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Sample records for low-energy ri beams

  1. Study on astrophysical reactions using low-energy RI beams

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Hidetoshi

    2009-10-01

    In recent years, low-energy RI beams can be produced in a good intensity and they have been used for studying many astrophysical reactions. One of the facilities producing low-energy RI beams is CRIB (CNS Radio-Isotope Beam separator) [1,2], an RI-beam separator of Center for Nuclear Study, University of Tokyo. Taking CRIB as an example, recent improvements on the RI-beam production and experimental results on astrophysical studies are presented. Several experimental approaches have been taken for the studies on astrophysical reactions.The feature of each method are discussed based on real measurements performed at CRIB. One is the direct method, applied for measurements of reactions such as (α,p) [3]. Another is the measurement of proton/alpha resonance scattering using the thick target method in inverse kinematics, by which we can obtain information on the resonances relevant in astrophysical reactions [4,5]. A recent fruitful result was from a measurement of proton resonance scattering using a ^7Be beam [5]. The energy level structure of ^8B, revealed by the experiment, is especially of interest as it is related with the ^7Be(p,γ) ^8B reaction, responsible for the production of ^8B neutrinos in the sun. We successfully determined parameters of resonances in ^8B below 6.7 MeV, which may affect the ^7Be(p,γ)^8B reaction rate at the solar temparature. Indirect methods, such as ANC and the Trojan Horse Method, were also used in some of the measurements.[4pt] [1] S. Kubono et al., Eur. Phys. J. A13 (2002) 217.[0pt] [2] Y. Yanagisawa et al., Nucl. Instrum. Meth. Phys. Res., Sect. A 539 (2005) 74.[0pt] [3] M. Notani et al., Nucl. Phys. A 764 (2004) 113c.[0pt] [4] T. Teranishi et al., Phys. Lett. B 650 (2007) 129.[0pt] [5] H. Yamaguchi et al., Phys. Lett. B 672 (2009) 230.

  2. Experimental studies using a low-energy RI beam separator at CNS

    NASA Astrophysics Data System (ADS)

    Teranishi, T.; Kubono, S.; Shimoura, S.; Notani, M.; Yanagisawa, Y.; Michimasa, S.; Ue, K.; Iwasaki, H.; Kurokawa, M.; Satou, Y.; Morikawa, T.; Saito, A.; Baba, H.; Lee, J. H.; Lee, C. S.; Fülöp, Zs.; Kato, S.

    2003-05-01

    Radioactive-ion (RI) beams of 10C, 14O, 12N and 11C with energies low 10 A MeV were produced by using a low-energy in-flight RI beam separator newly constructed by CNS, University of Tokyo. Using the 12N and 11C beams, some resonance states were identified in the proton elastic scattering 12N+p and 11C+p, respectively.

  3. Nuclear Astrophysics and Structure Studies Using Low-energy RI Beams at CRIB

    NASA Astrophysics Data System (ADS)

    Yamaguchi, H.; Hashimoto, T.; Hayakawa, S.; Binh, D. N.; Kahl, D.; Kubono, S.

    2010-05-01

    CRIB (CNS Radioactive Ion Beam separator) is a low-energy RI beam separator at the Center for Nuclear Study (CNS) of the University of Tokyo. Using the RI beams at CRIB, Many measurements on proton and alpha resonance scatterings, (α,p) reactions, and others were peformed in recent years, mainly for studying astrophysical reactions and exotic nuclear structure. Among them, the results on the 7Be+p and 7Li+α resonance scatterings are presented.

  4. Alpha-induced reaction studies using low-energy RI beams at CRIB

    SciTech Connect

    Yamaguchi, H.; Kahl, D.; Hu, J.; Kubono, S.; Hayakawa, S.; Hashimoto, T.

    2012-11-12

    CRIB (CNS Radioactive Ion Beam separator) is a low-energy RI beam separator at the Center for Nuclear Study (CNS) of the University of Tokyo. Studies on proton and alpha resonance scatterings, ({alpha}, p) reactions, and other types of measurements ({beta}-decay lifetimes etc.) have been performed using RI beams at CRIB, motivated by interests on astrophysical reactions and exotic nuclear structure. Among the studies at CRIB, the measurement of {sup 7}Li+{alpha}/{sup 7}Be+{alpha} resonant scatterings are presented.

  5. Alpha-induced reaction studies using low-energy RI beams at CRIB

    NASA Astrophysics Data System (ADS)

    Yamaguchi, H.; Kahl, D.; Hu, J.; Kubono, S.; Hayakawa, S.; Hashimoto, T.

    2012-11-01

    CRIB (CNS Radioactive Ion Beam separator) is a low-energy RI beam separator at the Center for Nuclear Study (CNS) of the University of Tokyo. Studies on proton and alpha resonance scatterings, (α, p) reactions, and other types of measurements (β-decay lifetimes etc.) have been performed using RI beams at CRIB, motivated by interests on astrophysical reactions and exotic nuclear structure. Among the studies at CRIB, the measurement of 7Li+α/7Be+α resonant scatterings are presented.

  6. Nuclear Astrophysics Programs with Low-Energy RI Beams at CRIB

    SciTech Connect

    Kubono, S.; Binh, Dam N.; Hayakawa, S.; Hashimoto, T.; Kahl, D. M.; Yamaguchi, H.; Wakabayashi, Y.; Teranishi, T.; Iwasa, N.; Komatsubara, T.; Kato, S.; Khiem, Le H.

    2010-04-30

    Nuclear astrophysics activities with CNS RI beam separator (CRIB) are reported together with the present status of the CRIB facility which is supported by the AVF upgrade project for the total development of the low-energy RIB facility. The activities include direct and indirect measurements of stellar reactions especially relevant to explosive burning processes such as nova and supernovae. Some recent results are discussed together with a scope of the facility.

  7. Nuclear Astrophysics Programs with Low-Energy RI Beams at CRIB

    NASA Astrophysics Data System (ADS)

    Kubono, S.; Binh, Dam N.; Hayakawa, S.; Hashimoto, T.; Kahl, D. M.; Yamaguchi, H.; Wakabayashi, Y.; Teranishi, T.; Iwasa, N.; Komatsubara, T.; Kato, S.; Khiem, Le H.

    2010-04-01

    Nuclear astrophysics activities with CNS RI beam separator (CRIB) are reported together with the present status of the CRIB facility which is supported by the AVF upgrade project for the total development of the low-energy RIB facility. The activities include direct and indirect measurements of stellar reactions especially relevant to explosive burning processes such as nova and supernovae. Some recent results are discussed together with a scope of the facility.

  8. Nuclear Astrophysical studies using low-energy RI beams at CRIB

    NASA Astrophysics Data System (ADS)

    Yamaguchi, H.; Wakabayashi, Y.; Hayakawa, S.; Binh, D. N.; Kahl, D.; Kurihara, Y.; Kubono, S.; Teranishi, T.; He, J. J.; Kwon, Y. K.; Nishimura, S.; Togano, Y.; Iwasa, N.; Niikura, M.; Khiem, L. H.

    2009-05-01

    CRIB (CNS Radioactive Ion Beam separator) is a low-energy RI beam separator at the Center for Nuclear Study (CNS) of the University of Tokyo, used for various studies covering nuclear-astrophysical topics. An application of the RI beam at CRIB for the astrophysical studies is a new measurement of the proton resonance scattering on 7Be. The measurement was performed up to the excitation energy of 6.8 MeV, ans the excitation function above 3.5 MeV was successfully measured for the first time, providing important information about the reaction rate of 7Be(p,γ)8B, which is the key reaction in the solar 8B neutrino production. A preliminary result of the 7Be+p experiment is presented.

  9. Nuclear Astrophysical studies using low-energy RI beams at CRIB

    SciTech Connect

    Yamaguchi, H.; Wakabayashi, Y.; Hayakawa, S.; Binh, D. N.; Kahl, D.; Kurihara, Y.; Kubono, S.; Niikura, M.; Teranishi, T.; He, J. J.; Kwon, Y. K.; Nishimura, S.; Togano, Y.; Iwasa, N.; Khiem, L. H.

    2009-05-04

    CRIB (CNS Radioactive Ion Beam separator) is a low-energy RI beam separator at the Center for Nuclear Study (CNS) of the University of Tokyo, used for various studies covering nuclear-astrophysical topics. An application of the RI beam at CRIB for the astrophysical studies is a new measurement of the proton resonance scattering on {sup 7}Be. The measurement was performed up to the excitation energy of 6.8 MeV, ans the excitation function above 3.5 MeV was successfully measured for the first time, providing important information about the reaction rate of {sup 7}Be(p,{gamma}){sup 8}B, which is the key reaction in the solar {sup 8}B neutrino production. A preliminary result of the {sup 7}Be+p experiment is presented.

  10. Studying astrophysical reactions with low-energy RI beams at CRIB

    NASA Astrophysics Data System (ADS)

    Yamaguchi, H.; Kahl, D.; Hayakawa, S.; Sakaguchi, Y.; Wakabayashi, Y.; Hashimoto, T.; Cherubini, S.; Gulino, M.; Spitaleri, C.; Rapisarda, G. G.; La Cognata, M.; Lamia, L.; Romano, S.; Kubono, S.; Iwasa, N.; Teranishi, T.; Kawabata, T.; Kwon, Y. K.; Binh, D. N.; Khiem, L. H.; Duy, N. N.; Kato, S.; Komatsubara, T.; Coc, A.; De Sereville, N.; Hammache, F.; Kiss, G.; Bishop, S.

    2016-05-01

    Studies on nuclear astrophysics, nuclear structure, and other interests have been performed using the radioactive-isotope (RI) beams at the low-energy RI beam separator CRIB, operated by Center for Nuclear Study (CNS), the University of Tokyo. A typical measurement performed at CRIB is the elastic resonant scattering with the inverse kinematics. One recent experiment was on the α resonant scattering with 7Li and 7Be beams. This study is related to the astrophysical 7Li/7Be(α,γ) reactions, important at hot p-p chain and νp-process in supernovae. There have also been measurements based on other experimental methods. The first THM measurement using an RI beam has been performed at CRIB, to study the 18F(p, α)15O reaction at astrophysical energies via the three body reaction 2H(18F, α15O)n. The 18F(p, α) 15O reaction rate is crucial to understand the 511-keV γ-ray production in nova explosion phenomena, and we successfully evaluated the reaction cross section at novae temperature and below experimentally for the first time.

  11. Experimental Approach to High-Temperature Stellar Reactions with Low-Energy RI Beams

    NASA Astrophysics Data System (ADS)

    Kubono, S.; Yamaguchi, H.; Amadio, G.; Hayakawa, S.; Wakabayashi, Y.; Kurihara, Y.; He, J. J.; Saito, A.; Fujikawa, H.; Khiem, Le Hong; Niikura, M.; Teranishi, T.; Nishimura, S.; Kato, S.; Lee, C. S.; Kwon, Y. K.; Hahn, I. S.; Kim, A.

    2008-04-01

    The experimental efforts for the stellar reactions under high-temperature and high densities have been made as the major program using the RI beams from the CNS low-energy in-flight RI beam separator (CRIB) of University of Tokyo, in order to understand the evolution of the universe as well as various stellar phenomena. Specifically, two subjects of hydrogen burning are discussed here. One is a reaction study of the pp-chain and the second is of the explosive hydrogen burning, the rp-process. Some s-wave resonances have been identified by the thick target method in the crucial reaction processes in the hydrogen burning. The resonant scattering with the thick target method also succeeded in identifying inelastic resonant scattering, giving proton widths for the first excited state of the target nucleus. This provides very efficiently the reaction rate estimate for the process under high-temperature equilibrium condition. Possibilities of the CRIB facility in near future are also briefly discussed.

  12. A gas circulation and purification system for gas-cell-based low-energy RI-beam production

    NASA Astrophysics Data System (ADS)

    Sonoda, T.; Tsubota, T.; Wada, M.; Katayama, I.; Kojima, T. M.; Reponen, M.

    2016-06-01

    A gas circulation and purification system was developed at the RIKEN Radioactive Isotope Beam Factory that can be used for gas-cell-based low-energy RI-beam production. A high-flow-rate gas cell filled with one atmosphere of buffer gas (argon or helium) is used for the deceleration and thermalization of high-energy RI-beams. The exhausted buffer gas is efficiently collected using a compact dry pump and returned to the gas cell with a recovery efficiency of >97%. The buffer gas is efficiently purified using two gas purifiers as well as collision cleaning, which eliminates impurities in the gas. An impurity level of one part per billion is achieved with this method.

