition considered.

  8. Heavy ion beam probing

    SciTech Connect

    Hickok, R L

    1980-07-01

    This report consists of the notes distributed to the participants at the IEEE Mini-Course on Modern Plasma Diagnostics that was held in Madison, Wisconsin in May 1980. It presents an overview of Heavy Ion Beam Probing that briefly describes the principles and discuss the types of measurements that can be made. The problems associated with implementing beam probes are noted, possible variations are described, estimated costs of present day systems, and the scaling requirements for large plasma devices are presented. The final chapter illustrates typical results that have been obtained on a variety of plasma devices. No detailed calculations are included in the report, but a list of references that will provide more detailed information is included.

  9. Ion beam sputtering in electric propulsion facilities

    NASA Technical Reports Server (NTRS)

    Sovey, James S.; Patterson, Michael J.

    1991-01-01

    Experiments were undertaken to determine sputter yields of potential ion beam target materials, to assess the impact of charge exchange on beam diagnostics in large facilities, and to examine material erosion and deposition after a 957-hour test of a 5 kW-class ion thruster. The xenon ion sputter yield of flexible graphite was lower than other graphite forms especialy at high angles of incidence. Ion beam charge exchange effects were found to hamper beam probe current collection diagnostics even at pressures from 0.7 to 1.7 mPa. Estimates of the xenon ion beam envelope were made and predictions of the thickness of sputter deposited coatings in the facility were compared with measurements.

  10. Ion beam sputtering in electric propulsion facilities

    NASA Technical Reports Server (NTRS)

    Sovey, James S.; Patterson, Michael J.

    1991-01-01

    Experiments were undertaken to determine sputter yields of potential ion beam target materials, to assess the impact of charge exchange on beam diagnostics in large facilities, and to examine material erosion and deposition after a 957 hr test of a 5 kW-class ion thruster. The xenon ion sputter yield of flexible graphite was lower than other graphite forms especially at high angles of incidence. Ion beam charge exchange effects were found to hamper beam probe current collection diagnostics even at pressures from 0.7 to 1.7 mPa. Estimates of the xenon ion beam envelope were made and predictions of the thickness of sputter deposited coatings in the facility were compared with measurements.

  11. Comparison of thermoluminescence characteristics in γ-ray and C(5+) ion beam-irradiated LiCaAlF6 :Ce phosphor.

    PubMed

    Yerpude, M M; Dhoble, N S; Lochab, S P; Dhoble, S J

    2016-08-01

    We compare the thermoluminescence (TL) behavior of Ce(3+) ion-activated LiCaAlF6 exposed to γ-rays and a carbon ion beam. The reported phosphor is synthesized using an in-house precipitation method with varying concentrations of activator ion and is characterized by X-ray diffraction (XRD) and TL. Rietveld refinement is performed to study the structural statistics. The TL glow curve consists of a prominent glow peak at 232°C with three shoulders at 115, 159 and 333°C when exposed to γ-rays from a (60) Co source. When exposed to a C(5+) ion beam, the TL glow curve consists of five peaks with peak temperatures near 156, 221, 250, 287 and 330°C, and is found to vary slightly with changing fluence. Glow curve convolution deconvolution (GCCD) functions are applied to the TL curves for complete analysis of the glow curve structure and TL traps. The order of kinetics (b), activation energy (E) and frequency factor are determined using Chen's peak shape method and theoretical curves are drawn using GCCD functions. A track interaction model (TIM) is used to explain the sublinearity/saturation at higher fluences. Ion beam parameters are analyzed using Monte-Carlo simulation-based SRIM-2013 code. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26768666

  12. TOPICAL REVIEW Dosimetry for ion beam radiotherapy

    NASA Astrophysics Data System (ADS)

    Karger, Christian P.; Jäkel, Oliver; Palmans, Hugo; Kanai, Tatsuaki

    2010-11-01

    Recently, ion beam radiotherapy (including protons as well as heavier ions) gained considerable interest. Although ion beam radiotherapy requires dose prescription in terms of iso-effective dose (referring to an iso-effective photon dose), absorbed dose is still required as an operative quantity to control beam delivery, to characterize the beam dosimetrically and to verify dose delivery. This paper reviews current methods and standards to determine absorbed dose to water in ion beam radiotherapy, including (i) the detectors used to measure absorbed dose, (ii) dosimetry under reference conditions and (iii) dosimetry under non-reference conditions. Due to the LET dependence of the response of films and solid-state detectors, dosimetric measurements are mostly based on ion chambers. While a primary standard for ion beam radiotherapy still remains to be established, ion chamber dosimetry under reference conditions is based on similar protocols as for photons and electrons although the involved uncertainty is larger than for photon beams. For non-reference conditions, dose measurements in tissue-equivalent materials may also be necessary. Regarding the atomic numbers of the composites of tissue-equivalent phantoms, special requirements have to be fulfilled for ion beams. Methods for calibrating the beam monitor depend on whether passive or active beam delivery techniques are used. QA measurements are comparable to conventional radiotherapy; however, dose verification is usually single field rather than treatment plan based. Dose verification for active beam delivery techniques requires the use of multi-channel dosimetry systems to check the compliance of measured and calculated dose for a representative sample of measurement points. Although methods for ion beam dosimetry have been established, there is still room for developments. This includes improvement of the dosimetric accuracy as well as development of more efficient measurement techniques.

  13. Effect of annealing on magnetic properties of Nd-Fe-B thin films prepared by ECR ion beam sputtering method

    NASA Astrophysics Data System (ADS)

    Tokumaru, R.; Tamano, S.; Goto, S.; Madeswaran, S.; Tokiwa, K.; Watanabe, T.

    2009-11-01

    Nd-Fe-B thin films were prepared by electron cyclotron resonance (ECR) ion beam sputtering and subsequent annealing. The influence of annealing on the magnetic properties and X-ray diffraction patterns of the product films was investigated. Amorphous films deposited at room temperature were annealed at temperatures between 600 and 800 °C. The c-axis oriented crystallization of the Nd2Fe14B phase did not appear by annealing of the buffer layer and magnetic Nd-Fe-B layer deposited at room temperature, and the hysteresis loops of the films indicated magnetic isotropy.

  14. Microdosimetry in ion-beam therapy

    NASA Astrophysics Data System (ADS)

    Magrin, Giulio; Mayer, Ramona

    2015-05-01

    The information of the dose is not sufficiently describing the biological effects of ions on tissue since it does not express the radiation quality, i.e. the heterogeneity of the processes due to the slowing-down and the fragmentation of the particles when crossing a target. Depending on different circumstances, the radiation quality can be determined using measurements, calculations, or simulations. Microdosimeters are the primary tools used to provide the experimental information of the radiation quality and their role is becoming crucial for the recent clinical developments in particular with carbon ion therapy. Microdosimetry is strongly linked to the biological effectiveness of the radiation since it provides the physical parameters which explicitly distinguish the radiation for its capability of damaging cells. In the framework of ion-beam therapy microdosimetry can be used in the preparation of the treatment to complement radiobiological experiments and to analyze the modification of the radiation quality in phantoms. A more ambitious goal is to perform the measurements during the irradiation procedure to determine the non-targeted radiation and, more importantly, to monitor the modification of the radiation quality inside the patient. These procedures provide the feedback of the treatment directly beneficial for the single patient but also for the characterization of the biological effectiveness in general with advantages for all future treatment. Traditional and innovative tools are currently under study and an outlook of present experience and future development is presented here.

  15. Upgoing ion beams. I - Microscopic analysis

    NASA Astrophysics Data System (ADS)

    Kaufmann, R. L.; Kintner, P. M.

    1982-12-01

    The stability of electrostatic waves with frequencies near the hydrogen cyclotron frequency is investigated for an auroral plasma containing an ion beam by studying the relationship between low-frequency waves (0-1 kHz) and particles seen by the S3-3 satellite. It is concluded that only electrostatic hydrogen ion cyclotron (EHC) waves can be generated at the observed frequencies by the observed energetic particles, with the waves being produced either by drifting electrons or by the ion beam. In the model developed, ion beams are seen with their observed temperatures because they have evolved to a weakly unstable configuration in which the wave growth length is comparable to the width of the beam region. Waves are well confined to the beams because they are damped rapidly in the adjacent plasma, and the mirror effect can maintain a weak instability over a considerable altitude range. It is proposed that this effect is a source for strong pitch angle scattering, as well as an explanation for the nonexistence of downgoing ion beams.

  16. The role of electronic energy loss in ion beam modification of materials

    DOE PAGESBeta

    Weber, William J.; Duffy, Dorothy M.; Thome, Lionel; Zhang, Yanwen

    2014-10-05

    The interaction of energetic ions with solids results in energy loss to both atomic nuclei and electrons in the solid. In this article, recent advances in understanding and modeling the additive and competitive effects of nuclear and electronic energy loss on the response of materials to ion irradiation are reviewed. Experimental methods and large-scale atomistic simulations are used to study the separate and combined effects of nuclear and electronic energy loss on ion beam modification of materials. The results demonstrate that nuclear and electronic energy loss can lead to additive effects on irradiation damage production in some materials; while inmore » other materials, the competitive effects of electronic energy loss leads to recovery of damage induced by elastic collision cascades. Lastly, these results have significant implications for ion beam modification of materials, non-thermal recovery of ion implantation damage, and the response of materials to extreme radiation environments.« less

  17. The role of electronic energy loss in ion beam modification of materials

    SciTech Connect

    Weber, William J.; Duffy, Dorothy M.; Thome, Lionel; Zhang, Yanwen

    2014-10-05

    The interaction of energetic ions with solids results in energy loss to both atomic nuclei and electrons in the solid. In this article, recent advances in understanding and modeling the additive and competitive effects of nuclear and electronic energy loss on the response of materials to ion irradiation are reviewed. Experimental methods and large-scale atomistic simulations are used to study the separate and combined effects of nuclear and electronic energy loss on ion beam modification of materials. The results demonstrate that nuclear and electronic energy loss can lead to additive effects on irradiation damage production in some materials; while in other materials, the competitive effects of electronic energy loss leads to recovery of damage induced by elastic collision cascades. Lastly, these results have significant implications for ion beam modification of materials, non-thermal recovery of ion implantation damage, and the response of materials to extreme radiation environments.

  18. Applications of ion beam technology

    NASA Technical Reports Server (NTRS)

    Gelerinter, E.; Spielberg, N.

    1980-01-01

    Wire adhesion in steel belted radial tires; carbon fibers and composite; cold welding, brazing, and fabrication; hydrogen production, separation, and storage; membrane use; catalysis; sputtering and texture; and ion beam implantation are discussed.

  19. Interface magnetoelectric effect in the layered heterostructures with Co layers on the polished and ion-beam planarized ceramic PZT substrates

    NASA Astrophysics Data System (ADS)

    Stognij, Alexandre I.; Novitskii, Nickolaj; Poddubnaya, Natalia; Sharko, Sergei; Ketsko, Valerij; Mikhailov, Vladimir; Dyakonov, Vladimir; Szymczak, Henryk

    2015-01-01

    The low-frequency room temperature interface magnetoelectric (ME) effect was observed in the layered heterostructures comprising the ferromagnetic (FM) Co layers and ferroelectric (FE) ceramic substrates on the base of lead zirconate titanate PbZr0.45Ti0.55O3 (PZT). The Co films 1-12 μm in thickness were deposited by ion-beam sputtering/deposition technics onto the 400 μm PZT substrates. Results of X-ray, magnetic and ME experiments have shown the existence of ME effect in Co/PZT/Co and (Co/PZT/Co)3 heterostructures obtained by the above mentioned techniques being independent on ferromagnetic/ferroelectric interface roughness. The values of ME voltage coefficient in heterostructures with ion-beam planarized PZT surfaces are much higher than that in heterostructures with mechanochemically polished ceramic substrate surfaces. The heterostructures possess ME effect of the same order as those obtained by means of the mechanical bonding of FM and FE sheets with organic binders and have the typical ME hysteresis curves. The structures obtained are perspective for application as energy-independent elements in magnetic field sensors and magnetic memory.

  20. High-Speed Nano-Processing with Cluster Ion Beams

    NASA Astrophysics Data System (ADS)

    Seki, T.; Matsuo, J.

    2006-11-01

    The gas cluster ion beam process has a high potential for material processing in nano-technology devices, such as photonic crystals, thin film transistors (TFTs) and micro-electromechanical systems (MEMS). In order to fabricate the devices, one needs to etch target materials with a high-speed, low-damage and ultra-smooth process. Extremely high rate sputtering was realized by high-energy cluster ion beam. We have been using this technique for poly-Si TFTs. There are many hillocks on poly-Si films formed by using a laser anneal technique, and they cause degradation of devices. When the laser crystallized poly-Si film was irradiated with cluster ion beam, the higher hillocks could be etched selectively and the surfaces of poly-Si films could be processed with low ion dose. High-speed nano-processing was realized by cluster ion beam.

  1. Effect of using stencil masks made by focused ion beam milling on permalloy (Ni81Fe19) nanostructures.

    PubMed

    Bates, J R; Miyahara, Y; Burgess, J A J; Iglesias-Freire, O; Grütter, P

    2013-03-22

    Focused ion beam (FIB) milling is a common fabrication technique to make nanostencil masks which has the unintended consequence of gallium ion implantation surrounding milled features in silicon nitride membranes. We observe major changes in film structure, chemical composition, and magnetic behaviour of permalloy nanostructures deposited by electron beam evaporation using silicon nitride stencil masks made by a FIB as compared to stencil masks made by regular lithography techniques. We characterize the stenciled structures and both types of masks using transmission electron microscopy, electron energy loss spectroscopy, energy dispersive x-ray spectroscopy, magnetic force microscopy and kelvin probe force microscopy. All these techniques demonstrate distinct differences at a length scale of a 1-100 nm for the structures made using stencil mask fabricated using a FIB. The origin of these differences seems to be related to the presence of implanted ions, a detailed understanding of the mechanism however remains to be developed. PMID:23449320

  2. The effect of CH4/H2 ratio on the surface properties of HDPE treated by CHx ion beam bombardment

    NASA Astrophysics Data System (ADS)

    Ding, Wanyu; Guo, Yuanyuan; Ju, Dongying; Sato, Susumu; Tsunoda, Teruo

    2016-06-01

    The surface of high density polyethylene (HDPE) substrate was bombarded by the CHx group ion beam, which was generated by the mixture of CH4/H2. Varying the CH4/H2 ratio, HDPE surfaces with different chemical bond structures and properties were obtained. Raman and XPS results show that sp2 and sp3 bond structures are formed at HDPE surface bombarded by CHx group ions. The sp3 bond fraction at bombarded HDPE surface depends on the H2 ratio in CH4/H2 mixture, because the H ion/atom/molecule can improve the growth of sp3 bond structure. For HDPE surface bombarded by CH4/H2 = 50/50, sp3 bond fraction reaches the maximum of 30.5%, the surface roughness decreases to 17.04 nm, and the static contact angle of polar H2O molecule increased to 140.2∘.

  3. A novel ion-beam-mutation effect application in identification of gene involved in bacterial antagonism to fungal infection of ornamental crops

    NASA Astrophysics Data System (ADS)

    Mahadtanapuk, S.; Teraarusiri, W.; Nanakorn, W.; Yu, L. D.; Thongkumkoon, P.; Anuntalabhochai, S.

    2014-05-01

    This work is on a novel application of ion beam effect on biological mutation. Bacillus licheniformis (B. licheniformis) is a common soil bacterium with an antagonistic effect on Curcuma alismatifolia Gagnep. and Chrysanthemum indicum Linn. In an attempt to control fungal diseases of local crops by utilizing B. licheniformis, we carried out gene analysis of the bacterium to understand the bacterial antagonistic mechanism. The bacterial cells were bombarded to induce mutations using nitrogen ion beam. After ion bombardment, DNA analysis revealed that the modified polymorphism fragment present in the wild type was missing in a bacterial mutant which lost the antifungal activity. The fragments conserved in the wild type but lost in the mutant bacteria was identified to code for the thioredoxin reductase (TrxR) gene. The gene analysis showed that the TrxR gene from B. licheniformis had the expression of the antagonism to fungi in a synchronous time evolution with the fungus inhibition when the bacteria were co-cultivated with the fungi. The collective results indicate the TrxR gene responsible for the antagonism of bacteria B. licheniformis to fungal infection.

  4. Focused ion beam and electron microscopy characterization of nanosharp tips and microbumps on silicon and metal thin films formed via localized single-pulse laser irradiation

    SciTech Connect

    Moening, Joseph P.; Georgiev, Daniel G.; Lawrence, Joseph G.

    2011-01-01

    Cross-sections of laser fabricated nanosharp tips and microbumps on silicon and metal thin films are produced and examined in this work. These structures are formed with a Q-switched neodymium doped yttrium aluminum garnet nanosecond-pulse laser, emitting at its fourth harmonic of 266 nm, using a mask projection technique to generate circular laser spots, several microns in diameter. Cross-section of selected structures were produced using a focused ion beam and were characterized via electron microscopy. The diffraction patterns of the silicon samples indicate that the laser formed tip maintains the same single crystal structure as the original silicon film. Examinations of the laser formed structures in metal films confirm that the microbumps are hollow, while revealing that the vertical protrusions are solid.

  5. Intense ion beams accelerated by ultra-intense laser pulses

    NASA Astrophysics Data System (ADS)

    Roth, Markus; Cowan, T. E.; Gauthier, J. C.; Vehn, J. Meyer-Ter; Allen, M.; Audebert, P.; Blazevic, A.; Fuchs, J.; Geissel, M.; Hegelich, M.; Karsch, S.; Pukhov, A.; Schlegel, T.

    2002-04-01

    The discovery of intense ion beams off solid targets irradiated by ultra-intense laser pulses has become the subject of extensive international interest. These highly collimated, energetic beams of protons and heavy ions are strongly depending on the laser parameters as well as on the properties of the irradiated targets. Therefore we have studied the influence of the target conditions on laser-accelerated ion beams generated by multi-terawatt lasers. The experiments were performed using the 100 TW laser facility at Laboratoire pour l'Utilisation des Laser Intense (LULI). The targets were irradiated by pulses up to 5×1019 W/cm2 (~300 fs,λ=1.05 μm) at normal incidence. A strong dependence on the surface conditions, conductivity, shape and purity was observed. The plasma density on the front and rear surface was determined by laser interferometry. We characterized the ion beam by means of magnetic spectrometers, radiochromic film, nuclear activation and Thompson parabolas. The strong dependence of the ion beam acceleration on the conditions on the target back surface was confirmed in agreement with predictions based on the target normal sheath acceleration (TNSA) mechanism. Finally shaping of the ion beam has been demonstrated by the appropriate tailoring of the target. .

  6. Relationship between electron density and effective densities of body tissues for stopping, scattering, and nuclear interactions of proton and ion beams

    SciTech Connect

    Kanematsu, Nobuyuki; Inaniwa, Taku; Koba, Yusuke

    2012-02-15

    Purpose: In treatment planning of charged-particle radiotherapy, patient heterogeneity is conventionally modeled as variable-density water converted from CT images to best reproduce the stopping power, which may lead to inaccuracies in the handling of multiple scattering and nuclear interactions. Although similar conversions can be defined for these individual interactions, they would be valid only for specific CT systems and would require additional tasks for clinical application. This study aims to improve the practicality of the interaction-specific heterogeneity correction. Methods: The authors calculated the electron densities and effective densities for stopping power, multiple scattering, and nuclear interactions of protons and ions, using the standard elemental-composition data for body tissues to construct the invariant conversion functions. The authors also simulated a proton beam in a lung-like geometry and a carbon-ion beam in a prostate-like geometry to demonstrate the procedure and the effects of the interaction-specific heterogeneity correction. Results: Strong correlations were observed between the electron density and the respective effective densities, with which the authors formulated polyline conversion functions. Their effects amounted to 10% differences in multiple-scattering angle and nuclear interaction mean free path for bones compared to those in the conventional heterogeneity correction. Although their realistic effect on patient dose distributions would be generally small, it could be at the level of a few percent when a carbon-ion beam traverses a large bone. Conclusions: The present conversion functions are invariant and may be incorporated in treatment planning systems with a common function relating CT number to electron density. This will enable improved beam dose calculation while minimizing initial setup and quality management of the user's specific system.

  7. Effects of ion beam irradiation on transition metals embedded polymer matrix

    NASA Astrophysics Data System (ADS)

    Gavade, Chaitali

    The rapidly expanding oil sands of western Canada, the third largest reserves in the world, are creating serious challenges, such as ecological harm, labour shortages, and extensive natural gas consumption. This thesis develops three practical real options models to evaluate the feasibility of oil sands projects and to estimate the optimal rate of oil sands expansion, while accounting for the stated concerns. (Abstract shortened by UMI.).

  8. Effects of focused ion beam milling on the compressive behavior of directionally solidified micro-pillars and the nanoindentation response of an electro-polished surface

    SciTech Connect

    Shim, Sang Hoon; Bei, Hongbin; Miller, Michael K; Pharr, George Mathews; George, Easo P

    2009-01-01

    Focused ion beam (FIB) milling is the typical way in which micro-pillars are fabricated to study small-scale plasticity and size effects in uniaxial compression. However, FIB milling can introduce defects into the milled pillars. To investigate the effects of FIB damage on mechanical behavior, we tested Mo-alloy micro-pillars that were FIB milled following directional solidification, and compared their compressive response to pillars that were not FIB milled. We also FIB milled at glancing incidence a Mo-alloy single-crystal surface, and compared its nanoindentation response to an electro-polished surface of the same crystal. Consequences for the interpretation of data obtained from FIB milled micro-pillars are discussed.

  9. Effects of Ga[sup +] milling on InGaAsP quantum well laser with mirrors milled by focused ion beam

    NASA Astrophysics Data System (ADS)

    Vallini, F.; Figueira, D. S. L.; Jarschel, P. F.; Barea, L. A. M.; von Zuben, A. A. G.; Frateschi, N. C.

    InGaAsP/InP quantum wells (QW) ridge waveguide lasers were fabricated for the evaluation of Ga+ Focused Ion Beam (FIB) milling of mirrors. Electrical and optical proprieties were investigated. A 7% increment in threshold current, a 17% reduction in external quantum efficiency and 15 nm blue shift in the emission spectrum were observed after milling as compared to the as cleaved facet result. Annealing in inert atmosphere partially revert these effects resulting in 4% increment in threshold current, 11% reduction in external efficiency and 13 nm blue shift with the as cleaved result. The current-voltage behavior after milling and annealing shows a very small increase in leakage current indicating that optical damage is the main effect of the milling process.

  10. Effects of arrival rate and gas pressure on the chemical bonding and composition in titanium nitride films prepared on Si(100) substrates by ion beam and vapor deposition

    SciTech Connect

    Matsuoka, M.; Isotani, S.; Mittani, J.C.R.; Chubaci, J.F.D.; Ogata, K.; Kuratani, N.

    2005-01-01

    Thin titanium nitride films were prepared at room temperature by titanium metal vapor deposition on silicon substrates with simultaneous irradiation by a 2 keV nitrogen ion beam. Arrival rate ratios, ARR(N/Ti), defined as the ratio of the flux of incident atomic nitrogen particles in the ion beam relative to the flux of titanium atoms transported to the substrate, ranged from 0.17 to 2.5. The gas pressure in the vacuum chamber was maintained at 1.3x10{sup -3} or 6.7x10{sup -3} Pa during the deposition and irradiation process. Analyses of Ti 2p x-ray photoelectron spectroscopy spectra indicated the presence of metal Ti{sup 0}, nitride TiN, oxide TiO{sub 2}, oxynitride TiN{sub x}O{sub y}, and carbide TiC phases. The Ti{sup 0} phase was observed exclusively and predominantly in the films prepared at 1.3x10{sup -3} Pa and ARR(N/Ti)=0.17, 0.21, and 0.28, and the TiN phase is major in the others, as confirmed by the x-ray diffractometry analyses. The chemical composition ratio N/Ti in the films prepared at 1.3x10{sup -3} Pa increased linearly with increasing ARR(N/Ti) up to ARR(N/Ti)=0.42 and tended to be constant with further increase in ARR(N/Ti), while this ratio in the films prepared at 6.7x10{sup -3} Pa was almost constant independently of ARR(N/Ti), similar to the constant value observed at 1.3x10{sup -3} Pa and higher ARR(N/Ti). This dependence may be understood by comparison with the flux of evaporated titanium atoms, the flux of nitrogen in the beam, and the impingement rate of nitrogen gas in the vacuum chamber, evaluated through the kinetic theory of gases. On the other hand, titanium is known to be one of the chemically active materials which form stable compounds with gases by chemisorption, this fact leading to considerable incorporation of contaminant oxygen and carbon in the depositing titanium film.

  11. Ion beam modification of metals

    NASA Astrophysics Data System (ADS)

    Dearnaley, G.

    1990-04-01

    Energetic ions beams may be used in various ways to modify and so improve the tribological properties of metals. These methods include: — ion implantation of selected additive species; — ion beam mixing of thin deposited coatings; — ion-beam-assisted deposition of thicker overlay coatings. The first of these techniques has been widely used to modify the electronic properties of semiconductors, but has since been extended for the treatment of all classes of material. Tool steels can be strengthened by the ion implantation of nitrogen or titanium, to produce fine dispersions of hard second-phase precipitates. Solid solution strengthening, by combinations of substitutional and interstitial species, such as yttrium and nitrogen, has also been successful. Both ion beam mixing (IBM) and ion-beam-assisted deposition (IBAD) use a combination of coating and ion bombardment. In the first case, the objective is to intermix the coating and substrate by the aid of radiation-enhanced diffusion. In the latter case, the coating is densified and modified during deposition and the process can be continued in order to build up overlay coatings several μm in thickness. The surface can then be tailored, for instance to provide a hard and adherent ceramic such as silicon nitride, boron nitride or titanium nitride. It is an advantage that all the above processes can be applied at relatively low temperatures, below about 200° C, thereby avoiding distortion of precision components. Ion implantation is also being successfully applied for the reduction of corrosion, especially at high temperatures or in the atmosphere and to explore the mechanisms of oxidation. Ion-assisted coatings, being compact and adherent, provide a more substantial protection against corrosion: silicon nitride and boron nitride are potentially useful in this respect. Examples will be given of the successful application of these methods for the surface modification of metals and alloys, and developments in the

  12. Advanced techniques for characterization of ion beam modified materials

    DOE PAGESBeta

    Zhang, Yanwen; Debelle, Aurélien; Boulle, Alexandre; Kluth, Patrick; Tuomisto, Filip

    2014-10-30

    Understanding the mechanisms of damage formation in materials irradiated with energetic ions is essential for the field of ion-beam materials modification and engineering. Utilizing incident ions, electrons, photons, and positrons, various analysis techniques, including Rutherford backscattering spectrometry (RBS), electron RBS, Raman spectroscopy, high-resolution X-ray diffraction, small-angle X-ray scattering, and positron annihilation spectroscopy, are routinely used or gaining increasing attention in characterizing ion beam modified materials. The distinctive information, recent developments, and some perspectives in these techniques are reviewed in this paper. Applications of these techniques are discussed to demonstrate their unique ability for studying ion-solid interactions and the corresponding radiationmore » effects in modified depths ranging from a few nm to a few tens of μm, and to provide information on electronic and atomic structure of the materials, defect configuration and concentration, as well as phase stability, amorphization and recrystallization processes. Finally, such knowledge contributes to our fundamental understanding over a wide range of extreme conditions essential for enhancing material performance and also for design and synthesis of new materials to address a broad variety of future energy applications.« less

  13. Advanced techniques for characterization of ion beam modified materials

    SciTech Connect

    Zhang, Yanwen; Debelle, Aurélien; Boulle, Alexandre; Kluth, Patrick; Tuomisto, Filip

    2014-10-30

    Understanding the mechanisms of damage formation in materials irradiated with energetic ions is essential for the field of ion-beam materials modification and engineering. Utilizing incident ions, electrons, photons, and positrons, various analysis techniques, including Rutherford backscattering spectrometry (RBS), electron RBS, Raman spectroscopy, high-resolution X-ray diffraction, small-angle X-ray scattering, and positron annihilation spectroscopy, are routinely used or gaining increasing attention in characterizing ion beam modified materials. The distinctive information, recent developments, and some perspectives in these techniques are reviewed in this paper. Applications of these techniques are discussed to demonstrate their unique ability for studying ion-solid interactions and the corresponding radiation effects in modified depths ranging from a few nm to a few tens of μm, and to provide information on electronic and atomic structure of the materials, defect configuration and concentration, as well as phase stability, amorphization and recrystallization processes. Finally, such knowledge contributes to our fundamental understanding over a wide range of extreme conditions essential for enhancing material performance and also for design and synthesis of new materials to address a broad variety of future energy applications.

  14. Synthesis of silicon oxynitride by ion beam sputtering and the effects of nitrogen ion-assisted bombardment

    NASA Astrophysics Data System (ADS)

    Lambrinos, M. F.; Valizadeh, R.; Colligon, J. S.

    1997-05-01

    Thin silicon oxynitride (SiO xN y) films were synthesised without substrate heating by means of N 2+ ion-beam sputtering of a silicon nitride target at an energy of 1000 eV in a N 2 and O 2 ambient with and without 200 eV N 2+ ion assistance. Unassisted films were deposited in a controlled O 2 partial pressure ranging from ambient to 5.0 × 10 -3 Pa whereas assisted films were deposited at a fixed O 2 partial pressure of 1.0 × 10 -3 Pa. The O/(O+N) atomic fraction and the SiO xN y asymmetric stretch mode IR absorption peak wavenumber of unassisted films increased almost linearly with increasing O 2 partial pressure, from 0.2 to 1.0 and 860 cm -1 to 1050 cm -1, respectively, while their refractive indices decreased from 1.92 to 1.46. The behaviour of the SiO xN y film refractive index with the SiO 2 fraction has been compared to that predicted by Drude, Lorentz-Lorenz and Bruggeman models under the assumption that the film is a mixture of SiO 2 and Si 3N 4 phases. For a fixed O 2 partial pressure, the O content of the N 2+ ion-assisted films increased with an increase in the N + ion to Si atom arrival ratio from 0 to 3. This increase in O content correlate with changes in the film refractive index and SiO xN y asymmetric stretch mode absorption peak position, from 1.56 to 1.43 and 1014 cm -1 to 1054 cm -1, respectively, indicating that the O/N atomic ratio increases with increasing N + ion to Si atom ratio until film properties consistent with stoichiometric SiO 2 are obtained.

  15. An ion beam deceleration lens for ultra-low-energy ion bombardment of naked DNA

    NASA Astrophysics Data System (ADS)

    Thopan, P.; Prakrajang, K.; Thongkumkoon, P.; Suwannakachorn, D.; Yu, L. D.