  13. A gas circulation and purification system for gas-cell-based low-energy RI-beam production.

    PubMed

    Sonoda, T; Tsubota, T; Wada, M; Katayama, I; Kojima, T M; Reponen, M

    2016-06-01

    A gas circulation and purification system was developed at the RIKEN Radioactive Isotope Beam Factory that can be used for gas-cell-based low-energy RI-beam production. A high-flow-rate gas cell filled with one atmosphere of buffer gas (argon or helium) is used for the deceleration and thermalization of high-energy RI-beams. The exhausted buffer gas is efficiently collected using a compact dry pump and returned to the gas cell with a recovery efficiency of >97%. The buffer gas is efficiently purified using two gas purifiers as well as collision cleaning, which eliminates impurities in the gas. An impurity level of one part per billion is achieved with this method. PMID:27370494

  14. Low-energy RI beam technology and nuclear clusters in the explosive pp-chain breakout process

    SciTech Connect

    Kubono, S.; Yamaguchi, H.; Kahl, D. M.; Ohshiro, Y.; Watanabe, S.; Yamazaki, N.; Teranishi, T.; Yanagisawa, Y.; Wakabayashi, Y.; Kase, M.; Hayakawa, S.; Kwon, Y. K.; Hashimoto, T.; Fukuda, Y.; He, J. J.; Goto, A.; Muto, H.

    2014-05-09

    The lecture includes two parts: One is a discussion on the technology for developing RIB beam facility based on the in-flight method and relevant experimental technology. The second part is a discussion on experimental efforts for studying the breakout process from the pp-chain region based on recent works with low energy RI beams. The discussion of the second part specifically covers the problem of the vp-process in type II supernovae in terms of alpha cluster nature for the reactions.

  15. Low-energy nuclear reaction studies with RI beams in nuclear astrophysics

    NASA Astrophysics Data System (ADS)

    Kubono, S.; Teranishi, T.; Kato, S.

    2003-07-01

    After a brief discussion on the recent development in nuclear astrophysics, two reaction studies of typical astrophysical reactions at low energies where nuclear reactions play the main contributions to the nucleosynthesis in the universe, are discussed. One is the proton capture reaction, 11C(p, γ)12N, studied by the direct method using a 11C beam produced with a new low-energy RIB separator CRIB at CNS, Japan. The second one is the 13C(α, n)16O rearrangement reaction, which is believed to be the main neutron source for the s-process at low temperatures, investigated by an indirect method using the direct α-transfer reaction 13C(6Li, d)17O. Detailed investigations are suggested on the nuclear reactions relevant.

  16. Low energy antiproton beams

    NASA Astrophysics Data System (ADS)

    Klapisch, R.

    1992-04-01

    It was the invention of stochastic cooling by S. Van Meer that has allowed antiproton beams to become a powerful tool for the physicist. As a byproduct of the high energy proton-antiproton collider, a versatile low-energy facility, LEAR has been operating at CERN since 1984. The facility and its characteristics will be described as well as examples of its use for studying fundamental properties of the antiproton and for topics in atomic, nuclear and particle Physics.

  17. Intense low energy positron beams

    SciTech Connect

    Lynn, K.G.; Jacobsen, F.M.

    1993-12-31

    Intense positron beams are under development or being considered at several laboratories. Already today a few accelerator based high intensity, low brightness e{sup +} beams exist producing of the order of 10{sup 8} {minus} 10{sup 9} e{sup +}/sec. Several laboratories are aiming at high intensity, high brightness e{sup +} beams with intensities greater than 10{sup 9} e{sup +}/sec and current densities of the order of 10{sup 13} {minus} 10{sup 14} e{sup +} sec{sup {minus}} {sup 1}cm{sup {minus}2}. Intense e{sup +} beams can be realized in two ways (or in a combination thereof) either through a development of more efficient B{sup +} moderators or by increasing the available activity of B{sup +} particles. In this review we shall mainly concentrate on the latter approach. In atomic physics the main trust for these developments is to be able to measure differential and high energy cross-sections in e{sup +} collisions with atoms and molecules. Within solid state physics high intensity, high brightness e{sup +} beams are in demand in areas such as the re-emission e{sup +} microscope, two dimensional angular correlation of annihilation radiation, low energy e{sup +} diffraction and other fields. Intense e{sup +} beams are also important for the development of positronium beams, as well as exotic experiments such as Bose condensation and Ps liquid studies.

  18. Riken RI Beam Factory, Harvest Time

    NASA Astrophysics Data System (ADS)

    En'yo, H.

    2015-06-01

    At RIKEN RI Beam Factory (RIBF), having all the experimental facilities in place, the uranium-beam intensity recorded 25pnA in 2014. With use of this powerful beam many experiments are begin performed by variety of researchers from all over the world, producing a lot of new data which were just a dream in several years ago. Recent status of RIKEN RI Beam Factory (RIBF) is presented with future prospects in science and an accelerator plan.

  19. RHIC low energy beam loss projections

    SciTech Connect

    Satogata,T.

    2009-08-01

    For RHIC low-energy operations, we plan to collide Au beams with energies of E = 2:5-10 GeV/u in RHIC. Beams are injected into collision optics, and RHIC runs as a storage ring with no acceleration. At these low energies, observed beam lifetimes are minutes, with measured beam lifetimes of 3.5 min (fast) and 50 min (slow) at E=4.6 GeV/u in the March 2008 test run. With these lifetimes we can operate RHIC as a storage ring to produce reasonable integrated luminosity. This note estimates beam losses and collimator/dump energy deposition in normal injection modes of low energy operation. The main question is whether a normal injection run is feasible for an FY10 10-15 week operations run from a radiation safety perspective. A peripheral question is whether continuous injection operations is feasible from a radiation safety perspective. In continuous injection mode, we fill both rings, then continuously extract and reinject the oldest bunches that have suffered the most beam loss to increase the overall integrated luminosity. We expect to gain a factor of 2-3 in integrated luminosity from continuous injection at lowest energies if implemented[1]. Continuous injection is feasible by FY11 from an engineering perspective given enough effort, but the required extra safety controls and hardware dose risk make it unappealing for the projected luminosity improvement. Low-energy electron cooling will reduce beam losses by at least an order of magnitude vs normal low-energy operations, but low energy cooling is only feasible in the FY13 timescale and therefore beyond the scope of this note. For normal injection low energy estimates we assume the following: (1) RHIC beam total energies are E=2.5-10 GeV/u. (Continuous injection mode is probably unnecessary above total energies of E=7-8 GeV/u.); (2) RHIC operates only as a storage ring, with no acceleration; (3) 110 bunches of about 0.5-1.0 x 10{sup 9} initial bunch intensities (50-100% injection efficiency, likely conservative

  20. Low energy beam transport system developments

    NASA Astrophysics Data System (ADS)

    Dudnikov, V.; Han, B.; Stockli, M.; Welton, R.; Dudnikova, G.

    2015-04-01

    For high brightness beam production it is important to preserve the brightness in the low energy beam transport system (LEBT) used to transport and match the ion beams to the next stage of acceleration, usually an RFQ. While electrostatic focusing can be problematic for high current beam transport, reliable electrostatic LEBT operation has been demonstrated with H- beams up to 60 mA. Now, however, it is commonly accepted that an optimal LEBT for high current accelerator applications consists of focusing solenoids with space charge compensation. Two-solenoid LEBTs are successfully used for high current (>100 mA) proton beam transport. Preservation of low emittances (~0.15 π mm-mrad) requires the addition of a heavy gas (Xe, Kr), which causes ~5% of proton loss in a 1 m long LEBT. Similar Xe densities would be required to preserve low emittances of H- beams, but such gas densities cause unacceptably high H- beam losses. A short LEBT with only one short solenoid, movable for RFQ matching, can be used for reduced negative ion stripping. A strong electrostatic-focusing LEBT has been successfully adopted for transport of high current H- beams in the SNS Front End. Some modifications of such electrostatic LEBTs are expected to improve the reliable transport of intense positive and negative ion beams without greatly degrading their low emittances. We concentrate on processes that determine the beam brightness degradation and on their prevention. Proposed improvements to the SNS electrostatic LEBT are discussed.

  1. Low energy beam transport system developments

    SciTech Connect

    Dudnikov, V.; Han, B.; Stockli, M.; Welton, R.; Dudnikova, G.

    2015-04-08

    For high brightness beam production it is important to preserve the brightness in the low energy beam transport system (LEBT) used to transport and match the ion beams to the next stage of acceleration, usually an RFQ. While electrostatic focusing can be problematic for high current beam transport, reliable electrostatic LEBT operation has been demonstrated with H{sup −} beams up to 60 mA. Now, however, it is commonly accepted that an optimal LEBT for high current accelerator applications consists of focusing solenoids with space charge compensation. Two-solenoid LEBTs are successfully used for high current (>100 mA) proton beam transport. Preservation of low emittances (~0.15 π mm-mrad) requires the addition of a heavy gas (Xe, Kr), which causes ~5% of proton loss in a 1 m long LEBT. Similar Xe densities would be required to preserve low emittances of H{sup −} beams, but such gas densities cause unacceptably high H{sup −} beam losses. A short LEBT with only one short solenoid, movable for RFQ matching, can be used for reduced negative ion stripping. A strong electrostatic-focusing LEBT has been successfully adopted for transport of high current H{sup −} beams in the SNS Front End. Some modifications of such electrostatic LEBTs are expected to improve the reliable transport of intense positive and negative ion beams without greatly degrading their low emittances. We concentrate on processes that determine the beam brightness degradation and on their prevention. Proposed improvements to the SNS electrostatic LEBT are discussed.

  2. Nuclear clusters studied with alpha resonant scatterings using RI beams at CRIB

    NASA Astrophysics Data System (ADS)

    Yamaguchi, H.; Kahl, D.; Nakao, T.; Wakabayashi, Y.; Hashimoto, T.; Hayakawa, S.; Kawabata, T.; Teranishi, T.; Kwon, Y. K.; Binh, D. N.; Khiem, L. H.; Duy, N. N.; Kubono, S.; Suhara, T.; Kanada-En'yo, Y.; Moon, J. Y.; Kim, A.; Iwasa, N.; Lee, P. S.; Chae, K. Y.; Cha, S. M.; Gwak, M. S.; Kim, D. H.; Milman, E.

    2014-12-01

    Alpha resonant scattering is a simple and promising method to study α-cluster structure in nuclei. It has several good features which enable us to perform measurements with short-lived and relatively low-intense RI beams. Several measurements on alpha resonant scattering have been carried out at CRIB (CNS Radioactive Ion Beam separator), which is a low-energy RI beam separator at Center for Nuclear Study (CNS) of the University of Tokyo. Recent α resonant scattering studies at CRIB, using 7Li, 7Be and 10Be beams with a helium gas target, are discussed.

  3. Straight low energy beam transport for intense uranium beams

    NASA Astrophysics Data System (ADS)

    Xiao, C.; Groening, L.; Vormann, H.; Mickat, S.; Hollinger, R.; Adonin, A.; Orzhekhovskaya, A.; Maier, M.; Al-Omari, H.; Barth, W.; Kester, O. K.; Yaramyshev, S.

    2015-07-01

    A new high current uranium ion source and dedicated Low Energy Beam Transport (LEBT) will be built at the GSI High Current Injector (HSI). This LEBT will be integrated into the existing complex which already comprises two branches. The paper presents the design and dynamics simulation using the TRACE-3D and TRACK code. The simulation results illustrate that this straight LEBT can transport uranium beams over a wide range of space-charge compensation, and can provide 15.4 (14.2) mA U4+ inside of the effective acceptance of the subsequent RFQ assuming the space-charge is compensated to 100% (95%).

  4. Beam lifetime and limitations during low-energy RHIC operation

    SciTech Connect

    Fedotov, A.V.; Bai, M.; Blaskiewicz, M.; Fischer, W.; Kayran, D.; Montag, C.; Satogata, T.; Tepikian, S.; Wang, G.

    2011-03-28

    The low-energy physics program at the Relativistic Heavy Ion Collider (RHIC), motivated by a search for the QCD phase transition critical point, requires operation at low energies. At these energies, large nonlinear magnetic field errors and large beam sizes produce low beam lifetimes. A variety of beam dynamics effects such as Intrabeam Scattering (IBS), space charge and beam-beam forces also contribute. All these effects are important to understand beam lifetime limitations in RHIC at low energies. During the low-energy RHIC physics run in May-June 2010 at beam {gamma} = 6.1 and {gamma} = 4.1, gold beam lifetimes were measured for various values of space-charge tune shifts, transverse acceptance limitation by collimators, synchrotron tunes and RF voltage. This paper summarizes our observations and initial findings.

  5. Cryogenic gas target system for intense RI beam productions in nuclear astrophysics

    SciTech Connect

    Wakabayashi, Y.; Yamaguchi, H.; Hayakawa, S.; Kurihara, Y.; Amadio, G.; Fujikawa, H.; Kubono, S.; Binh, D. N.; He, J. J.; Kim, A.

    2008-05-21

    A cryogenic gas target system was newly developed to produce intense RI beams at the low-energy in-flight radio-isotope beam separator (CRIB) of the University of Tokyo. The main features of the cryogenic gas target system are the direct cooling of the target cell by a liquid N{sub 2} finger and the circulation of the target gas that goes through the liquid N{sub 2} tank. Hydrogen gas was cooled down to 85-90 K by liquid nitrogen and used as a secondary beam production target which has a thickness of 2.3 mg/cm{sup 2} at the gas pressure of 760 Torr. Intense RI beams, such as a {sup 7}Be beam of 2x10{sup 8} particles per second, were successfully produced using the target.

  6. Construction of the SCRIT electron scattering facility at the RIKEN RI Beam Factory

    NASA Astrophysics Data System (ADS)

    Wakasugi, M.; Ohnishi, T.; Wang, S.; Miyashita, Y.; Adachi, T.; Amagai, T.; Enokizono, A.; Enomoto, A.; Haraguchi, Y.; Hara, M.; Hori, T.; Ichikawa, S.; Kikuchi, T.; Kitazawa, R.; Koizumi, K.; Kurita, K.; Miyamoto, T.; Ogawara, R.; Shimakura, Y.; Takehara, H.; Tamae, T.; Tamaki, S.; Togasaki, M.; Yamaguchi, T.; Yanagi, K.; Suda, T.

    2013-12-01

    The SCRIT electron scattering facility, aiming at electron scattering off short-lived unstable nuclei, has been constructed at the RIKEN RI Beam Factory. This facility consists of a racetrack microtron (RTM), an electron storage ring (SR2) equipped with the SCRIT system, and a low-energy RI separator (ERIS). SCRIT (self-confining radioactive isotope ion targeting) is a novel technique to form internal targets in an electron storage ring. Experiments for evaluating performance of the SCRIT system have been carried out using the stable 133Cs1+ beam and the 132Xe1+ beam supplied from ERIS. Target ions were successfully trapped in the SCRIT system with 90% efficiency at a 250 mA electron beam current, and luminosity exceeding 1026/(cm2 s) was maintained for more than 1 s. Electrons elastically scattered from the target ions were successfully measured. Applicability of the SCRIT system to electron scattering for unstable nuclei has been established in experiments.

  7. Low energy ion beam dynamics of NANOGAN ECR ion source

    NASA Astrophysics Data System (ADS)

    Kumar, Sarvesh; Mandal, A.

    2016-04-01

    A new low energy ion beam facility (LEIBF) has been developed for providing the mass analyzed highly charged intense ion beams of energy ranging from a few tens of keV to a few MeV for atomic, molecular and materials sciences research. The new facility consists of an all permanent magnet 10 GHz electron cyclotron resonance (ECR) ion source (NANOGAN) installed on a high voltage platform (400 kV) which provides large currents of multiply charged ion beams. Higher emittance at low energy of intense ion beam puts a tremendous challenge to the beam optical design of this facility. The beam line consists of mainly the electrostatic quadrupoles, an accelerating section, analyzing cum switching magnet and suitable beam diagnostics including vacuum components. The accelerated ion beam is analyzed for a particular mass to charge (m/q) ratio as well as guided to three different lines along 75°, 90° and 105° using a large acceptance analyzing cum switching magnet. The details of transverse beam optics to all the beam lines with TRANSPORT and GICOSY beam optics codes are being described. Field computation code, OPERA 3D has been utilized to design the magnets and electrostatic quadrupoles. A theoretical estimation of emittance for optimized geometry of ion source is given so as to form the basis of beam optics calculations. The method of quadrupole scan of the beam is used to characterize the emittance of the final beam on the target. The measured beam emittance increases with m/q ratios of various ion beams similar to the trend observed theoretically.

  8. Study on electron beam in a low energy plasma focus

    SciTech Connect

    Khan, Muhammad Zubair; Ling, Yap Seong; San, Wong Chiow

    2014-03-05

    Electron beam emission was investigated in a low energy plasma focus device (2.2 kJ) using copper hollow anode. Faraday cup was used to estimate the energy of the electron beam. XR100CR X-ray spectrometer was used to explore the impact of the electron beam on the target observed from top-on and side-on position. Experiments were carried out at optimized pressure of argon gas. The impact of electron beam is exceptionally notable with two different approaches using lead target inside hollow anode in our plasma focus device.

  9. Pin diode calibration - beam overlap monitoring for low energy cooling

    SciTech Connect

    Drees, A.; Montag, C.; Thieberger, P.

    2015-09-30

    We were trying to address the question whether or not the Pin Diodes, currently installed approximately 1 meter downstream of the RHIC primary collimators, are suitable to monitor a recombination signal from the future RHIC low energy cooling section. A maximized recombination signal, with the Au+78 ions being lost on the collimator, will indicate optimal Au-electron beam overlap as well as velocity matching of the electron beam in the cooling section.

  10. MEIC Proton Beam Formation with a Low Energy Linac

    SciTech Connect

    Zhang, Yuhong

    2015-09-01

    The MEIC proton and ion beams are generated, accumulated, accelerated and cooled in a new green-field ion injector complex designed specifically to support its high luminosity goal. This injector consists of sources, a linac and a small booster ring. In this paper we explore feasibility of a short ion linac that injects low-energy protons and ions into the booster ring.

  11. Linac4 low energy beam measurements with negative hydrogen ions

    SciTech Connect

    Scrivens, R. Bellodi, G.; Crettiez, O.; Dimov, V.; Gerard, D.; Granemann Souza, E.; Guida, R.; Hansen, J.; Lallement, J.-B.; Lettry, J.; Lombardi, A.; Midttun, Ø.; Pasquino, C.; Raich, U.; Riffaud, B.; Roncarolo, F.; Valerio-Lizarraga, C. A.; Wallner, J.; Yarmohammadi Satri, M.; Zickler, T.

    2014-02-15

    Linac4, a 160 MeV normal-conducting H{sup −} linear accelerator, is the first step in the upgrade of the beam intensity available from the LHC proton injectors at CERN. The Linac4 Low Energy Beam Transport (LEBT) line from the pulsed 2 MHz RF driven ion source, to the 352 MHz RFQ (Radiofrequency Quadrupole) has been built and installed at a test stand, and has been used to transport and match to the RFQ a pulsed 14 mA H{sup −} beam at 45 keV. A temporary slit-and-grid emittance measurement system has been put in place to characterize the beam delivered to the RFQ. In this paper a description of the LEBT and its beam diagnostics is given, and the results of beam emittance measurements and beam transmission measurements through the RFQ are compared with the expectation from simulations.

  12. 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.

  13. Molecular Ion Beam Transportation for Low Energy Ion Implantation

    SciTech Connect

    Kulevoy, T. V.; Kropachev, G. N.; Seleznev, D. N.; Yakushin, P. E.; Kuibeda, R. P.; Kozlov, A. V.; Koshelev, V. A.; Hershcovitch, A.; Johnson, B. M.; Gushenets, V. I.; Oks, E. M.; Polozov, S. M.; Poole, H. J.

    2011-01-07

    A joint research and development of steady state intense boron ion sources for 100's of electron-volt ion implanters has been in progress for the past five years. Current density limitation associated with extracting and transporting low energy ion beams result in lower beam currents that in turn adversely affects the process throughput. The transport channel with electrostatic lenses for decaborane (B{sub 10}H{sub 14}) and carborane (C{sub 2}B{sub 10}H{sub 12}) ion beams transportation was developed and investigated. The significant increase of ion beam intensity at the beam transport channel output is demonstrated. The transport channel simulation, construction and experimental results of ion beam transportation are presented.

  14. Developments in low energy electron beam machinery and processes

    NASA Astrophysics Data System (ADS)

    Nablo, S. V.; Chrusciel, J.; Cleghorn, D. A.; Rangwalla, I.

    2003-08-01

    The engineering and development of a new generation of low energy, high power electron beam equipment is presented. Operating voltages range from 80 to 125 kV at widths to 1.65 m. At 110 kV these systems deliver 1000 Mrad m min -1 at 110 kV. Equipment operating power levels and their impact on reducing equipment size and cost are reviewed. The advantages of electron curing at these reduced operating voltages are described. The principles of the electron beam fluidized bed process for the treatment of powders and particulates in high-speed pneumatic transport are discussed. Typical system performances for polymer dissociation and crosslinking, or for agroproduct disinfestation and disinfection are presented. A process for the sterilization of polymer food containers employing the injection of low energy electrons through the open mouth has been developed. Some of its sterilization capabilities for bottles up to 2 l capacity are described.

  15. Spin-Isospin responses via charge exchange reactions of RI beams at SHARAQ

    SciTech Connect

    Shimoura, Susumu

    2012-11-12

    Nuclear spectroscopy via direct reactions of RI beams is discussed focusing on characteristics of charge-exchange reactions of RI beams. Recent experiments using the SHARAQ spectrometer at the RIBF are presented, where isovector spin monopole and spin-non-flip monopole responses are studied by charge exchange reaction of RI beams. Some experimental plans and perspectives are also presented.

  16. A universal slow RI-beam facility at RIKEN RIBF

    SciTech Connect

    Wada, M.; Ishida, Y.; Nakamura, T.; Lioubimov, V.; Kambara, T.; Kanai, Y.; Kojima, T. M.; Nakai, Y.; Okada, K.; Takamine, A.; Yamazaki, Y.; Shiba, S.; Yoshida, A.; Kubo, T.; Ohtani, S.; Noda, K.; Katayama, I.; Varentsov, V.; Wollnik, H.; Schuessler, H. A.

    2006-11-02

    A next-generation slow radioactive nuclear ion beam facility (SLOWRI) which provides slow, high-purity and small emittance ion beams of all elements has been proposed as one of the pricipal experimental facilities at the RIKEN RI-beam factory (RIBF). High energy radioactive ion beams from the projectile fragment separator BigRIPS are thermalized in a large gas catcher cell. The thermal ions in the gas cell are guided and extracted to vacuum by a combination of DC electric fields and inhomogeneous rf fields in the cell (rf ion guide). In the R and D works at the present RIKEN facility, an overall efficiency of {approx_equal} 5% for {approx_equal} 100A MeV 8Li ion beam from the present projectile fragment separator RIPS was achieved and the dependence of the efficiency on the beam intensity was investigated. A first spectroscopy experiment at the prototype SLOWI was performed on Be isotopes.

  17. Low-energy beam transport studies supporting the Spallation Neutron Source 1-MW beam operationa

    SciTech Connect

    Han, Baoxi; Kalvas, T.; Tarvainen, O.; Welton, Robert F; Murray Jr, S N; Pennisi, Terry R; Santana, Manuel; Stockli, Martin P

    2012-01-01

    The H- injector consisting of a cesium enhanced RF-driven ion source and a 2-lens electrostatic low-energy beam transport (LEBT) system supports the Spallation Neutron Source 1-MW beam operation with ~38 mA beam current in the linac at 60 Hz with a pulse length of up to ~1.0 ms. In this work, two important issues associated with the low-energy beam transport are discussed: 1) inconsistent dependence of the post-RFQ beam current on the ion source tilt angle, and 2) high power beam losses on the LEBT electrodes under some off-nominal conditions compromising their reliability.

  18. Low energy, high power hydrogen neutral beam for plasma heating

    NASA Astrophysics Data System (ADS)

    Deichuli, P.; Davydenko, V.; Ivanov, A.; Korepanov, S.; Mishagin, V.; Smirnov, A.; Sorokin, A.; Stupishin, N.