    2013-07-01

    Study of low-energy ion bombardment effect on biological living materials is of significance. High-energy ion beam irradiation of biological materials such as organs and cells has no doubt biological effects. However, ion energy deposition in the ion-bombarded materials dominantly occurs in the low-energy range. To investigate effects from very-low-energy ion bombardment on biological materials, an ion beam deceleration lens is necessary for uniform ion energy lower than keV. A deceleration lens was designed and constructed based on study of the beam optics using the SIMION program. The lens consisted of six electrodes, able to focus and decelerate primary ion beam, with the last one being a long tube to obtain a parallel uniform exiting beam. The deceleration lens was installed to our 30-kV bioengineering-specialized ion beam line. The final decelerated-ion energy was measured using a simple electrostatic field to bend the beam to range from 10 eV to 1 keV controlled by the lens parameters and the primary beam condition. In a preliminary test, nitrogen ion beam at 60 eV decelerated from a primary 20-keV beam bombarded naked plasmid DNA. The original DNA supercoiled form was found to change to relaxed and linear forms, indicating single or double strand breaks. The study demonstrated that the ion bombardment with energy as low as several-tens eV was possible to break DNA strands and thus potential to cause genetic modification of biological cells.

  16. Treatment Planning for Ion Beam Therapy

    NASA Astrophysics Data System (ADS)

    Greilich, Steffen; Jäkel, Oliver

    2010-01-01

    Beams of charged particles offer an improved dose conformation to the target volume as compared to photon radiotherapy, with better sparing of normal tissue structures close to the target. In addition, beams of ions heavier than helium exhibit a strong increase of the Linear Energy Transfer (LET) in the Bragg peak as compared to the entrance region, resulting in a higher biological efficiency in the target region. These physical and biological properties make ion beams more favorable for radiation therapy of cancer than photon beams. As a consequence, particle therapy with heavy ions has gained increasing interest worldwide. To fully benefit from the advantages of ion radiotherapy, appropriate treatment planning has to be done—taking into account the specific characteristics of ion beams, e.g. the inverted depth-dose profile, nuclear fragmentation, and increase radiobiological effectiveness. This paper describes in brief the approach taken at GSI Darmstadt and HIT Heidelberg for an active 3D beam scanning system.

  17. Laser-cooled continuous ion beams

    SciTech Connect

    Schiffer, J.P.; Hangst, J.S.; Nielsen, J.S.

    1995-08-01

    A collaboration with a group in Arhus, Denmark, using their storage ring ASTRID, brought about better understanding of ion beams cooled to very low temperatures. The longitudinal Schottky fluctuation noise signals from a cooled beam were studied. The fluctuation signals are distorted by the effects of space charge as was observed in earlier measurements at other facilities. However, the signal also exhibits previously unobserved coherent components. The ions` velocity distribution, measured by a laser fluorescence technique suggests that the coherence is due to suppression of Landau damping. The observed behavior has important implications for the eventual attainment of a crystalline ion beam in a storage ring. A significant issue is the transverse temperature of the beam -- where no direct diagnostics are available and where molecular dynamics simulations raise interesting questions about equilibrium.

  18. Focused ion beams in biology.

    PubMed

    Narayan, Kedar; Subramaniam, Sriram

    2015-11-01

    A quiet revolution is under way in technologies used for nanoscale cellular imaging. Focused ion beams, previously restricted to the materials sciences and semiconductor fields, are rapidly becoming powerful tools for ultrastructural imaging of biological samples. Cell and tissue architecture, as preserved in plastic-embedded resin or in plunge-frozen form, can be investigated in three dimensions by scanning electron microscopy imaging of freshly created surfaces that result from the progressive removal of material using a focused ion beam. The focused ion beam can also be used as a sculpting tool to create specific specimen shapes such as lamellae or needles that can be analyzed further by transmission electron microscopy or by methods that probe chemical composition. Here we provide an in-depth primer to the application of focused ion beams in biology, including a guide to the practical aspects of using the technology, as well as selected examples of its contribution to the generation of new insights into subcellular architecture and mechanisms underlying host-pathogen interactions. PMID:26513553

  19. Medical applications of ion beam processes

    NASA Astrophysics Data System (ADS)

    Sioshansi, P.

    The use of ions beams for treatment of surfaces in medical prostheses has gained increasing interest in the past few years. The application of ion beams has taken different forms: (1) ion implantation has been used for increasing the hardness and wear resistance of the new generation titanium based alloys, as well as reducing the wear of the mating polyethylene component used in orthopedic total joint replacement. Spire Corporation has been successful in commercializing ion implantation technology and is processing several thousand artificial knees and hips per year. (Spire uses the tradename IONGUARD™ for this application.) (2) Similarly, ion implantation has proven to be very effective for increasing the corrosion resistance of the Co-Cr based alloys that have traditionally been used in orthopedic prostheses. This application should be of particular interest in resolving the issues surrounding ion release problems associated with these alloys. (3) Ion beam etching/milling has been used for producing a highly textured surface for tissue ingrowth in applications ranging from porous orthopedic implants and percutaneous devices to artificial skin and the process should have a significant impact in this application. (4) There are indications that ion implantation is a useful process for increasing biocompatibility and tissue attachment on metallic samples. This subject deserves considerable attention in the coming years.

  20. Ion beam requirements for fast ignition of inertial fusion targets

    SciTech Connect

    Honrubia, J. J.; Murakami, M.

    2015-01-15

    Ion beam requirements for fast ignition are investigated by numerical simulation taking into account new effects, such as ion beam divergence, not included before. We assume that ions are generated by the TNSA scheme in a curved foil placed inside a re-entrant cone and focused on the cone apex or beyond. From the focusing point to the compressed core, ions propagate with a given divergence angle. Ignition energies are obtained for two compressed fuel configurations heated by proton and carbon ion beams. The dependence of the ignition energies on the beam divergence angle and on the position of the ion beam focusing point has been analyzed. Comparison between TNSA and quasi-monoenergetic ions is also shown.

  1. Modeling of a multicharged ion beam line using SIMION

    NASA Astrophysics Data System (ADS)

    Korwin-Pawlowski, Michael L.; Amiz, Karima; Elsayed-Ali, Hani

    2009-06-01

    Multicharged ion beams (MCI) are promising tools to probe or modify the surface of materials with applications in microelectronics and nanotechnology. Ion beam lines are parts of the MCI systems connecting the ion source with the processing chamber and they perform the function of extracting, accelerating, decelerating, focusing and scanning the ion beam on the surface of the target. In our work we present results of modeling of an MCI beam line using the SIMION code to simulate the flight of ions, with the purpose of optimizing the yield of the line and avoiding spurious effects due to interaction of the ions with the metallic elements of the line, such as heating, outgassing and excessive Xray emission. We show that a two stage ion extractor could significantly reduce ion beam losses.

  2. Lattice structure transformation and change in surface hardness of Ni3Nb and Ni3Ta intermetallic compounds induced by energetic ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Kojima, H.; Yoshizaki, H.; Kaneno, Y.; Semboshi, S.; Hori, F.; Saitoh, Y.; Okamoto, Y.; Iwase, A.

    2016-04-01

    Ni3Nb and Ni3Ta intermetallic compounds, which show the complicated lattice structures were irradiated with 16 MeV Au5+ ions at room temperature. The X-ray diffraction measurement revealed that the lattice structure of these intermetallic compounds changed from the ordered structures to the amorphous state by the ion irradiation. The irradiation-induced amorphization caused the increase in Vickers hardness. The result was compared with our previous results for Ni3Al and Ni3V, and was discussed in terms of the intrinsic lattice structures of the samples.

  3. Fluorine-ion-beam modification of magnetic properties of thin GaMnAs films

    SciTech Connect

    Mello, S. L. A. E-mail: mms@if.ufrj.br; Sant'Anna, M. M. E-mail: mms@if.ufrj.br Codeço, C. F. S.; Dong, S. N.; Liu, X.; Furdyna, J. K. E-mail: mms@if.ufrj.br; Yoo, T.

    2015-05-07

    Magnetic and electrical transport properties of fluorine-ion-beam irradiated GaMnAs films were studied as a function of ion fluence and energy of impinging ions. The different nature of defects created by ions of low- and high-energies is explored in this work by means of transport and magnetization measurements. Our results show that the saturation magnetization of the irradiated samples is suppressed as the ion fluence is increased. Interestingly, however, the same effect is not observed in the case of critical temperature, which remains nearly the same for irradiated and non-irradiated samples measured by superconducting quantum interference device. Magnetotransport measurements appear to provide more reliable results regarding the critical temperature, since they are consistent with the ion-irradiation-induced disorder in the GaMnAs film, quantified here as the increase of the resistivity. We discuss this behavior based on the inhomogeneity of damages caused by the irradiation process.

  4. Ion-beam Plasma Neutralization Interaction Images

    SciTech Connect

    Igor D. Kaganovich; Edward Startsev; S. Klasky; Ronald C. Davidson

    2002-04-09

    Neutralization of the ion beam charge and current is an important scientific issue for many practical applications. The process of ion beam charge and current neutralization is complex because the excitation of nonlinear plasma waves may occur. Computer simulation images of plasma neutralization of the ion beam pulse are presented.

  5. Topography evolution of 500 keV Ar(4+) ion beam irradiated InP(100) surfaces - formation of self-organized In-rich nano-dots and scaling laws.

    PubMed

    Sulania, Indra; Agarwal, Dinesh C; Kumar, Manish; Kumar, Sunil; Kumar, Pravin

    2016-07-27

    We report the formation of self-organized nano-dots on the surface of InP(100) upon irradiating it with a 500 keV Ar(4+) ion beam. The irradiation was carried out at an angle of 25° with respect to the normal at the surface with 5 different fluences ranging from 1.0 × 10(15) to 1.0 × 10(17) ions per cm(2). The morphology of the ion-irradiated surfaces was examined by atomic force microscopy (AFM) and the formation of the nano-dots on the irradiated surfaces was confirmed. The average size of the nano-dots varied from 44 ± 14 nm to 94 ± 26 nm with increasing ion fluence. As a function of the ion fluence, the variation in the average size of the nano-dots has a great correlation with the surface roughness, which changes drastically up to the ion fluence of 1.0 × 10(16) ions per cm(2) and attains almost a saturation level for further irradiation. The roughness and the growth exponent values deduced from the scaling laws suggest that the kinetic sputtering and the large surface diffusion steps of the atoms are the primary reasons for the formation of the self-organized nanodots on the surface. X-ray photo-electron spectroscopy (XPS) studies show that the surface stoichiometry changes with the ion fluence. With irradiation, the surface becomes more indium (In)-rich owing to the preferential sputtering of the phosphorus atoms (P) and the pure metallic In nano-dots evolve at the highest ion fluence. The cross-sectional scanning electron microscopy (SEM) analysis of the sample irradiated with the highest fluence showed the absence of the nanostructuring beneath the surface. The surface morphological changes at this medium energy ion irradiation are discussed in correlation with the low and high energy experiments to shed more light on the mechanism of the well separated nano-dot formation. PMID:27400760

  6. Measurement of secondary particle production induced by particle therapy ion beams impinging on a PMMA target

    NASA Astrophysics Data System (ADS)

    Toppi, M.; Battistoni, G.; Bellini, F.; Collamati, F.; De Lucia, E.; Durante, M.; Faccini, R.; Frallicciardi, P. M.; Marafini, M.; Mattei, I.; Morganti, S.; Muraro, S.; Paramatti, R.; Patera, V.; Pinci, D.; Piersanti, L.; Rucinski, A.; Russomando, A.; Sarti, A.; Sciubba, A.; Senzacqua, M.; Solfaroli Camillocci, E.; Traini, G.; Voena, C.

    2016-05-01

    Particle therapy is a technique that uses accelerated charged ions for cancer treatment and combines a high irradiation precision with a high biological effectiveness in killing tumor cells [1]. Informations about the secondary particles emitted in the interaction of an ion beam with the patient during a treatment can be of great interest in order to monitor the dose deposition. For this purpose an experiment at the HIT (Heidelberg Ion-Beam Therapy Center) beam facility has been performed in order to measure fluxes and emission profiles of secondary particles produced in the interaction of therapeutic beams with a PMMA target. In this contribution some preliminary results about the emission profiles and the energy spectra of the detected secondaries will be presented.

  7. Focusing dynamics of high-energy density, laser-driven ion beams.

    PubMed

    Chen, S N; d'Humières, E; Lefebvre, E; Romagnani, L; Toncian, T; Antici, P; Audebert, P; Brambrink, E; Cecchetti, C A; Kudyakov, T; Pipahl, A; Sentoku, Y; Borghesi, M; Willi, O; Fuchs, J

    2012-02-01

    The dynamics of the focusing of laser-driven ion beams produced from concave solid targets was studied. Most of the ion beam energy is observed to converge at the center of the cylindrical targets with a spot diameter of 30  μm, which can be very beneficial for applications requiring high beam energy densities. Also, unbalanced laser irradiation does not compromise the focusability of the beam. However, significant filamentation occurs during the focusing, potentially limiting the localization of the energy deposition region by these beams at focus. These effects could impact the applicability of such high-energy density beams for applications, e.g., in proton-driven fast ignition. PMID:22400936

  8. High intensity ion beam injection into the 88-inch cyclotron

    SciTech Connect

    Wutte, Daniela; Clark, Dave J.; Laune, Bernard; Leitner,Matthaeus A.; Lyneis, Claude M.

    2000-05-31

    Low cross section experiments to produce super-heavyelements have increased the demand for high intensity heavy ion beams atenergies of about 5 MeV/nucleon at the 88-Inch Cyclotron at the LawrenceBerkeley National Laboratory. Therefore, efforts are underway to increasethe overall ion beam transmission through the axial injection line andthe cyclotron. The ion beam emittance has been measured for various ionmasses and charge states. Beam transport simulations including spacecharge effects were performed for both of the injection line and the ionsource extraction. The relatively low nominal injection voltage of 10 kVwas found to be the main factor for ion beam losses, because of beam blowup due to space charge forces at higher intensities. Consequently,experiments and simulations have been performed at higherinjectionenergies, and it was demonstrated that the ion beams could still becentered in the cyclotron at these energies. Therefore, the new injectorion source VENUS and its ion beam transport system (currently underconstruction at the 88-Inch Cyclotron) are designed for extractionvoltages up to 30 kV.

  9. Oxygen ion-beam microlithography

    DOEpatents

    Tsuo, Y.S.

    1991-08-20

    A method of providing and developing a resist on a substrate for constructing integrated circuit (IC) chips includes the following steps: of depositing a thin film of amorphous silicon or hydrogenated amorphous silicon on the substrate and exposing portions of the amorphous silicon to low-energy oxygen ion beams to oxidize the amorphous silicon at those selected portions. The nonoxidized portions are then removed by etching with RF-excited hydrogen plasma. Components of the IC chip can then be constructed through the removed portions of the resist. The entire process can be performed in an in-line vacuum production system having several vacuum chambers. Nitrogen or carbon ion beams can also be used. 5 figures.

  10. Oxygen ion-beam microlithography

    DOEpatents

    Tsuo, Y. Simon

    1991-01-01

    A method of providing and developing a resist on a substrate for constructing integrated circuit (IC) chips includes the following steps: of depositing a thin film of amorphous silicon or hydrogenated amorphous silicon on the substrate and exposing portions of the amorphous silicon to low-energy oxygen ion beams to oxidize the amorphous silicon at those selected portions. The nonoxidized portions are then removed by etching with RF-excited hydrogen plasma. Components of the IC chip can then be constructed through the removed portions of the resist. The entire process can be performed in an in-line vacuum production system having several vacuum chambers. Nitrogen or carbon ion beams can also be used.

  11. Ion beam microtexturing of surfaces

    NASA Technical Reports Server (NTRS)

    Robinson, R. S.

    1981-01-01

    Some recent work in surface microtecturing by ion beam sputtering is described. The texturing is accomplished by deposition of an impurity onto a substrate while simultaneously bombarding it with an ion beam. A summary of the theory regarding surface diffusion of impurities and the initiation of cone formation is provided. A detailed experimental study of the time-development of individual sputter cones is described. A quasi-liquid coating was observed that apparently reduces the sputter rate of the body of a cone compared to the bulk material. Experimental measurements of surface diffusion activation energies are presented for a variety of substrate-seed combinations and range from about 0.3 eV to 1.2 eV. Observations of apparent crystal structure in sputter cones are discussed. Measurements of the critical temperature for cone formation are also given along with a correlation of critical temperature with substrate sputter rate.

  12. Ion beam inertial confinement target

    DOEpatents

    Bangerter, Roger O.; Meeker, Donald J.

    1985-01-01

    A target for implosion by ion beams composed of a spherical shell of frozen DT surrounded by a low-density, low-Z pusher shell seeded with high-Z material, and a high-density tamper shell. The target has various applications in the inertial confinement technology. For certain applications, if desired, a low-density absorber shell may be positioned intermediate the pusher and tamper shells.

  13. Integration of scanning probes and ion beams

    SciTech Connect

    Persaud, A.; Park, S.J.; Liddle, J.A.; Schenkel, T.; Bokor, J.; Rangelow, I.

    2005-03-30

    We report the integration of a scanning force microscope with ion beams. The scanning probe images surface structures non-invasively and aligns the ion beam to regions of interest. The ion beam is transported through a hole in the scanning probe tip. Piezoresistive force sensors allow placement of micromachined cantilevers close to the ion beam lens. Scanning probe imaging and alignment is demonstrated in a vacuum chamber coupled to the ion beam line. Dot arrays are formed by ion implantation in resist layers on silicon samples with dot diameters limited by the hole size in the probe tips of a few hundred nm.

  14. He and H irradiation effects on the nanoindentation hardness of CLAM steel

    NASA Astrophysics Data System (ADS)

    Jiang, Siben; Peng, Lei; Ge, Hongen; Huang, Qunying; Xin, Jingping; Zhao, Ziqiang

    2014-12-01

    In this study, He and H ion irradiation induced hardening behavior of China Low Activation Martensitic (CLAM) steel was investigated, and the influence of Si on irradiation hardening was also examined. CLAM steel with different Si contents, Heat 0912 and Heat 0408D, were irradiated with single He (He concentration range from 0 to 2150 appm) ion beam and He/H dual ion beams. Then nanoindentation tests were applied to evaluate the ion irradiation induced hardening effect. The result of Heat 0912 showed hardening effect would be more serious with higher He concentration, and the trend saturated when He concentration reach 1000 appm. Comparing the result of Heat 0912 and Heat 0408D, higher Si content might improve the resistance to hardening.

  15. Electron Cooling of Intense Ion Beam

    SciTech Connect

    Dietrich, J.; Kamerdjiev, V.; Maier, R.; Prasuhn, D.; Stein, J.; Stockhorst, H.; Korotaev, Yu.; Meshkov, I.; Sidorin, A.; Smirnov, A.

    2006-03-20

    Results of experimental studies of the electron cooling of a proton beam at COSY (Juelich, Germany) are presented. Intensity of the proton beam is limited by two general effects: particle loss directly after the injection and development of instability in a deep cooled ion beam. Results of the instability investigations performed at COSY during last years are presented in this report in comparison with previous results from HIMAC (Chiba, Japan) CELSIUS (Uppsala, Sweden) and LEAR (CERN). Methods of the instability suppression, which allow increasing the cooled beam intensity, are described. This work is supported by RFBR grant no. 05-02-16320 and INTAS grant no. 03-54-5584.

  16. Peculiarities of temperature dependent ion beam sputtering and channeling of crystalline bismuth

    NASA Astrophysics Data System (ADS)

    Langegger, Rupert; Hradil, Klaudia; Steiger-Thirsfeld, Andreas; Bertagnolli, Emmerich; Lugstein, Alois

    2014-08-01

    In this paper, we report on the surface evolution of focused ion beam treated single crystalline Bi(001) with respect to different beam incidence angles and channeling effects. ‘Erosive’ sputtering appears to be the dominant mechanism at room temperature (RT) and diffusion processes during sputtering seem to play only a minor role for the surface evolution of Bi. The sputtering yield of Bi(001) shows anomalous behavior when increasing the beam incidence angle along particular azimuthal angles of the specimen. The behavior of the sputtering yield could be related to channeling effects and the relevant channeling directions are identified. Dynamic annealing processes during ion irradiation retain the crystalline quality of the Bi specimen allowing ion channeling at RT. Lowering the specimen temperature to T = -188 °C reduces dynamic annealing processes and thereby disables channeling effects. Furthermore unexpected features are observed at normal beam incidence angle. Spike-like features appear during the ion beam induced erosion, whose growth directions are not determined by the ion beam but by the channeling directions of the Bi specimen.

  17. Measurement of ultra-low ion energy of decelerated ion beam using a deflecting electric field

    NASA Astrophysics Data System (ADS)

    Thopan, P.; Suwannakachorn, D.; Tippawan, U.; Yu, L. D.

    2015-12-01

    In investigation on ultra-low-energy ion bombardment effect on DNA, an ion beam deceleration lens was developed for high-quality ultra-low-energy ion beam. Measurement of the ion energy after deceleration was necessary to confirm the ion beam really decelerated as theoretically predicted. In contrast to conventional methods, this work used a simple deflecting electrostatic field after the deceleration lens to bend the ion beam. The beam bending distance depended on the ion energy and was described and simulated. A system for the measurement of the ion beam energy was constructed. It consisted of a pair of parallel electrode plates to generate the deflecting electrical field, a copper rod measurement piece to detect ion beam current, a vernier caliper to mark the beam position, a stepping motor to translate the measurement rod, and a webcam-camera to read the beam bending distance. The entire system was installed after the ion-beam deceleration lens inside the large chamber of the bioengineering vertical ion beam line. Moving the measurement rod across the decelerated ion beam enabled to obtain beam profiles, from which the beam bending distance could be known and the ion beam energy could be calculated. The measurement results were in good agreement with theoretical and simulated results.

  18. The effect of substrate bias voltages on impact resistance of CrAlN coatings deposited by modified ion beam enhanced magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Chunyan, Yu; Linhai, Tian; Yinghui, Wei; Shebin, Wang; Tianbao, Li; Bingshe, Xu

    2009-01-01

    CrAlN coatings were deposited on silicon and AISI H13 steel substrates using a modified ion beam enhanced magnetron sputtering system. The effect of substrate negative bias voltages on the impact property of the CrAlN coatings was studied. The X-ray diffraction (XRD) data show that all CrAlN coatings were crystallized in the cubic NaCl B1 structure, with the (1 1 1), (2 0 0) (2 2 0) and (2 2 2) diffraction peaks observed. Two-dimensional surface morphologies of CrAlN coatings were investigated by atomic force microscope (AFM). The results show that with increasing substrate bias voltage the coatings became more compact and denser, and the microhardness and fracture toughness of the coatings increased correspondingly. In the dynamic impact resistance tests, the CrAlN coatings displayed better impact resistance with the increase of bias voltage, due to the reduced emergence and propagation of the cracks in coatings with a very dense structure and the increase of hardness and fracture toughness in coatings.

  19. Effect of titanium incorporation on the structural, mechanical and biocompatible properties of DLC thin films prepared by reactive-biased target ion beam deposition method

    NASA Astrophysics Data System (ADS)

    Bharathy, P. Vijai; Nataraj, D.; Chu, Paul K.; Wang, Huaiyu; Yang, Q.; Kiran, M. S. R. N.; Silvestre-Albero, J.; Mangalaraj, D.

    2010-10-01

    Amorphous diamond like carbon (DLC) and titanium incorporated diamond like carbon (Ti-DLC) thin films were deposited by using reactive-biased target ion beam deposition method. The effects of Ti incorporation and target bias voltage on the microstructure and mechanical properties of the as-deposited films were investigated by means of X-ray photoelectron spectroscopy, Raman spectroscopy, transmission electron microscopy and nano-indentation. It was found that the Ti content in Ti-DLC films gets increased with increasing target bias voltage. At about 4.2 at.% of Ti, uniform sized well dispersed nanocrystals were seen in the DLC matrix. Using FFT analysis, a facility available in the TEM, it was found that the nanocrystals are in cubic TiC phase. Though at the core, the incorporated Ti atoms react with carbon to form cubic TiC; most of the surface exposed Ti atoms were found to react with the atmospheric oxygen to form weakly bonded Ti-O. The presence of TiC nanocrystals greatly modified the sp 3/sp 2 hybridized bonding ratio and is reflected in mechanical hardness of Ti-DLC films. These films were then tested for their biocompatibility by an invitro cell culturing test. Morphological observation and the cell proliferation test have demonstrated that the human osteoblast cells well attach and proliferate on the surface of Ti incorporated DLC films, suggesting possible applications in bone related implant coatings.

  20. Effect of discharge current and deposition temperature on roughness and density of NbC films fabricated by ion beam sputtering technique

    SciTech Connect

    Dhawan, Rajnish Rai, Sanjay Lodha, G. S.

    2014-04-24

    NbC films were prepared using Ion beam sputtering system at various discharges current from 0.4 amps to 1.2 amps at room temperature. Effect of temperature on NbC films were also studied by depositing NbC films at various temperatures from room temperature to 200,300,400 and 600°C. X-ray reflectivity (XRR) study shows that surface roughness of the film decreases with decrease in discharge current. The optimum lowest roughness 3.2Å having density 92% of bulk was achieved at discharge current 0.6 amps at 3.0 cm{sup 3}/min Ar gas flow. X-ray study also shows that film roughness decreases with increase in temperature of the film and after a certain temperature it increases with increase in temperature. The lowest surface roughness 2.1Å was achieved at 300°C with density 83% of bulk NbC at constant discharge current 0.6 amps.

  1. Maskless, resistless ion beam lithography

    SciTech Connect

    Ji, Qing

    2003-03-10

    As the dimensions of semiconductor devices are scaled down, in order to achieve higher levels of integration, optical lithography will no longer be sufficient for the needs of the semiconductor industry. Alternative next-generation lithography (NGL) approaches, such as extreme ultra-violet (EUV), X-ray, electron-beam, and ion projection lithography face some challenging issues with complicated mask technology and low throughput. Among the four major alternative NGL approaches, ion beam lithography is the only one that can provide both maskless and resistless patterning. As such, it can potentially make nano-fabrication much simpler. This thesis investigates a focused ion beam system for maskless, resistless patterning that can be made practical for high-volume production. In order to achieve maskless, resistless patterning, the ion source must be able to produce a variety of ion species. The compact FIB system being developed uses a multicusp plasma ion source, which can generate ion beams of various elements, such as O{sub 2}{sup +}, BF{sub 2}{sup +}, P{sup +} etc., for surface modification and doping applications. With optimized source condition, around 85% of BF{sub 2}{sup +}, over 90% of O{sub 2}{sup +} and P{sup +} have been achieved. The brightness of the multicusp-plasma ion source is a key issue for its application to maskless ion beam lithography. It can be substantially improved by optimizing the source configuration and extractor geometry. Measured brightness of 2 keV He{sup +} beam is as high as 440 A/cm{sup 2} {center_dot} Sr, which represents a 30x improvement over prior work. Direct patterning of Si thin film using a focused O{sub 2}{sup +} ion beam has been investigated. A thin surface oxide film can be selectively formed using 3 keV O{sub 2}{sup +} ions with the dose of 10{sup 15} cm{sup -2}. The oxide can then serve as a hard mask for patterning of the Si film. The process flow and the experimental results for directly patterned poly-Si features

  2. Plasma focus ion beam-scaling laws

    NASA Astrophysics Data System (ADS)

    Saw, S. H.

    2014-08-01

    Measurements on plasma focus ion beams include various advanced techniques producing a variety of data which has yet to produce benchmark numbers. Recent numerical experiments using an extended version of the Lee Code has produced reference numbers and scaling trends for number and energy fluence of deuteron beams as functions of stored energy E0. At the pinch exit the ion number fluence (ions m-2) and energy fluence (J m-2) computed as 2.4-7.8×1020 and 2.2-33×106 respectively were found to be independent of E0 from 0.4 - 486 kJ. This work was extended to the ion beams for various gases. The results show that, for a given plasma focus, the fluence, flux, ion number and ion current decrease from the lightest to the heaviest gas except for trend-breaking higher values for Ar fluence and flux. The energy fluence, energy flux, power flow and damage factors are relatively constant from H2 to N2 but increase for Ne, Ar, Kr and Xe due to radiative cooling and collapse effects. This paper reviews this work and in a concluding section attempts to put the accumulating large amounts of data into the form of a scaling law of beam energy Ebeam versus storage energy E0 taking the form for deuteron as: {Ebeam} = 18.2{E}01.23; where Ebeam is in J and E0 is in kJ. It is hoped that the establishment of such scaling laws places on a firm footing the reference quantitative ideas for plasma focus ion beams.

  3. Ion beam mixing of Fe with sapphire and silica

    SciTech Connect

    Sinha, S. K.; Vigen, K. M.; Kothari, D. C.; Som, T.; Kulkarni, V. N.; Nair, K. G. M.

    1999-06-10

    We have studied ion beam mixing of Fe with sapphire, silica, Al and Si using different mass of the ions (Ne{sup +},Ar{sup +}), different doses (5x10{sup 15} to 2x10{sup 17} ions/cm{sup 2}) and different temperatures (273 deg. K, 423 deg. K and 573 deg. K). Thin film of Fe was deposited by thermal evaporation method. Ion energy was chosen from 30 to 110 keV so that F{sub d} is maximum at the interface. All the specimens were analyzed by RBS. It is found that the square of the diffusion length Dt is proportional to the ion dose for both types of the substrates (Al{sub 2}O{sub 3} and SiO{sub 2}) implying that mixing is due to the ballistic effect (i.e. cascade mixing). Also mixing is more when irradiated by Ar{sup +} ions than Ne{sup +} ions. Comparison of Dt's shows that mixing is less in ceramics than in pure-elements Al and Si. In Fe-Al{sub 2}O{sub 3} samples, mixing decreases with increase in irradiation temperatures implying de-mixing in crystalline ionic bonded oxide whereas mixing increases in the covalently bonded oxide SiO{sub 2}. Irradiated annealed samples of Fe/Al{sub 2}O{sub 3} and Fe/SiO{sub 2} show de-mixing and mixing respectively.

  4. Neon Ion Beam Lithography (NIBL).

    PubMed

    Winston, Donald; Manfrinato, Vitor R; Nicaise, Samuel M; Cheong, Lin Lee; Duan, Huigao; Ferranti, David; Marshman, Jeff; McVey, Shawn; Stern, Lewis; Notte, John; Berggren, Karl K

    2011-10-12

    Existing techniques for electron- and ion-beam lithography, routinely employed for nanoscale device fabrication and mask/mold prototyping, do not simultaneously achieve efficient (low fluence) exposure and high resolution. We report lithography using neon ions with fluence <1 ion/nm(2), ∼1000× more efficient than using 30 keV electrons, and resolution down to 7 nm half-pitch. This combination of resolution and exposure efficiency is expected to impact a wide array of fields that are dependent on beam-based lithography. PMID:21899279

  5. An investigation on focused electron/ion beam induced degradation mechanisms of conjugated polymers.

    PubMed

    Sezen, Meltem; Plank, Harald; Fisslthaler, Evelin; Chernev, Boril; Zankel, Armin; Tchernychova, Elena; Blümel, Alexander; List, Emil J W; Grogger, Werner; Pölt, Peter

    2011-12-01

    Irradiation damage, caused by the use of beams in the electron microscopes, leads to undesired physical/chemical material property changes or uncontrollable modification of structures that are being processed. Particularly, soft matter such as polymers or biological materials is highly susceptible and very much prone to react on irradiation by electron and ion beams. The effect is even higher when materials are subjected to energetic species such as ions that possess high momentum and relatively low mean path due to their mass. Especially when Ga(+) ions (used as the ion source in Focused Ion Beam (FIB) instruments) are considered, the end-effect might even be the total loss of the material's properties. This paper will discuss the possible types of degradation mechanisms and defect formations that can take place during ion and electron beam irradiation of the conjugated polymers: e.g. polyfluorene (PF) and poly-3-hexylthiophene (P3HT) thin films. For the investigation of the irradiation induced degradation mechanisms in this study, complementary analytical techniques such as Raman Spectroscopy (RS), Infrared Spectroscopy (IR), Electron Energy Loss Spectroscopy (EELS), Atomic Force Microscopy (AFM), and Fluorescence Microscopy including Photoluminescence (PL) and Electroluminescence (EL) Microscopy were applied. PMID:21993473

  6. Graphene engineering by neon ion beams

    DOE PAGESBeta

    Iberi, Vighter; Ievlev, Anton V.; Vlassiouk, Ivan; Jesse, Stephen; Kalinin, Sergei V.; Joy, David C.; Rondinone, Adam J.; Belianinov, Alex; Ovchinnikova, Olga S.

    2016-02-18

    Achieving the ultimate limits of materials and device performance necessitates the engineering of matter with atomic, molecular, and mesoscale fidelity. While common for organic and macromolecular chemistry, these capabilities are virtually absent for 2D materials. In contrast to the undesired effect of ion implantation from focused ion beam (FIB) lithography with gallium ions, and proximity effects in standard e-beam lithography techniques, the shorter mean free path and interaction volumes of helium and neon ions offer a new route for clean, resist free nanofabrication. Furthermore, with the advent of scanning helium ion microscopy, maskless He+ and Ne+ beam lithography of graphenemore » based nanoelectronics is coming to the forefront. Here, we will discuss the use of energetic Ne ions in engineering graphene devices and explore the mechanical, electromechanical and chemical properties of the ion-milled devices using scanning probe microscopy (SPM). By using SPM-based techniques such as band excitation (BE) force modulation microscopy, Kelvin probe force microscopy (KPFM) and Raman spectroscopy, we demonstrate that the mechanical, electrical and optical properties of the exact same devices can be quantitatively extracted. Additionally, the effect of defects inherent in ion beam direct-write lithography, on the overall performance of the fabricated devices is elucidated.« less

  7. Data-driven RBE parameterization for helium ion beams

    NASA Astrophysics Data System (ADS)

    Mairani, A.; Magro, G.; Dokic, I.; Valle, S. M.; Tessonnier, T.; Galm, R.; Ciocca, M.; Parodi, K.; Ferrari, A.; Jäkel, O.; Haberer, T.; Pedroni, P.; Böhlen, T. T.

    2016-01-01

    Helium ion beams are expected to be available again in the near future for clinical use. A suitable formalism to obtain relative biological effectiveness (RBE) values for treatment planning (TP) studies is needed. In this work we developed a data-driven RBE parameterization based on published in vitro experimental values. The RBE parameterization has been developed within the framework of the linear-quadratic (LQ) model as a function of the helium linear energy transfer (LET), dose and the tissue specific parameter {{(α /β )}\\text{ph}} of the LQ model for the reference radiation. Analytic expressions are provided, derived from the collected database, describing the \\text{RB}{{\\text{E}}α}={α\\text{He}}/{α\\text{ph}} and {{\\text{R}}β}={β\\text{He}}/{β\\text{ph}} ratios as a function of LET. Calculated RBE values at 2 Gy photon dose and at 10% survival (\\text{RB}{{\\text{E}}10} ) are compared with the experimental ones. Pearson’s correlation coefficients were, respectively, 0.85 and 0.84 confirming the soundness of the introduced approach. Moreover, due to the lack of experimental data at low LET, clonogenic experiments have been performed irradiating A549 cell line with {{(α /β )}\\text{ph}}=5.4 Gy at the entrance of a 56.4 MeV u-1He beam at the Heidelberg Ion Beam Therapy Center. The proposed parameterization reproduces the measured cell survival within the experimental uncertainties. A RBE formula, which depends only on dose, LET and {{(α /β )}\\text{ph}} as input parameters is proposed, allowing a straightforward implementation in a TP system.

  8. Ion irradiation effects on metallic nanocrystals

    NASA Astrophysics Data System (ADS)

    Kluth, P.; Johannessen, B.; Giulian, R.; Schnohr, C. S.; Foran, G. J.; Cookson, D. J.; Byrne, A. P.; Ridgway, M. C.

    We have investigated structural and morphological properties of metallic nanocrystals (NCs) exposed to ion irradiation. NCs were characterized by transmission electron microscopy in combination with advanced synchrotron-based analytical techniques, in particular X-ray absorption spectroscopy and small-angle X-ray scattering. A number of different effects were observed depending on the irradiation conditions. At energies where nuclear stopping is predominant, structural disorder/amorphization followed by inverse Ostwald ripening/dissolution due to ion beam mixing was observed for Au and Cu NCs embedded in SiO2. The ion-irradiation-induced crystalline to amorphous transition in the NCs, which cannot be achieved in the corresponding bulk metals, was attributed to their initially higher structural energy as compared to bulk material and possibly preferential nucleation of the amorphous phase at the NC/SiO2 interface. At very high irradiation energies (swift heavy ion irradiation), where the energy loss is nearly entirely due to electronic stopping, a size-dependent shape transformation of the NCs from spheres to rod like shapes was apparent in Au NCs. Our preliminary results are in good agreement with considerations on melting of the NCs in the ion track as one mechanism involved in the shape transformation.

  9. Ion irradiation effects on metallic nanocrystals

    SciTech Connect

    Kluth, P.; Johannessen, B.; Giulian, R.; Schnohr, C.S.; Foran, G.J.; Cookson, D.J.; Byrne, A.P.; Ridgway, M.C.

    2008-04-02

    We have investigated structural and morphological properties of metallic nanocrystals (NCs) exposed to ion irradiation. NCs were characterized by transmission electron microscopy in combination with advanced synchrotron-based analytical techniques, in particular X-ray absorption spectroscopy and small-angle X-ray scattering. A number of different effects were observed depending on the irradiation conditions. At energies where nuclear stopping is predominant, structural disorder/amorphization followed by inverse Ostwald ripening/dissolution due to ion beam mixing was observed for Au and Cu NCs embedded in SiO{sub 2}. The ion-irradiation-induced crystalline to amorphous transition in the NCs, which cannot be achieved in the corresponding bulk metals, was attributed to their initially higher structural energy as compared to bulk material and possibly preferential nucleation of the amorphous phase at the NC/SiO{sub 2} interface. At very high irradiation energies (swift heavy ion irradiation), where the energy loss is nearly entirely due to electronic stopping, a size-dependent shape transformation of the NCs from spheres to rod like shapes was apparent in Au NCs. Our preliminary results are in good agreement with considerations on melting of the NCs in the ion track as one mechanism involved in the shape transformation.

  10. The initial stage of surface modification of magnesium alloys by high intensity pulse ions beam

    NASA Astrophysics Data System (ADS)

    Li, P.; Liu, Z. H.; Zhang, Z. P.

    2016-06-01

    The initial stage of high intensity pulsed ion beam irradiated magnesium alloys was studied by MD simulation. Specimens containing Mg17Al12 precipitation were modeled to investigate the evolution of magnesium alloys during several picoseconds after a high-energy ion impacting. It was found that the Mg17Al12 precipitation has little effects on the kinetic energy evolution in the heat zone, but considerable effects on strength of kinetic energy peak moving to the deep matrix and on the surface morphology of the magnesium alloy at thermal equilibrium state. The thickness of the heat zone is independent on the temperature of surface region.

  11. MeV ion beam interaction with polymer films containing cross-linking agents

    SciTech Connect

    Evelyn, A. L.

    1999-06-10

    Polymer films containing cross linking enhancers were irradiated with MeV alpha particles to determine the effects of MeV ion beam interaction on these materials. The contributed effects from the electronic and nuclear stopping powers were separated by irradiating stacked thin films of polyvinyl chloride (PVC), polystyrene (PS) and polyethersulfone (PES). This layered system allowed most of the effects of the electronic energy deposited to be experienced by the first layers and the last layers to receive most of the effects of the nuclear stopping power. RGA, Raman microprobe analysis, RBS and FTIR measured changes in the chemical structures of the irradiated films. The characterization resolved the effects of the stopping powers on the PVC, PS and PES and the results were compared with those from previously studied polymers that did not contain any cross linking agents.

  12. Shape-modification of patterned nanoparticles by an ion beam treatment

    NASA Astrophysics Data System (ADS)

    Heo, Kyong Chan; Gwag, Jin Seog

    2015-02-01

    This paper evaluated a practical approach to the fabrication of arrays of non-spherical nanoparticles by colloidal etching without a mask involving exposure to a low energy ion beam. A spherical nanoparticle array was transferred using a soft nanolithography technique, which is a simple and effective pattern transfer method for nanostructures on the surface of thin adhesive polymers on a planar substrate, after placing the spherical nanoparticles on a patterned PDMS [poly(dimethysiloxane)] stamp produced from a patterned Si wafer. The resulting non-spherical nanoparticle array was driven from a spherical nanoparticle array shape-modified by ion beam irradiation. A well-arrayed layer of cone-like-shapes were produced using a head-on ion beam for different exposure times. Also, a variety of mushroom-like-shapes depending on the exposure angle were produced on a substrate with a well-arranged spherical nanoparticle array. This technique has potential applications in nanophotonics, field emission displays (FEDs) and microfluid.

  13. Ion-beam-induced epitaxial crystallization of implanted and chemical vapor deposited amorphous silicon

    NASA Astrophysics Data System (ADS)

    La Ferla, A.; Priolo, F.; Spinella, C.; Rimini, E.; Baroetto, F.; Ferla, G.

    1989-03-01

    The dependence of ion-beam enhanced epitaxial growth of amorphous Si layers on impurities either dissolved in the film or present at the film-substrate interface is considered. In the case of ion implanted layers, electrically active dopants, like B, P, As at concentrations above 1 × 10 20/cm 3, enhance the rate by a factor of 2 with respect to the undoped layer. The enhancement shows also a weak dependence on the dopant concentration. Inert impurities, like Ar, which prevent pure thermal regrowth, do not show any appreciable influence on the ion-beam-induced growth rate. Chemical vapor deposited Si layers with a thin native interfacial oxide layer can also be epitaxially regrown under ion irradiation. A critical fluence is needed before the interfacial oxide breaks down and broadens, allowing the epitaxial crystallization to take place. This process is characterized by an activation energy of 0.44 eV. The complex phenomenon of ion-beam-induced crystallization involves a dynamical interaction between production and annealing of point defects. The presence of electrically active dopants probably influences the lifetime of point defects. Impurities which prevent thermal regrowth are instead dissolved by ballistic effects and/or radiation-enhanced mixing.

  14. Whistler Wave Excitation and Effects of Self-Focusing on Ion Beam Propagation through a Background Plasma along a Solenoidal Magnetic Field

    SciTech Connect

    Mikhail, Dorf A.; Kaganovich, Igor D.; Startsev, Edward A.; Davidson, Ronald C.

    2010-02-02

    This paper extends studies of ion beam transport through a background plasma along a solenoidal magnetic field [I. Kaganovich et al., Phys. Plasmas 15, 103108 (2008)] to the important regime of moderate magnetic field strength satisfying ωce > 2βbωpe . Here, ωce and ω pe are the electron cyclotron frequency and electron plasma frequency, respectively, and βb = vb/ c is the directed ion beam velocity normalized to the speed of light. The electromagnetic field perturbations excited by the ion beam pulse in this regime are calculated analytically, and verified by comparison with the numerical simulations. The degrees of beam charge neutralization and current neutralization are estimated, and the transverse component of the Lorentz force associated with the excited electromagnetic field is calculated. It is found that the plasma response to the ion beam pulse is significantly different depending on whether the value of the solenoidal magnetic field is below or above the threshold value specified by ω cr ce = 2βbωpe, and corresponding to the resonant excitation of large-amplitude whistler waves. The use of intense whistler wave excitations for diagnostic purposes is also discussed.

  15. Time resolved ion beam induced charge collection

    SciTech Connect

    SEXTON,FREDERICK W.; WALSH,DAVID S.; DOYLE,BARNEY L.; DODD,PAUL E.

    2000-04-01

    Under this effort, a new method for studying the single event upset (SEU) in microelectronics has been developed and demonstrated. Called TRIBICC, for Time Resolved Ion Beam Induced Charge Collection, this technique measures the transient charge-collection waveform from a single heavy-ion strike with a {minus}.03db bandwidth of 5 GHz. Bandwidth can be expanded up to 15 GHz (with 5 ps sampling windows) by using an FFT-based off-line waveform renormalization technique developed at Sandia. The theoretical time resolution of the digitized waveform is 24 ps with data re-normalization and 70 ps without re-normalization. To preserve the high bandwidth from IC to the digitizing oscilloscope, individual test structures are assembled in custom high-frequency fixtures. A leading-edge digitized waveform is stored with the corresponding ion beam position at each point in a two-dimensional raster scan. The resulting data cube contains a spatial charge distribution map of up to 4,096 traces of charge (Q) collected as a function of time. These two dimensional traces of Q(t) can cover a period as short as 5 ns with up to 1,024 points per trace. This tool overcomes limitations observed in previous multi-shot techniques due to the displacement damage effects of multiple ion strikes that changed the signal of interest during its measurement. This system is the first demonstration of a single-ion transient measurement capability coupled with spatial mapping of fast transients.

  16. Patient position verification in ion-beam therapy using ion-beam radiography and fiducial markers

    NASA Astrophysics Data System (ADS)

    Huber, Lucas; Telsemeyer, Julia; Martišíková, Mária; Jäkel, Oliver

    2011-11-01

    The basic rationale for radiation therapy using ion-beams is its high local precision of dose deposition. Therefore accurate patient positioning prior to and during beam application is a crucial part of the therapy. The current standard position verification procedure uses X-ray based imaging before each beam application. The patient is assumed to remain in his position throughout irradiation. Currently there is no monitoring of the patient position or organ movement during treatment. The aim of this study is to investigate the possibility of verifying the position of a fiducial marker during therapy using ion radiography. Some modern ion therapy facilities like the Heidelberg Ion-Beam Therapy Center (HIT), where our measurements were carried out, use scanning pencil beams to apply dose. Exploiting them for imaging allows to solely irradiate regions of interest in the patient's body, e.g. tissue containing medical markers. The advantage of this technique is that it can be performed quickly in turn with therapeutic beam application and irradiates only very little tissue. For our measurements we used conventional medical metal markers embedded in phantom material mimicking body tissue. To image the residual beam we use a Perkin Elmer RID256-L flat panel detector. In an idealized setup the marker contrast was measured to be as high as 60%, which was reduced by a factor of 2-2.5 when the marker was placed at distances to the detector in the phantom material larger than 10 cm. It was shown that applying 2ṡ105 carbon ions suffices to make the markers' position visible in a setup of realistic material thickness and marker depth. While the dose is comparable to X-ray imaging, the irradiated volume and, consequently, also the integral dose is considerably reduced. However, in realistic geometries there are large particle range differences in lateral direction yielding steep signal gradients in the radiography. Thus, the useful image area with unambiguous signal

  17. Ion beam sputtering of fluoropolymers. [etching polymer films and target surfaces

    NASA Technical Reports Server (NTRS)

    Sovey, J. S.

    1978-01-01

    Ion beam sputter processing rates as well as pertinent characteristics of etched targets and films are described. An argon ion beam source was used to sputter etch and deposit the fluoropolymers PTFE, FEP, and CTFE. Ion beam energy, current density, and target temperature were varied to examine effects on etch and deposition rates. The ion etched fluoropolymers yield cone or spire-like surface structures which vary depending upon the type of polymer, ion beam power density, etch time, and target temperature. Sputter target and film characteristics documented by spectral transmittance measurements, X-ray diffraction, ESCA, and SEM photomicrographs are included.

  18. Theory and simulation of emittance, space charge and electron pressure effects on focusing of neutralized ion beams

    SciTech Connect

    Lemons, D.S.; Jones, M.E.

    1986-01-01

    We investigate the final focus mode characterized by warm comoving electrons and vacuum propagation. In particular, we extend a previous envelope equation analysis of ion focusing in this mode to include the effects of ion emittance as well as ion space charge and initial electron temperature. Our major result is a simple equation relating initial R/sub o/ and final R/sub f/ beam radii to ion emittance epsilon and perveance K and electron Debye length lambda/sub D/ which is supported by one dimensional, electrostatic, particle-in-cell simulations of radial ion focusing. Finally, we use this equation to find the allowed temperature of neutralizing electrons for typical Heavy Ion Fusion reactor and High Temperature Experiment scenarios.

  19. Effect of film thickness on the magneto-structural properties of ion beam sputtered transition metal–metalloid FeCoNbB/Si (100) alloy thin films

    NASA Astrophysics Data System (ADS)

    Gupta, Pooja; Tripathi, Yagyanidhi; Kumar, Dileep; Rai, S. K.; Gupta, Mukul; Reddy, V. R.; Svec, Peter

    2016-08-01

    The structure and magnetic properties of ion beam sputtered transition metal–metalloid FeCoNbB/Si(100) alloy thin film have been studied as a function of film thickness using complementary techniques of x-ray reflectivity (XRR), grazing incidence x-ray diffraction, and magneto optical Kerr effect. Thicknesses of the films range from ∼200 to 1500 Å. The coercivity of all the films ranges between 4 and 14 Oe, which suggests soft magnetic nature of FeCoNbB/Si thin films. Films with thickness up to 800 Å are amorphous in nature and are found to possess uniaxial magnetic anisotropy in the film plane, although no magnetic field was applied during deposition. The presence of the two fold symmetry in such amorphous thin films may be attributed to quenched-in stresses developed during deposition. Upon increasing the film thickness to ∼1200 Å and above, the structure of FeCoNbB films transforms from amorphous to partially nanocrystalline structure and has bcc-FeCo nanocrystalline phase dispersed in remaining amorphous matrix. The crystalline volume fraction (cvf) of the films is found to be proportional to the film thickness. Azimuthal angle dependence of remanence confirms the presence of in-plane four-fold anisotropy (FFA) in the crystalline film with cvf ∼75%. Synchrotron x-ray diffraction measurement using area detector suggests random orientation of crystallites and thus clearly establishes that FFA is not related to texture/cubic symmetry in such polycrystalline thin films. As supported by asymmetric Bragg diffraction measurements, the origin of FFA in such partially crystalline thin film is ascribed to the additional compressive stresses developed in the film upon crystallization. Results indicate that promising soft magnetic properties in such films can be optimized by controlling the film thickness. The revelation of controllable and tunable anisotropy suggests that FeCoNbB thin films can have potential application in electromagnetic applications.

  20. Precise milling of nano-gap chains in graphene with a focused helium ion beam

    NASA Astrophysics Data System (ADS)

    Zhou, Yangbo; Maguire, Pierce; Jadwiszczak, Jakub; Muruganathan, Manoharan; Mizuta, Hiroshi; Zhang, Hongzhou

    2016-08-01

    A focused helium ion beam was used to introduce nano-sized gap chains in graphene. The effect of beam scanning strategies in the fabrication of the nano-gap chains was investigated. The tuning of graphene conductivity has been achieved by modulating the magnitude and uniformity of the ion dose and hence the morphology of the nano-gap chains. A model based on the site-specific and dose-dependent conductivity was built to understand the tuning of the conductivity, taking into account the nanoscale non-uniformity of irradiation.

  1. Precise milling of nano-gap chains in graphene with a focused helium ion beam.

    PubMed

    Zhou, Yangbo; Maguire, Pierce; Jadwiszczak, Jakub; Muruganathan, Manoharan; Mizuta, Hiroshi; Zhang, Hongzhou

    2016-08-12

    A focused helium ion beam was used to introduce nano-sized gap chains in graphene. The effect of beam scanning strategies in the fabrication of the nano-gap chains was investigated. The tuning of graphene conductivity has been achieved by modulating the magnitude and uniformity of the ion dose and hence the morphology of the nano-gap chains. A model based on the site-specific and dose-dependent conductivity was built to understand the tuning of the conductivity, taking into account the nanoscale non-uniformity of irradiation. PMID:27347752

  2. Surface modification using low energy ground state ion beams

    NASA Technical Reports Server (NTRS)

    Chutjian, Ara (Inventor); Hecht, Michael H. (Inventor); Orient, Otto J. (Inventor)

    1990-01-01

    A method of effecting modifications at the surfaces of materials using low energy ion beams of known quantum state, purity, flux, and energy is presented. The ion beam is obtained by bombarding ion-generating molecules with electrons which are also at low energy. The electrons used to bombard the ion generating molecules are separated from the ions thus obtained and the ion beam is directed at the material surface to be modified. Depending on the type of ion generating molecules used, different ions can be obtained for different types of surface modifications such as oxidation and diamond film formation. One area of application is in the manufacture of semiconductor devices from semiconductor wafers.

  3. Radially uniform circular sweep of ion beam

    SciTech Connect

    Akhmetov, T.D.; Davydenko, V.I.; Ivanov, A.A.; Kobets, V.V.; Medvedko, A.S.; Skorobogatov, D.N.; Tiunov, M.A.

    2006-03-15

    A spiral sweep of the ion beam was suggested to provide sufficiently uniform irradiation of a circular target. It is shown that if the beam radius is small enough, the radius of the beam center should increase as a square root of time to provide uniform radial irradiation of the target. In the complex for Boron Neutron Capture Therapy developed at the Budker Institute of Nuclear Physics, the proton beam sweep will be performed by a sweeper with uniform magnetic field with strength up to 500 G and axial length {approx}20 cm, rotating at 100-2000 Hz, and scanning over the radius at a 1-10 Hz frequency. The sweeper field is produced by four longitudinal flat current windings placed near the inner walls of a box-shaped yoke with the inner opening of a square cross section. A similar sweeping technique can be used in a 200 keV oxygen implanter, which is also under development at the Budker Institute.

  4. Surface modification using MeV ion beams

    NASA Technical Reports Server (NTRS)

    Tombrello, T. A.

    1983-01-01

    Electronic excitation induced by MeV/amu ion beams in a variety of materials has been employed successfully for a number of applications. The examples that will be presented are: modification of the surface reflectivities of optical materials; sputter-erosion of dielectrics; and enhancement of the adhesion of thin film coatings. All of these effects arise from the loss of energy by the ion beam to electrons in the target material; the mechanisms involved are at best qualitatively understood. This paper will stress not only the exploitation of such high energy bombardment techniques but will also briefly review attempts to expose the underlying causes.

  5. ION BEAM FOCUSING MEANS FOR CALUTRON

    DOEpatents

    Backus, J.G.

    1959-06-01

    An ion beam focusing arrangement for calutrons is described. It provides a virtual focus of origin for the ion beam so that the ions may be withdrawn from an arc plasma of considerable width providing greater beam current and accuracy. (T.R.H.)

  6. Perspectives of the Pixel Detector Timepix for Needs of Ion Beam Therapy

    NASA Astrophysics Data System (ADS)

    Martišíková, M.; Hartmann, B.; Jäkel, O.; Granja, C.; Jakubek, J.

    2012-08-01

    Radiation therapy with ion beams is a highly precise kind of cancer treatment. In ion beam therapy the finite range of the ion beams in tissue and the increase of ionization density at the end of their path, the Bragg-peak, are exploited. Ions heavier than protons offer in addition increased biological effectiveness and decreased scattering. In this contribution we discuss the potential of a quantum counting and position sensitive semiconductor detector Timepix for its applications in ion beam therapy measurements. It provides high sensitivity and high spatial resolution (pixel pitch 55 μm). The detector, developed by the Medipix Collaboration, consists of a silicon sensor bump bonded to a pixelated readout chip (256 × 256 pixels with 55 μm pitch). An integrated USB-based readout interface together with the Pixelman software enable registering single particles online with 2D-track visualization. The experiments were performed at the Heidelberg Ion Beam Therapy Center (HIT), which is a modern ion beam therapy facility. Patient treatments are performed with proton and carbon ions, which are accelerated by a synchrotron. For dose delivery to the patient an active technique is used: narrow pencil-like beams are scanned over the target volume. The possibility to use the detector for two different applications was investigated: ion spectroscopy and beam delivery monitoring by measurement of secondary charged particles around the patient. During carbon ion therapy, a variety of ion species is created by nuclear fragmentation processes of the primary beam. Since they differ in their biological effectiveness, it is of large interest to measure the ion spectra created under different conditions and to visualize their spatial distribution. The possibility of measurements of ion energy loss in silicon makes Timepix a promising detector for ion-spectroscopic studies in patient-like phantoms. Unpredictable changes in the patient can alter the range of the ion beam in the body

  7. Induction of apoptosis by accelerated heavy-ion beams in cultured fetal rat testes and its modification

    NASA Astrophysics Data System (ADS)

    Wang, Bing; Tanaka, Kaoru; Shang, Yi; Fujita, Kazuko; Ninomiya, Yasuharu; Moreno, Stephanie G.; Coffigny, Herve; Hayata, Isamu; Murakami, Masahiro; Eguchi-Kasai, Kiyomi; Nenoi, Mitsuru

    The increasing human activities in space missions make the study on effects from high-LET ionizing radiation an important issue to be addressed. We reported previously that prenatal irradiations with heavy-ion beams on gestation day 15 generally induced markedly detrimental effects on prenatal gonads, postnatal testicular development and male breeding activity in rats. To explore the mechanisms involved in radiation-induced gonocyte apoptosis in fetal gonads, which played a critical role in the fate of postnatal testis development, accelerated heavy-ion irradiations and organotypic culture of Wistar fetal rat testes were applied to investigations focused on cellular and molecular events after irradiations with or without chemical addition. Results showed that, in addition to the clustered distribution, both the time course and the percentage of apoptosis in gonocytes on gestation day 15 equivalent in vitro appeared similar to that in utero after exposure to either carbon-ion beams with a LET value of about 13 keV/µm or neon-ion beams with a LET value of about 30 keV/µm. Irradiations induced increased p53 expression in a dose dependent manner and decreased expressions of p21 and Bcl- 2 by Western Blot examination. Administration of pan-caspase inhibitor prior to irradiations effectively inhibited apoptosis occurrence and reduced the extent of clustered apoptosis, while such effects were not observed with the presence of p53 inhibitor, gap junction inhibitor, or nitric oxide specific scavenger. These findings indicated that irradiations of cultured fetal rat testes manifested pathologically similar apoptosis induction in gonocytes to that in utero. P53 expression was possibly responsible for the response to radiation damage rather than induction of apoptosis. The syncytial organization of gonocytes played a key role in formation of the clustered apoptosis, an event that both gap junction inhibitor and nitric oxide specific scavenger were incapable of preventing.

  8. MeV ion beam lithography of biocompatible halogenated Parylenes using aperture masks

    NASA Astrophysics Data System (ADS)

    Whitlow, Harry J.; Norarat, Rattanaporn; Roccio, Marta; Jeanneret, Patrick; Guibert, Edouard; Bergamin, Maxime; Fiorucci, Gianni; Homsy, Alexandra; Laux, Edith; Keppner, Herbert; Senn, Pascal

    2015-07-01

    Parylenes are poly(p-xylylene) polymers that are widely used as moisture barriers and in biomedicine because of their good biocompatibility. We have investigated MeV ion beam lithography using 16O+ ions for writing defined patterns in Parylene-C, which is evaluated as a coating material for the Cochlear Implant (CI) electrode array, a neuroprosthesis to treat some forms of deafness. Parylene-C and -F on silicon and glass substrates as well as 50 μm thick PTFE were irradiated to different fluences (1 ×1013 - 1 ×1016 1 MeV 16O+ ions cm-2) through aperture masks under high vacuum and a low pressure (<10-3 mbar) oxygen atmosphere. Biocompatibility of the irradiated and unirradiated surfaces was tested by cell-counting to determine the proliferation of murine spiral ganglion cells. The results reveal that an oxygen ion beam can be used to pattern Parylene-C and -F without using a liquid solvent developer in a similar manner to PTFE but with a ∼25× smaller removal rate. Biocompatibility tests showed no difference in cell adhesion between irradiated and unirradiated areas or ion fluence dependence. Coating the Parylene surface with an adhesion-promoting protein mixture had a much greater effect on cell proliferation.

  9. Radiological physics characteristics of the extracted heavy ion beams of the bevatron.

    NASA Technical Reports Server (NTRS)

    Tobias, C. A.; Lyman, J. T.; Chatterjee, A.; Howard, J.; Maccabee, H. D.; Raju, M. R.; Smith, A. R.; Sperinde, J. M.; Welch, G. P.

    1971-01-01

    Studies of the depth-ionization properties and the biological effects of heavy ion beams produced at the bevatron have extended work previously done with less energetic beams from other sources. Results indicate that heavy ion beams are suitable for tumor therapy, studies relating to space biology, and fundamental radiobiology.

  10. Kinetic Simulations of Ion Beam Neutralization

    SciTech Connect

    Chang, O.; Wang, J.

    2011-05-20

    Full particle PIC simulations are performed to study the neutralization of an ion beam in the cohesionless, mesothermal regime. Simulations further confirmed that neutralization is achieved through interactions between the trapped electrons and the potential well established by the propagation of the beam front along the beam direction and is not through plasma instabilities as previous studies suggested. In the transverse direction, the process is similar to that of the expansion of mesothermal plasma into vacuum. Parametric simulations are also performed to investigate the effects of beam radius and domain boundary condition on the neutralization process. The results suggests that, while the qualitative behavior may be similar in ground tests, quantitative parameters such as the beam potential will be affected significantly by the vacuum chamber because of the limits imposed on the expansion process by the finite chamber space.

  11. Development of polyatomic ion beam system using liquid organic materials

    NASA Astrophysics Data System (ADS)

    Takaoka, G. H.; Nishida, Y.; Yamamoto, T.; Kawashita, M.

    2005-08-01

    We have developed a new type of polyatomic ion beam system using liquid organic materials such as octane and ethanol, which consists of a capillary type of nozzle, an ionizer, a mass-separator and a substrate holder. Ion current extracted after ionization was 430 μA for octane and 200 μA for ethanol, respectively. The mass-analysis was realized using a compact E × B mass filter, and the mass-analyzed ion beams were transferred toward the substrate. The ion current density at the substrate was a few μA/cm2 for the mass-separated ion species. Interactions of polyatomic ion beams with silicon (Si) surfaces were investigated by utilizing the ellipsometry measurement. It was found that the damaged layer thickness irradiated by the polyatomic ions with a mass number of about 40 was smaller than that by Ar ion irradiation at the same incident energy and ion fluence. The result indicated that the rupture of polyatomic ions occurred upon its impact on the Si surface with an incident energy larger than a few keV. In addition, the chemical modification of Si surfaces such as wettability could be achieved by adjusting the incident energy for the ethanol ions, which included all the fragment ions.