    2015-11-01

    A high power, relatively low energy neutral beam injector was developed to upgrade of the neutral beam system of the gas dynamic trap device and C2-U experiment. The ion source of the injector produces a proton beam with the particle energy of 15 keV, current of up to 175 A, and pulse duration of a few milliseconds. The plasma emitter of the ion source is produced by superimposing highly ionized plasma jets from an array of four arc-discharge plasma generators. A multipole magnetic field produced with permanent magnets at the periphery of the plasma box is used to increase the efficiency and improve the uniformity of the plasma emitter. Multi-slit grids with 48% transparency are fabricated from bronze plates, which are spherically shaped to provide geometrical beam focusing. The focal length of the Ion Optical System (IOS) is 3.5 m and the initial beam diameter is 34 cm. The IOS geometry and grid potentials were optimized numerically to ensure accurate beam formation. The measured angular divergences of the beam are ±0.01 rad parallel to the slits and ±0.03 rad in the transverse direction.

  19. Low energy, high power hydrogen neutral beam for plasma heating.

    PubMed

    Deichuli, P; Davydenko, V; Ivanov, A; Korepanov, S; Mishagin, V; Smirnov, A; Sorokin, A; Stupishin, N

    2015-11-01

    A high power, relatively low energy neutral beam injector was developed to upgrade of the neutral beam system of the gas dynamic trap device and C2-U experiment. The ion source of the injector produces a proton beam with the particle energy of 15 keV, current of up to 175 A, and pulse duration of a few milliseconds. The plasma emitter of the ion source is produced by superimposing highly ionized plasma jets from an array of four arc-discharge plasma generators. A multipole magnetic field produced with permanent magnets at the periphery of the plasma box is used to increase the efficiency and improve the uniformity of the plasma emitter. Multi-slit grids with 48% transparency are fabricated from bronze plates, which are spherically shaped to provide geometrical beam focusing. The focal length of the Ion Optical System (IOS) is 3.5 m and the initial beam diameter is 34 cm. The IOS geometry and grid potentials were optimized numerically to ensure accurate beam formation. The measured angular divergences of the beam are ±0.01 rad parallel to the slits and ±0.03 rad in the transverse direction. PMID:26628137

  20. Low energy, high power hydrogen neutral beam for plasma heating

    SciTech Connect

    Deichuli, P.; Davydenko, V.; Ivanov, A. Mishagin, V.; Sorokin, A.; Stupishin, N.; Korepanov, S.; Smirnov, A.

    2015-11-15

    A high power, relatively low energy neutral beam injector was developed to upgrade of the neutral beam system of the gas dynamic trap device and C2-U experiment. The ion source of the injector produces a proton beam with the particle energy of 15 keV, current of up to 175 A, and pulse duration of a few milliseconds. The plasma emitter of the ion source is produced by superimposing highly ionized plasma jets from an array of four arc-discharge plasma generators. A multipole magnetic field produced with permanent magnets at the periphery of the plasma box is used to increase the efficiency and improve the uniformity of the plasma emitter. Multi-slit grids with 48% transparency are fabricated from bronze plates, which are spherically shaped to provide geometrical beam focusing. The focal length of the Ion Optical System (IOS) is 3.5 m and the initial beam diameter is 34 cm. The IOS geometry and grid potentials were optimized numerically to ensure accurate beam formation. The measured angular divergences of the beam are ±0.01 rad parallel to the slits and ±0.03 rad in the transverse direction.

  1. Low energy beam transport in the NSLS UV-FEL

    SciTech Connect

    Zhang, X.; Gallardo, J.C.

    1993-06-01

    A design of the injection low energy transport line for the proposed NSLS UV-FEL is presented. The main concern is to control the beam transverse emittance dilution due to space charge, energy spread and non-linear forces introduced by magnetic elements. The design considerations to optimize the transport line are discussed including the deleterious effects of space charge and energy spread as modeled by the particle code PARMELA. The results from PARMELA are analyzed, and the concept of slice emittance is used to examine the causes of emittance growth.

  2. Low energy beam transport in the NSLS UV-FEL

    SciTech Connect

    Zhang, X.; Gallardo, J.C.

    1993-01-01

    A design of the injection low energy transport line for the proposed NSLS UV-FEL is presented. The main concern is to control the beam transverse emittance dilution due to space charge, energy spread and non-linear forces introduced by magnetic elements. The design considerations to optimize the transport line are discussed including the deleterious effects of space charge and energy spread as modeled by the particle code PARMELA. The results from PARMELA are analyzed, and the concept of slice emittance is used to examine the causes of emittance growth.

  3. Beam simulation studies of ECR beam extraction and low energy beam transport for FRIB

    NASA Astrophysics Data System (ADS)

    Ren, Haitao; Pozdeyev, Eduard; Lund, Steven M.; Machicoane, Guillaume; Wu, Xiaoyu; Morgan, Glenn

    2016-02-01

    To meet the beam power requirements of 400 kW at the fragmentation target for facility for Rare Isotope Beams (FRIB), simultaneous acceleration of two-charge states should be used for heavier ions. These intense multi-charged ion beams will be produced by a 28 GHz electron cyclotron resonance (ECR) ion source at a high voltage of 35 kV. After extraction, the ion beam will be pre-accelerated to 12 keV/u with a 50 kV platform, transported down to an achromatic charge state selection (CSS) system followed by a vertical transport line, and then injected into a radio frequency quadrupole accelerator. The TRACK code developed at ANL is used to perform the simulations of the ECR beam extraction and low energy beam transport for FRIB. In this study, we include the magnetic field of ECR ion source into simulations. Different initial beam conditions as well as different space charge neutralization levels are tested for the ECR beamline. The beam loss in CSS system and the corresponding protective measures are discussed. The detailed results about the beam dynamic simulation and beam loss in CSS system will be presented in this paper.

  4. Low-energy beam transport studies supporting the spallation neutron source 1-MW beam operation

    SciTech Connect

    Han, B. X.; Welton, R. F.; Murray, S. N. Jr.; Pennisi, T. R.; Santana, M.; Stockli, M. P.; Kalvas, T.; Tarvainen, O.

    2012-02-15

    The H{sup -} injector consisting of a cesium enhanced RF-driven ion source and a 2-lens electrostatic low-energy beam transport (LEBT) system supports the spallation neutron source 1 MW beam operation with {approx}38 mA beam current in the linac at 60 Hz with a pulse length of up to {approx}1.0 ms. In this work, two important issues associated with the low-energy beam transport are discussed: (1) inconsistent dependence of the post-radio frequency quadrupole accelerator beam current on the ion source tilt angle and (2) high power beam losses on the LEBT electrodes under some off-nominal conditions compromising their reliability.

  5. Low-energy beam transport studies supporting the spallation neutron source 1-MW beam operation

    SciTech Connect

    Kalvas, T.; Welton, Robert F; Pennisi, Terry R

    2012-01-01

    The H{sup -} injector consisting of a cesium enhanced RF-driven ion source and a 2-lens electrostatic low-energy beam transport (LEBT) system supports the spallation neutron source 1 MW beam operation with {approx}38 mA beam current in the linac at 60 Hz with a pulse length of up to {approx}1.0 ms. In this work, two important issues associated with the low-energy beam transport are discussed: (1) inconsistent dependence of the post-radio frequency quadrupole accelerator beam current on the ion source tilt angle and (2) high power beam losses on the LEBT electrodes under some off-nominal conditions compromising their reliability.

  6. H{sup -} beam transport experiments in a solenoid low energy beam transport

    SciTech Connect

    Gabor, C.; Back, J. J.; Faircloth, D. C.; Lawrie, S. R.; Letchford, A. P.; Izaola, Z.

    2012-02-15

    The Front End Test Stand (FETS) is located at Rutherford Appleton Laboratory and aims for a high current, fast chopped 3 MeV H{sup -} ion beam suitable for future high power proton accelerators like ISIS upgrade. The main components of the front end are the Penning ion source, a low energy beam transport line, an radio-frequency quadrupole (RFQ) and a medium energy beam transport (MEBT) providing also a chopper section and rebuncher. FETS is in the stage of commissioning its low energy beam transport (LEBT) line consisting of three solenoids. The LEBT has to transport an H{sup -} high current beam (up to 60 mA) at 65 keV. This is the injection energy of the beam into the RFQ. The main diagnostics are slit-slit emittance scanners for each transversal plane. For optimizing the matching to the RFQ, experiments have been performed with a variety of solenoid settings to better understand the actual beam transport. Occasionally, source parameters such as extractor slit width and beam energy were varied as well. The paper also discusses simulations based on these measurements.

  7. Beam dynamics simulations of post low energy beam transport section in RAON heavy ion accelerator

    NASA Astrophysics Data System (ADS)

    Jin, Hyunchang; Jang, Ji-Ho; Jang, Hyojae; Hong, In-Seok

    2016-02-01

    RAON (Rare isotope Accelerator Of Newness) heavy ion accelerator of the rare isotope science project in Daejeon, Korea, has been designed to accelerate multiple-charge-state beams to be used for various science programs. In the RAON accelerator, the rare isotope beams which are generated by an isotope separation on-line system with a wide range of nuclei and charges will be transported through the post Low Energy Beam Transport (LEBT) section to the Radio Frequency Quadrupole (RFQ). In order to transport many kinds of rare isotope beams stably to the RFQ, the post LEBT should be devised to satisfy the requirement of the RFQ at the end of post LEBT, simultaneously with the twiss parameters small. We will present the recent lattice design of the post LEBT in the RAON accelerator and the results of the beam dynamics simulations from it. In addition, the error analysis and correction in the post LEBT will be also described.

  8. Performance of ion surfing rf-carpets for RI beam gas catcher

    NASA Astrophysics Data System (ADS)

    Arai, Fumiya; Ito, Yuta; Katayama, Ichirou; Schury, Peter; Sonoda, Tetsu; Wada, Michiharu; Wollnik, Hermann

    2014-09-01

    High-energy RI beams produced in-flight by fragmentation or fission are used in ion trap-based precision experiments after being stopped in a gas catcher. The stopped ions can be extracted from the gas catcher as a low energy ion beam. In order to transport and extract ions quickly and efficiently, an rf-carpet (RFC) method utilizing a dc potential gradient has been the standard technique. However, such a method is restricted by the transport time to longer half-life isotopes due to the maximum dc gradient that can be supported before electric discharges occur in the gas catcher. To avoid that limitation, a hybrid technique wherein the dc gradient is replaced by a traveling potential wave was proposed, called ``ion surfing''. Recently, we have demonstrated ion extraction using a circular RFC under low and intermediate pressures. For the first time we demonstrated the ion extraction using an rf-carpet in high-pressure He gas. An efficiency of nearly 100% was obtained at 200 mbar He gas pressure for K+ ions.

  9. Transport of intense ion beams and space charge compensation issues in low energy beam lines (invited)

    SciTech Connect

    Chauvin, N.; Delferriere, O.; Duperrier, R.; Gobin, R.; Nghiem, P. A. P.; Uriot, D.

    2012-02-15

    Over the last few years, the interest of the international scientific community for high power accelerators in the megawatt range has been increasing. For such machines, the ion source has to deliver a beam intensity that ranges from several tens up to a hundred of mA. One of the major challenges is to extract and transport the beam while minimizing the emittance growth and optimizing its injection into the radio frequency quadrupole. Consequently, it is crucial to perform precise simulations and cautious design of the low energy beam transport (LEBT) line. In particular, the beam dynamics calculations have to take into account not only the space charge effects but also the space charge compensation of the beam induced by ionization of the residual gas. The physical phenomena occurring in a high intensity LEBT and their possible effects on the beam are presented, with a particular emphasis on space charge compensation. Then, beam transport issues in different kind of LEBTs are briefly reviewed. The SOLMAXP particle-in-cell code dedicated to the modeling of the transport of charge particles under a space charge compensation regime is described. Finally, beam dynamics simulations results obtained with SOLMAXP are presented in the case of international fusion materials irradiation facility injector.