  12. Ion-beam-induced bending of freestanding amorphous nanowires: The importance of the substrate material and charging

    SciTech Connect

    Cui, Ajuan; Li, Wuxia; Liu, Zhe; Luo, Qiang; Gu, Changzhi; Fenton, J. C.; Shen, Tiehan H.

    2013-05-27

    Ion-beam irradiation offers great flexibility and controllability in the construction of freestanding nanostructures with multiple advanced functionalities. Here, we present and discuss the bending of free-standing nanowires, against, towards, and ultimately parallel to a flux of directional ion irradiation. Bending components both along and perpendicular to the incident ion beam were observed, and the bending behavior was found to depend both on the ion beam scanning strategy and on the conductivity of the supporting substrate. This behavior is explained by an ion-irradiation-related electrostatic interaction. Our findings suggest the prospect of exploiting this technique to engineer 3D nanostructures for advanced applications.

  13. Ion-beam-induced bending of freestanding amorphous nanowires: The importance of the substrate material and charging

    NASA Astrophysics Data System (ADS)

    Cui, Ajuan; Fenton, J. C.; Li, Wuxia; Shen, Tiehan H.; Liu, Zhe; Luo, Qiang; Gu, Changzhi

    2013-05-01

    Ion-beam irradiation offers great flexibility and controllability in the construction of freestanding nanostructures with multiple advanced functionalities. Here, we present and discuss the bending of free-standing nanowires, against, towards, and ultimately parallel to a flux of directional ion irradiation. Bending components both along and perpendicular to the incident ion beam were observed, and the bending behavior was found to depend both on the ion beam scanning strategy and on the conductivity of the supporting substrate. This behavior is explained by an ion-irradiation-related electrostatic interaction. Our findings suggest the prospect of exploiting this technique to engineer 3D nanostructures for advanced applications.

  14. Ion beam deposited protective films

    NASA Technical Reports Server (NTRS)

    Mirtich, M. J.

    1981-01-01

    Sputter deposition of adherent thin films on complex geometric surfaces by ion beam sources is examined in order to evaluate three different types of protective coatings for die materials. In the first experiment, a 30 cm diameter argon ion source was used to sputter deposit adherent metallic films up to eight microns thick on H-13 steel, and a thermal fatigue test specimen sputter deposited with metallic coatings one micron thick was immersed in liquid aluminum and cooled by water for 15,000 cycles to simulate operational environments. Results show that these materials do protect the steel by reducing thermal fatigue and thereby increasing die lifetime. The second experiment generated diamond-like carbon films using a dual beam ion source system that directed an eight cm argon ion source beam at the substrates. These films are still in the process of being evaluated for crystallinity, hardness and infrared absorption. The third experiment coated a fiber glass beam shield incorporated in the eight-cm diameter mercury ion thruster with molybdenum to ensure proper electrical and thermal properties. The coating maintained its integrity even under acceleration tests.

  15. Effects of carbon ion irradiation and X-ray irradiation on the ubiquitylated protein accumulation

    PubMed Central

    ISOZAKI, TETSURO; FUJITA, MAYUMI; YAMADA, SHIGERU; IMADOME, KAORI; SHOJI, YOSHIMI; YASUDA, TAKESHI; NAKAYAMA, FUMIAKI; IMAI, TAKASHI; MATSUBARA, HISAHIRO

    2016-01-01

    C-ion radiotherapy is associated with improved local control and survival in several types of tumors. Although C-ion irradiation is widely reported to effectively induce DNA damage in tumor cells, the effects of irradiation on proteins, such as protein stability or degradation in response to radiation stress, remain unknown. We aimed to compare the effects of C-ion and X-ray irradiation focusing on the cellular accumulation of ubiquitylated proteins. Cells from two human colorectal cancer cell lines, SW620 and SW480, were subjected to C-ion or X-ray irradiation and determination of ubiquitylated protein levels. High levels of ubiquitylated protein accumulation were observed in the C-ion-irradiated SW620 with a peak at 3 Gy; the accumulation was significantly lower in the X-ray-irradiated SW620 at all doses. Enhanced levels of ubiquitylated proteins were also detected in C-ion or X-ray-irradiated SW480, however, those levels were significantly lower than the peak detected in the C-ion-irradiated SW620. The levels of irradiation-induced ubiquitylated proteins decreased in a time-dependent manner, suggesting that the proteins were eliminated after irradiation. The treatment of C-ion-irradiated SW620 with a proteasome inhibitor (epoxomicin) enhanced the cell killing activity. The accumulated ubiquitylated proteins were co-localized with γ-H2AX, and with TP53BP1, in C-ion-irradiated SW620, indicating C-ion-induced ubiquitylated proteins may have some functions in the DNA repair system. Overall, we showed C-ion irradiation strongly induces the accumulation of ubiquitylated proteins in SW620. These characteristics may play a role in improving the therapeutic ratio of C-ion beams; blocking the clearance of ubiquitylated proteins may enhance sensitivity to C-ion radiation. PMID:27175736

  16. Effects of carbon ion irradiation and X-ray irradiation on the ubiquitylated protein accumulation.

    PubMed

    Isozaki, Tetsuro; Fujita, Mayumi; Yamada, Shigeru; Imadome, Kaori; Shoji, Yoshimi; Yasuda, Takeshi; Nakayama, Fumiaki; Imai, Takashi; Matsubara, Hisahiro

    2016-07-01

    C-ion radiotherapy is associated with improved local control and survival in several types of tumors. Although C-ion irradiation is widely reported to effectively induce DNA damage in tumor cells, the effects of irradiation on proteins, such as protein stability or degradation in response to radiation stress, remain unknown. We aimed to compare the effects of C-ion and X-ray irradiation focusing on the cellular accumulation of ubiquitylated proteins. Cells from two human colorectal cancer cell lines, SW620 and SW480, were subjected to C-ion or X-ray irradiation and determination of ubiquitylated protein levels. High levels of ubiquitylated protein accumulation were observed in the C-ion-irradiated SW620 with a peak at 3 Gy; the accumulation was significantly lower in the X-ray-irradiated SW620 at all doses. Enhanced levels of ubiquitylated proteins were also detected in C-ion or X-ray-irradiated SW480, however, those levels were significantly lower than the peak detected in the C-ion-irradiated SW620. The levels of irradiation-induced ubiquitylated proteins decreased in a time-dependent manner, suggesting that the proteins were eliminated after irradiation. The treatment of C-ion-irradiated SW620 with a proteasome inhibitor (epoxomicin) enhanced the cell killing activity. The accumulated ubiquitylated proteins were co-localized with γ-H2AX, and with TP53BP1, in C-ion-irradiated SW620, indicating C-ion-induced ubiquitylated proteins may have some functions in the DNA repair system. Overall, we showed C-ion irradiation strongly induces the accumulation of ubiquitylated proteins in SW620. These characteristics may play a role in improving the therapeutic ratio of C-ion beams; blocking the clearance of ubiquitylated proteins may enhance sensitivity to C-ion radiation. PMID:27175736

  17. Kinetic Simulations of Ion Beam Neutralization

    SciTech Connect

    Wang, Joseph

    2010-05-21

    Ion beam emission/neutralization is one of the most fundamental problems in spacecraft plasma interactions and electric propulsion. Although ion beam neutralization is readily achieved in experiments, the understanding of the underlying physical process remains at a rather primitive level. No theoretical or simulation models have convincingly explained the detailed neutralization mechanism, and no conclusions have been reached. This paper presents a fully kinetic simulation of ion beam neutralization and plasma beam propagation and discusses the physics of electron-ion coupling and the resulting propagation of a neutralized mesothermal plasma.

  18. Effect of Ar Ion Beam Implantation on Morphological and Physiological Characteristics of Liquorice (Glycyrrhiza uralensis Fisch) Under Short-Term Artificial Drought Conditions

    NASA Astrophysics Data System (ADS)

    Zhang, Xiangsheng; Wu, Lijun; Yu, Lixiang; Wei, Shenglin; Liu, Jingnan; Yu, Zengliang

    2007-04-01

    Ar+ ion beam with low energy of 30 keV was implanted into liquorice (Glycyrrhiza uralensis Fisch) seeds at the doses of 0, 600, 900 and 1200 × (2.6 × 1013) ions/cm2, respectively. The seeds were sowed in pots and after one month the plants were subjected to different drought conditions for two months. Then the plants' morphological and physiological characteristics, anti-oxidation enzymes and levels of endogenous hormones were investigated. The results showed that ion implantation at a proper dose can greatly enhance the liquorice seedlings' resistance against drought stress.

  19. Tuning the interface conductivity of LaAlO3/SrTiO3 using ion beams: implications for patterning.

    PubMed

    Mathew, Sinu; Annadi, Anil; Chan, Taw Kuei; Asmara, Teguh Citra; Zhan, Da; Wang, Xiao Renshaw; Azimi, Sara; Shen, Zexiang; Rusydi, Andrivo; Ariando; Breese, Mark B H; Venkatesan, T

    2013-12-23

    Patterning of the two-dimensional electron gas formed at the interface of two band insulators such as LaAlO3/SrTiO3 is one of the key challenges in oxide electronics. The use of energetic ion beam exposure for engineering the interface conductivity has been investigated. We found that this method can be utilized to manipulate the conductivity at the LaAlO3/SrTiO3 interface by carrier localization, arising from the defects created by the ion beam exposure, eventually producing an insulating ground state. This process of ion-beam-induced defect creation results in structural changes in SrTiO3 as revealed by the appearance of first-order polar TO2 and TO4 vibrational modes which are associated with Ti-O bonds in the Raman spectra of the irradiated samples. Furthermore, significant observation drawn from the magnetotransport measurements is that the irradiated (unirradiated) samples showed a negative (positive) magnetoresistance along with simultaneous emergence of first-order (only second order) Raman modes. In spectroscopic ellipsometry measurements, the optical conductivity features of the irradiated interface are broadened because of the localization effects, along with a decrease of spectral weight from 4.2 to 5.4 eV. These experiments allow us to conclude that the interface ground state (metallic/insulating) at the LaAlO3/SrTiO3 can be controlled by tailoring the defect structure of the SrTiO3 with ion beam exposure. A resist-free, single-step direct patterning of a conducting LaAlO3/SrTiO3 interface has been demonstrated. Patterns with a spatial resolution of 5 μm have been fabricated using a stencil mask, while nanometer scale patterns may be possible with direct focused ion beam writing. PMID:24266519

  20. Hydrodynamic Efficiency of Ablation Propulsion with Pulsed Ion Beam

    SciTech Connect

    Buttapeng, Chainarong; Yazawa, Masaru; Harada, Nobuhiro; Suematsu, Hisayuki; Jiang Weihua; Yatsui, Kiyoshi

    2006-05-02

    This paper presents the hydrodynamic efficiency of ablation plasma produced by pulsed ion beam on the basis of the ion beam-target interaction. We used a one-dimensional hydrodynamic fluid compressible to study the physics involved namely an ablation acceleration behavior and analyzed it as a rocketlike model in order to investigate its hydrodynamic variables for propulsion applications. These variables were estimated by the concept of ablation driven implosion in terms of ablated mass fraction, implosion efficiency, and hydrodynamic energy conversion. Herein, the energy conversion efficiency of 17.5% was achieved. In addition, the results show maximum energy efficiency of the ablation process (ablation efficiency) of 67% meaning the efficiency with which pulsed ion beam energy-ablation plasma conversion. The effects of ion beam energy deposition depth to hydrodynamic efficiency were briefly discussed. Further, an evaluation of propulsive force with high specific impulse of 4000s, total impulse of 34mN and momentum to energy ratio in the range of {mu}N/W was also analyzed.

  1. Drag of ballistic electrons by an ion beam

    SciTech Connect

    Gurevich, V. L.; Muradov, M. I.

    2015-12-15

    Drag of electrons of a one-dimensional ballistic nanowire by a nearby one-dimensional beam of ions is considered. We assume that the ion beam is represented by an ensemble of heavy ions of the same velocity V. The ratio of the drag current to the primary current carried by the ion beam is calculated. The drag current turns out to be a nonmonotonic function of velocity V. It has a sharp maximum for V near v{sub nF}/2, where n is the number of the uppermost electron miniband (channel) taking part in conduction and v{sub nF} is the corresponding Fermi velocity. This means that the phenomenon of ion beam drag can be used for investigation of the electron spectra of ballistic nanostructures. We note that whereas observation of the Coulomb drag between two parallel quantum wires may in general be complicated by phenomena such as tunneling and phonon drag, the Coulomb drag of electrons of a one-dimensional ballistic nanowire by an ion beam is free of such spurious effects.

  2. Neurosurgical applications of ion beams

    NASA Astrophysics Data System (ADS)

    Fabrikant, Jacob I.; Levy, Richard P.; Phillips, Mark H.; Frankel, Kenneth A.; Lyman, John T.

    1989-04-01

    The program at Donner Pavilion has applied nuclear medicine research to the diagnosis and radiosurgical treatment of life-threatening intracranial vascular disorders that affect more than half a million Americans. Stereotactic heavy-charged-particle Bragg peak radiosurgery, using narrow beams of heavy ions, demonstrates superior biological and physical characteristics in brain over X-and γ-rays, viz., improved dose distribution in the Bragg peak and sharp lateral and distal borders and less scattering of the beam. Examination of CNS tissue response and alteration of cerebral blood-flow dynamics related to heavy-ion Bragg peak radiosurgery is carried out using three-dimensional treatment planning and quantitative imaging utilizing cerebral angiography, computerized tomography (CT), magnetic resonance imaging (MRI), cine-CT, xenon X-ray CT and positron emission tomography (PET). Also under examination are the physical properties of narrow heavy-ion beams for improving methods of dose delivery and dose distribution and for establishing clinical RBE/LET and dose-response relationships for human CNS tissues. Based on the evaluation and treatment with stereotactically directed narrow beams of heavy charged particles of over 300 patients, with cerebral angiography, CT scanning and MRI and PET scanning of selected patients, plus extensive clinical and neuroradiological followup, it appears that Stereotactic charged-particle Bragg peak radiosurgery obliterates intracranial arteriovenous malformations or protects against rebleeding with reduced morbidity and no mortality. Discussion will include the method of evaluation, the clinical research protocol, the Stereotactic neuroradiological preparation, treatment planning, the radiosurgery procedure and the protocol for followup. Emphasis will be placed on the neurological results, including the neuroradiological and clinical response and early and late delayed injury in brain leading to complications (including vasogenic edema

  3. Two-dimensional silicon-based detectors for ion beam therapy

    NASA Astrophysics Data System (ADS)

    Martišíková, M.; Granja, C.; Jakůbek, J.; Hartmann, B.; Telsemeyer, J.; Huber, L.; Brons, S.; Pospíšil, S.; Jäkel, O.

    2012-02-01

    Radiation therapy with ion beams is a highly precise kind of cancer treatment. As ion beams traverse material, the highest ionization density occurs at the end of their path. Due to this Bragg-peak, ion beams enable higher dose conformation to the tumor and increased sparing of the surrounding tissue, in comparison to standard radiation therapy using high energy photons. Ions heavier than protons offer in addition increased biological effectiveness and lower scattering. The Heidelberg Ion Beam Therapy Center (HIT) is a state-of-the-art ion beam therapy facility and the first hospital-based facility in Europe. It provides proton and carbon ion treatments. A synchrotron is used for ion acceleration. For dose delivery to the patient, narrow pencil-like beams are scanned over the target volume.

  4. Design and performance analysis of an ultraprecision ion beam polishing tool.

    PubMed

    Lu, Ying; Xie, Xuhui; Zhou, Lin

    2016-03-01

    First, we introduce requirements for the ion beam polishing tool used in the subnanometer precision process. Based on the ion beam figuring (IBF) principle, the definitive factor of the IBF capability is analyzed, and the deficiencies of the ion beam polishing tool are identified. The effect of focused ion optics on the ion beam removal function is based on theoretic calculation and computer simulation; and focused three-grid ion optics are developed and tested. Finally, a 150 mm flat optics element is figured and results show that the contour error decreases from 15.58 nm RMS to 0.796 nm RMS, demonstrating that the ion beam polishing tool is very efficient for optical IBF. PMID:26974611

  5. Biomedical applications of ion-beam technology

    NASA Technical Reports Server (NTRS)

    Banks, B. A.; Weigand, A. J.; Gibbons, D. F.; Vankampen, C. L.; Babbush, C. A.

    1979-01-01

    Microscopically-rough surface texture of various biocompatible alloys and polymers produced by ion-beam sputtering may result in improvements in response of hard or soft tissue to various surgical implants.

  6. Ion beam microtexturing and enhanced surface diffusion

    NASA Technical Reports Server (NTRS)

    Robinson, R. S.

    1982-01-01

    Ion beam interactions with solid surfaces are discussed with particular emphasis on microtexturing induced by the deliberate deposition of controllable amounts of an impurity material onto a solid surface while simultaneously sputtering the surface with an ion beam. Experimental study of the optical properties of microtextured surfaces is described. Measurements of both absorptance as a function of wavelength and emissivity are presented. A computer code is described that models the sputtering and ion reflection processes involved in microtexture formation.

  7. Anomalous resistivity effect on multiple ion beam emission and hard x-ray generation in a Mather type plasma focus device

    SciTech Connect

    Behbahani, R. A.; Aghamir, F. M.

    2011-10-15

    Multi ion beam and hard x-ray emissions were detected in a high inductance (more than 100 nH) Mather type plasma focus (PF) device at different filling gas pressures and charging voltages. The signal analysis was performed through the current trace, as it is the fundamental signal from which all of the phenomena in a PF device can be extracted. Two different fitting processes were carried out according to Lee's computational (snow-plow) model. In the first process, only plasma dynamics and classical (Spitzer) resistances were considered as energy consumer parameters for plasma. This led to an unsuccessful fitting and did not answer the energy transfer mechanism into plasma. A second fitting process was considered through the addition of anomalous resistance, which provided the best fit. Anomalous resistance was the source of long decrease in current trace, and multi dips and multi peaks of high voltage probe. Multi-peak features were interpreted considering the second fitting process along with the mechanisms for ion beam production and hard x-ray emission. To show the important role of the anomalous resistance, the duration of the current drop was discussed.

  8. The LICPA accelerator of dense plasma and ion beams

    NASA Astrophysics Data System (ADS)

    Badziak, J.; Jabloński, S.; Pisarczyk, T.; Chodukowski, T.; Parys, P.; Raczka, P.; Rosiński, M.; Krousky, E.; Ullschmied, J.; Liska, R.; Kucharik, M.; Torrisi, L.

    2014-04-01

    Laser-induced cavity pressure acceleration (LICPA) is a novel scheme of acceleration of dense matter having a potential to accelerate plasma projectiles with the energetic efficiency much higher than the achieved so far with other methods. In this scheme, a projectile placed in a cavity is irradiated by a laser beam introduced into the cavity through a hole and accelerated along a guiding channel by the thermal pressure created in the cavity by the laser-produced plasma or by the photon pressure of the ultraintense laser radiation trapped in the cavity. This paper summarizes briefly the main results of our recent LICPA studies, in particular, experimental investigations of ion beam generation and heavy macroparticle acceleration in the hydrodynamic LICPA regime (at moderate laser intensities ~ 1015W/cm2) and numerical, particle-in-cell (PIC) studies of production of ultraintense ion beams and fast macroparticles using the photon pressure LICPA regime (at high laser intensities > 1020 W/cm2). It is shown that in both LICPA regimes the macroparticles and ion beams can be accelerated much more efficiently than in other laser-based acceleration scheme commonly used and the accelerated plasma/ion bunches can have a wide variety of parameters. It creates a prospect for a broad range of applications of the LICPA accelerator, in particular in such domains as high energy density physics, ICF research (ion fast ignition, impact ignition) or nuclear physics.

  9. Relationship between plant growth and cytological effect in root apical meristem after exposure of wheat dry seeds to carbon ion beams

    NASA Astrophysics Data System (ADS)

    Liu, Qingfang; Wang, Zhuanzi; Zhou, Libin; Qu, Ying; Lu, Dong; Yu, Lixia; Du, Yan; Jin, Wenjie; Li, Wenjian

    2013-06-01

    In order to analyze the relationship between plant growth and cytological effects, wheat dry seeds were exposed to various doses of 12C6+ beams and the biological endpoints reflecting plant growth and root apical meristem (RAM) activities were investigated. The results showed that most of the seeds were able to germinate normally within all dose range, while the plant survival rate descended at higher doses. The seedling growth including root length and seedling height also decreased significantly at higher doses. Mitotic index (MI) in RAM had no changes at 10 and 20 Gy and decreased obviously at higher doses and the proportion of prophase cells had the same trend with MI. These data suggested that RAM cells experienced cell cycle arrest, which should be responsible for the inhibition of root growth after exposure to higher doses irradiation. Moreover, various types of chromosome aberrations (CAs) were observed in the mitotic cells. The frequencies of mitotic cells with lagging chromosomes and these with anaphase bridges peaked around 60 Gy, while the frequencies of these with fragments increased as the irradiation doses increased up to 200 Gy. The total frequencies of mitotic cells with CAs induced by irradiation increased significantly with the increasing doses. The serious damage of mitotic chromosomes maybe caused cell cycle arrest or cell death. These findings suggested that the influences of 12C6+ beams irradiation on plant growth were related to the alternation of mitotic activities and the chromosomal damages in RAM.

  10. Production of highly charged ion beams with SECRALa)

    NASA Astrophysics Data System (ADS)

    Sun, L. T.; Zhao, H. W.; Lu, W.; Zhang, X. Z.; Feng, Y. C.; Li, J. Y.; Cao, Y.; Guo, X. H.; Ma, H. Y.; Zhao, H. Y.; Shang, Y.; Ma, B. H.; Wang, H.; Li, X. X.; Jin, T.; Xie, D. Z.

    2010-02-01

    Superconducting electron cyclotron resonance ion source with advanced design in Lanzhou (SECRAL) is an all-superconducting-magnet electron cyclotron resonance ion source (ECRIS) for the production of intense highly charged ion beams to meet the requirements of the Heavy Ion Research Facility in Lanzhou (HIRFL). To further enhance the performance of SECRAL, an aluminum chamber has been installed inside a 1.5 mm thick Ta liner used for the reduction of x-ray irradiation at the high voltage insulator. With double-frequency (18+14.5 GHz) heating and at maximum total microwave power of 2.0 kW, SECRAL has successfully produced quite a few very highly charged Xe ion beams, such as 10 e μA of Xe37+, 1 e μA of Xe43+, and 0.16 e μA of Ne-like Xe44+. To further explore the capability of the SECRAL in the production of highly charged heavy metal ion beams, a first test run on bismuth has been carried out recently. The main goal is to produce an intense Bi31+ beam for HIRFL accelerator and to have a feel how well the SECRAL can do in the production of very highly charged Bi beams. During the test, though at microwave power less than 3 kW, more than 150 e μA of Bi31+, 22 e μA of Bi41+, and 1.5 e μA of Bi50+ have been produced. All of these results have again demonstrated the great capability of the SECRAL source. This article will present the detailed results and brief discussions to the production of highly charged ion beams with SECRAL.

  11. Production of highly charged ion beams with SECRAL.

    PubMed

    Sun, L T; Zhao, H W; Lu, W; Zhang, X Z; Feng, Y C; Li, J Y; Cao, Y; Guo, X H; Ma, H Y; Zhao, H Y; Shang, Y; Ma, B H; Wang, H; Li, X X; Jin, T; Xie, D Z

    2010-02-01

    Superconducting electron cyclotron resonance ion source with advanced design in Lanzhou (SECRAL) is an all-superconducting-magnet electron cyclotron resonance ion source (ECRIS) for the production of intense highly charged ion beams to meet the requirements of the Heavy Ion Research Facility in Lanzhou (HIRFL). To further enhance the performance of SECRAL, an aluminum chamber has been installed inside a 1.5 mm thick Ta liner used for the reduction of x-ray irradiation at the high voltage insulator. With double-frequency (18+14.5 GHz) heating and at maximum total microwave power of 2.0 kW, SECRAL has successfully produced quite a few very highly charged Xe ion beams, such as 10 e microA of Xe(37+), 1 e microA of Xe(43+), and 0.16 e microA of Ne-like Xe(44+). To further explore the capability of the SECRAL in the production of highly charged heavy metal ion beams, a first test run on bismuth has been carried out recently. The main goal is to produce an intense Bi(31+) beam for HIRFL accelerator and to have a feel how well the SECRAL can do in the production of very highly charged Bi beams. During the test, though at microwave power less than 3 kW, more than 150 e microA of Bi(31+), 22 e microA of Bi(41+), and 1.5 e microA of Bi(50+) have been produced. All of these results have again demonstrated the great capability of the SECRAL source. This article will present the detailed results and brief discussions to the production of highly charged ion beams with SECRAL. PMID:20192339

  12. Fast optimization and dose calculation in scanned ion beam therapy

    SciTech Connect

    Hild, S.; Graeff, C.; Trautmann, J.; Kraemer, M.; Zink, K.; Durante, M.; Bert, C.

    2014-07-15

    Purpose: Particle therapy (PT) has advantages over photon irradiation on static tumors. An increased biological effectiveness and active target conformal dose shaping are strong arguments for PT. However, the sensitivity to changes of internal geometry complicates the use of PT for moving organs. In case of interfractionally moving objects adaptive radiotherapy (ART) concepts known from intensity modulated radiotherapy (IMRT) can be adopted for PT treatments. One ART strategy is to optimize a new treatment plan based on daily image data directly before a radiation fraction is delivered [treatment replanning (TRP)]. Optimizing treatment plans for PT using a scanned beam is a time consuming problem especially for particles other than protons where the biological effective dose has to be calculated. For the purpose of TRP, fast optimization and fast dose calculation have been implemented into the GSI in-house treatment planning system (TPS) TRiP98. Methods: This work reports about the outcome of a code analysis that resulted in optimization of the calculation processes as well as implementation of routines supporting parallel execution of the code. To benchmark the new features, the calculation time for therapy treatment planning has been studied. Results: Compared to the original version of the TPS, calculation times for treatment planning (optimization and dose calculation) have been improved by a factor of 10 with code optimization. The parallelization of the TPS resulted in a speedup factor of 12 and 5.5 for the original version and the code optimized version, respectively. Hence the total speedup of the new implementation of the authors' TPS yielded speedup factors up to 55. Conclusions: The improved TPS is capable of completing treatment planning for ion beam therapy of a prostate irradiation considering organs at risk in this has been overseen in the review process. Also see below 6 min.

  13. Magnetron deposition of TCO films using ion beam

    NASA Astrophysics Data System (ADS)

    Asainov, O.; Umnov, S.; Chinin, A.

    2015-11-01

    Thin films of tin oxide (TO) were deposited on the glass substrates at room temperature using reactive magnetron sputtering at various oxygen partial pressures. After the deposition the films were irradiated with argon ions beam. The change of the optical and electrical properties of the films depending on the irradiation time was studied. Films optical properties in the range of 300-1100 nm were investigated by photometry as well as their structural properties were studied using X-ray diffraction. Diffractometric research showed that the films, deposited on a substrate, have a crystal structure, and after argon ions irradiation they become quasi-crystalline (amorphous). It was found that the transmission increases proportionally with the irradiation time, but the surface resistance -disproportionally.

  14. Mass spectrometer and methods of increasing dispersion between ion beams

    DOEpatents

    Appelhans, Anthony D.; Olson, John E.; Delmore, James E.

    2006-01-10

    A mass spectrometer includes a magnetic sector configured to separate a plurality of ion beams, and an electrostatic sector configured to receive the plurality of ion beams from the magnetic sector and increase separation between the ion beams, the electrostatic sector being used as a dispersive element following magnetic separation of the plurality of ion beams. Other apparatus and methods are provided.

  15. Cluster ion beam assisted fabrication of metallic nanostructures for plasmonic applications

    NASA Astrophysics Data System (ADS)

    Saleem, Iram; Tilakaratne, Buddhi P.; Li, Yang; Bao, Jiming; Wijesundera, Dharshana N.; Chu, Wei-Kan

    2016-08-01

    We report a high-throughput, single-step method for fabricating rippled plasmonic nanostructure arrays via self-assembly induced by oblique angle cluster ion beam irradiation of metal surfaces. This approach does not require lithographic or chemical processes and has the prominent advantage of possible large surface area coverage and applicability to different starting materials. The polarization dependent plasmonic property of the gold nano-ripple is due to their one dimension structure. The localized plasmon resonance frequency of synthesized nano-ripple arrays is tunable by changing nano-ripple dimensions that can be engineered by changing the cluster ion beam irradiation parameters. In this specific case presented, using 30 keV Ar-gas cluster ion beam, we fabricate gold nano-ripple arrays that show localized plasmon resonance in the visible range through near IR range, tunable by varying cluster ion irradiation fluence.

  16. Multiscale approach predictions for biological outcomes in ion-beam cancer therapy.

    PubMed

    Verkhovtsev, Alexey; Surdutovich, Eugene; Solov'yov, Andrey V

    2016-01-01

    Ion-beam therapy provides advances in cancer treatment, offering the possibility of excellent dose localization and thus maximising cell-killing within the tumour. The full potential of such therapy can only be realised if the fundamental mechanisms leading to lethal cell damage under ion irradiation are well understood. The key question is whether it is possible to quantitatively predict macroscopic biological effects caused by ion radiation on the basis of physical and chemical effects related to the ion-medium interactions on a nanometre scale. We demonstrate that the phenomenon-based MultiScale Approach to the assessment of radiation damage with ions gives a positive answer to this question. We apply this approach to numerous experiments where survival curves were obtained for different cell lines and conditions. Contrary to other, in essence empirical methods for evaluation of macroscopic effects of ionising radiation, the MultiScale Approach predicts the biodamage based on the physical effects related to ionisation of the medium, transport of secondary particles, chemical interactions, thermo-mechanical pathways of biodamage, and heuristic biological criteria for cell survival. We anticipate this method to give great impetus to the practical improvement of ion-beam cancer therapy and the development of more efficient treatment protocols. PMID:27297618

  17. Multiscale approach predictions for biological outcomes in ion-beam cancer therapy

    NASA Astrophysics Data System (ADS)

    Verkhovtsev, Alexey; Surdutovich, Eugene; Solov’Yov, Andrey V.

    2016-06-01

    Ion-beam therapy provides advances in cancer treatment, offering the possibility of excellent dose localization and thus maximising cell-killing within the tumour. The full potential of such therapy can only be realised if the fundamental mechanisms leading to lethal cell damage under ion irradiation are well understood. The key question is whether it is possible to quantitatively predict macroscopic biological effects caused by ion radiation on the basis of physical and chemical effects related to the ion-medium interactions on a nanometre scale. We demonstrate that the phenomenon-based MultiScale Approach to the assessment of radiation damage with ions gives a positive answer to this question. We apply this approach to numerous experiments where survival curves were obtained for different cell lines and conditions. Contrary to other, in essence empirical methods for evaluation of macroscopic effects of ionising radiation, the MultiScale Approach predicts the biodamage based on the physical effects related to ionisation of the medium, transport of secondary particles, chemical interactions, thermo-mechanical pathways of biodamage, and heuristic biological criteria for cell survival. We anticipate this method to give great impetus to the practical improvement of ion-beam cancer therapy and the development of more efficient treatment protocols.

  18. Multiscale approach predictions for biological outcomes in ion-beam cancer therapy

    PubMed Central

    Verkhovtsev, Alexey; Surdutovich, Eugene; Solov’yov, Andrey V.

    2016-01-01

    Ion-beam therapy provides advances in cancer treatment, offering the possibility of excellent dose localization and thus maximising cell-killing within the tumour. The full potential of such therapy can only be realised if the fundamental mechanisms leading to lethal cell damage under ion irradiation are well understood. The key question is whether it is possible to quantitatively predict macroscopic biological effects caused by ion radiation on the basis of physical and chemical effects related to the ion-medium interactions on a nanometre scale. We demonstrate that the phenomenon-based MultiScale Approach to the assessment of radiation damage with ions gives a positive answer to this question. We apply this approach to numerous experiments where survival curves were obtained for different cell lines and conditions. Contrary to other, in essence empirical methods for evaluation of macroscopic effects of ionising radiation, the MultiScale Approach predicts the biodamage based on the physical effects related to ionisation of the medium, transport of secondary particles, chemical interactions, thermo-mechanical pathways of biodamage, and heuristic biological criteria for cell survival. We anticipate this method to give great impetus to the practical improvement of ion-beam cancer therapy and the development of more efficient treatment protocols. PMID:27297618

  19. Ion-beam-induced nanodots formation from Au/Si thin films on quartz surface

    NASA Astrophysics Data System (ADS)

    Datta, D. P.; Siva, V.; Singh, A.; Joshi, S. R.; Kanjilal, D.; Sahoo, P. K.

    2016-07-01

    We report the synthesis of Si nanodots on quartz surface using ion irradiation. When a bi-layer of ultrathin Au and Si on quartz surface is irradiated by 500 keV Xe-ion beam, the bi-layer spontaneously transforms into nanodots at a fluence of 5 × 1014 ions cm-2. The spatial density and diameter of the nanodots are reduced with increase in applied ion fluence. The nanostructures exhibit photoluminescence in the visible range at room temperature where the intensity and wavelength depends upon ion fluence. The observed evolution seems to be correlated to ion beam mixing induced silicide formation at Au-Si interface.

  20. Optical studies of ion-beam synthesized metal alloy nanoparticles

    SciTech Connect

    Magudapathy, P. Srivatsava, S. K.; Gangopadhyay, P.; Amirthapandian, S.; Sairam, T. N.; Panigrahi, B. K.

    2015-06-24

    Au{sub x}Ag{sub 1-x} alloy nanoparticles with tunable surface plasmon resonance (SPR) have been synthesized on a silica glass substrate. A small Au foil on an Ag foil is irradiated as target substrates such that ion beam falls on both Ag foil and Au foils. Silica slides are kept at an angle ∼45° with respect to the metallic foils. While irradiating the metallic foils with 100 keV Ar{sup +} ions, sputtered Au and Ag atoms get deposited on the silica-glass. In this configuration the foils have been irradiated by Ar{sup +} ions to various fluences at room temperature and the sputtered species are collected on silica slides. Formation of Au{sub x}Ag{sub 1-x} nanoparticles has been confirmed from the optical absorption measurements. With respect to the exposure area of Au and Ag foils to the ion beam, the SPR peak position varies from 450 to 500 nm. Green photoluminescence has been observed from these alloy metal nanoparticles.

  1. Ion-beam apparatus and method for analyzing and controlling integrated circuits

    DOEpatents

    Campbell, Ann N.; Soden, Jerry M.

    1998-01-01

    An ion-beam apparatus and method for analyzing and controlling integrated circuits. The ion-beam apparatus comprises a stage for holding one or more integrated circuits (ICs); a source means for producing a focused ion beam; and a beam-directing means for directing the focused ion beam to irradiate a predetermined portion of the IC for sufficient time to provide an ion-beam-generated electrical input signal to a predetermined element of the IC. The apparatus and method have applications to failure analysis and developmental analysis of ICs and permit an alteration, control, or programming of logic states or device parameters within the IC either separate from or in combination with applied electrical stimulus to the IC for analysis thereof. Preferred embodiments of the present invention including a secondary particle detector and an electron floodgun further permit imaging of the IC by secondary ions or electrons, and allow at least a partial removal or erasure of the ion-beam-generated electrical input signal.

  2. Ion-beam apparatus and method for analyzing and controlling integrated circuits

    DOEpatents

    Campbell, A.N.; Soden, J.M.

    1998-12-01

    An ion-beam apparatus and method for analyzing and controlling integrated circuits are disclosed. The ion-beam apparatus comprises a stage for holding one or more integrated circuits (ICs); a source means for producing a focused ion beam; and a beam-directing means for directing the focused ion beam to irradiate a predetermined portion of the IC for sufficient time to provide an ion-beam-generated electrical input signal to a predetermined element of the IC. The apparatus and method have applications to failure analysis and developmental analysis of ICs and permit an alteration, control, or programming of logic states or device parameters within the IC either separate from or in combination with applied electrical stimulus to the IC for analysis thereof. Preferred embodiments of the present invention including a secondary particle detector and an electron floodgun further permit imaging of the IC by secondary ions or electrons, and allow at least a partial removal or erasure of the ion-beam-generated electrical input signal. 4 figs.

  3. Nanopatterning of silicon surfaces by low-energy ion-beam sputtering: dependence on the angle of ion incidence

    NASA Astrophysics Data System (ADS)

    Gago, R.; Vázquez, L.; Cuerno, R.; Varela, M.; Ballesteros, C.; Albella, J. M.

    2002-06-01

    We report on the production of nanoscale patterning on Si substrates by low-energy ion-beam sputtering. The surface morphology and structure of the irradiated surface were studied by atomic force microscopy (AFM) and high-resolution transmission electron microscopy (HRTEM). Under ion irradiation at off-normal incidence angle (~50°), AFM images show the formation of both nanoripple and sawtooth-like structures for sputtering times longer than 20 min. The latter feature coarsens appreciably after 60 min of sputtering, inducing a large increase in the surface roughness. This behaviour is attributed to the preferential direction determined on the substrate by the ion beam for this incidence angle, leading to shadowing effects among surface features in the sputtering process. Under irradiation at normal incidence, the formation of an hexagonal array of nanodots is induced for irradiation times longer than 2 min. The shape and crystallinity of the nanodots were determined by HRTEM. At this incidence angle, the surface roughness is very low and remains largely unchanged even after 16 h of sputtering. For the two angle conditions studied, the formation of the corresponding surface structures can be understood as the interplay between an instability due to the sputtering yield dependence on the local surface curvature and surface smoothing processes such as surface diffusion.

  4. On the role of ion-based imaging methods in modern ion beam therapy

    SciTech Connect

    Magallanes, L. Rinaldi, I.; Brons, S.; Marcelos, T. Parodi, K.; Takechi, M.; Voss, B.; Jäkel, O.

    2014-11-07

    External beam radiotherapy techniques have the common aim to maximize the radiation dose to the target while sparing the surrounding healthy tissues. The inverted and finite depth-dose profile of ion beams (Bragg peak) allows for precise dose delivery and conformai dose distribution. Furthermore, increased radiobiological effectiveness of ions enhances the capability to battle radioresistant tumors. Ion beam therapy requires a precise determination of the ion range, which is particularly sensitive to range uncertainties. Therefore, novel imaging techniques are currently investigated as a tool to improve the quality of ion beam treatments. Approaches already clinically available or under development are based on the detection of secondary particles emitted as a result of nuclear reactions (e.g., positron-annihilation or prompt gammas, charged particles) or transmitted high energy primary ion beams. Transmission imaging techniques make use of the beams exiting the patient, which have higher initial energy and lower fluence than the therapeutic ones. At the Heidelberg Ion Beam Therapy Center, actively scanned energetic proton and carbon ion beams provide an ideal environment for the investigation of ion-based radiography and tomography. This contribution presents the rationale of ion beam therapy, focusing on the role of ion-based transmission imaging methods towards the reduction of range uncertainties and potential improvement of treatment planning.

  5. On the role of ion-based imaging methods in modern ion beam therapy

    NASA Astrophysics Data System (ADS)

    Magallanes, L.; Brons, S.; Marcelos, T.; Takechi, M.; Voss, B.; Jäkel, O.; Rinaldi, I.; Parodi, K.

    2014-11-01

    External beam radiotherapy techniques have the common aim to maximize the radiation dose to the target while sparing the surrounding healthy tissues. The inverted and finite depth-dose profile of ion beams (Bragg peak) allows for precise dose delivery and conformai dose distribution. Furthermore, increased radiobiological effectiveness of ions enhances the capability to battle radioresistant tumors. Ion beam therapy requires a precise determination of the ion range, which is particularly sensitive to range uncertainties. Therefore, novel imaging techniques are currently investigated as a tool to improve the quality of ion beam treatments. Approaches already clinically available or under development are based on the detection of secondary particles emitted as a result of nuclear reactions (e.g., positron-annihilation or prompt gammas, charged particles) or transmitted high energy primary ion beams. Transmission imaging techniques make use of the beams exiting the patient, which have higher initial energy and lower fluence than the therapeutic ones. At the Heidelberg Ion Beam Therapy Center, actively scanned energetic proton and carbon ion beams provide an ideal environment for the investigation of ion-based radiography and tomography. This contribution presents the rationale of ion beam therapy, focusing on the role of ion-based transmission imaging methods towards the reduction of range uncertainties and potential improvement of treatment planning.

  6. Variable-spot ion beam figuring

    NASA Astrophysics Data System (ADS)

    Wu, Lixiang; Qiu, Keqiang; Fu, Shaojun

    2016-03-01

    This paper introduces a new scheme of ion beam figuring (IBF), or rather variable-spot IBF, which is conducted at a constant scanning velocity with variable-spot ion beam collimated by a variable diaphragm. It aims at improving the reachability and adaptation of the figuring process within the limits of machine dynamics by varying the ion beam spot size instead of the scanning velocity. In contrast to the dwell time algorithm in the conventional IBF, the variable-spot IBF adopts a new algorithm, which consists of the scan path programming and the trajectory optimization using pattern search. In this algorithm, instead of the dwell time, a new concept, integral etching time, is proposed to interpret the process of variable-spot IBF. We conducted simulations to verify its feasibility and practicality. The simulation results indicate the variable-spot IBF is a promising alternative to the conventional approach.

  7. Pseudo ribbon metal ion beam source

    SciTech Connect

    Stepanov, Igor B. Ryabchikov, Alexander I.; Sivin, Denis O.; Verigin, Dan A.

    2014-02-15

    The paper describes high broad metal ion source based on dc macroparticle filtered vacuum arc plasma generation with the dc ion-beam extraction. The possibility of formation of pseudo ribbon beam of metal ions with the parameters: ion beam length 0.6 m, ion current up to 0.2 A, accelerating voltage 40 kV, and ion energy up to 160 kV has been demonstrated. The pseudo ribbon ion beam is formed from dc vacuum arc plasma. The results of investigation of the vacuum arc evaporator ion-emission properties are presented. The influence of magnetic field strength near the cathode surface on the arc spot movement and ion-emission properties of vacuum-arc discharge for different cathode materials are determined. It was shown that vacuum-arc discharge stability can be reached when the magnetic field strength ranges from 40 to 70 G on the cathode surface.

  8. Confined ion beam sputtering device and method

    DOEpatents

    Sharp, Donald J.

    1988-01-01

    A hollow cylindrical target, lined internally with a sputter deposit material and open at both ends, surrounds a substrate on which sputtered deposition is to be obtained. An ion beam received through either one or both ends of the open cylindrical target is forced by a negative bias applied to the target to diverge so that ions impinge at acute angles at different points of the cylindrical target surface. The ion impingement results in a radially inward and downstream directed flux of sputter deposit particles that are received by the substrate. A positive bias applied to the substrate enhances divergence of the approaching ion beams to generate a higher sputtered deposition flux rate. Alternatively, a negative bias applied to the substrate induces the core portion of the ion beams to reach the substrate and provide ion polishing of the sputtered deposit thereon.

  9. Confined ion beam sputtering device and method

    DOEpatents

    Sharp, D.J.

    1986-03-25

    A hollow cylindrical target, lined internally with a sputter deposit material and open at both ends, surrounds a substrate on which sputtered deposition is to be obtained. An ion beam received through either one or both ends of the open cylindrical target is forced by a negative bias applied to the target to diverge so that ions impinge at acute angles at different points of the cylindrical target surface. The ion impingement results in a radially inward and downstream directed flux of sputter deposit particles that are received by the substrate. A positive bias applied to the substrate enhances divergence of the approaching ion beams to generate a higher sputtered deposition flux rate. Alternatively, a negative bias applied to the substrate induces the core portion of the ion beams to reach the substrate and provide ion polishing of the sputtered deposit thereon.

  10. Heavy ion beam-ionosphere interactions - Electron acceleration

    NASA Technical Reports Server (NTRS)

    Kaufmann, R. L.; Arnoldy, R. L.; Moore, T. E.; Kintner, P. M.; Cahill, L. J., Jr.

    1985-01-01

    Moore et al. (1982) described a number of unexpected effects which were observed during the first Argon Release Controlled Study (ARCS 1, or rocket flight 29:014). The present paper provides a description of detailed analyses of the interaction of the argon beam with the ionosphere. An important feature of the considered test was that all detectors and the Ar(+) gun remained attached to the rocket throughout the flight. It is pointed out that the most dramatic effect of ion gun operation on ARCS 1 involved large changes in the fluxes of electrons with energies below about 600 eV. The observations are discussed, taking into account the distribution functions, azimuth dependence, and electron and ion trajectories. Attention is given to the perpendicular ion beam, the parallel ion beam, the acceleration of downgoing and upgoing electrons, and aspects of wave generation.

  11. Heavy ion beam-ionosphere interactions - Electron acceleration

    NASA Astrophysics Data System (ADS)

    Kaufmann, R. L.; Arnoldy, R. L.; Moore, T. E.; Kintner, P. M.; Cahill, L. J., Jr.

    1985-10-01

    Moore et al. (1982) described a number of unexpected effects which were observed during the first Argon Release Controlled Study (ARCS 1, or rocket flight 29:014). The present paper provides a description of detailed analyses of the interaction of the argon beam with the ionosphere. An important feature of the considered test was that all detectors and the Ar(+) gun remained attached to the rocket throughout the flight. It is pointed out that the most dramatic effect of ion gun operation on ARCS 1 involved large changes in the fluxes of electrons with energies below about 600 eV. The observations are discussed, taking into account the distribution functions, azimuth dependence, and electron and ion trajectories. Attention is given to the perpendicular ion beam, the parallel ion beam, the acceleration of downgoing and upgoing electrons, and aspects of wave generation.

  12. Large Area Microcorrals and Cavity Formation on Cantilevers using a Focused Ion Beam

    SciTech Connect

    Saraf, Laxmikant V.; Britt, David W.

    2011-09-14

    We utilize focused ion beam (FIB) to explore various sputtering parameters to form large area microcorrals and cavities on cantilevers. Microcorrals were rapidly created by modifying ion beam blur and overlaps. Modification in FIB sputtering parameters affects the periodicity and shape of corral microstructure. Cantilever deflections show ion beam amorphization effects as a function of sputtered area and cantilever base cavities with or without side walls. The FIB sputtering parameters address a method for rapid creation of a cantilever tensiometer with integrated fluid storage and delivery.

  13. Graphene engineering by neon ion beams

    NASA Astrophysics Data System (ADS)

    Iberi, Vighter; Ievlev, Anton V.; Vlassiouk, Ivan; Jesse, Stephen; Kalinin, Sergei V.; Joy, David C.; Rondinone, Adam J.; Belianinov, Alex; Ovchinnikova, Olga S.

    2016-03-01

    Achieving the ultimate limits of lithographic resolution and material performance necessitates engineering of matter with atomic, molecular, and mesoscale fidelity. With the advent of scanning helium ion microscopy, maskless He+ and Ne+ beam lithography of 2D materials, such as graphene-based nanoelectronics, is coming to the forefront as a tool for fabrication and surface manipulation. However, the effects of using a Ne focused-ion-beam on the fidelity of structures created out of 2D materials have yet to be explored. Here, we will discuss the use of energetic Ne ions in engineering graphene nanostructures and explore their mechanical, electromechanical and chemical properties using scanning probe microscopy (SPM). By using SPM-based techniques such as band excitation (BE) force modulation microscopy, Kelvin probe force microscopy (KPFM) and Raman spectroscopy, we are able to ascertain changes in the mechanical, electrical and optical properties of Ne+ beam milled graphene nanostructures and surrounding regions. Additionally, we are able to link localized defects around the milled graphene to ion milling parameters such as dwell time and number of beam passes in order to characterize the induced changes in mechanical and electromechanical properties of the graphene surface.

  14. Graphene engineering by neon ion beams.

    PubMed

    Iberi, Vighter; Ievlev, Anton V; Vlassiouk, Ivan; Jesse, Stephen; Kalinin, Sergei V; Joy, David C; Rondinone, Adam J; Belianinov, Alex; Ovchinnikova, Olga S

    2016-03-29

    Achieving the ultimate limits of lithographic resolution and material performance necessitates engineering of matter with atomic, molecular, and mesoscale fidelity. With the advent of scanning helium ion microscopy, maskless He(+) and Ne(+) beam lithography of 2D materials, such as graphene-based nanoelectronics, is coming to the forefront as a tool for fabrication and surface manipulation. However, the effects of using a Ne focused-ion-beam on the fidelity of structures created out of 2D materials have yet to be explored. Here, we will discuss the use of energetic Ne ions in engineering graphene nanostructures and explore their mechanical, electromechanical and chemical properties using scanning probe microscopy (SPM). By using SPM-based techniques such as band excitation (BE) force modulation microscopy, Kelvin probe force microscopy (KPFM) and Raman spectroscopy, we are able to ascertain changes in the mechanical, electrical and optical properties of Ne(+) beam milled graphene nanostructures and surrounding regions. Additionally, we are able to link localized defects around the milled graphene to ion milling parameters such as dwell time and number of beam passes in order to characterize the induced changes in mechanical and electromechanical properties of the graphene surface. PMID:26890062

  15. Ion beam figuring of small optical components

    NASA Astrophysics Data System (ADS)

    Drueding, Thomas W.; Fawcett, Steven C.; Wilson, Scott R.; Bifano, Thomas G.

    1995-12-01

    Ion beam figuring provides a highly deterministic method for the final precision figuring of optical components with advantages over conventional methods. The process involves bombarding a component with a stable beam of accelerated particles that selectively removes material from the surface. Figure corrections are achieved by rastering the fixed-current beam across the workplace at appropriate, time-varying velocities. Unlike conventional methods, ion figuring is a noncontact technique and thus avoids such problems as edge rolloff effects, tool wear, and force loading of the workpiece. This work is directed toward the development of the precision ion machining system at NASA's Marshall Space Flight Center. This system is designed for processing small (approximately equals 10-cm diam) optical components. Initial experiments were successful in figuring 8-cm-diam fused silica and chemical-vapor-deposited SiC samples. The experiments, procedures, and results of figuring the sample workpieces to shallow spherical, parabolic (concave and convex), and non-axially-symmetric shapes are discussed. Several difficulties and limitations encountered with the current system are discussed. The use of a 1-cm aperture for making finer corrections on optical components is also reported.

  16. Theory of Nanocluster Size Distributions from Ion Beam Synthesis

    SciTech Connect

    Yuan, C.W.; Yi, D.O.; Sharp, I.D.; Shin, S.J.; Liao, C.Y.; Guzman, J.; Ager III, J.W.; Haller, E.E.; Chrzan, D.C.

    2008-06-13

    Ion beam synthesis of nanoclusters is studied via both kinetic Monte Carlo simulations and the self-consistent mean-field solution to a set of coupled rate equations. Both approaches predict the existence of a steady state shape for the cluster size distribution that depends only on a characteristic length determined by the ratio of the effective diffusion coefficient to the ion flux. The average cluster size in the steady state regime is determined by the implanted species/matrix interface energy.

  17. Potential biomedical applications of ion beam technology

    NASA Technical Reports Server (NTRS)

    Banks, B. A.; Weigand, A. J.; Babbush, C. A.; Vankampen, C. L.

    1976-01-01

    Electron bombardment ion thrusters used as ion sources have demonstrated a unique capability to vary the surface morphology of surgical implant materials. The microscopically rough surface texture produced by ion beam sputtering of these materials may result in improvements in the biological response and/or performance of implanted devices. Control of surface roughness may result in improved attachment of the implant to soft tissue, hard tissue, bone cement, or components deposited from blood. Potential biomedical applications of ion beam texturing discussed include: vascular prostheses, artificial heart pump diaphragms, pacemaker fixation, percutaneous connectors, orthopedic pros-thesis fixtion, and dental implants.

  18. Potential biomedical applications of ion beam technology

    NASA Technical Reports Server (NTRS)

    Banks, B. A.; Weigand, A. J.; Van Kampen, C. L.; Babbush, C. A.

    1976-01-01

    Electron bombardment ion thrusters used as ion sources have demonstrated a unique capability to vary the surface morphology of surgical implant materials. The microscopically rough surface texture produced by ion beam sputtering of these materials may result in improvements in the biological response and/or performance of implanted devices. Control of surface roughness may result in improved attachment of the implant to soft tissue, hard tissue, bone cement, or components deposited from blood. Potential biomedical applications of ion beam texturing discussed include: vascular prostheses, artificial heart pump diaphragms, pacemaker fixation, percutaneous connectors, orthopedic prosthesis fixation, and dental implants.

  19. Focused ion beam source method and apparatus

    DOEpatents

    Pellin, Michael J.; Lykke, Keith R.; Lill, Thorsten B.

    2000-01-01

    A focused ion beam having a cross section of submicron diameter, a high ion current, and a narrow energy range is generated from a target comprised of particle source material by laser ablation. The method involves directing a laser beam having a cross section of critical diameter onto the target, producing a cloud of laser ablated particles having unique characteristics, and extracting and focusing a charged particle beam from the laser ablated cloud. The method is especially suited for producing focused ion beams for semiconductor device analysis and modification.

  20. Ion-beam technology and applications

    NASA Technical Reports Server (NTRS)

    Hudson, W. R.; Robson, R. R.; Sovey, J. S.

    1977-01-01

    Ion propulsion research and development yields a mature technology that is transferable to a wide range of nonpropulsive applications, including terrestrial and space manufacturing. A xenon ion source was used for an investigation into potential ion-beam applications. The results of cathode tests and discharge-chamber experiments are presented. A series of experiments encompassing a wide range of potential applications is discussed. Two types of processes, sputter deposition, and erosion were studied. Some of the potential applications are thin-film Teflon capacitor fabrication, lubrication applications, ion-beam cleaning and polishing, and surface texturing.

  1. Copper Ion Beam Irradiation-Induced Effects on Structural, Morphological and Optical Properties of Tin Dioxide Nanowires

    NASA Astrophysics Data System (ADS)

    A. Khan, M.; Qayyum, A.; I., Ahmed; T., Iqbal; A. Khan, A.; Waleed, R.; Mohuddin, B.; Malik, M.

    2016-07-01

    Not Available Supported by the Department of Physics, the University of AJK, High Tech. Centralized Instrumentation Lab, the University of AJK, Pakistan and the Experimental Physics Division, and the National Center for Physics, Islamabad Pakistan.

  2. Tilting of carbon encapsulated metallic nanocolumns in carbon-nickel nanocomposite films by ion beam assisted deposition

    SciTech Connect

    Krause, Matthias; Muecklich, Arndt; Zschornak, Matthias; Wintz, Sebastian; Gemming, Sibylle; Abrasonis, Gintautas; Oates, Thomas W. H.; Luis Endrino, Jose

    2012-07-30

    The influence of assisting low-energy ({approx}50-100 eV) ion irradiation effects on the morphology of C:Ni ({approx}15 at. %) nanocomposite films during ion beam assisted deposition (IBAD) is investigated. It is shown that IBAD promotes the columnar growth of carbon encapsulated metallic nanoparticles. The momentum transfer from assisting ions results in tilting of the columns in relation to the growing film surface. Complex secondary structures are obtained, in which a significant part of the columns grows under local epitaxy via the junction of sequentially deposited thin film fractions. The influence of such anisotropic film morphology on the optical properties is highlighted.

  3. Simulation of ion beam injection and extraction in an EBIS

    NASA Astrophysics Data System (ADS)

    Zhao, L.; Kim, J. S.

    2016-02-01

    An example simulation of Au+ charge breeding using FAR-TECH's integrated EBIS (electron beam ion source) modeling toolset is presented with the emphasis on ion beam injection and extraction. The trajectories of injected ions are calculated with PBGUNS (particle beam gun simulation) self-consistently by including the space charges from both ions and electrons. The ion beam, starting with initial conditions within the 100% acceptance of the electron beam, is then tracked by EBIS-PIC (particle-in-cell EBIS simulation code). In the trap, the evolution of the ion charge state distribution is estimated by charge state estimator. The extraction of charge bred ions is simulated with PBGUNS. The simulations of the ion injections show significant ion space charge effects on beam capture efficiency and the ionization efficiency.

  4. Recent advances for ion beam therapy accelerators using synchrotrons

    NASA Astrophysics Data System (ADS)

    Weinrich, U.

    2011-12-01

    Ion beam therapy has evolved a lot during the last years. After more than a decade of successful clinical studies and first treatment in hospital environment, the carbon beam treatment, which always relies on a synchrotron as main accelerator, has clearly shown its own potential. The clinical success of carbon beam treatment is indicated by the growing number of new fully clinical based facilities. There is a lot of improvement potential for these facilities in order to increase their treatment quality, functionality and capacity as well as the cost effectiveness of the patient treatment. This article focuses on the currently ongoing investigations to fully explore this potential. It can be concluded that synchrotron based ion beam facilities are improving into many directions. This will further improve their impact on the cancer treatment and consequently their benefit to the whole society.

  5. Intense ion beam neutralization using underdense background plasma

    SciTech Connect

    Berdanier, William; Roy, Prabir K.; Kaganovich, Igor

    2015-01-15

    Producing an overdense background plasma for neutralization purposes with a density that is high compared to the beam density is not always experimentally possible. We show that even an underdense background plasma with a small relative density can achieve high neutralization of intense ion beam pulses. Using particle-in-cell simulations, we show that if the total plasma electron charge is not sufficient to neutralize the beam charge, electron emitters are necessary for effective neutralization but are not needed if the plasma volume is so large that the total available charge in the electrons exceeds that of the ion beam. Several regimes of possible underdense/tenuous neutralization plasma densities are investigated with and without electron emitters or dense plasma at periphery regions, including the case of electron emitters without plasma, which does not effectively neutralize the beam. Over 95% neutralization is achieved for even very underdense background plasma with plasma density 1/15th the beam density. We compare results of particle-in-cell simulations with an analytic model of neutralization and find close agreement with the particle-in-cell simulations. Further, we show experimental data from the National Drift Compression experiment-II group that verifies the result that underdense plasma can neutralize intense heavy ion beams effectively.

  6. The role of space charge compensation for ion beam extraction and ion beam transport (invited)

    SciTech Connect

    Spädtke, Peter

    2014-02-15

    Depending on the specific type of ion source, the ion beam is extracted either from an electrode surface or from a plasma. There is always an interface between the (almost) space charge compensated ion source plasma, and the extraction region in which the full space charge is influencing the ion beam itself. After extraction, the ion beam is to be transported towards an accelerating structure in most cases. For lower intensities, this transport can be done without space charge compensation. However, if space charge is not negligible, the positive charge of the ion beam will attract electrons, which will compensate the space charge, at least partially. The final degree of Space Charge Compensation (SCC) will depend on different properties, like the ratio of generation rate of secondary particles and their loss rate, or the fact whether the ion beam is pulsed or continuous. In sections of the beam line, where the ion beam is drifting, a pure electrostatic plasma will develop, whereas in magnetic elements, these space charge compensating electrons become magnetized. The transport section will provide a series of different plasma conditions with different properties. Different measurement tools to investigate the degree of space charge compensation will be described, as well as computational methods for the simulation of ion beams with partial space charge compensation.

  7. Biophysical models in ion beam radiotherapy

    NASA Astrophysics Data System (ADS)

    Scholz, Michael; Elsässer, Thilo

    One major rationale for the application of heavy ion beams in tumor therapy is their increased relative biological effectiveness (RBE) in the Bragg peak region. For dose prescription, the increased effectiveness has to be taken into account in treatment planning. Hence, the complex dependencies of RBE on the dose level, biological endpoint, position in the field etc. require biophysical models, which have to fulfill two important criteria: simplicity and quantitative precision. Simplicity means that the number of free parameters should be kept at a minimum. Due to the lack of precise quantitative data, at least at present, this requirement is incompatible with approaches aiming at the molecular modeling of the whole chain of production, processing and repair of biological damages. Quantitative precision is required since steep gradients in the dose response curves are observed for most tumor and normal tissues; thus, even small uncertainties in the estimation of the biologically effective dose can transform into large uncertainties in the clinical outcome. The paper will give a general introduction into the field, followed by a description of a specific model, the so called 'Local Effect Model' (LEM). This model has been successfully applied within treatment planning in the GSI pilot project for carbon ion tumor therapy over almost 10 years now. The model is based on the knowledge of charged particle track structure in combination with the response of the cells or tissues under consideration to conventional photon radiation. The model is compared to other approaches developed for the calculation of the biological effects of high-LET radiation. Furthermore, recent improvements of the model are described. Due to the quantitative precision, besides applications in tumor therapy the LEM seems to be adequate for the calculation of stochastic radiation effects, i.e. in the framework of radiation protection. Examples for the calculation of cell transformation are

  8. Space processing applications of ion beam technology. [surface finishing, welding, milling and film deposition

    NASA Technical Reports Server (NTRS)

    Grodzka, P. G.

    1977-01-01

    Ion thruster engines for spacecraft propulsion can serve as ion beam sources for potential space processing applications. The advantages of space vacuum environments and the possible gravity effects on thruster ion beam materials operations such as thin film growth, ion milling, and surface texturing were investigated. The direct gravity effect on sputter deposition and vapor deposition processes are discussed as well as techniques for cold and warm welding.

  9. Focused ion beam induced deflections of freestanding thin films

    NASA Astrophysics Data System (ADS)

    Kim, Y.-R.; Chen, P.; Aziz, M. J.; Branton, D.; Vlassak, J. J.