  10. Design study of low-energy beam transport for multi-charge beams at RAON

    NASA Astrophysics Data System (ADS)

    Bahng, Jungbae; Qiang, Ji; Kim, Eun-San

    2015-12-01

    The Rare isotope Accelerator Of Newness (RAON) at the Rare Isotope Science Project (RISP) is being designed to simultaneously accelerate beams with multiple charge states. It includes a driver superconducting (SC) linac for producing 200 MeV/u and 400 kW continuous wave (CW) heavy ion beams from protons to uranium. The RAON consists of a few electron cyclotron resonance ion sources, a low-energy beam transport (LEBT) system, a CW 81.25 MHz, 500 keV/u radio frequency quadrupole (RFQ) accelerator, a medium-energy beam transport system, the SC linac, and a charge-stripper system. The LEBT system for the RISP accelerator facility consists of a high-voltage platform, two 90° dipoles, a multi-harmonic buncher (MHB), solenoids, electrostatic quadrupoles, a velocity equalizer, and a diagnostic system. The ECR ion sources are located on a high-voltage platform to reach an initial beam energy of 10 keV/u. After extraction, the ion beam is transported through the LEBT system to the RFQ accelerator. The generated charge states are selected by an achromatic bending system and then bunched by the MHB in the LEBT system. The MHB is used to achieve a small longitudinal emittance in the RFQ by generating a sawtooth wave with three harmonics. In this paper, we present the results and issues of the beam dynamics of the LEBT system.

  11. Scheme for Low Energy Beam Transport with a Non-Neutralized Section

    SciTech Connect

    Shemyakin, A.; Prost, L.

    2015-04-23

    A typical Low Energy Beam Transport (LEBT) design relies on dynamics with nearly complete beam space charge neutralization over the entire length of the LEBT. This paper argues that, for a beam with modest perveance and uniform current density distribution when generated at the source, a downstream portion of the LEBT can be un-neutralized without significant emittance growth.

  12. Precision shape modification of nanodevices with a low-energy electron beam

    DOEpatents

    Zettl, Alex; Yuzvinsky, Thomas David; Fennimore, Adam

    2010-03-09

    Methods of shape modifying a nanodevice by contacting it with a low-energy focused electron beam are disclosed here. In one embodiment, a nanodevice may be permanently reformed to a different geometry through an application of a deforming force and a low-energy focused electron beam. With the addition of an assist gas, material may be removed from the nanodevice through application of the low-energy focused electron beam. The independent methods of shape modification and material removal may be used either individually or simultaneously. Precision cuts with accuracies as high as 10 nm may be achieved through the use of precision low-energy Scanning Electron Microscope scan beams. These methods may be used in an automated system to produce nanodevices of very precise dimensions. These methods may be used to produce nanodevices of carbon-based, silicon-based, or other compositions by varying the assist gas.

  13. 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.

  14. Synthesis of sputtered thin films in low energy ion beams

    NASA Astrophysics Data System (ADS)

    Howson, R. P.

    1997-01-01

    Magnetron sputtering is a process which gives a highly energetic depositing species. The growing film can be further bombarded with ions of the heavy gas used for sputtering by directing a plasma of it onto the surface. This can be done quite simply by using an unbalanced magnetron. The immersion of an insulating or isolated substrate-film combination in this plasma leads to a self-bias of around 30 V appearing on it's surface and a bombardment of low energy ions of the sputtering gas of several milli-amps per square centimetre. If the residual gas contains a reactive component, to form a compound film, then the gas is made much more reactive and less is needed to form the stoichiometric film. This can take place in a continuously operating system made stable using partial pressure control of the reactive gas with plasma emission monitoring or something similar. It can also be operated when the process of deposition is separated in time from the process of reaction and is repeated to build the film. We have called this process successive-plasma-anodisation (SPA) and it can be achieved by mechanically transferring the substrate between two magnetrons, one to deposit the metal film and one, which is unbalanced, to provide an oxygen plasma. It can also be operated by pulsing the reactive gas under carefully controlled conditions. Examples are given of the synthesis of compound films using low energy ion bombardment with these techniques and it is demonstrated that excellent films of a large range of oxides and nitrides can be made.

  15. Sub-microsecond beam notching at low energy

    SciTech Connect

    Moehs, D.P.; /Fermilab

    2005-09-01

    A technique for creating a burst of 100 ns notches (beam extinctions) in an H{sup -} beam at 454 kHz has been developed at {le} 20 keV utilizing a Magnetron ion source with a slit extraction system and a split extractor. Each half of the extractor is treated as part of a 50 ohm transmission line which can be pulsed at {+-} 700 volts creating a 1400 volt gradient across the extractor. A beam current reduction of better than 95% has been observed at the end of the Fermilab 400 MeV Linac. Notched multi-turn charge-exchange injection into the Booster, a 400 MeV to 8 GeV synchrotron, has been demonstrated with a charge reduction in the resulting beam gap of 83%. Presently, the trailing edge of the notch may be adversely affected by space charge resulting in a beam recovery with two different time constants. Efforts to minimize this effect are discussed.

  16. Status of the PXIE Low Energy Beam Transport Line

    SciTech Connect

    Prost, Lionel; Andrews, Richard; Chen, Alex; Hanna, Bruce; Scarpine, Victor; Shemyakin, Alexander; Steimel, Jim; D'Arcy, Richard

    2014-07-01

    A CW-compatible, pulsed H- superconducting RF linac (a.k.a. PIP-II) is envisaged as a possible path for upgrading Fermilab’s injection complex [1]. To validate the concept of the front-end of such machine, a test accelerator (a.k.a. PXIE) [2] is under construction. The warm part of this accelerator comprises a 10 mA DC, 30 keV H- ion source, a 2m-long LEBT, a 2.1 MeV CW RFQ, and a MEBT that feeds the first cryomodule. In addition to operating in the nominal CW mode, the LEBT should be able to produce a pulsed beam for both PXIE commissioning and modelling of the front-end nominal operation in the pulsed mode. Concurrently, it needs to provide effective means of inhibiting beam as part of the overall machine protection system. A peculiar feature of the present LEBT design is the capability of using the ~1m-long section immediately preceding the RFQ in two regimes of beam transport dynamics: neutralized and space charge dominated. This paper introduces the PXIE LEBT, reports on the status of the ion source and LEBT installation, and presents the first beam measurements.

  17. Universal Slow RI-Beam Facility at RIKEN RIBF for Laser Spectroscopy of Short-Lived Nuclei

    SciTech Connect

    Wada, M.; Takamine, A.; Okada, K.; Sonoda, T.; Schury, P.; Kanai, Y.; Kojima, T. M.; Lioubimov, V.; Yamazaki, Y.; Yoshida, A.; Kubo, T.; Iimura, H.; Katayama, I.; Ohtani, S.; Wollnik, H.; Schuessler, H. A.

    2009-03-17

    A universal slow RI-beam facility (SLOWRI) for precision atomic spectroscopy is being built at the RIKEN RI-beam factory. The facility will provide a wide variety of low-energy nuclear ions of all elements produced by projectile fragmentation of high-energy heavy-ion beams and thermalized by an RF-carpet ion guide. At prototype SLOWRI, radioactive Be isotope ions produced at 1 GeV were decelerated and cooled in an ion trap down to 1 {mu}eV by employing laser cooling. The ground state hyperfine structures of {sup 7}Be{sup +} and {sup 11}Be{sup +} were measured accurately by laser microwave double resonance spectroscopy. Measurements of the S{sub 1/2}{yields}P{sub 1/2}, P{sub 3/2} transition frequencies of {sup 7,9,10,11}Be{sup +} ions are also in progress aiming at the study of the nuclear charge radii. Other possible experiment at SLOWRI, such as mass spectroscopy, are also discussed.

  18. Space charge compensation in the Linac4 low energy beam transport line with negative hydrogen ions

    SciTech Connect

    Valerio-Lizarraga, Cristhian A.; Lallement, Jean-Baptiste; Lettry, Jacques; Scrivens, Richard; Leon-Monzon, Ildefonso; Midttun, Øystein

    2014-02-15

    The space charge effect of low energy, unbunched ion beams can be compensated by the trapping of ions or electrons into the beam potential. This has been studied for the 45 keV negative hydrogen ion beam in the CERN Linac4 Low Energy Beam Transport using the package IBSimu [T. Kalvas et al., Rev. Sci. Instrum. 81, 02B703 (2010)], which allows the space charge calculation of the particle trajectories. The results of the beam simulations will be compared to emittance measurements of an H{sup −} beam at the CERN Linac4 3 MeV test stand, where the injection of hydrogen gas directly into the beam transport region has been used to modify the space charge compensation degree.

  19. Beam life time studies and design optimization of the Ultra-low energy Storage Ring

    NASA Astrophysics Data System (ADS)

    Welsch, C. P.; Papash, A. I.; Harasimowicz, J.; Karamyshev, O.; Karamysheva, G. A.; Newton, D.; Panniello, M.; Putignano, M.; Siggel-King, M. R. F.; Smirnov, A.

    2014-04-01

    The Ultra-low energy electrostatic Storage Ring (USR) at the future Facility for Low-energy Antiproton and Ion Research (FLAIR) will provide cooled beams of antiprotons in the energy range between 300 keV down to 20 keV. Based on the original design concept developed in 2005, the USR has been completely redesigned over the past few years by the QUASAR Group. The ring structure is now based on a 'split achromat' lattice. This ensures compact ring dimensions of 10 m × 10 m, whilst allowing both, in-ring experiments with gas jet targets and studies with extracted beams. In the USR, a wide range of beam parameters shall be provided, ranging from very short pulses in the nanosecond regime to a coasting beam. In addition, a combined fast and slow extraction scheme will be featured that allows for providing external experiments with cooled beams of different time structure. Detailed investigations into the dynamics of low energy beams, including studies into the long term beam dynamics and ion kinetics, beam life time, equilibrium momentum spread and equilibrium lateral spread during collisions with an internal target were carried out. This required the development of new simulation tools to further the understanding of beam storage with electrostatic fields. In addition, studies into beam diagnostics methods for the monitoring of ultra-low energy ions at beam intensities less than 10 6 were carried out. This includes instrumentation for the early commissioning of the machine, as well as for later operation with antiprotons. In this paper, on overview of the technical design of the USR is given with emphasis on two of the most important operating modes, long term beam dynamics and the design of the beam diagnostics system.

  20. Analysis methodology of movable emittance-meter measurements for low energy electron beams.

    PubMed

    Mostacci, A; Bacci, A; Boscolo, M; Chiadroni, E; Cianchi, A; Filippetto, D; Migliorati, M; Musumeci, P; Ronsivalle, C; Rossi, A R

    2008-01-01

    The design of photoinjectors for modern free electron laser linac relies heavily on particular beam behavior in the few meters after the gun. To experimentally characterize it a movable emittance meter was proposed and built [L. Catani et al., Rev. Sci. Instrum. 77, 093301 (2006)] based on the beam slicing technique. This paper addresses all the aspects of analysis of the data acquired with the emittance meter and common to any slit based emittance measurement for low energy beams. PMID:18248027

  1. Surface modification of structural materials by low-energy high-current pulsed electron beam treatment

    SciTech Connect

    Panin, A. V. E-mail: kms@ms.tsc.ru; Kazachenok, M. S. E-mail: kms@ms.tsc.ru; Sinyakova, E. A.; Borodovitsina, O. M.; Ivanov, Yu. F.; Leontieva-Smirnova, M. V.

    2014-11-14

    Microstructure formation in surface layers of pure titanium and ferritic-martensitic steel subjected to electron beam treatment is studied. It is shown that low energy high-current pulsed electron beam irradiation leads to the martensite structure within the surface layer of pure titanium. Contrary, the columnar ferrite grains grow during solidification of ferritic-martensitic steel. The effect of electron beam energy density on the surface morphology and microstructure of the irradiated metals is demonstrated.

  2. Low-energy run of Fermilab Electron Cooler's beam generation system

    SciTech Connect

    Prost, Lionel; Shemyakin, Alexander; Fedotov, Alexei; Kewisch, Jorg; /Brookhaven

    2010-08-01

    As a part of a feasibility study of using the Fermilab Electron Cooler for a low-energy Relativistic Heavy Ion Collider (RHIC) run at Brookhaven National Laboratory (BNL), the cooler operation at 1.6 MeV electron beam energy was tested in a short beam line configuration. The main result of the study is that the cooler beam generation system is suitable for BNL needs. In a striking difference with running 4.3 MeV beam, no unprovoked beam recirculation interruptions were observed.