    2006-11-01

    Prominent deflections are shown to occur in freestanding silicon nitride thin membranes when exposed to a 50keV gallium focused ion beam for ion doses between 1014 and 1017ions/cm2. Atomic force microscope topographs were used to quantify elevations on the irradiated side and corresponding depressions of comparable magnitude on the back side, thus indicating that what at first appeared to be protrusions are actually the result of membrane deflections. The shape in high-stress silicon nitride is remarkably flat-topped and differs from that in low-stress silicon nitride. Ion beam induced biaxial compressive stress generation, which is a known deformation mechanism for other amorphous materials at higher ion energies, is hypothesized to be the origin of the deflection. A continuum mechanical model based on this assumption convincingly reproduces the profiles for both low-stress and high-stress membranes and provides a family of unusual shapes that can be created by deflection of freestanding thin films under beam irradiation.

  10. Studies of Ion Beam Charge Neutralization by Ferroelectric Plasma Sources

    NASA Astrophysics Data System (ADS)

    Stepanov, A.; Gilson, E. P.; Grisham, L.; Davidson, R. C.

    2013-10-01

    Space-charge forces limit the possible transverse compression of high perveance ion beams that are used in ion-beam-driven high energy density physics applications; the minimum radius to which a beam can be focused is an increasing function of perveance. The limit can be overcome if a plasma is introduced in the beam path between the focusing element and the target in order to neutralize the space charge of the beam. This concept has been implemented on the Neutralized Drift Compression eXperiment (NDCX) at LBNL using Ferroelectric Plasma Sources (FEPS). In our experiment at PPPL, we propagate a perveance-dominated ion beam through a FEPS to study the effect of the neutralizing plasma on the beam envelope and its evolution in time. A 30-60 keV space-charge-dominated Argon beam is focused with an Einzel lens into a FEPS located at the beam waist. The beam is intercepted downstream from the FEPS by a movable Faraday cup that provides time-resolved 2D current density profiles of the beam spot on target. We report results on: (a) dependence of charge neutralization on FEPS plasma density; (b) effects on beam emittance, and (c) time evolution of the beam envelope after the FEPS pulse. Research supported by the U.S. Department of Energy.

  11. Metal Ion Sources for Ion Beam Implantation

    SciTech Connect

    Zhao, W. J.; Zhao, Z. Q.; Ren, X. T.

    2008-11-03

    In this paper a theme touched upon the progress of metal ion sources devoted to metal ion beam implantation (MIBI) will be reviewed. A special emphasis will be given to some kinds of ion sources such as ECR, MEVVA and Cluster ion sources. A novel dual hollow cathode metal ion source named DUHOCAMIS will be introduced and discussed.

  12. Focused ion beam micromilling and articles therefrom

    DOEpatents

    Lamartine, Bruce C.; Stutz, Roger A.

    1998-01-01

    An ultrahigh vacuum focused ion beam micromilling apparatus and process are isclosed. Additionally, a durable data storage medium using the micromilling process is disclosed, the durable data storage medium capable of storing, e.g., digital or alphanumeric characters as well as graphical shapes or characters.

  13. Metal assisted focused-ion beam nanopatterning

    NASA Astrophysics Data System (ADS)

    Kannegulla, Akash; Cheng, Li-Jing

    2016-09-01

    Focused-ion beam milling is a versatile technique for maskless nanofabrication. However, the nonuniform ion beam profile and material redeposition tend to disfigure the surface morphology near the milling areas and degrade the fidelity of nanoscale pattern transfer, limiting the applicability of the technique. The ion-beam induced damage can deteriorate the performance of photonic devices and hinders the precision of template fabrication for nanoimprint lithography. To solve the issue, we present a metal assisted focused-ion beam (MAFIB) process in which a removable sacrificial aluminum layer is utilized to protect the working material. The new technique ensures smooth surfaces and fine milling edges; in addition, it permits direct formation of v-shaped grooves with tunable angles on dielectric substrates or metal films, silver for instance, which are rarely achieved by using traditional nanolithography followed by anisotropic etching processes. MAFIB was successfully demonstrated to directly create nanopatterns on different types of substrates with high fidelity and reproducibility. The technique provides the capability and flexibility necessary to fabricate nanophotonic devices and nanoimprint templates.

  14. Metal assisted focused-ion beam nanopatterning.

    PubMed

    Kannegulla, Akash; Cheng, Li-Jing

    2016-09-01

    Focused-ion beam milling is a versatile technique for maskless nanofabrication. However, the nonuniform ion beam profile and material redeposition tend to disfigure the surface morphology near the milling areas and degrade the fidelity of nanoscale pattern transfer, limiting the applicability of the technique. The ion-beam induced damage can deteriorate the performance of photonic devices and hinders the precision of template fabrication for nanoimprint lithography. To solve the issue, we present a metal assisted focused-ion beam (MAFIB) process in which a removable sacrificial aluminum layer is utilized to protect the working material. The new technique ensures smooth surfaces and fine milling edges; in addition, it permits direct formation of v-shaped grooves with tunable angles on dielectric substrates or metal films, silver for instance, which are rarely achieved by using traditional nanolithography followed by anisotropic etching processes. MAFIB was successfully demonstrated to directly create nanopatterns on different types of substrates with high fidelity and reproducibility. The technique provides the capability and flexibility necessary to fabricate nanophotonic devices and nanoimprint templates. PMID:27479713

  15. Heavy ion beams for inertial fusion

    SciTech Connect

    Godlove, T.F.; Herrmannsfeldt, W.B.

    1980-05-01

    The United States' program in inertial confinement fusion (ICF) is described in this paper, with emphasis on the studies of the use of intense high energy beams of heavy ions to provide the power and energy needed to initiate thermonuclear burn. Preliminary calculations of the transport of intense ion beams in an electrostatic quadrupole focussing structure are discussed.

  16. Focused ion beam micromilling and articles therefrom

    DOEpatents

    Lamartine, B.C.; Stutz, R.A.

    1998-06-30

    An ultrahigh vacuum focused ion beam micromilling apparatus and process are disclosed. Additionally, a durable data storage medium using the micromilling process is disclosed, the durable data storage medium capable of storing, e.g., digital or alphanumeric characters as well as graphical shapes or characters. 6 figs.

  17. Depth-dose relations for heavy ion beams

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.

    1977-01-01

    Radiation transport of heavy ions in matter is of interest to radiological protection in space and high-altitude aircraft. In addition, heavy ion beams are expected to be of advantage in radiotherapy since their characteristic Bragg curve allows a relative reduction of the dose in reaching a tumor site and the near elimination of exposure beyond the tumor region as the beam exits the body. Furthermore, the radioresistance of tumorous cells due to their hypoxic state may be reduced or eliminated by the high specific ionization of heavy ion beams. The depth-dose distribution of heavy ion beams consists of energy deposited by the attenuated primary beam with its characteristic Bragg curve and a relatively unstructured background due to secondary radiations produced in nuclear reactions. As the ion mass increases, the secondary contribution becomes more structured and may add significantly to the Bragg peak of the primary ions. The result for heavy ions (z greater than 20) is a greatly broadened Bragg peak region, especially in comparison to straggling effects, which may prove to be of importance in radiotherapy and biomedical research.

  18. Intense Pulsed Heavy Ion Beam Technology

    NASA Astrophysics Data System (ADS)

    Masugata, Katsumi; Ito, Hiroaki

    Development of intense pulsed heavy ion beam accelerator technology is described for the application of materials processing. Gas puff plasma gun and vacuum arc discharge plasma gun were developed as an active ion source for magnetically insulated pulsed ion diode. Source plasma of nitrogen and aluminum were successfully produced with the gas puff plasma gun and the vacuum arc plasma gun, respectively. The ion diode was successfully operated with gas puff plasma gun at diode voltage 190 kV, diode current 2.2 kA and nitrogen ion beam of ion current density 27 A/cm2 was obtained. The ion composition was evaluated by a Thomson parabola spectrometer and the purity of the nitrogen ion beam was estimated to be 86%. The diode also operated with aluminum ion source of vacuum arc plasma gun. The ion diode was operated at 200 kV, 12 kA, and aluminum ion beam of current density 230 A/cm2 was obtained. The beam consists of aluminum ions (Al(1-3)+) of energy 60-400 keV, and protons (90-130 keV), and the purity was estimated to be 89 %. The development of the bipolar pulse accelerator (BPA) was reported. A double coaxial type bipolar pulse generator was developed as the power supply of the BPA. The generator was tested with dummy load of 7.5 ohm, bipolar pulses of -138 kV, 72 ns (1st pulse) and +130 kV, 70 ns (2nd pulse) were succesively generated. By applying the bipolar pulse to the drift tube of the BPA, nitrogen ion beam of 2 A/cm2 was observed in the cathode, which suggests the bipolar pulse acceleration.

  19. Aqueous corrosion of ion beam mixed Ta films on 13% chromium steel

    NASA Astrophysics Data System (ADS)

    Huang, N. K.

    1993-06-01

    The effect of aqueous corrosion of ion beam mixed Ta on 13 wt% chromium steel in 1M H 2SO 4 or 0.1N NaCl solution has been investigated. The results show that Ta ion mixing can evidently improve the corrosion resistance of chromium steel. The corrosion resistances of the ion beam mixed Ta films are affected by the nature of the substrates. Some suggestions are proposed according to microanalysis results by using SEM, RBS and XPS techniques.

  20. Ion beam induced nanosized Ag metal clusters in glass

    NASA Astrophysics Data System (ADS)

    Mahnke, H.-E.; Schattat, B.; Schubert-Bischoff, P.; Novakovic, N.

    2006-04-01

    Silver metal clusters have been formed in soda lime glass by high-energy heavy-ion irradiation at ISL. The metal cluster formation was detected with X-ray absorption spectroscopy (EXAFS) in fluorescence mode, and the shape of the clusters was imaged with transmission electron microscopy. While annealing in reducing atmosphere alone, leads to the formation of metal clusters in Ag-containing glasses, where the Ag was introduced by ion-exchange, such clusters are not very uniform in size and are randomly distributed over the Ag-containing glass volume. Irradiation with 600-MeV Au ions followed by annealing, however, results in clusters more uniform in size and arranged in chains parallel to the direction of the ion beam.

  1. Optics of ion beams for the neutral beam injection system on HL-2A Tokamak

    SciTech Connect

    Zou, G. Q.; Lei, G. J.; Cao, J. Y.; Duan, X. R.

    2012-07-15

    The ion beam optics for the neutral beam injection system on HL-2A Tokomak is studied by two- dimensional numerical simulation program firstly, where the emitting surface is taken at 100 Debye lengths from the plasma electrode. The mathematical formulation, computation techniques are described. Typical ion orbits, equipotential contours, and emittance diagram are shown. For a fixed geometry electrode, the effect of plasma density, plasma potential and plasma electron temperature on ion beam optics is examined, and the calculation reliability is confirmed by experimental results. In order to improve ion beam optics, the application of a small pre-acceleration voltage ({approx}100 V) between the plasma electrode and the arc discharge anode is reasonable, and a lower plasma electron temperature is desired. The results allow optimization of the ion beam optics in the neutral beam injection system on HL-2A Tokomak and provide guidelines for designing future neutral beam injection system on HL-2M Tokomak.

  2. Optics of ion beams for the neutral beam injection system on HL-2A Tokamak.

    PubMed

    Zou, G Q; Lei, G J; Cao, J Y; Duan, X R

    2012-07-01

    The ion beam optics for the neutral beam injection system on HL-2A Tokomak is studied by two- dimensional numerical simulation program firstly, where the emitting surface is taken at 100 Debye lengths from the plasma electrode. The mathematical formulation, computation techniques are described. Typical ion orbits, equipotential contours, and emittance diagram are shown. For a fixed geometry electrode, the effect of plasma density, plasma potential and plasma electron temperature on ion beam optics is examined, and the calculation reliability is confirmed by experimental results. In order to improve ion beam optics, the application of a small pre-acceleration voltage (∼100 V) between the plasma electrode and the arc discharge anode is reasonable, and a lower plasma electron temperature is desired. The results allow optimization of the ion beam optics in the neutral beam injection system on HL-2A Tokomak and provide guidelines for designing future neutral beam injection system on HL-2M Tokomak. PMID:22852685

  3. Ion-beam sputtering increases solar-cell efficiency

    NASA Technical Reports Server (NTRS)

    Burk, D. E.; Dubow, J. B.; Sites, R. R.

    1977-01-01

    Ion-beam sputtering, fabrication of oxide-semiconductor-on-silicon (OSOS) solar cells, results in cells of 12% efficiency. Ion-beam sputtering technique is compatible with low-cost continuous fabrication and requires no high-temperature processing.

  4. Cluster Ion Beam Induced Nano Metallic Rippled Structures for Localized Surface Plasmon Resonance (LSPR) Based Sensors

    NASA Astrophysics Data System (ADS)

    Saleem, Iram; Tilakaratne, Buddhi; He, Yanzhi; Nzumbe, Epie; Wijesundera, Dharshana; Chen, Quark; Chu, Wei-Kan

    2015-03-01

    Localized surface plasmon resonance (LSPR) based bio sensors have a high sensitivity and exploit a label free real time analytical detection mechanism. We have produced plasmonic nano-structured substrates by cluster ion beam irradiation of thin gold films and have studied their effectiveness as potential plasmonic sensors. By adsorbing a mono-layer of thiolated organic compounds on the surface of these substrates we identified the shift in the LSPR peaks triggered by the change of dielectric function in the neighborhood of the structures. These plasmonic nano-metallic structures can be utilized to observe the change of LSPR resonance frequency due to adsorption, re-adsorption and reactions taking place on the surface that can potentially be mapped to reaction mechanics

  5. Ion beam sputter etching and deposition of fluoropolymers

    NASA Technical Reports Server (NTRS)

    Banks, B. A.; Sovey, J. S.; Miller, T. B.; Crandall, K. S.

    1978-01-01

    Fluoropolymer etching and deposition techniques including thermal evaporation, RF sputtering, plasma polymerization, and ion beam sputtering are reviewed. Etching and deposition mechanisms and material characteristics are discussed. Ion beam sputter etch rates for polytetrafluoroethylene (PTFE) were determined as a function of ion energy, current density and ion beam power density. Peel strengths were measured for epoxy bonds to various ion beam sputtered fluoropolymers. Coefficients of static and dynamic friction were measured for fluoropolymers deposited from ion bombarded PTFE.

  6. Ion beam sputter etching and deposition of fluoropolymers

    NASA Technical Reports Server (NTRS)

    Banks, B. A.; Sovey, J. S.; Miller, T. B.; Crandall, K. S.

    1978-01-01

    Fluoropolymer etching and deposition techniques including thermal evaporation, RF sputtering, plasma polymerization, and ion beam sputtering are reviewed. Etching and deposition mechanism and material characteristics are discussed. Ion beam sputter etch rates for polytetrafluoroethylene (PTFE) were determined as a function of ion energy, current density and ion beam power density. Peel strengths were measured for epoxy bonds to various ion beam sputtered fluoropolymers. Coefficients of static and dynamic friction were measured for fluoropolymers deposited from ion bombarded PTFE.

  7. Effect of ion irradiation on the stability of amorphous Ge 2Sb 2Te 5 thin films

    NASA Astrophysics Data System (ADS)

    De Bastiani, R.; Piro, A. M.; Crupi, I.; Grimaldi, M. G.; Rimini, E.

    2008-05-01

    The archival life of phase-change memories (PCM) is determined by the thermal stability of amorphous phase in a crystalline matrix. In this paper, we report the effect of ion beam irradiation on the crystallization kinetics of amorphous Ge2Sb2Te5 alloy (GST). The transition rate of amorphous GST films was measured by in situ time resolved reflectivity (TRR). The amorphous to crystal transformation time decreases considerably in irradiated amorphous GST samples when ion fluence increases. The stability of amorphous Ge2Sb2Te5 thin films subjected to ion irradiation is discussed in terms of the free energy variation of the amorphous state because of damage accumulation.

  8. Cellular track model for study of heavy ion beams

    NASA Technical Reports Server (NTRS)

    Shinn, Judy L.; Katz, Robert; Cucinotta, Francis A.; Wilson, John W.; Ngo, Duc M.

    1993-01-01

    Track theory is combined with a realistic model of a heavy ion beam to study the effects of nuclear fragmentation on cell survival and biological effectiveness. The effects of secondary reaction products are studied as a function of depth in a water column. Good agreement is found with experimental results for the survival of human T-l cells exposed to monoenergetic carbon, neon, and argon beams under aerobic and hypoxia conditions. The present calculation, which includes the effect of target fragmentation, is a significant improvement over an earlier calculation because of the use of a vastly improved beam model with no change in the track theory or cellular response parameters.

  9. Ion Beam Analysis applied to laser-generated plasmas

    NASA Astrophysics Data System (ADS)

    Cutroneo, M.; Macková, A.; Havranek, V.; Malinsky, P.; Torrisi, L.; Kormunda, M.; Barchuk, M.; Ullschmied, J.; Dudzak, R.

    2016-04-01

    This paper presents the research activity on Ion Beam Analysis methods performed at Tandetron Laboratory (LT) of the Institute of Nuclear Physics AS CR, Rez, Czech Republic. Recently, many groups are paying attention to implantation by laser generated plasma. This process allows to insert a controllable amount of energetic ions into the surface layers of different materials modifying the physical and chemical properties of the surface material. Different substrates are implanted by accelerated ions from plasma through terawatt iodine laser, at nominal intensity of 1015 W/cm2, at the PALS Research Infrastructure AS CR, in the Czech Republic. This regime of the laser matter interaction generates, multi-MeV proton beams, and multi-charged ions that are tightly confined in time (hundreds ps) and space (source radius of a few microns). These ion beams have a much lower transverse temperature, a much shorter duration and a much higher current than those obtainable from conventional accelerators. The implementation of protons and ions acceleration driven by ultra-short high intensity lasers is exhibited by adopting suitable irradiation conditions as well as tailored targets. An overview of implanted targets and their morphological and structural characterizations is presented and discussed.

  10. Ion beam neutralization using three-dimensional electron confinement by surface modification of magnetic poles

    NASA Astrophysics Data System (ADS)

    Nicolaescu, Dan; Sakai, Shigeki; Gotoh, Yasuhito; Ishikawa, Junzo

    2011-07-01

    Advanced implantation systems used for semiconductor processing require transportation of quasi-parallel ion beams, which have low energy ( 11B +, 31P +, 75As +, Eion=200-1000 eV). Divergence of the ion beam due to space charge effects can be compensated through injection of electrons into different regions of the ion beam. The present study shows that electron confinement takes place in regions of strong magnetic field such as collimator magnet provided with surface mirror magnetic fields and that divergence of the ion beam passing through such regions is largely reduced. Modeling results have been obtained using Opera3D/Tosca/Scala. Electrons may be provided by collision between ions and residual gas molecules or may be injected by field emitter arrays. The size of surface magnets is chosen such as not to disturb ion beam collimation, making the approach compatible with ion beam systems. Surface magnets may form thin magnetic layers with thickness h=0.5 mm or less. Conditions for spacing of surface magnet arrays for optimal electron confinement are outlined.

  11. Ion beam driven warm dense matter experiments

    NASA Astrophysics Data System (ADS)

    Bieniosek, F. M.; Ni, P. A.; Leitner, M.; Roy, P. K.; More, R.; Barnard, J. J.; Kireeff Covo, M.; Molvik, A. W.; Yoneda, H.

    2007-11-01

    We report plans and experimental results in ion beam-driven warm dense matter (WDM) experiments. Initial experiments at LBNL are at 0.3-1 MeV K+ beam (below the Bragg peak), increasing toward the Bragg peak in future versions of the accelerator. The WDM conditions are envisioned to be achieved by combined longitudinal and transverse neutralized drift compression to provide a hot spot on the target with a beam spot size of about 1 mm, and pulse length about 1-2 ns. The range of the beams in solid matter targets is about 1 micron, which can be lengthened by using porous targets at reduced density. Initial experiments include an experiment to study transient darkening at LBNL; and a porous target experiment at GSI heated by intense heavy-ion beams from the SIS 18 storage ring. Further experiments will explore target temperature and other properties such as electrical conductivity to investigate phase transitions and the critical point.

  12. Rhenium ion beam for implantation into semiconductors

    SciTech Connect

    Kulevoy, T. V.; Seleznev, D. N.; Alyoshin, M. E.; Kraevsky, S. V.; Yakushin, P. E.; Khoroshilov, V. V.; Gerasimenko, N. N.; Smirnov, D. I.; Fedorov, P. A.; Temirov, A. A.

    2012-02-15

    At the ion source test bench in Institute for Theoretical and Experimental Physics the program of ion source development for semiconductor industry is in progress. In framework of the program the Metal Vapor Vacuum Arc ion source for germanium and rhenium ion beam generation was developed and investigated. It was shown that at special conditions of ion beam implantation it is possible to fabricate not only homogenous layers of rhenium silicides solid solutions but also clusters of this compound with properties of quantum dots. At the present moment the compound is very interesting for semiconductor industry, especially for nanoelectronics and nanophotonics, but there is no very developed technology for production of nanostructures (for example quantum sized structures) with required parameters. The results of materials synthesis and exploration are presented.

  13. Optical Faraday Cup for Heavy Ion Beams

    SciTech Connect

    Bieniosek, Frank; Bieniosek, F.M.; Eylon, S.; Roy, P.K.; Yu, S.S.

    2007-06-25

    We have been using alumina scintillators for imaging beams in heavy-ion beam fusion experiments in 2 to 4 transverse dimensions [1]. The scintillator has a limited lifetime under bombardment by the heavy ion beams. As a possible replacement for the scintillator, we are studying the technique of imaging the beam on a gas cloud. A gas cloud for imaging the beam may be created on a solid hole plate placed in the path of the beam, or by a localized gas jet. It is possible to image the beam using certain fast-quenching optical lines that closely follow beam current density and are independent of gas density. We describe this technique and show preliminary experimental data. This approach has promise to be a new fast beam current diagnostic on a nanosecond time scale.

  14. Ion Beam Scattering by Background Helium

    NASA Astrophysics Data System (ADS)

    Grillet, Anne; Hughes, Thomas; Boerner, Jeremiah

    2015-11-01

    The presence of background gases can cause charged particle beams to become more diffuse due to scattering. Calculations for the transport of an ion beam have been performed using Aleph, a particle-in-cell plasma modeling code, and verified against a general envelop equation for charged particle beams. We have investigated the influence of background helium on the coherence and transmitted current of the ion beam. Collisions between ions and neutral particles were calculated assuming isotropic elastic scattering. Since this tends to predict larger scattering angles than are expected at high energies, these are conservative estimates for beam scattering. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration.

  15. Scanning He+ Ion Beam Microscopy and Metrology

    SciTech Connect

    Joy, David C.

    2011-11-10

    The CD-SEM has been the tool of choice for the imaging and metrology of semiconductor devices for the past three decades but now, with critical dimensions at the nanometer scale, electron beam instruments can no longer deliver adequate performance. A scanning microscope using a He+ ion beam offers superior resolution and depth of field, and provides enhanced imaging contrast. Device metrology performed using ion beam imaging produces data which is comparable to or better than that from a conventional CD-SEM although there are significant differences in the experimental conditions required and in the details of image formation. The charging generated by a He+ beam, and the sample damage that it can cause, require care in operation but are not major problems.

  16. Nanodosimetric characterization of ion beams

    NASA Astrophysics Data System (ADS)

    Bug, Marion Ute; Hilgers, Gerhard; Baek, Woon Yong; Rabus, Hans

    2014-08-01

    The characterization of particle track structure is essential for an estimation of radiobiological effects, particularly in the case of densely ionizing radiation. The particle track structure can be characterized by nanodosimetric quantities which are measurable by means of a nanodosimeter. Results obtained from experiments with the nanodosimeter can be used to validate track structure simulations, which are essential for estimating track structure parameters in biological material. For this purpose, the dedicated Monte Carlo code PTra has been developed to simulate the nanodosimeter setup as well as nanometric targets consisting of water. Recently, electron-impact cross section data of DNA constituents measured at PTB were implemented into PTra. A calculation of nanodosimetric quantities in DNA-analog media shows considerable differences to results obtained in water medium, particularly for electron energies lower than 200 eV. These discrepancies become more considerable when nanodosimetric quantities are used to estimate biological effects. This paper aims to provide an overview of the present status of nanodosimetry, focusing on the experimental and simulation work at PTB. Furthermore, the suitability of simple models directly linking nanodosimetric track structure characteristics and radiobiological effectiveness is discussed.

  17. Ion-beam nitriding of steels

    NASA Technical Reports Server (NTRS)

    Salik, J.

    1985-01-01

    The application of the ion beam technique to the nitriding of steels is described. It is indicated that the technique can be successfully applied to nitriding. Some of the structural changes obtained by this technique are similar to those obtained by ion nitriding. The main difference is the absence of the iron nitride diffraction lines. It is found that the dependence of the resultant microhardness on beam voltage for super nitralloy is different from that of 304 stainless steel.

  18. Ion-beam nitriding of steels

    NASA Technical Reports Server (NTRS)

    Salik, J.

    1984-01-01

    The application of the ion beam technique to the nitriding of steels is described. It is indicated that the technique can be successfully applied to nitriding. Some of the structural changes obtained by this technique are similar to those obtained by ion nitriding. The main difference is the absence of the iron nitride diffraction lines. It is found that the dependence of the resultant microhardness on beam voltage for super nitralloy is different from that of 304 stainless steel.

  19. Ion beam figuring system in NUDT

    NASA Astrophysics Data System (ADS)

    Zhou, Lin; Xie, Xuhui; Dai, Yifan; Jiao, Changjun; Li, Shengyi

    2007-12-01

    Ion beam figuring (IBF) is an optical fabrication technique that provides highly deterministic process to correct surface figure error of previously polished surfaces by using a directed, inert and neutralized ion beam to physically sputter material from the optic surface. Recently, an ion beam figuring system KDIFS-500 has been designed and built in National University of Defense Technology (NUDT) of the P.R. China. KDIFS-500 is capable of processing workpiece up to Φ500mm. Line scanning process was discussed in detail for estimating the parameters of the beam removal function (BRF) in process. Experiments were conducted to demonstrate that the BRF increases gradually in process and by employing a stability control, the BRF can be kept stable in process. Finally, a Φ95 mm plano optical sample of CVD coated SiC substrate has been figured in two process iterations for demonstrating the correction capability of the KDIFS-500. Their figure convergence ratios reached 5.8 and 2.1 respectively. The actual figure residual errors were basically consistent with the predicted error. These consistencies indicated that the IBF processes on KDIFS-500 are predictable deterministic processes.

  20. Physics of ion beam cancer therapy: A multiscale approach

    NASA Astrophysics Data System (ADS)

    Solov'Yov, Andrey V.; Surdutovich, Eugene; Scifoni, Emanuele; Mishustin, Igor; Greiner, Walter

    2009-01-01

    We propose a multiscale approach to understand the physics related to ion-beam cancer therapy. It allows the calculation of the probability of DNA damage as a result of irradiation of tissues with energetic ions, up to 430MeV/u . This approach covers different scales, starting from the large scale, defined by the ion stopping, followed by a smaller scale, defined by secondary electrons and radicals, and ending with the shortest scale, defined by interactions of secondaries with the DNA. We present calculations of the probabilities of single and double strand breaks of DNA, suggest a way to further expand such calculations, and also make some estimates for glial cells exposed to radiation.

  1. Fundamental aspects on ion-beam surface modification: defect production and migration processes

    SciTech Connect

    Rehn, L.E.; Averback, R.S.; Okamoto, P.R.

    1984-09-01

    Ion-beam modification of metals is generating increasing scientific interest not only because it has exciting technological potential, but also because it has raised fundamental questions concerning radiation-induced diffusion processes. In addition to the implanted species, several defect production and migration mechanisms contribute to changes in the near-surface composition of an alloy during ion bombardment, e.g., atoms exchange positions via displacements and replacement sequences; preferential sputtering effects arise; radiation-enhanced diffusion and radiation-induced segregation occur. The latter two defect migration mechanisms are of particular significance since they can alter the composition to depths which are much greater than the implanted ion range. By altering various parameters such as irradiation temperature, ion mass, energy, and current density, and initial alloying distributions, a rich variety of near-surface composition profiles can be created. We have utilized changes in ion mass and energy, and irradiation temperature to distinguish defect production from defect migration effects. Experimental results are presented which provide a guide to the relative efficiencies of different mechanisms under various irradiation conditions. 46 references.

  2. Method of cold welding using ion beam technology

    NASA Technical Reports Server (NTRS)

    Sater, B. L. (Inventor)

    1981-01-01

    A method for cold welding metal joints is described. In order to remove the contamination layer on the surface of the metal, an ion beam generator is used in a vacuum environment. A gas, such as xenon or argon, is ionized and accelerated toward the metal surface. The beam of gas effectively sputters away the surface oxides and contamination layer so that clean underlying metal is exposed in the area to be welded. The use of this method allows cold welding with minimal deformation. Both similar and dissimilar metals can be cold welded with this method.

  3. Physics design of linear accelerators for intense ion beams

    SciTech Connect

    Wangler, T.P.

    1988-01-01

    Advances in the physics and technology of linear accelerators for intense ion beams are leading to new methods for the design of such machines. The physical effects that limit beam current and brightness are better understood and provide the criteria for choosing the rf frequency and for determining optimum focusing configurations to control longitudinal and transverse emittances. During the past decade, the use of developments such as the radio-frequency quadrupole, multiple beams, funneling, ramped-field linac tanks, and self-matching linac tanks is leading to greater design flexibility and improved performance capabilities. 39 refs., 3 tabs., 1 fig.

  4. Effects of irradiated biodegradable polymer in endothelial cell monolayer formation

    NASA Astrophysics Data System (ADS)

    Arbeitman, Claudia R.; del Grosso, Mariela F.; Behar, Moni; García Bermúdez, Gerardo

    2013-11-01

    In this work we study cell adhesion, proliferation and cell morphology of endothelial cell cultured on poly-L-lactide acid (PLLA) modified by heavy ion irradiation. Thin films of PLLA samples were irradiated with sulfur (S) at energies of 75 MeV and gold (Au) at 18 MeV ion-beams. Ion beams were provided by the Tandar (Buenos Aires, Argentina) and Tandetron (Porto Alegre, Brazil) accelerators, respectively. The growth of a monolayer of bovine aortic endothelial cells (BAEC) onto unirradiated and irradiated surfaces has been studied by in vitro techniques in static culture. Cell viability and proliferation increased on modified substrates. But the results on unirradiated samples, indicate cell death (necrosis/apoptosis) with the consequent decrease in proliferation. We analyzed the correlation between irradiation parameters and cell metabolism and morphology.