  3. Production of drip-line nuclei at RIKEN RI Beam Factory

    NASA Astrophysics Data System (ADS)

    Saito, Atsumi

    2014-09-01

    Production cross-sections and secondary-beam yields of very neutron rich nuclei near neutron drip-line at 200--250 MeV/u have been investigated at RIKEN RI Beam Factory (RIBF). RIBF is the next generation RI beam facility, which can produce a variety of exotic nuclei with high intensity. The measurement of production yields of 19B, 22C, which are located on the neutron drip-line, and neighboring isotopes was made on the occasion of the Coulomb and nuclear breakup experiments of these halo nuclei at SAMURAI (Superconducting Analyzer for MUlti-particle from RAdioIsotope beams) facility at RIBF. We used 345 MeV/u 48Ca beam as primary beam, which impinged on 30 mm-thick Be target, to obtain secondary beams by projectile fragmentation. The projectile fragments were then separated through Superconducting RI beam separator BigRIPS, and were identified by measuring time of flight (TOF), energy loss (ΔE), and magnetic rigidity (Bρ) by the standard detectors at 2nd stage of BigRIPS. We thus obtained production cross-sections and yields of carbon and boron isotopes. The production cross-sections and yields extracted were compared with the simulation code LISE using EPAX. We discuss these results and comparisons in this poster presentation.

  4. The production of low-energy neutral oxygen beams by grazing-incidence neutralization

    NASA Technical Reports Server (NTRS)

    Albridge, R. G.; Haglund, R. F.; Tolk, N. H.; Daech, A. F.

    1987-01-01

    The Vanderbilt University neutral oxygen facility produces beams of low-energy neutral oxygen atoms by means of grazing-incidence collisions between ion beams and metal surfaces. Residual ions are reflected by applied electric fields. This method can utilize initial ion beams of either O(+) or O2(+) since a very large percentage of molecular oxygen ions are dissociated when they undergo grazing-incidence neutralization. The method of neutralization is applicable to low-energy beams and to all ions. Particular emphasis is on O and N2 beams for simulation of the low Earth orbit space environment. Since the beam is a pure O-neutral beam and since measurements of the interaction of the beam with solid surfaces are made spectroscopically, absolute reaction rates can be determined. The technique permits the beams to be used in conjunction with electron and photon irradiation for studies of synergistic effects. Comparisons of optical spectra of Kapton excited by 2.5-keV O, O(+), and O2(+) show significant differences. Optical spectra of Kapton excited by neutral oxygen beams of less than 1 keV have been recorded.

  5. Studies of slow-positron production using low-energy primary electron beams.

    SciTech Connect

    Lessner, E.

    1999-04-20

    Slow-positron beams produced from negative-work-function solid-state moderators have found numerous applications in condensed matter physics. There are potential advantages in using low-energy primary electron beams for positron production, including reduced radiation damage to single-crystal moderators and reduced activation of nearby components. We present numerical calculations of positron yields and other beam parameters for various target-moderator configurations using the Argonne Wakefield Accelerator (AWA) [1] and Advanced Photon Source (APS) [2] electron linacs [3] as examples of sources for the primary electron beams. The status of experiments at these facilities is reviewed.

  6. Research methods for parameters of accelerated low-energy proton beam

    NASA Astrophysics Data System (ADS)

    Bystritsky, V. M.; Dudkin, G. N.; Kyznetsov, S. I.; Nechaev, B. A.; Padalko, V. N.; Philippov, A. V.; Sadovsky, A. B.; Varlachev, V. A.; Zvaygintsev, O. A.

    2015-07-01

    To study the pd-reaction cross-section it is necessary to know the main parameters of the accelerated hydrogen ion beam with a high accuracy. These parameters include: the energy ion dispersion; the content of neutrals; the ratio of atomic and molecular ions of hydrogen in the flux of accelerated particles. This work is aimed at development of techniques and the measurement of the above mentioned parameters of the low-energy proton beam.

  7. Low-energy neutrino-nucleus interactions and beta-beam neutrino

    SciTech Connect

    Jachowicz, N.; Pandey, V.

    2015-05-15

    We present an overview of neutrino-nucleus scattering at low energies with cross sections obtained within a continuum random phase approximation (CRPA) formalism. We highlight potential applications of beta-beam neutrino experiments for neutrino astrophysics. Our calculations are compared with MiniBooNe data at intermediate energies.

  8. A new beam loss detector for low-energy proton and heavy-ion accelerators

    NASA Astrophysics Data System (ADS)

    Liu, Zhengzheng; Crisp, Jenna; Russo, Tom; Webber, Robert; Zhang, Yan

    2014-12-01

    The Facility for Rare Isotope Beams (FRIB) to be constructed at Michigan State University shall deliver a continuous, 400 kW heavy ion beam to the isotope production target. This beam is capable of inflicting serious damage on accelerator components, e.g. superconducting RF accelerating cavities. A Beam Loss Monitoring (BLM) System is essential for detecting beam loss with sufficient sensitivity and promptness to inform the machine protection system (MPS) and operations personnel of impending dangerous losses. Radiation transport simulations reveal shortcomings in the use of ionization chambers for the detection of beam losses in low-energy, heavy-ion accelerators. Radiation cross-talk effects due to the folded geometry of the FRIB LINAC pose further complications to locating specific points of beam loss. We propose a newly developed device, named the Loss Monitor Ring (LMR1

  9. Design study of the Low Energy Beam Transport system at RISP

    NASA Astrophysics Data System (ADS)

    Bahng, Jungbae; Kim, Eunsan; Kim, Yonghwan; Hong, In-Seok

    2013-03-01

    We present the design status of LEBT for the RISP that consists of two 90 degree dipoles, a multi-harmonic buncher, pair solenoids, electrostatic quadrupoles and a high voltage platform. After ECR-IS with an energy of 10 keV/u, heavy-ion beams are selected by achromatic bending systems and then be bunched in the LEBT. A multi-harmonic buncher is used to achieve a small longitudinal emittance in the RFQ. We show the results on the optics design by using the TRANSPORT code and the beam tracking of two-charge beams by using the code IMPACT. We present the results and issues on beam dynamics simulaitons in the designed LEBT system. For heavy ion beams in the low energy system, we have to separate and select desire beam. we also transport beam from ECR to RFQ with high transmission.

  10. An electron cyclotron resonance ion source based low energy ion beam platform.

    PubMed

    Sun, L T; Shang, Y; Ma, B H; Zhang, X Z; Feng, Y C; Li, X X; Wang, H; Guo, X H; Song, M T; Zhao, H Y; Zhang, Z M; Zhao, H W; Xie, D Z

    2008-02-01

    To satisfy the requirements of surface and atomic physics study in the field of low energy multiple charge state ion incident experiments, a low energy (10 eV/q-20 keV/q) ion beam platform is under design at IMP. A simple test bench has been set up to test the ion beam deceleration systems. Considering virtues such as structure simplicity, easy handling, compactness, cost saving, etc., an all-permanent magnet ECRIS LAPECR1 [Lanzhou all-permanent magnet electron cyclotron resonance (ECR) ion source No. 1] working at 14.5 GHz has been adopted to produce intense medium and low charge state ion beams. LAPECR1 source has already been ignited. Some intense low charge state ion beams have been produced on it, but the first test also reveals that many problems are existing on the ion beam transmission line. The ion beam transmission mismatches result in the depressed performance of LAPECR1, which will be discussed in this paper. To obtain ultralow energy ion beam, after being analyzed by a double-focusing analyzer magnet, the selected ion beam will be further decelerated by two afocal deceleration lens systems, which is still under design. This design has taken into consideration both ions slowing down and also ion beam focusing. In this paper, the conceptual design of deceleration system will be discussed. PMID:18315202

  11. 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.

  12. Low-Energy Run of Fermilab Electron Cooler's Beam Generation System

    SciTech Connect

    Prost, L.R.; Shemyakin, A.; Fedotov, A.; Kewisch, J.; /Brookhaven

    2011-03-14

    In the context of the evaluation of possibly using the Fermilab Electron Cooler for the proposed low-energy RHIC run at BNL, operating the cooler at 1.6 MeV electron beam energy was tested in a short beam line configuration. The main conclusion of this feasibility study is that the cooler's beam generation system is suitable for BNL needs. The beam recirculation was stable for all tested parameters. In particular, a beam current of 0.38 A was achieved with the cathode magnetic field up to the maximum value presently available of 250 G. The energy ripple was measured to be 40 eV. A striking difference with running the 4.3 MeV beam (nominal for operation at FNAL) is that no unprovoked beam recirculation interruptions were observed. Electron cooling proposed to increase the luminosity of the RHIC collider for heavy ion beam energies below 10 GeV/nucleon [1] needs a good quality, 0.9-5 MeV electron beam. Preliminary design studies indicate that the scheme of the Recycler's electron cooler at FNAL is suitable for low-energy RHIC cooling and most parts of the cooler can be re-used after the end of the Tevatron Run II. To analyze issues related to the generation of the electron beam in the energy recovery mode and to gain experience with the beam transport at lower beam energy, a dedicated study was performed at FNAL with a beam run through a short beam line (so called U-bend). This report summarizes our findings and observations in the course of the measurements.

  13. Restoration of RI-beams from a projectile fragment separator by Laser Ionization gas Catcher-PALIS-

    SciTech Connect

    Sonoda, T.; Takamine, A.; Schury, P.; Yamazaki, Y.; Wada, M.; Okada, K.; Yoshida, A.; Kubo, T.; Matsuo, Y.; Furukawa, T.; Wakui, T.; Shinozuka, T.; Iimura, H.; Katayama, I.; Ohtani, S.; Wollnik, H.; Schuessler, H. A.; Kudryavtsev, Yu.; Van Duppen, P.; Huyse, M.

    2009-03-17

    A fragment separator at heavy ion accelerator facilities is a versatile instrument to provide wide variety of radioactive isotope (RI) beams. However, more than 99.99% of precious RI-ions are simply dumped in the slits or elsewhere in the fragment separator. A novel concept to restore such RI-ions for parasitic slow RI-beams is proposed. Installation of a laser ionization gas catcher in the vicinity of the first or second focal point of the fragment separator enables to collect dead isotopes in the slits. The design concept and expected performance are discussed.

  14. 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.

  15. Low energy nuclear reactions with RIBRAS, Radioactive Ion Beam in Brasil, system

    NASA Astrophysics Data System (ADS)

    Guimarães, V.; Lépine-Szily, A.; Lichtenthäler, R.; de Faria, P. N.; Barioni, A.; Pires, K. C. C.; Morcelle, V.; Mendes, D. R.; Zamora, J. C.; Morais, M. C.; Condori, R. P.; Benjamim, E. A.; Monteiro, D. S.; Crema, E.; Moro, A. M.; Lubian, J.

    2011-09-01

    RIBRAS, Radioactive Ion beam in Brasil, is a system based on superconducting solenoids which can produce low energy RNB (Radioactive Nuclear Beams) at the University of São Paulo, Brazil. Secondary radioactive beams of light particles such as 6He, 7Be and 8Li have been produced and low energy elastic scattering and transfer reaction experiments have been performed. The recent scientific program using this facility includes elastic scattering and transfer reactions of 6He halo nucleus on 9Be, 27Al, 51V and 120Sn targets and 8Li on 9Be, 12C and 51V targets. The total reaction cross section as a function of energy has been extracted from the elastic scattering data and the role of breakup of weakly bound or exotic nuclei is discussed. Also spectroscopic factors have been obtained from the transfer reactions.

  16. Scintillating screens sensitivity and resolution studies for low energy, low intensity beam diagnostics.

    PubMed

    Harasimowicz, Janusz; Cosentino, Luigi; Finocchiaro, Paolo; Pappalardo, Alfio; Welsch, Carsten P

    2010-10-01

    In order to investigate the limits of scintillating screens for beam profile monitoring in the ultra-low energy, ultra-low intensity regime, CsI:Tl, YAG:Ce, and a Tb glass-based scintillating fiber optic plate (SFOP) were tested. The screens response to 200 and 50 keV proton beams with intensities ranging from a few picoampere down to the subfemtoampere region was examined. In the following paper, the sensitivity and resolution studies are presented in detail for CsI:Tl and the SFOP, the two most sensitive screens. In addition, a possible use of scintillators for ultra-low energy antiproton beam monitoring is discussed. PMID:21034082

  17. Low-Energy Plasma Focus Device as an Electron Beam Source

    PubMed Central

    Seong Ling, Yap; Naresh Kumar, Nitturi; Lian Kuang, Lim; Chiow San, Wong

    2014-01-01

    A low-energy plasma focus device was used as an electron beam source. A technique was developed to simultaneously measure the electron beam intensity and energy. The system was operated in Argon filling at an optimum pressure of 1.7 mbar. A Faraday cup was used together with an array of filtered PIN diodes. The beam-target X-rays were registered through X-ray spectrometry. Copper and lead line radiations were registered upon usage as targets. The maximum electron beam charge and density were estimated to be 0.31 μC and 13.5 × 1016/m3, respectively. The average energy of the electron beam was 500 keV. The high flux of the electron beam can be potentially applicable in material sciences. PMID:25544952

  18. Charge neutralized low energy beam transport at Brookhaven 200 MeV linac

    NASA Astrophysics Data System (ADS)

    Raparia, D.; Alessi, J.; Atoian, G.; Zelenski, A.

    2016-02-01

    The H- magnetron source provides about 100 mA H- beam to be match into the radio-frequency quadrupole accelerator. As H- beam traverses through low energy transport, it ionizes the residual gas and electrons are repelled and positive ions are trapped in the beam, due to negative potential of the beam, providing charge neutralization for the H- beam. The neutralization time for the critical density depends upon the background gas and its pressure. Critical density for xenon gas at 35 keV is about 43 times smaller than that of hydrogen and stripping cross section is only 5 times than that of hydrogen gas. We are using xenon gas to reduce neutralization time and to improve transmission through the 200 MeV linac. We are also using pulse nitrogen gas to improve transmission and stability of polarized H- beam from optically pumped polarized ion source.

  19. Charge neutralized low energy beam transport at Brookhaven 200 MeV linac.

    PubMed

    Raparia, D; Alessi, J; Atoian, G; Zelenski, A

    2016-02-01

    The H(-) magnetron source provides about 100 mA H(-) beam to be match into the radio-frequency quadrupole accelerator. As H(-) beam traverses through low energy transport, it ionizes the residual gas and electrons are repelled and positive ions are trapped in the beam, due to negative potential of the beam, providing charge neutralization for the H(-) beam. The neutralization time for the critical density depends upon the background gas and its pressure. Critical density for xenon gas at 35 keV is about 43 times smaller than that of hydrogen and stripping cross section is only 5 times than that of hydrogen gas. We are using xenon gas to reduce neutralization time and to improve transmission through the 200 MeV linac. We are also using pulse nitrogen gas to improve transmission and stability of polarized H(-) beam from optically pumped polarized ion source. PMID:26932107

  20. SUPERCONDUCTING RING CYCLOTRON FOR RIKEN RI BEAM FACTORY IN JAPAN

    SciTech Connect

    Okuno, H.; Dantsuka, T.; Yamada, K.; Kase, M.; Maie, T.; Kamigaito, O.

    2010-04-09

    Since 1997, RIKEN Nishina Center has been constructing the Radioactive Isotope Beam Factory (RIBF) and succeeded in beam commissioning of its accelerator complex at the end of 2006. The world's first superconducting ring cyclotron (SRC) is the final booster in the RIBF accelerator complex which is able to accelerate all-element heavy ions to a speed of about 70% of the velocity of light. The ring cyclotron consists of 6 major superconducting sector magnets with a maximum field of 3.8 T. The total stored energy is 235 MJ, and its overall sizes are 19 m diameter, 8 m height and 8,300 tons. The magnet system assembly was completed in August 2005, and successfully reached the maximum field in November 2005. The first beam was extracted at the end of 2006 and the first uranium beam was extracted in March 2007. However operation of the helium refrigerator was not satisfactory although the commissioning of SRC was successful. Operation was stopped every two month due to degradation of its cooling power. In February 2008 the reason of the degradation was revealed to be oil contamination. Operation of the cryogenic system was restarted from August 2008 after hard task to clean up the helium refrigerator and to add oil separators to the compressor. After restoration long-term steady operation to keep the magnet superconducting continued for about 8 months with no sign of degradation of cooling capacity.

  1. Performance Studies of the Vibration Wire Monitor on the Test Stand with Low Energy Electron Beam

    NASA Astrophysics Data System (ADS)

    Okabe, Kota; Yoshimoto, Masahiro; Kinsho, Michikazu

    In the high intensity proton accelerator as the Japan Proton Accelerator Research Complex (J-PARC) accelerators, serious radiation and residual dose is induced by a small beam loss such a beam halo. Therefore, diagnostics of the beam halo formation is one of the most important issues to control the beam loss. For the beam halo monitor, the vibration wire monitor (VWM) has a potential for investigating the beam halo and weak beam scanning. The VWM has a wide dynamic range, high resolution and the VWM is not susceptible to secondary electrons and electric noises. We have studied the VWM features as a new beam-halo monitor on the test stand with low energy electron gun. The frequency shift of the irradiated vibration wire was confirmed about wire material and the electron beam profile measured by using the VWM was consistent with the results of the Faraday cup measurement. Also we calculated a temperature distribution on the vibration wire which is irradiated by the electron beam with the numerical simulation. The simulations have been fairly successful in reproducing the transient of the irradiated vibration wire frequency measured by test stand experiments. In this paper, we will report a result of performance evaluation for the VWM on the test stands and discuss the VWM for beam halo diagnostic

  2. 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.

  3. Studies on low energy beam transport for high intensity high charged ions at IMP.

    PubMed

    Yang, Y; Sun, L T; Hu, Q; Cao, Y; Lu, W; Feng, Y C; Fang, X; Zhang, X Z; Zhao, H W; Xie, D Z

    2014-02-01

    Superconducting Electron Cyclotron Resonance ion source with Advanced design in Lanzhou (SECRAL) is an advanced fully superconducting ECR ion source at IMP designed to be operational at the microwave frequency of 18-24 GHz. The existing SECRAL beam transmission line is composed of a solenoid lens and a 110° analyzing magnet. Simulations of particle tracking with 3D space charge effect and realistic 3D magnetic fields through the line were performed using particle-in-cell code. The results of the beam dynamics show that such a low energy beam is very sensitive to the space charge effect and significantly suffers from the second-order aberration of the analyzing magnet resulting in large emittance. However, the second-order aberration could be reduced by adding compensating sextupole components in the beam line. On this basis, a new 110° analyzing magnet with relatively larger acceptance and smaller aberration is designed and will be used in the design of low energy beam transport line for a new superconducting ECR ion source SECRAL-II. The features of the analyzer and the corresponding beam trajectory calculation will be detailed and discussed in this paper. PMID:24593453

  4. Studies on low energy beam transport for high intensity high charged ions at IMP

    SciTech Connect

    Yang, Y. Lu, W.; Fang, X.; University of Chinese Academy of Sciences, Beijing 100039 ; Sun, L. T.; Hu, Q.; Cao, Y.; Feng, Y. C.; Zhang, X. Z.; Zhao, H. W.; Xie, D. Z.

    2014-02-15

    Superconducting Electron Cyclotron Resonance ion source with Advanced design in Lanzhou (SECRAL) is an advanced fully superconducting ECR ion source at IMP designed to be operational at the microwave frequency of 18–24 GHz. The existing SECRAL beam transmission line is composed of a solenoid lens and a 110° analyzing magnet. Simulations of particle tracking with 3D space charge effect and realistic 3D magnetic fields through the line were performed using particle-in-cell code. The results of the beam dynamics show that such a low energy beam is very sensitive to the space charge effect and significantly suffers from the second-order aberration of the analyzing magnet resulting in large emittance. However, the second-order aberration could be reduced by adding compensating sextupole components in the beam line. On this basis, a new 110° analyzing magnet with relatively larger acceptance and smaller aberration is designed and will be used in the design of low energy beam transport line for a new superconducting ECR ion source SECRAL-II. The features of the analyzer and the corresponding beam trajectory calculation will be detailed and discussed in this paper.

  5. High beam current shut-off systems in the APS linac and low energy transfer line

    SciTech Connect

    Wang, X.; Knott, M.; Lumpkin, A.

    1994-11-01

    Two independent high beam current shut-off current monitoring systems (BESOCM) have been installed in the APS linac and the low energy transport line to provide personnel safety protection in the event of acceleration of excessive beam currents. Beam current is monitored by a fast current transformer (FCT) and fully redundant supervisory circuits connected to the Access Control Interlock System (ACIS) for beam intensity related shutdowns of the linac. One FCT is located at the end of the positron linac and the other in the low energy transport line, which directs beam to the positron accumulator ring (PAR). To ensure a high degree of reliability, both systems employ a continuous self-checking function, which injects a test pulse to a single-turn test winding after each ``real`` beam pulse to verify that the system is fully functional. The system is designed to be fail-safe for all possible system faults, such as loss of power, open or shorted signal or test cables, loss of external trigger, malfunction of gated integrator, etc. The system has been successfully commissioned and is now a reliable part of the total ACIS.

  6. High-flux source of low-energy neutral beams using reflection of ions from metals

    NASA Technical Reports Server (NTRS)

    Cuthbertson, John W.; Motley, Robert W.; Langer, William D.

    1992-01-01

    Reflection of low-energy ions from surfaces can be applied as a method of producing high-flux beams of low-energy neutral particles, and is an important effect in several areas of plasma technology, such as in the edge region of fusion devices. We have developed a beam source based on acceleration and reflection of ions from a magnetically confined coaxial RF plasma source. The beam provides a large enough flux to allow the energy distribution of the reflected neutrals to be measured despite the inefficiency of detection, by means of an electrostatic cylindrical mirror analyzer coupled with a quadrupole mass spectrometer. Energy distributions have been measured for oxygen, nitrogen, and inert gas ions incident with from 15 to 70 eV reflected from amorphous metal surfaces of several compositions. For ions of lighter atomic mass than the reflecting metal, reflected beams have peaked energy distributions; beams with the peak at 4-32 eV have been measured. The energy and mass dependences of the energy distributions as well as measurements of absolute flux, and angular distribution and divergence are reported. Applications of the neutral beams produced are described.

  7. A feasibility study of beam-chopping at low energy for LANSCE

    SciTech Connect

    Tai-Sen Wang; Channell, P.J.; Mottershead, C.T.

    1996-10-01

    This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). If a beam-chopping system could be developed for the Los Alamos Meson Physics Facility low-energy beam line, there would be potential to operate the Los Alamos Neutron Scattering Center (LANSCE) at much higher power and duty factor and enable such operation with a radio-frequency quadrapole (RFQ) injector. This would greatly extend the capability of the facility. To accommodate LANSCE operation in the new configuration, a chopped beam must be created in the low-energy transport line before the RFQ. Chopping in this region has never been demonstrated and constitutes the major uncertainty of the proposal and determines the critical path for project completion. This study produces a better understanding of the physics involved in chopping an H-beam in a dilute plasma background, and in transporting a chopped H-beam through a neutralized or partially neutralized plasma channel, as well as an estimate for the optimum neutralization strategy for the beam chopping and transport between the ion source and the RFQ.

  8. Low-energy ion beam-based deposition of gallium nitride

    NASA Astrophysics Data System (ADS)

    Vasquez, M. R.; Wada, M.

    2016-02-01

    An ion source with a remote plasma chamber excited by a 13.56 MHz radio frequency power was used for low-energy broad ion beam extraction. Optical emission spectral analyses showed the sputtering and postionization of a liquid gallium (Ga) target placed in a chamber separated from the source bombarded by argon (Ar) plasma guided by a bent magnetic field. In addition, an E × B probe successfully showed the extraction of low-energy Ga and Ar ion beams using a dual-electrode extractor configuration. By introducing dilute amounts of nitrogen gas into the system, formation of thin Ga-based films on a silicon substrate was demonstrated as determined from X-ray diffraction and X-ray reflectivity studies.

  9. Low-energy ion beam-based deposition of gallium nitride.

    PubMed

    Vasquez, M R; Wada, M

    2016-02-01

    An ion source with a remote plasma chamber excited by a 13.56 MHz radio frequency power was used for low-energy broad ion beam extraction. Optical emission spectral analyses showed the sputtering and postionization of a liquid gallium (Ga) target placed in a chamber separated from the source bombarded by argon (Ar) plasma guided by a bent magnetic field. In addition, an E × B probe successfully showed the extraction of low-energy Ga and Ar ion beams using a dual-electrode extractor configuration. By introducing dilute amounts of nitrogen gas into the system, formation of thin Ga-based films on a silicon substrate was demonstrated as determined from X-ray diffraction and X-ray reflectivity studies. PMID:26932113

  10. 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.