  5. Site-controlled fabrication of Ga nanodroplets by focused ion beam

    SciTech Connect

    Xu, Xingliang; Wang, Zhiming M.; Wu, Jiang; Li, Handong; Zhou, Zhihua; Wang, Xiaodong

    2014-03-31

    Ga droplets are created by focused ion beam irradiation of GaAs surface. We report that ordered Ga droplets can be formed on the GaAs surface without any implantation damage. The droplets are characterized with bigger sizes than those droplets formed on damaged area. These aligned Ga droplets are formed via the migration of Ga atoms from ion irradiation area to the edge of undamaged GaAs surface and further nucleation into droplets. The morphological evolution and size distribution of these nanodroplets are investigated systematically with different beam irradiation time and incident angles. Based on this method, well positioned Ga nanodroplets, such as chains, are achieved by using focus ion beam patterning. The controllable assembly of droplets on undamaged semiconductor surface can be used to fabricate templates, to fabricate quantum structures and quantum devices by droplet epitaxy technique.

  6. Ion beam enhancement in magnetically insulated ion diodes for high-intensity pulsed ion beam generation in non-relativistic mode

    NASA Astrophysics Data System (ADS)

    Zhu, X. P.; Zhang, Z. C.; Pushkarev, A. I.; Lei, M. K.

    2016-01-01

    High-intensity pulsed ion beam (HIPIB) with ion current density above Child-Langmuir limit is achieved by extracting ion beam from anode plasma of ion diodes with suppressing electron flow under magnetic field insulation. It was theoretically estimated that with increasing the magnetic field, a maximal value of ion current density may reach nearly 3 times that of Child-Langmuir limit in a non-relativistic mode and close to 6 times in a highly relativistic mode. In this study, the behavior of ion beam enhancement by magnetic insulation is systematically investigated in three types of magnetically insulated ion diodes (MIDs) with passive anode, taking into account the anode plasma generation process on the anode surface. A maximal enhancement factor higher than 6 over the Child-Langmuir limit can be obtained in the non-relativistic mode with accelerating voltage of 200-300 kV. The MIDs differ in two anode plasma formation mechanisms, i.e., surface flashover of a dielectric coating on the anode and explosive emission of electrons from the anode, as well as in two insulation modes of external-magnetic field and self-magnetic field with either non-closed or closed drift of electrons in the anode-cathode (A-K) gap, respectively. Combined with ion current density measurement, energy density characterization is employed to resolve the spatial distribution of energy density before focusing for exploring the ion beam generation process. Consistent results are obtained on three types of MIDs concerning control of neutralizing electron flows for the space charge of ions where the high ion beam enhancement is determined by effective electron neutralization in the A-K gap, while the HIPIB composition of different ion species downstream from the diode may be considerably affected by the ion beam neutralization during propagation.

  7. Simulation of ion beam scattering in a gas stripper

    NASA Astrophysics Data System (ADS)

    Maxeiner, Sascha; Suter, Martin; Christl, Marcus; Synal, Hans-Arno

    2015-10-01

    Ion beam scattering in the gas stripper of an accelerator mass spectrometer (AMS) enlarges the beam phase space and broadens its energy distribution. As the size of the injected beam depends on the acceleration voltage through phase space compression, the stripper becomes a limiting factor of the overall system transmission especially for low energy AMS system in the sub MV region. The spatial beam broadening and collisions with the accelerator tube walls are a possible source for machine background and energy loss fluctuations influence the mass resolution and thus isotope separation. To investigate the physical processes responsible for these effects, a computer simulation approach was chosen. Monte Carlo simulation methods are applied to simulate elastic two body scattering processes in screened Coulomb potentials in a (gas) stripper and formulas are derived to correctly determine random collision parameters and free path lengths for arbitrary (and non-homogeneous) gas densities. A simple parametric form for the underlying scattering cross sections is discussed which features important scaling behaviors. An implementation of the simulation was able to correctly model the data gained with the TANDY AMS system at ETH Zurich. The experiment covered transmission measurements of uranium ions in helium and beam profile measurements after the ion beam passed through the He-stripper. Beam profiles measured up to very high stripper densities could be understood in full system simulations including the relevant ion optics. The presented model therefore simulates the fundamental physics of the interaction between an ion beam and a gas stripper reliably. It provides a powerful and flexible tool for optimizing existing AMS stripper geometries and for designing new, state of the art low energy AMS systems.

  8. Cluster Size Dependence of Etching by Reactive Gas Cluster Ion Beams

    SciTech Connect

    Toyoda, Noriaki; Yamada, Iaso

    2008-11-03

    Mass-selected reactive gas cluster ion beams (GCIB) were formed using a permanent magnetic filter. Irradiations of CO{sub 2} GCIB on amorphous carbon films and irradiations of SF{sub 6} and SF{sub 6}/Ar mixed GCIB on Si surfaces were performed to study the cluster size dependence on etching yields by reactive GCIB. The reactive sputtering yield of carbon by CO{sub 2} GCIB was almost ten times higher than that by Ar GCIB. In the case of (CO{sub 2}){sub 20000} GCIB with energy of 20 keV (1 eV/atom), it showed the high sputtering yield of 200 atoms/ion, however, there was little crater formation on the carbon surface. It is thought that very soft etching without crater formation would take place in this condition. In the case of SF{sub 6} GCIB on Si, the etching depth of Si showed maximum value when the fraction of SF{sub 6} to Ar was around 50%. As the etching yield was higher than pure SF{sub 6} GCIB, there was a strong ion assisted etching effects in the case of Ar/SF{sub 6} mixed cluster ion irradiations.

  9. Thermoacoustic imaging using heavy ion beams

    SciTech Connect

    Claytor, T.N.; Tesmer, J.R.; Deemer, B.C.; Murphy, J.C.

    1995-10-01

    Ion beams have been used for surface modification, semiconductor device fabrication and for material analysis, which makes ion-material interactions of significant importance. Ion implantation will produce new compositions near the surface by ion mixing or directly by implanting desired ions. Ions exchange their energy to the host material as they travel into the material by several different processes. High energy ions ionize the host atoms before atomic collisions transfer the remaining momentum and stop the incident ion. As they penetrate the surface, the low energy ions ionize the host atoms, but also have a significantly large momentum transfer mechanism near the surface of the material. This leads to atoms, groups of atoms and electrons being ejected from the surface, which is the momentum transfer process of sputtering. This talk addresses the acoustic waves generated during ion implantation using modulated heavy ion beams. The mechanisms for elastic wave generation during ion implantation, in the regimes where sputtering is significant and where implantation is dominant and sputtering is negligible, has been studied. The role of momentum transfer and thermal energy production during ion implantation was compared to laser generated elastic waves in an opaque solid as a reference, since laser generated ultrasound has been extensively studied and is fairly well understood. The thermoelastic response dominated in both high and low ion energy regimes since, apparently, more energy is lost to thermal heat producing mechanisms than momentum transfer processes. The signal magnitude was found to vary almost linearly with incident energy as in the laser thermoelastic regime. The time delays for longitudinal and shear waves-were characteristic of those expected for a purely thermal heating source. The ion beams are intrinsically less sensitive to the albedo of the surface.

  10. Plasma formed ion beam projection lithography system

    SciTech Connect

    Leung, Ka-Ngo; Lee, Yung-Hee Yvette; Ngo, Vinh; Zahir, Nastaran

    2002-01-01

    A plasma-formed ion-beam projection lithography (IPL) system eliminates the acceleration stage between the ion source and stencil mask of a conventional IPL system. Instead a much thicker mask is used as a beam forming or extraction electrode, positioned next to the plasma in the ion source. Thus the entire beam forming electrode or mask is illuminated uniformly with the source plasma. The extracted beam passes through an acceleration and reduction stage onto the resist coated wafer. Low energy ions, about 30 eV, pass through the mask, minimizing heating, scattering, and sputtering.

  11. High current ion beam transport using solenoids

    SciTech Connect

    Hollinger, R.; Spaedtke, P.

    2008-02-15

    In the framework of the future project FAIR several upgrade programs and construction of new facilities are in progress such as the U{sup 4+} upgrade for the existing high current injector and the new 70 MeV proton injector. For both injectors solenoids in the low energy beam transport section are foreseen to inject the beam into the following rf accelerator. The paper presents beam quality measurements of high current ion beams behind a solenoid using a slit-grid emittance measurement device, viewing targets, and a pepper pot measurement device at the high current test bench at GSI.

  12. Physics with fast molecular-ion beams

    SciTech Connect

    Kanter, E.P.

    1980-01-01

    Fast (MeV) molecular-ion beams provide a unique source of energetic projectile nuclei which are correlated in space and time. The recognition of this property has prompted several recent investigations of various aspects of the interactions of these ions with matter. High-resolution measurements on the fragments resulting from these interactions have already yielded a wealth of new information on such diverse topics as plasma oscillations in solids and stereochemical structures of molecular ions as well as a variety of atomic collision phenomena. The general features of several such experiments will be discussed and recent results will be presented.

  13. Ion-beam cleaning for cold welds

    NASA Technical Reports Server (NTRS)

    Slater, B. L.

    1980-01-01

    1000 eV beam bombarding metal surfaces to be joined removes oxides and contaminants at rate of several atomic layers per second for current density of 1 mA/squ. cm. Clean surfaces can then be joined by squeezing them together. With ion-beam cleaning, mating force for strong bond is low enough to cause only 1% deformation. Conventional cold-welding requires about 70% deformation for bonding. Technique was tested successfully on aluminum to aluminum welds, copper to copper, copper to aluminum, copper to nickel, and silver to iron. Base metals failed before welds in tear test.

  14. Spectrometer for cluster ion beam induced luminescence

    SciTech Connect

    Ryuto, H. Sakata, A.; Takeuchi, M.; Takaoka, G. H.; Musumeci, F.

    2015-02-15

    A spectrometer to detect the ultra-weak luminescence originated by the collision of cluster ions on the surfaces of solid materials was constructed. This spectrometer consists of 11 photomultipliers with band-pass interference filters that can detect the luminescence within the wavelength ranging from 300 to 700 nm and of a photomultiplier without filter. The calibration of the detection system was performed using the photons emitted from a strontium aluminate fluorescent tape and from a high temperature tungsten filament. Preliminary measurements show the ability of this spectrometer to detect the cluster ion beam induced luminescence.

  15. Enhancement of exchange bias and training effect in ion-beam sputtered Fe{sub 46}Mn{sub 54}/Ni{sub 81}Fe{sub 19} bilayers

    SciTech Connect

    Fulara, Himanshu; Chaudhary, Sujeet Kashyap, Subhash C.; Granville, Simon

    2014-01-28

    We present a remarkable enhancement by 300% of the exchange-bias field at room temperature, without affecting the coercivity value, via optimum magnetic annealing (250 °C/3 kOe) in ion-beam sputtered FeMn(30 nm)/NiFe(10 nm) bilayers. This specific behavior has been attributed to a higher degree of γ-FeMn(111) orientation that offers more interfacial FeMn moments to get pinned with the moments of the adjacent NiFe layer. Unlike the absence of training effect at room temperature, a pronounced training effect and an accompanying magnetization reversal asymmetry are evidenced upon field cooling below 50 K due to the presence of biaxial exchange induced anisotropy across the interdiffused FeMn/NiFe interface. The present findings not only have technological significance but also are of relevance to the understanding of interfacial spin disorder and frustration in these exchange-biased systems.

  16. Study of focused-ion-beam-induced structural and compositional modifications in nanoscale bilayer systems by combined grazing incidence x ray reflectivity and fluorescence

    SciTech Connect

    Arac, Erhan; Burn, David M.; Eastwood, David S.; Atkinson, Del; Hase, Thomas P. A.

    2012-02-15

    A detailed analysis of the structural and compositional changes in NiFe/Au bilayers induced by a focused ion beam (FIB) is presented. NiFe/Au bilayers with different thickness were irradiated with a focused 30 keV Ga{sup +} ion beam, and the evaluation of the individual layers and interfaces were investigated systematically as a function of a broad range of irradiation fluence using grazing incidence x ray reflectivity (GIXRR) and angular dependent x ray fluorescence (ADXRF) techniques carried out at synchrotron radiation sources. Experimental data were collected from 1.3 mm x 4.5 mm structures, and irradiation of such a broad areas with a 100-nm-wide focused ion beam is a challenging task. Two irradiation regimes were identified: For Ga{sup +} fluences < 15.6 x 10{sup 14} ion/cm{sup 2} (low dose regime), the main influence of the focused ion beam is on the interface and, beyond this dose (high dose regime), sputtering effects and ion implantation becomes significant, eventually causing amorphization of the bilayer system. The broadening of the NiFe/Au interface occurs even at the lowest dose, and above a critical fluence ({Phi} = 1.56 x 10{sup 14} ion/cm{sup 2}) can be represented by an interfacial-intermixed layer (Ni{sub x}Fe{sub y}Au{sub (1-x-y)}; x = 0.5-0.6, y 0.1-0.15) formed between the NiFe and Au layers. The thickness of this layer increases with irradiation fluence in the low dose regime. A linear relationship is found between the squared intermixing length and irradiation fluence, indicating that FIB-induced mixing is diffusion controlled. The ballistic model fails to describe FIB-induced intermixing, indicating that thermodynamical factors, which might be originated from FIB specific features, should be taken into account. Despite the complexity of the chemical and structural formation, good agreement between the experiment and theory highlights the functionality of the combined GIXRR and ADXRF techniques for studying intermixing in high resolution.

  17. Study of focused-ion-beam-induced structural and compositional modifications in nanoscale bilayer systems by combined grazing incidence x ray reflectivity and fluorescence

    NASA Astrophysics Data System (ADS)

    Arac, Erhan; Burn, David M.; Eastwood, David S.; Hase, Thomas P. A.; Atkinson, Del

    2012-02-01

    A detailed analysis of the structural and compositional changes in NiFe/Au bilayers induced by a focused ion beam (FIB) is presented. NiFe/Au bilayers with different thickness were irradiated with a focused 30 keV Ga+ ion beam, and the evaluation of the individual layers and interfaces were investigated systematically as a function of a broad range of irradiation fluence using grazing incidence x ray reflectivity (GIXRR) and angular dependent x ray fluorescence (ADXRF) techniques carried out at synchrotron radiation sources. Experimental data were collected from 1.3 mm × 4.5 mm structures, and irradiation of such a broad areas with a 100-nm-wide focused ion beam is a challenging task. Two irradiation regimes were identified: For Ga+ fluences < 15.6 × 1014 ion/cm2 (low dose regime), the main influence of the focused ion beam is on the interface and, beyond this dose (high dose regime), sputtering effects and ion implantation becomes significant, eventually causing amorphization of the bilayer system. The broadening of the NiFe/Au interface occurs even at the lowest dose, and above a critical fluence (Φ = 1.56 × 1014 ion/cm2) can be represented by an interfacial-intermixed layer (NixFeyAu(1-x-y); x = 0.5-0.6, y = 0.1-0.15) formed between the NiFe and Au layers. The thickness of this layer increases with irradiation fluence in the low dose regime. A linear relationship is found between the squared intermixing length and irradiation fluence, indicating that FIB-induced mixing is diffusion controlled. The ballistic model fails to describe FIB-induced intermixing, indicating that thermodynamical factors, which might be originated from FIB specific features, should be taken into account. Despite the complexity of the chemical and structural formation, good agreement between the experiment and theory highlights the functionality of the combined GIXRR and ADXRF techniques for studying intermixing in high resolution.

  18. Local modifications of magnetism and structure in FePt (001) epitaxial thin films by focused ion beam: Two-dimensional perpendicular patterns

    SciTech Connect

    Albertini, F.; Nasi, L.; Casoli, F.; Fabbrici, S.; Valeri, S.; Contri, S. F.

    2008-09-01

    Focused ion beam was utilized to locally modify magnetism and structure of L1{sub 0} FePt perpendicular thin films. As a first step, we have performed a magnetic, morphological, and structural study of completely irradiated FePt films with different Ga{sup +} doses (1x10{sup 13} -4x10{sup 16} ions/cm{sup 2}) and ion beam energy of 30 keV. For doses of 1x10{sup 14} ions/cm{sup 2} and above a complete transition from the ordered L1{sub 0} to the disordered A1 phase was found to occur, resulting in a drop of magnetic anisotropy and in the consequent moment reorientation from out-of-plane to in-plane. The lowest effective dose in disordering the structure (1x10{sup 14} ions/cm{sup 2}) was found not to affect the film morphology. Taking advantage of these results, continuous two-dimensional (2D) patterns of perpendicular magnetic structures (250 nm dots, 1 {mu}m dots, 1 {mu}m-large stripes) were produced by focused ion beam without affecting the morphology. The 2D patterns were revealed by means of magnetic force microscopy, that evidenced peculiar domain structures in the case of 1 {mu}m dots.

  19. Superintense ion beam with high energy density

    NASA Astrophysics Data System (ADS)

    Dudnikov, Vadim; Dudnikova, Galina

    2008-04-01

    The energy density of ion beam accumulated in a storage ring can be increased dramatically with using of space charge compensation as was demonstrated in experiments [1]. The intensity of said superintense beam can be far greater than a space charge limit without space charge compensation. The model of secondary plasma build up with secondary ion-electron emission as a source of delayed electrons has been presented and discussed. This model can be used for explanation of bunched beam instability with electron surviving after gap, for prediction of e-cloud generation in coasting and long bunches beam, and can be important for pressure rise in worm and cold sections of storage rings. A fast desorption by ion of physically adsorbed molecules can explain a ``first pulse Instability''. Application of this model for e-p instability selfstabilization and superintense circulating beam accumulation is considered. Importance of secondary plasma for high perveance ion beam stabilization in ion implantation will be considered. Preliminary results of simulation of electron and ion accumulation will be presented. [1]. Belchenko et al., Xth International Particle Accelerator Conference, Protvino, 1977, Vol. 2, p. 287.

  20. Multiple Electron Stripping of Heavy Ion Beams

    SciTech Connect

    D. Mueller; L. Grisham; I. Kaganovich; R. L. Watson; V. Horvat; K. E. Zaharakis; Y. Peng

    2002-06-25

    One approach being explored as a route to practical fusion energy uses heavy ion beams focused on an indirect drive target. Such beams will lose electrons while passing through background gas in the target chamber, and therefore it is necessary to assess the rate at which the charge state of the incident beam evolves on the way to the target. Accelerators designed primarily for nuclear physics or high energy physics experiments utilize ion sources that generate highly stripped ions in order to achieve high energies economically. As a result, accelerators capable of producing heavy ion beams of 10 to 40 Mev/amu with charge state 1 currently do not exist. Hence, the stripping cross-sections used to model the performance of heavy ion fusion driver beams have, up to now, been based upon theoretical calculations. We have investigated experimentally the stripping of 3.4 Mev/amu Kr 7+ and Xe +11 in N2; 10.2 MeV/amu Ar +6 in He, N2, Ar and Xe; 19 MeV/amu Ar +8 in He, N2, Ar and Xe; 30 MeV He 1 + in He, N2, Ar and Xe; and 38 MeV/amu N +6 in He, N2, Ar and Xe. The results of these measurements are compared with the theoretical calculations to assess their applicability over a wide range of parameters.

  1. Model for compound formation during ion-beam mixing

    SciTech Connect

    Desimoni, J.; Traverse, A. )

    1993-11-01

    We propose an ion-beam-mixing model that accounts for compound formation at a boundary between two materials during ion irradiation. It is based on Fick's law together with a chemical driving force in order to simulate the chemical reaction at the boundary. The behavior of the squared thickness of the mixed layer, [ital X][sup 2], with the irradiation fluence, [Phi], has been found in several mixing experiments to be either quadratic ([ital X][sup 2][alpha][Phi][sup 2]) or linear ([ital X][sup 2][alpha][Phi]), a result which is qualitatively reproduced. Depending on the fluence range, compound formation or diffusion is the limiting process of mixing kinetics. A criterion is established in terms of the ratio of the diffusion coefficient [ital D] due to irradiation to the chemical reaction rate squared which allows us to predict quadratic or linear behavior. When diffusion is the limiting process, [ital D] is enhanced by a factor which accounts for the formation of a compound in the mixed layer. Good agreement is found between the calculated mixing rates and the data taken from mixing experiments in metal/Si bilayers.

  2. Aifira: An ion beam facility for multidisciplinary research

    NASA Astrophysics Data System (ADS)

    Sorieul, S.; Alfaurt, Ph.; Daudin, L.; Serani, L.; Moretto, Ph.

    2014-08-01

    During the last decade, the CENBG (Centre d'Études Nucléaires de Bordeaux Gradignan) commissioned a new facility called AIFIRA (Applications Interdisciplinaires des Faisceaux d'ions en Région Aquitaine). It allowed the development of a multidisciplinary activity based on the "in-house" expertise of CENBG in ion beam analysis. The great flexibility offered by the five beam lines confers a lot of possibilities for chemical analysis and nuclear physics. Indeed, not only the macrobeam and the external beam lines provide the full set of IBA techniques for routine sample analysis but an additional beam line is devoted to the production of monoenergetic neutrons through the interaction of the incoming ion with selected targets. In addition, the two high-resolution microbeam lines are used for chemical analyses, 2D/3D imaging, and targeted cell irradiation. Besides, the combination of the nanobeam line flexibility, the uniqueness of the micro-irradiation design completed by the internal CENBG expertise confers a great specificity to AIFIRA in biomedical field. After a detailed technical overview of the platform, the article focuses on the two high-resolution lines as they tap most of the activity. Thus a quick overview of the most significant results concerning biomedical samples is proposed in order to highlight the analytical possibilities of AIFIRA microbeam lines. A summary of the development status of the micro-irradiation line is also done.

  3. Adhesion enhancement of ion beam mixed Cu/Al/polyimide

    NASA Astrophysics Data System (ADS)

    Chang, G. S.; Jung, S. M.; Lee, Y. S.; Choi, I. S.; Whang, C. N.; Woo, J. J.; Lee, Y. P.

    1997-01-01

    Cu (400 Å)/polyimide was mixed with 80 keV Ar+ and N2+ from 1.0×1015 to 2.0×1016 ions/cm2. The same processes were repeated for the Cu (400 Å)/Al (50 Å)/polyimide system which has Al as a buffer layer. The quantitative adhesion strength was measured by a standard scratch test. X-ray photoelectron spectroscopy was employed to investigate the change in the chemical bonds of the ion beam mixed polyimide substrate and the intermediate effects for the adhesion enhancement in Cu/Al/polyimide. Two distinct tendencies are observed in the adhesion strength: Cu/Al/polyimide is more adhesive than Cu/polyimide after ion beam mixing, and N2+ ions are more effective in the adhesion enhancement than Ar+. The formation of an interlayer compound of CuAl2O4 accounts for the former, while the latter is understood by the fact that N2+ ions produce more pyridinelike moiety, amide group and tertiary amine moiety which are known as adhesion promoters.

  4. Post-acceleration of laser-induced ion beams

    NASA Astrophysics Data System (ADS)

    Nassisi, V.; Delle Side, D.

    2015-04-01

    A complete review of the essential and recent developments in the field of post-acceleration of laser-induced ion beams is presented. After a brief introduction to the physics of low-intensity nanosecond laser-matter interaction, the details of ions extraction and acceleration are critically analyzed and the key parameters to obtain good-quality ion beams are illustrated. A description of the most common ion beam diagnosis system is given, together with the associated analytical techniques.

  5. First experimental-based characterization of oxygen ion beam depth dose distributions at the Heidelberg Ion-Beam Therapy Center

    NASA Astrophysics Data System (ADS)

    Kurz, C.; Mairani, A.; Parodi, K.

    2012-08-01

    Over the last decades, the application of proton and heavy-ion beams to external beam radiotherapy has rapidly increased. Due to the favourable lateral and depth dose profile, the superposition of narrow ion pencil beams may enable a highly conformal dose delivery to the tumour, with better sparing of the surrounding healthy tissue in comparison to conventional radiation therapy with photons. To fully exploit the promised clinical advantages of ion beams, an accurate planning of the patient treatments is required. The clinical treatment planning system (TPS) at the Heidelberg Ion-Beam Therapy Center (HIT) is based on a fast performing analytical algorithm for dose calculation, relying, among others, on laterally integrated depth dose distributions (DDDs) simulated with the FLUKA Monte Carlo (MC) code. Important input parameters of these simulations need to be derived from a comparison of the simulated DDDs with measurements. In this work, the first measurements of 16O ion DDDs at HIT are presented with a focus on the determined Bragg peak positions and the understanding of factors influencing the shape of the distributions. The measurements are compared to different simulation approaches aiming to reproduce the acquired data at best. A simplified geometrical model is first used to optimize important input parameters, not known a priori, in the simulations. This method is then compared to a more realistic, but also more time-consuming simulation approach better accounting for the experimental set-up and the measuring process. The results of this work contributed to a pre-clinical oxygen ion beam database, which is currently used by a research TPS for corresponding radio-biological cell experiments. A future extension to a clinical database used by the clinical TPS at HIT is foreseen. As a side effect, the performed investigations showed that the typical water equivalent calibration approach of experimental data acquired with water column systems leads to slight

  6. First experimental-based characterization of oxygen ion beam depth dose distributions at the Heidelberg Ion-Beam Therapy Center.

    PubMed

    Kurz, C; Mairani, A; Parodi, K

    2012-08-01

    Over the last decades, the application of proton and heavy-ion beams to external beam radiotherapy has rapidly increased. Due to the favourable lateral and depth dose profile, the superposition of narrow ion pencil beams may enable a highly conformal dose delivery to the tumour, with better sparing of the surrounding healthy tissue in comparison to conventional radiation therapy with photons. To fully exploit the promised clinical advantages of ion beams, an accurate planning of the patient treatments is required. The clinical treatment planning system (TPS) at the Heidelberg Ion-Beam Therapy Center (HIT) is based on a fast performing analytical algorithm for dose calculation, relying, among others, on laterally integrated depth dose distributions (DDDs) simulated with the FLUKA Monte Carlo (MC) code. Important input parameters of these simulations need to be derived from a comparison of the simulated DDDs with measurements. In this work, the first measurements of (16)O ion DDDs at HIT are presented with a focus on the determined Bragg peak positions and the understanding of factors influencing the shape of the distributions. The measurements are compared to different simulation approaches aiming to reproduce the acquired data at best. A simplified geometrical model is first used to optimize important input parameters, not known a priori, in the simulations. This method is then compared to a more realistic, but also more time-consuming simulation approach better accounting for the experimental set-up and the measuring process. The results of this work contributed to a pre-clinical oxygen ion beam database, which is currently used by a research TPS for corresponding radio-biological cell experiments. A future extension to a clinical database used by the clinical TPS at HIT is foreseen. As a side effect, the performed investigations showed that the typical water equivalent calibration approach of experimental data acquired with water column systems leads to slight

  7. Ion beam mixed oxidation protective coating on Zry-4 cladding

    NASA Astrophysics Data System (ADS)

    Park, Jae-Won; Kim, Jae-Un; Park, Jeong-Yong

    2016-06-01

    In this study, SiC was coated on the surface of Zry-4 cladding to improve the oxidation protectiveness. In the coating of SiC onto Zry-4, the prime concern was adhesion at an elevated temperature. Here, a 70 keV N ion beam was irradiated onto a SiC coating layer of ∼100 nm in thickness; this was deposited via the e-beam evaporation method. Additional coating to a target thickness was then carried out. The films deposited without ion-beam mixing (IBM) often peeled-off at an elevated temperature, while the IBM SiC film always adhered to Zry-4, even after heating to ∼1000 °C; at such a temperature, however, cracks formed in the film. X-ray photoelectron spectroscopy (XPS) analysis showed that the deposited SiC film contained about 20 at.% of O, while after annealing in air, 76 at.% of O was found on the surface layer. This implied that both the surface of SiC film and Zry-4 in the crack lines were oxidized. Comparing the Zr3d peak positions across the interface, a shift of binding energy by ∼1 eV was detected, representing that, in view of favorable thermodynamics, SiC/Zry-4 seems to be an acceptable system to apply IBM. To heal the crack, the process of IBM for a 1 μm thick coating and annealing was repeated. High-resolution field emission secondary electron microscopy (FE-SEM) showed that the crack lines, the main places at which oxidation occurred, were gradually covered as the process was repeated, ensuring enhanced oxidation protectiveness.

  8. High sensitivity charge amplifier for ion beam uniformity monitor

    DOEpatents

    Johnson, Gary W.

    2001-01-01

    An ion beam uniformity monitor for very low beam currents using a high-sensitivity charge amplifier with bias compensation. The ion beam monitor is used to assess the uniformity of a raster-scanned ion beam, such as used in an ion implanter, and utilizes four Faraday cups placed in the geometric corners of the target area. Current from each cup is integrated with respect to time, thus measuring accumulated dose, or charge, in Coulombs. By comparing the dose at each corner, a qualitative assessment of ion beam uniformity is made possible. With knowledge of the relative area of the Faraday cups, the ion flux and areal dose can also be obtained.

  9. Temporal development of ion beam mean charge state in pulsed vacuum arc ion sources

    SciTech Connect

    Oks, E. M.; Yushkov, G. Yu.; Anders, A.

    2008-02-15

    Vacuum arc ion sources, commonly also known as 'Mevva' ion sources, are used to generate intense pulsed metal ion beams. It is known that the mean charge state of the ion beam lies between 1 and 4, depending on cathode material, arc current, arc pulse duration, presence or absence of magnetic field at the cathode, as well as background gas pressure. A characteristic of the vacuum arc ion beam is a significant decrease in ion charge state throughout the pulse. This decrease can be observed up to a few milliseconds, until a ''noisy'' steady-state value is established. Since the extraction voltage is constant, a decrease in the ion charge state has a proportional impact on the average ion beam energy. This paper presents results of detailed investigations of the influence of arc parameters on the temporal development of the ion beam mean charge state for a wide range of cathode materials. It is shown that for fixed pulse duration, the charge state decrease can be reduced by lower arc current, higher pulse repetition rate, and reduction of the distance between cathode and extraction region. The latter effect may be associated with charge exchange processes in the discharge plasma.

  10. Focused ion beam techniques for fabricating geometrically-complex components and devices.

    SciTech Connect

    Mayer, Thomas Michael; Adams, David Price; Hodges, V. Carter; Vasile, Michael J.

    2004-03-01

    We have researched several new focused ion beam (FIB) micro-fabrication techniques that offer control of feature shape and the ability to accurately define features onto nonplanar substrates. These FIB-based processes are considered useful for prototyping, reverse engineering, and small-lot manufacturing. Ion beam-based techniques have been developed for defining features in miniature, nonplanar substrates. We demonstrate helices in cylindrical substrates having diameters from 100 {micro}m to 3 mm. Ion beam lathe processes sputter-define 10-{micro}m wide features in cylindrical substrates and tubes. For larger substrates, we combine focused ion beam milling with ultra-precision lathe turning techniques to accurately define 25-100 {micro}m features over many meters of path length. In several cases, we combine the feature defining capability of focused ion beam bombardment with additive techniques such as evaporation, sputter deposition and electroplating in order to build geometrically-complex, functionally-simple devices. Damascene methods that fabricate bound, metal microcoils have been developed for cylindrical substrates. Effects of focused ion milling on surface morphology are also highlighted in a study of ion-milled diamond.

  11. An improved Green's function for ion beam transport.

    PubMed

    Tweed, J; Wilson, J W; Tripathi, R K

    2004-01-01

    Ion beam transport theory allows testing of material transmission properties in the laboratory environment generated by particle accelerators. This is a necessary step in materials development and evaluation for space use. The approximations used in solving the Boltzmann transport equation for the space setting are often not sufficient for laboratory work and those issues are the main emphasis of the present work. In consequence, an analytic solution of the linear Boltzmann equation is pursued in the form of a Green's function allowing flexibility in application to a broad range of boundary value problems. It has been established that simple solutions can be found for high charge and energy (HZE) ions by ignoring nuclear energy downshifts and dispersion. Such solutions were found to be supported by experimental evidence with HZE ion beams when multiple scattering was added. Lacking from the prior solutions were range and energy straggling and energy downshift with dispersion associated with nuclear events. Recently, we have found global solutions including these effects providing a broader class of HZE ion solutions. PMID:15880918

  12. An Improved Green's Function for Ion Beam Transport

    NASA Technical Reports Server (NTRS)

    Tweed, J.; Wilson, J. W.; Tripathi, R. K.

    2003-01-01

    Ion beam transport theory allows testing of material transmission properties in the laboratory environment generated by particle accelerators. This is a necessary step in materials development and evaluation for space use. The approximations used in solving the Boltzmann transport equation for the space setting are often not sufficient for laboratory work and those issues are the main emphasis of the present work. In consequence, an analytic solution of the linear Boltzmann equation is pursued in the form of a Green's function allowing flexibility in application to a broad range of boundary value problems. It has been established that simple solutions can be found for the high charge and energy (HZE) by ignoring nuclear energy downshifts and dispersion. Such solutions were found to be supported by experimental evidence with HZE ion beams when multiple scattering was added. Lacking from the prior solutions were range and energy straggling and energy downshift with dispersion associated with nuclear events. Recently, we have found global solutions including these effects providing a broader class of HZE ion solutions.

  13. Modeling of nanocluster formation by ion beam implantation

    SciTech Connect

    Li, Kun-Dar

    2011-08-15

    A theoretical model was developed to investigate the mechanism of the formation of nanoclusters via ion beam implantation. The evolution of nanoclusters, including the nucleation and growth process known as Ostwald ripening, was rebuilt using numerical simulations. The effects of implantation parameters such as the ion energy, ion fluence, and temperature on the morphology of implanted microstructures were also studied through integration with the Monte Carlo Transport of Ions in Matter code calculation for the distribution profiles of implanted ions. With an appropriate ion fluence, a labyrinth-like nanostructure with broad size distributions of nanoclusters formed along the ion implantation range. In a latter stage, a buried layer of implanted impurity developed. With decreasing ion energy, the model predicted the formation of precipitates on the surface. These simulation results were fully consistent with many experimental observations. With increased temperature, the characteristic length and size of nanostructures would increase due to the high mobility. This theoretical model provides an efficient numerical approach for fully understanding the mechanism of the formation of nanoclusters, allowing for the design of ion beam experiments to form specific nanostructures through ion-implantation technology.

  14. An improved Green's function for ion beam transport

    NASA Technical Reports Server (NTRS)

    Tweed, J.; Wilson, J. W.; Tripathi, R. K.

    2004-01-01

    Ion beam transport theory allows testing of material transmission properties in the laboratory environment generated by particle accelerators. This is a necessary step in materials development and evaluation for space use. The approximations used in solving the Boltzmann transport equation for the space setting are often not sufficient for laboratory work and those issues are the main emphasis of the present work. In consequence, an analytic solution of the linear Boltzmann equation is pursued in the form of a Green's function allowing flexibility in application to a broad range of boundary value problems. It has been established that simple solutions can be found for high charge and energy (HZE) ions by ignoring nuclear energy downshifts and dispersion. Such solutions were found to be supported by experimental evidence with HZE ion beams when multiple scattering was added. Lacking from the prior solutions were range and energy straggling and energy downshift with dispersion associated with nuclear events. Recently, we have found global solutions including these effects providing a broader class of HZE ion solutions. c2004 COSPAR. Published by Elsevier Ltd. All rights reserved.

  15. Studies of Limits on Uncontrolled Heavy Ion Beam Losses for Allowing Hands-On Maintenance

    SciTech Connect

    Reginald M. Ronningen; Igor Remec

    2010-09-11

    Dose rates from accelerator components activated by 1 W/m beam losses are obtained semiempirically for a 1 GeV proton beam and by use of Monte Carlo transport codes for the proton beam and for 777 MeV/u 3He, 500 MeV/u 48Ca, 86Kr, 136Xe, and 400 MeV/u 238U ions. The dose rate obtained by the semi-empirical method, 0.99 mSv/h (99 mrem/h) at 30 cm, 4 h after 100 d irradiation by a 1-GeV proton beam, is consistent with studies at several accelerator facilities and with adopted hands-on maintenance dose rate limits. Monte Carlo simulations verify this result for protons and extend studies to heavy ion beam losses in drift-tube linac and superconducting linac accelerating structures. The studies indicate that the 1 W/m limit imposed on uncontrolled beam losses for high-energy proton beams might be relaxed for heavy ion beams. These studies further suggest that using the ratio of neutrons produced by a heavy ion beam to neutrons produced by a proton beam along with the dose rate from the proton beam (for thin-target scenarios) should allow an estimate of the dose rates expected from heavy ion beam losses.

  16. Micro/nanofabrication of poly(L-lactic acid) using focused ion beam direct etching

    NASA Astrophysics Data System (ADS)

    Oyama, Tomoko Gowa; Hinata, Toru; Nagasawa, Naotsugu; Oshima, Akihiro; Washio, Masakazu; Tagawa, Seiichi; Taguchi, Mitsumasa

    2013-10-01

    Micro/nanofabrication of biocompatible and biodegradable poly(L-lactic acid) (PLLA) using focused Ga ion beam direct etching was evaluated for future bio-device applications. The fabrication performance was determined with different ion fluences and fluxes (beam currents), and it was found that the etching speed and fabrication accuracy were affected by irradiation-induced heat. Focused ion beam (FIB)-irradiated surfaces were analyzed using micro-area X-ray photoelectron spectroscopy. Owing to reactions such as the physical sputtering of atoms and radiation-induced decomposition, PLLA was gradually carbonized with increasing C=C bonds. Controlled micro/nanostructures of PLLA were fabricated with C=C bond-rich surfaces expected to have good cell attachment properties.

  17. Application of ion-beam analysis techniques to the study of irradiationn damage in zirconium alloys

    SciTech Connect

    Howe, L.M.; Phillips, D.; Zou, H.; Forster, J.; Siegele, R.; Davies, J.A.; Motta, A.T.; Faldowski, J.A.; Okamoto, P.R.

    1995-12-01

    Ion-beam-analysis techniques are being used to provide an understanding of the nature of collision cascades, irradiation-induced phase changes, lattice location of solute atoms and defect-solute atom interactions in various zirconium alloys. In zirconium intermetallic compounds, such as Zr{sub 3}Fe, Zr{sub 2}Fe, ZrFe{sub 2}, Zr{sub 3}(Fe{sub x},Ni{sub 1-x}) and (Zr,M){sub 3}Fe, electron and ion irradiations have been used to obtain detailed information on the crystalline-to-amorphous transformation occurring during the irradiation. Transmission-electron-microscopy (TEM) observations have provided information on the nature of the damage produced in individual cascades, the critical dose required for amorphization, and the critical temperature for amorphization. In a study on the electron-energy dependence of amorphization in Zr{sub 3}Fe, Zr{sub 2},Fe and ZrCr{sub 2}, in situ high-voltage-electron-microscope investigations were combined with high-energy forward-elastic-recoil measurements to yield information on the threshold displacement energies for Zr and Fe or Cr in these lattices, as well as the role of secondary displacements of lattice atoms by recoil impurities (C,O) at low electron energies. In Zr implanted with {sup 56}Fe ions and subsequently bombarded with {sup 40}Ar ions at 723 K, subsequent secondary-ion-mass-spectrometry (SIMS) analyses were used to monitor the effect of irradiation on the migration of Fe in the Zr lattice. In addition, ion-channeling investigations have been used to determine the lattice sites of solute atoms in Zr as well as the details of the interaction between the solute atoms and the irradiation-produced defects.

  18. Adaptation of ion beam technology to microfabrication of solid state devices and transducers

    NASA Technical Reports Server (NTRS)

    Topich, J. A.

    1977-01-01

    It was found that ion beam texturing of silicon surfaces can be used to increase the effective surface area of MOS capacitors. There is, however, a problem with low dielectric breakdown. Preliminary work was begun on the fabrication of ion implanted resistors on textured surfaces and the potential improvement of wire bond strength by bonding to a textured surface. In the area of ion beam sputtering, the techniques for sputtering PVC were developed. A PVC target containing valinomycin was used to sputter an ion selective membrane on a field effect transistor to form a potassium ion sensor.

  19. Ion beam sputter deposited diamond like films

    NASA Technical Reports Server (NTRS)

    Banks, B. A.; Rutledge, S. K.

    1982-01-01

    A single argon ion beam source was used to sputter deposit carbon films on fused silica, copper, and tantalum substrates under conditions of sputter deposition alone and sputter deposition combined with simultaneous argon ion bombardment. Simultaneously deposited and ion bombarded carbon films were prepared under conditions of carbon atom removal to arrival ratios of 0, 0.036, and 0.71. Deposition and etch rates were measured for films on fused silica substrates. Resulting characteristics of the deposited films are: electrical resistivity of densities of 2.1 gm/cu cm for sputter deposited films and 2.2 gm/cu cm for simultaneously sputter deposited and Ar ion bombarded films. For films approximately 1700 A thick deposited by either process and at 5550 A wavelength light the reflectance was 0.2, the absorptance was 0.7, the absorption coefficient was 67,000 cm to the -1 and the transmittance was 0.1.

  20. Dispensing targets for ion beam particle generators

    NASA Technical Reports Server (NTRS)

    Miller, C. G. (Inventor)

    1974-01-01

    A target for dispensing high energy protons or neutrons or ionized atoms or ionized molecules is provided which comprises a container for the target gas, which is at atmospheric or higher pressure. The container material can release the target gas in the spot where the container is heated above a predetermined temperature by the impact of an ion beam where protons or neutrons are desired, or by electrons where ionized atoms or molecules are desired. On the outside of the container, except for the region where the beam is to impact, there is deposited a layer of a metal which is imperious to gaseous diffusion. A further protective coating of a material is placed over the layer of metal, except at the region of the ion impact area in order to adsorb any unreacted gas in the vacuum in which the target is placed, to thereby prevent reduction of the high vacuum, as well as contamination of the interior of the vacuum chamber.

  1. Ion-beam-assisted etching of diamond

    NASA Technical Reports Server (NTRS)

    Efremow, N. N.; Geis, M. W.; Flanders, D. C.; Lincoln, G. A.; Economou, N. P.

    1985-01-01

    The high thermal conductivity, low RF loss, and inertness of diamond make it useful in traveling wave tubes operating in excess of 500 GHz. Such use requires the controlled etching of type IIA diamond to produce grating like structures tens of micrometers deep. Previous work on reactive ion etching with O2 gave etching rates on the order of 20 nm/min and poor etch selectivity between the masking material (Ni or Cr) and the diamond. An alternative approach which uses a Xe(+) beam and a reactive gas flux of NO2 in an ion-beam-assisted etching system is reported. An etching rate of 200 nm/min was obtained with an etching rate ratio of 20 between the diamond and an aluminum mask.

  2. Ion beams from laser-generated plasmas

    NASA Technical Reports Server (NTRS)

    Hughes, R. H.; Anderson, R. J.; Gray, L. G.; Rosenfeld, J. P.; Manka, C. K.; Carruth, M. R.

    1980-01-01

    The paper describes the space-charge-limited beams produced by the plasma blowoffs generated by 20-MW bursts of 1.06-micron radiation from an active Q-switched Nd:YAG laser. Laser power densities near 10 to the 11th/sq cm on solid targets generate thermalized plasma plumes which drift to a 15-kV gridded extraction gap where the ions are extracted, accelerated, and electrostatically focused; the spatially defined ion beams are then magnetically analyzed to determine the charge state content in the beams formed from carbon, aluminum, copper, and lead targets. This technique preserves time-of-flight (TOF) information in the plasma drift region, which permits plasma ion temperatures and mass flow velocities to be determined from the Maxwellian ion curve TOF shapes for the individual charge species.

  3. Focused ion beam in dental research.

    PubMed

    Ngo, H; Cairney, J; Munroe, P; Vargas, M; Mount, G

    2000-11-01

    Focused ion beam (FIB) has been available for over 10 yrs but until recently its usage has been confined to the semiconductor industry. It has been developed as an important tool in defect analysis, circuit modification and recently transmission electron microscope sample preparation. This paper introduces FIB and demonstrates its application in dental research. Its ion and electron imaging modes complement the SEM while its ability to prepare TEM samples from a wide range of material will allow the study of new types of adhesive interface. As an example, its use is described in the characterization of the interface of resin to a tribochemically treated surface of an experimental fiber-reinforced resin-based composite. As with all new techniques, the initial learning curve was difficult to manage. This new instrument offers opportunities to expand research in dental materials to areas not possible before. PMID:11763915

  4. Ion Beam Sputtered Coatings of Bioglass

    NASA Technical Reports Server (NTRS)

    Hench, Larry L.; Wilson, J.; Ruzakowski, Patricia Henrietta Anne

    1982-01-01

    The ion beam sputtering technique available at the NASA-Lewis was used to apply coatings of bioglass to ceramic, metallic, and polymeric substrates. Experiments in vivo and in vitro described investigate these coatings. Some degree of substrate masking was obtained in all samples although stability and reactivity equivalent to bulk bioglass was not observed in all coated samples. Some degree of stability was seen in all coated samples that were reacted in vitro. Both metallic and ceramic substrates coated in this manner failed to show significantly improved coatings over those obtained with existing techniques. Implantation of the coated ceramic substrate samples in bone gave no definite bonding as seen with bulk glass; however, partial and patchy bonding was seen. Polymeric substrates in these studies showed promise of success. The coatings applied were sufficient to mask the underlying reactive test surface and tissue adhesion of collagen to bioglass was seen. Hydrophilic, hydrophobic, charged, and uncharged polymeric surfaces were successfully coated.

  5. Plasma focus ion beam fluence and flux—For various gases

    SciTech Connect

    Lee, S.; Institute for Plasma Focus Studies, 32 Oakpark Drive, Chadstone 3148; Physics Department, University of Malaya ; Saw, S. H.; Institute for Plasma Focus Studies, 32 Oakpark Drive, Chadstone 3148

    2013-06-15

    A recent paper derived benchmarks for deuteron beam fluence and flux in a plasma focus (PF) [S. Lee and S. H. Saw, Phys. Plasmas 19, 112703 (2012)]. In the present work we start from first principles, derive the flux equation of the ion beam of any gas; link to the Lee Model code and hence compute the ion beam properties of the PF. The results show that, for a given PF, the fluence, flux, ion number and ion current decrease from the lightest to the heaviest gas except for trend-breaking higher values for Ar fluence and flux. The energy fluence, energy flux, power flow, and damage factors are relatively constant from H{sub 2} to N{sub 2} but increase for Ne, Ar, Kr and Xe due to radiative cooling and collapse effects. This paper provides much needed benchmark reference values and scaling trends for ion beams of a PF operated in any gas.

  6. Preparation of high-purity Cu films by non-mass separated ion beam deposition

    NASA Astrophysics Data System (ADS)

    Lim, J.-W.; Mimura, K.; Miyake, K.; Yamashita, M.; Isshiki, M.

    2003-05-01

    Cu films were deposited on Si(1 0 0) substrates by applying a negative substrate bias voltage using non-mass separated ion beam deposition (IBD) method. By the SIMS results with Cs + ion beam, the Cu film deposited at VS=0 V was found to contain more impurities than the Cu film deposited at VS=-50 V. On the other hand, from the SIMS results with O 2+ ion beam, it was found that elements which are easy to be positive ions such as B, Mg, Na, Al, K, Ca and Fe seem to be increased slightly as compared to the those of the Cu film deposited at VS=0 V. As a result, higher-purity Cu film deposited at VS=-50 V could be obtained in comparison with the film deposited at VS=0 V. The purification effect of the Cu film deposited at VS=-50 V was described in details.

  7. Probe measurements in ion-beam plasma

    SciTech Connect

    Dudin, S.V.

    1994-12-31

    The particularities of the electric probe measurements in the ion-beam plasma (IBP) have been investigated. To find the electron density n{sub e} and temperature T{sub c} as well as electron energy distribution it is necessary to separate electron current from full probe current, because ion part of this current is often large enough to mask the electron part. According to collisionless probe theory, radius of ion layer in strongly non-isothermal plasma (as in their case) and consequently the ion current are determined by Child`s law. However, at presence of ion beam with high enough energy {var_epsilon}{sub b} >> e{var_phi}{sub p}, this law is broken. The author has found the dependence of Langmuir probe ion current I{sub i} on probe potential {var_phi}{sub p} at presence of IB. The constant ion density approach was used in cylindrical and spherical geometry of the probe layer. Dependence of ion current founded experimentally accords with Child`s law when the probe is placed outside the beam and linear--within the beam. Application of only the chemical Langmuir probe is insufficient for energoanalysis of IBP electrons because of ion current interference. To solve this problem combination of the techniques of cylindrical probe, large plate probe (5 x 5mm) and two-grid energoanalyzer was used. Design and parameters of the two-grid analyzer are presented. Measuring system is described for determination of electron energy distribution function in low temperature plasma by double differentiation of the electric probe volt-ampere characteristic by modulation method.

  8. Investigation of surface characteristics evolution and laser damage performance of fused silica during ion-beam sputtering

    NASA Astrophysics Data System (ADS)

    Xu, Mingjin; Dai, Yifan; Zhou, Lin; Shi, Feng; Wan, Wen; Xie, Xuhui; Sui, Tingting

    2016-08-01

    Surface characteristics have great influence on the optical properties especially the laser radiation resistivity of optics. In this paper, the surface characteristics evolutions of fused silica during ion-beam sputtering and their effects on the laser damage performance were investigated. The results show that roughness change is strongly removal depth dependent and a super-smooth surface (0.25 nm RMS) can be obtained by the ion-induced smoothing effect. The concentration of metal impurities (especially Ce element) in subsurface can be effectively decreased after the removal of polishing re-deposition layer. During ion-beam sputtering process, the plastic scratches can be removed while the brittle cracks can be broadened and passivated without increase in the depth direction. Laser damage threshold of fused silica improved by 36% after ion-beam sputtering treatment. Research results have a guiding significance for ion-beam sputtering process technology of fused silica optics.

  9. Symmetry of surface nanopatterns induced by ion-beam sputtering: Role of anisotropic surface diffusion

    NASA Astrophysics Data System (ADS)

    Renedo, Javier; Cuerno, Rodolfo; Castro, Mario; Muñoz-García, Javier

    2016-04-01

    Ion-beam sputtering (IBS) is a cost-effective technique able to produce ordered nanopatterns on the surfaces of different materials. To date, most theoretical studies of this process have focused on systems which become amorphous under irradiation, e.g., semiconductors at room temperature. Thus, in spite of the large amount of experimental work on metals, or more recently on semiconductors at high temperatures, such experimental contexts have received relatively little theoretical attention. These systems are characterized by transport mechanisms, e.g., surface diffusion, which are anisotropic as a reflection of the crystalline structure not being overruled by the irradiation. Here, we generalize a previous continuum theory of IBS at normal incidence, in order to account for anisotropic surface diffusion. We explore systematically our generalized model in order to understand the role of anisotropy in the space-ordering properties of the resulting patterns. In particular, we derive a height equation which predicts morphological transitions among hexagonal and rectangular patterns as a function of system parameters and employ an angular correlation function to assess these pattern symmetries. By suitably choosing experimental conditions, it is found that one might be able to experimentally control the type of order displayed by the patterns produced.

  10. Simulation of ion beam transport through the 400 Kv ion implanter at Michigan Ion Beam Laboratory

    SciTech Connect

    Naab, F. U.; Toader, O. F.; Was, G. S.

    2013-04-19

    The Michigan Ion Beam Laboratory houses a 400 kV ion implanter. An application that simulates the ion beam trajectories through the implanter from the ion source to the target was developed using the SIMION Registered-Sign code. The goals were to have a tool to develop an intuitive understanding of abstract physics phenomena and diagnose ion trajectories. Using this application, new implanter users of different fields in science quickly understand how the machine works and quickly learn to operate it. In this article we describe the implanter simulation application and compare the parameters of the implanter components obtained from the simulations with the measured ones. The overall agreement between the simulated and measured values of magnetic fields and electric potentials is {approx}10%.

  11. Preliminary study of irradiation effects on thorium phosphate-diphosphate

    NASA Astrophysics Data System (ADS)

    Pichot, E.; Dacheux, N.; Emery, J.; Chaumont, J.; Brandel, V.; Genet, M.

    2001-03-01

    Thorium phosphate-diphosphate (TPD): Th 4(PO 4) 4P 2O 7 is proposed as a host matrix for the long-term storage of high level radioactive wastes. Indeed, γ-rays, α and β particles due to the incorporated actinides or fission products will certainly produce several effects, particularly structural and chemical modifications, in the host material. In order to investigate these effects, powdered samples were irradiated with 1.5 Gy dose of γ-rays. The formation of PO 32- and POO rad free radicals was detected using electron spin resonance (ESR) and thermoluminescence (TL) methods. These free radicals do not modify the macroscopic properties of the TPD and disappear when the sample is heated at 400°C. The implantation of He + ions of 1.6 MeV (fluence: 10 16 particles cm -2) and Au 3+ ions of 5 MeV (fluence 4×10 15 particles cm -2) causes some damages on the surface of sintered samples. Amorphization and chemical decomposition of the matrix were observed for the dose of 10 15 particles cm -2 and higher when irradiated with Pb 2+ (200 keV) and Au 3+ (5 MeV) ion beams. These effects were evidenced by means of X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS).

  12. Expansion Discharge Source for Ion Beam Laser Spectroscopy of Cold Molecular Ions

    NASA Astrophysics Data System (ADS)

    Porambo, Michael; Pearson, Jessica; Riccardo, Craig; McCall, Benjamin J.

    2013-06-01

    Molecular ions are important in several fields of research, and spectroscopy acts as a key tool in the study of these ions. However, problems such as low ion abundance, ion-neutral confusion, and spectral congestion due to high internal temperatures can hinder effective spectroscopic studies. To circumvent these problems, we are developing a technique called Sensitive, Cooled, Resolved, Ion BEam Spectroscopy (SCRIBES). This ion beam spectrometer will feature a continuous supersonic expansion discharge source to produce cold molecular ions, electrostatic ion optics to focus the ions into an ion beam and bend the beam away from co-produced neutral molecules, an overlap region for cavity enhanced spectroscopy, and a time-of-flight mass spectrometer. When completed, SCRIBES will be an effective tool for the study of large, fluxional, and complex molecular ions that are difficult to study with other means. The ion beam spectrometer has been successfully implemented with a hot ion source. This talk will focus on the work of integrating a supersonic expansion discharge source into the instrument. To better understand how the source would work in the whole ion beam instrument, characterization studies are being performed with spectroscopy of HN_2^+ in a section of the system to ascertain the rotational temperature of the ion expansion. Attempts are also underway to measure the ion current from a beam formed from the expansion. Once the source in this environment is properly understood, we will reintegrate it to the rest of the ion beam system, completing SCRIBES. A. A. Mills, B. M. Siller, M. W. Porambo, M. Perera, H. Kreckel and B. J. McCall J. Chem. Phys., 135, 224201, (2011). K. N. Crabtree, C. A. Kauffman and B. J. McCall Rev. Sci. Instrum. 81, 086103, (2010).

  13. Identifying heavy-ion-beam fusion design and system features with high economic leverage

    SciTech Connect

    Meier, W.R.; Hogan, W.J.

    1985-03-03

    We have conducted parametric economic studies for heavy-ion-beam fusion electric power plants. We examined the effects on the cost of electricity of several design parameters: maximum achievable chamber pulse rate, driver cost, target gain, and electric conversion efficiency, and net electric power. We found with reasonable assumptions on driver cost, target gain, and electric conversion efficiency, a 2 to 3 GWe heavy-ion-beam fusion power plant, with a chamber pulse rate of 5 to 10 Hz, can be competitive with nuclear and coal power plants.

  14. Funnel cone for focusing intense ion beams on a target

    SciTech Connect

    Bieniosek, F.M.; Henestroza, E.; Ni, P.

    2009-10-05

    We describe a funnel cone for concentrating an ion beam on a target. The cone utilizes the reflection characteristic of ion beams on solid walls to focus the incident beam andincrease beam intensity on target. The cone has been modeled with the TRIM code. A prototype has been tested and installed for use in the 350-keV K+ NDCX target chamber.

  15. Development of a focused ion beam micromachining system

    SciTech Connect

    Pellerin, J.G.; Griffis, D.; Russell, P.E.

    1988-12-01

    Focused ion beams are currently being investigated for many submicron fabrication and analytical purposes. An FIB micromachining system consisting of a UHV vacuum system, a liquid metal ion gun, and a control and data acquisition computer has been constructed. This system is being used to develop nanofabrication and nanomachining techniques involving focused ion beams and scanning tunneling microscopes.

  16. Development of a pepper pot emittance probe and its application for ECR ion beam studies.

    SciTech Connect

    Kondrashev, S.; Barcikowski, A.; Mustapha, B.; Ostroumov, P.N.; Vinogradov, N.; Northern Illinois Univ.

    2009-07-21

    A pepper pot-scintillator screen system has been developed and used to measure the emittance of DC ion beams extracted from a high-intensity permanent magnet ECR ion source. The system includes a fast beam shutter with a minimum dwell time of 18 ms to reduce the degradation of the CsI(Tl) scintillator by DC ion beam irradiation and a CCD camera with a variable shutter speed in the range of 1 {micro}s-65 s. On-line emittance measurements are performed by an application code developed on a LabVIEW platform. The sensitivity of the device is sufficient to measure the emittance of DC ion beams with current densities down to about 100 nA/cm{sup 2}. The emittance of all ion species extracted from the ECR ion source and post-accelerated to an energy of 75-90 keV/charge have been measured downstream of the LEBT. As the mass-to-charge ratio of ion species increases, the normalized RMS emittances in both transverse phase planes decrease from 0.5-1.0 {pi} mm mrad for light ions to 0.05-0.09 {pi} mm mrad for highly charged {sup 209}Bi ions. The dependence of the emittance on ion's mass-to-charge ratio follows very well the dependence expected from beam rotation induced by decreasing ECR axial magnetic field. The measured emittance values cannot be explained by only ion beam rotation for all ion species and the contribution to emittance of ion temperature in plasma, non-linear electric fields and non-linear space charge is comparable or even higher than the contribution of ion beam rotation.

  17. Using the compute unified device architecture programming environment in simulation of ion-beam injection line with account for space charge effect

    NASA Astrophysics Data System (ADS)

    Yudin, I. P.; Perepelkin, E. E.; Tyutyunnikov, S. I.

    2011-11-01

    A simulation of the beam injection line in a synchrotron is performed within the Veksler and Baldin Laboratory of High Energy Physics, Joint Institute for Nuclear Research (VBLHEP JINR), project "The Development and Implementation of Units of a Synchrotron for Hadron Therapy." The parameters of the injection line are chosen for the transport of beams with intensities of 25-100 mA through the injection channel of the synchrotron with account for the space-charge effect. The simulation was performed using the method of macroparticles (the PIC method). The approach of massively parallel computations on graphics processors using Compute Unified Device Architecture (CUDA) technology was applied for the acceleration of computations. The 66-fold speedup of computations was obtained using the Tesla C1060 computing module instead of a single-core CPU with 2.4 GHz.

  18. Collective Focusing of a Plasma-Neutralized Intense Ion Beam Propagating Along a Weak Solenoidal Magnetic Field

    NASA Astrophysics Data System (ADS)

    Dorf, Mikhail A.; Kaganovich, Igor D.; Startsev, Edward A.; Davidson, Ronald C.

    2009-11-01

    Two schemes are considered for focusing intense ion beams utilizing the collective dynamics of plasma electrons. In the first approach, an ion beam propagates through a neutralizing background plasma along a uniform magnetic field. In the second approach, an ion beam passes through a finite size plasma, extracts neutralizing electrons from the plasma, and then enters a magnetic lens. In the both cases, a strong radial electric field is produced due to the collective electron dynamics. This self-electric field provides the enhanced transverse focusing of the ion beam. Detailed analytical and advanced numerical studies using particle-in-cell simulations are performed for both approaches. The radial focusing force acting on beam ions is calculated for an arbitrary ratio between the electron cyclotron and plasma frequencies. Collective focusing effects are shown to be important for the design of heavy ion drivers for high energy density and warm dense matter physics applications.

  19. 20 Years History of Fundamental Research on Gas Cluster Ion Beams, and Current Status of the Applications to Industry

    NASA Astrophysics Data System (ADS)

    Yamada, Isao

    2006-11-01

    This paper reviews the development of gas cluster ion beam (GCIB) technology, including the generation of cluster beams, fundamental characteristics of cluster ion to solid surface interactions, emerging industrial applications, and identification of some of the significant events which occurred as the technology has evolved into what it is today. More than 20 years have passed since the author first began to explore feasibility of processing by gas cluster ion beams at the Ion Beam Engineering Experimental Laboratory of Kyoto University. Processes employing ions of gaseous material clusters comprised of a few hundred to many thousand atoms are now being developed into a new field of ion beam technology. Cluster-surface collisions produce important non-linear effects which are being applied to shallow junction formation, to etching and smoothing of semiconductors, metals, and dielectrics, to assisted formation of thin films with nano-scale accuracy, and to other surface modification applications.

  20. Filter model based dwell time algorithm for ion beam figuring

    NASA Astrophysics Data System (ADS)

    Li, Yun; Xing, Tingwen; Jia, Xin; Wei, Haoming

    2010-10-01

    The process of Ion Beam Figuring (IBF) can be described by a two-dimensional convolution equation which including dwell time. Solving the dwell time is a key problem in IBF. Theoretically, the dwell time can be solved from a two-dimensional deconvolution. However, it is often ill-posed]; the suitable solution of that is hard to get. In this article, a dwell time algorithm is proposed, depending on the characters of IBF. Usually, the Beam Removal Function (BRF) in IBF is Gaussian, which can be regarded as a headstand Gaussian filter. In its stop-band, the filter has various filtering abilities for various frequencies. The dwell time algorithm proposed in this article is just based on this concept. The Curved Surface Smooth Extension (CSSE) method and Fast Fourier Transform (FFT) algorithm are also used. The simulation results show that this algorithm is high precision, effective, and suitable for actual application.