  11. Development of a low-energy beam transport system at KBSI heavy-ion accelerator

    NASA Astrophysics Data System (ADS)

    Bahng, Jungbae; Lee, Byoung-Seob; Sato, Yoichi; Ok, Jung-Woo; Park, Jin Yong; Yoon, Jang-Hee; Choi, Seyong; Won, Mi-Sook; Kim, Eun-San

    2015-01-01

    The Korea Basic Science Institute has developed a heavy ion accelerator for fast neutron radiography [1]. To meet the requirements for fast neutron generation, we have developed an accelerator system that consists of an electron cyclotron resonance ion source (ECR-IS), low-energy beam transport (LEBT) system, radio-frequency quadrupole (RFQ), medium-energy beam transport system, and drift tube linac. In this paper, we present the development of the LEBT system as a part of the heavy ion accelerator system, which operates from the ECR-IS to the RFQ entrance.

  12. Beam measurements on the H- source and Low Energy Beam Transport system for the Spallation Neutron Source

    SciTech Connect

    Thomae, R.; Gough, R.; Keller, R.; Leung, K.N.; Schenkel, T.; Aleksandrov, A.; Stockli, M.; Welton, R.

    2001-09-01

    The ion source and Low Energy Beam Transport section of the front-end systems presently being built by Berkeley Lab are required to provide 50 mA of H - beam current at 6% duty factor (1 ms pulses at 60 Hz) with a normalized rms emittance of less than 0.20 p-mm-mrad. Experimental results, including emittance, chopping, and steering measurements, on the performance of the ion source and LEBT system operated at the demanded beam parameters will be discussed.

  13. Low-impedance plasma systems for generation of high-current low-energy electron beams

    NASA Astrophysics Data System (ADS)

    Agafonov, A. V.

    2006-12-01

    The results of experimental investigation and numerical modeling of the generation of low-energy (tens of keV) high-current (up to tens of kA) electron beams in a low-impedance system consisting of a plasma-filled diode with a long plasma anode, an auxiliary hot cathode, and an explosive emission cathode. The low-current low-voltage beam from the auxiliary cathode in an external longitudinal magnetic field is used to produce a long plasma anode, which is simultaneously the channel of beam transportation by residual gas ionization. The high-current electron beam is formed from the explosive emission cathode placed in the preliminarily formed plasma. Numerical modeling is performed using the KARAT PIC code.

  14. Design of the low energy beam transport line between CARIBU and the EBIS charge breeder

    NASA Astrophysics Data System (ADS)

    Perry, A.; Ostroumov, P. N.; Barcikowski, A.; Dickerson, C.; Kondrashev, S. A.; Mustapha, B.; Savard, G.

    2015-01-01

    An Electron Beam Ion Source Charge Breeder (EBIS-CB) has been developed to breed radioactive beams from the CAlifornium Rare Isotope Breeder Upgrade (CARIBU) facility at ATLAS. The EBIS-CB will replace the existing ECR charge breeder to increase the intensity and improve the purity of reaccelerated radioactive ion beams. The EBIS-CB is in the final stage of off-line commissioning. Currently, we are developing a low energy beam transport (LEBT) system to transfer CARIBU beams to the EBIS-CB. As was originally planned, an RFQ cooler-buncher will precede the EBIS-CB. Recently, it was decided to include a multi-reflection time-of-flight (MR-TOF) mass-spectrometer following the RFQ. MR-TOF is a relatively new technology used to purify beams with a mass-resolving power up to 3×105 as was demonstrated in experiments at CERN/ISOLDE. Very high purity singly-charged radioactive ion beams will be injected into the EBIS for charge breeding and due to its inherent properties, the EBIS-CB will maintain the purity of the charge bred beams. Possible contamination of residual gas ions will be greatly suppressed by achieving ultra-high vacuum in the EBIS trap. This paper will present and discuss the design of the LEBT and the overall integration of the EBIS-CB into ATLAS.

  15. Design of the low energy beam transport line between CARIBU and the EBIS charge breeder

    SciTech Connect

    Perry, A.; Ostroumov, P. N.; Barcikowski, A.; Dickerson, C.; Kondrashev, S. A.; Mustapha, B.; Savard, G.

    2015-01-09

    An Electron Beam Ion Source Charge Breeder (EBIS-CB) has been developed to breed radioactive beams from the CAlifornium Rare Isotope Breeder Upgrade (CARIBU) facility at ATLAS. The EBIS-CB will replace the existing ECR charge breeder to increase the intensity and improve the purity of reaccelerated radioactive ion beams. The EBIS-CB is in the final stage of off-line commissioning. Currently, we are developing a low energy beam transport (LEBT) system to transfer CARIBU beams to the EBIS-CB. As was originally planned, an RFQ cooler-buncher will precede the EBIS-CB. Recently, it was decided to include a multi-reflection time-of-flight (MR-TOF) mass-spectrometer following the RFQ. MR-TOF is a relatively new technology used to purify beams with a mass-resolving power up to 3×10{sup 5} as was demonstrated in experiments at CERN/ISOLDE. Very high purity singly-charged radioactive ion beams will be injected into the EBIS for charge breeding and due to its inherent properties, the EBIS-CB will maintain the purity of the charge bred beams. Possible contamination of residual gas ions will be greatly suppressed by achieving ultra-high vacuum in the EBIS trap. This paper will present and discuss the design of the LEBT and the overall integration of the EBIS-CB into ATLAS.

  16. Nano-ranged low-energy ion-beam-induced DNA transfer in biological cells

    NASA Astrophysics Data System (ADS)

    Yu, L. D.; Wongkham, W.; Prakrajang, K.; Sangwijit, K.; Inthanon, K.; Thongkumkoon, P.; Wanichapichart, P.; Anuntalabhochai, S.

    2013-06-01

    Low-energy ion beams at a few tens of keV were demonstrated to be able to induce exogenous macromolecules to transfer into plant and bacterial cells. In the process, the ion beam with well controlled energy and fluence bombarded living cells to cause certain degree damage in the cell envelope in nanoscales to facilitate the macromolecules such as DNA to pass through the cell envelope and enter the cell. Consequently, the technique was applied for manipulating positive improvements in the biological species. This physical DNA transfer method was highly efficient and had less risk of side-effects compared with chemical and biological methods. For better understanding of mechanisms involved in the process, a systematic study on the mechanisms was carried out. Applications of the technique were also expanded from DNA transfer in plant and bacterial cells to DNA transfection in human cancer cells potentially for the stem cell therapy purpose. Low-energy nitrogen and argon ion beams that were applied in our experiments had ranges of 100 nm or less in the cell envelope membrane which was majorly composed of polymeric cellulose. The ion beam bombardment caused chain-scission dominant damage in the polymer and electrical property changes such as increase in the impedance in the envelope membrane. These nano-modifications of the cell envelope eventually enhanced the permeability of the envelope membrane to favor the DNA transfer. The paper reports details of our research in this direction.

  17. A pepper-pot emittance meter for low-energy heavy-ion beams

    SciTech Connect

    Kremers, H. R.; Beijers, J. P. M.; Brandenburg, S.

    2013-02-15

    A novel emittance meter has been developed to measure the four-dimensional, transverse phase-space distribution of a low-energy ion beam using the pepper-pot technique. A characteristic feature of this instrument is that the pepper-pot plate, which has a linear array of holes in the vertical direction, is scanned horizontally through the ion beam. This has the advantage that the emittance can also be measured at locations along the beam line where the beam has a large horizontal divergence. A set of multi-channel plates, scintillation screen, and ccd camera is used as a position-sensitive ion detector allowing a large range of beam intensities that can be handled. This paper describes the design, construction, and operation of the instrument as well as the data analysis used to reconstruct the four-dimensional phase-space distribution of an ion beam. Measurements on a 15 keV He{sup +} beam are used as an example.

  18. Status of the SNS H- ion source and low-energy beam transport system

    SciTech Connect

    Keller, R.; Thomae, R.; Stockli, M.; Welton, R.

    2002-04-01

    The ion source and Low-Energy Transport (LEBT) system that will provide H{sup -} ion beams to the Spallation Neutron Source (SNS) Front End and the accelerator chain have been developed into a mature unit that will satisfy the operational needs through the commissioning and early operating phases of SNS. The ion source was derived from the SSC ion source, and many of its original features have been improved to achieve reliable operation at 6% duty factor, producing beam currents in the 35-mA range and above. The LEBT utilizes purely electrostatic focusing and includes static beam-steering elements and a pre-chopper. This paper will discuss the latest design features of the ion source and LEBT, give performance data for the integrated system, and report on relevant commissioning results obtained with the SNS RFQ accelerator. Perspectives for further improvements will be outlined in concluding remarks.

  19. Neutralization of space charge on high-current low-energy ion beam by low-energy electrons supplied from silicon based field emitter arrays

    SciTech Connect

    Gotoh, Yasuhito; Tsuji, Hiroshi; Taguchi, Shuhei; Ikeda, Keita; Kitagawa, Takayuki; Ishikawa, Junzo; Sakai, Shigeki

    2012-11-06

    Neutralization of space charge on a high-current and low-energy ion beam was attempted to reduce the divergence with an aid of low-energy electrons supplied from silicon based field emitter arrays (Si-FEAs). An argon ion beam with the energy of 500 eV and the current of 0.25 mA was produced by a microwave ion source. The initial beam divergence and the emittance were measured at the entrance of the analysis chamber in order to estimate the intrinsic factors for beam divergence. The current density distribution of the beam after transport of 730 mm was measured by a movable Faraday cup, with and without electron supply from Si-FEAs. A similar experiment was performed with tungsten filaments as an electron source. The results indicated that the electron supply from FEA had almost the same effect as the thermionic filament, and it was confirmed that both electron sources can neutralize the ion beam.

  20. Transport of intense proton beam in the presence of subdominant species in a low energy beam transport system

    NASA Astrophysics Data System (ADS)

    Babu, P. Sing; Goswami, A.; Pandit, V. S.

    2016-04-01

    The dynamics of space-charge-dominated low energy proton beam in the presence of H2+ and H3+ beams has been studied in a solenoid based transport system using particle-in-cell (PIC) simulation method. Multispecies envelope equation and random search technique have been used to transport and match the primary beam considering two options. The PIC simulation shows the formation of hollow distribution of H2+ and H3+ beams around the proton beam in the first case where the waist of the proton beam is formed in between the solenoids and it is absent in the second case where the beam size is kept large in between the solenoids. Separation of hollow distribution appears more distinct as the proton fraction is increased and is almost independent of the combination of H2+ and H3+ beams for a given proton fraction. This effect helps to reject the unwanted species more effectively. The evolution of rms size and emittance of the proton beam has been studied in the presence of a circular aperture using KV and Gaussian distributions for the species in both the cases.

  1. Transferring Gus gene into intact rice cells by low energy ion beam

    NASA Astrophysics Data System (ADS)

    Zengliang, Yu; Jianbo, Yang; Yuejin, Wu; Beijiu, Cheng; Jianjun, He; Yuping, Huo

    1993-06-01

    A new technique of transferring genes by low energy ion beam has been reported in this paper. The Gus and CAT (chloramphenicol acetyltransferase) genes, as "foreign" genetic materials, were introduced into the suspension cells and ripe embryos or rice by implantation of 20-30 keV Ar + at doses ranging from 1 × 10 15 to 4 × 10 15 ions/cm 2. The activities of CAT and Gus were detected in the cells and embryos after several weeks. The results indicate that the transfer was a success.

  2. Overview of Alternative Bunching and Current-shaping Techniques for Low-Energy Electron Beams

    SciTech Connect

    Piot, Philippe

    2015-12-01

    Techniques to bunch or shape an electron beam at low energies (E <15 MeV) have important implications toward the realization of table-top radiation sources [1] or to the design of compact multi-user free-electron lasers[2]. This paper provides an overview of alternative methods recently developed including techniques such as wakefield-based bunching, space-charge-driven microbunching via wave-breaking [3], ab-initio shaping of the electron-emission process [4], and phase space exchangers. Practical applications of some of these methods to foreseen free-electron-laser configurations are also briefly discussed [5].

  3. Generation of a pulsed low-energy electron beam using the channel spark device.

    PubMed

    Elgarhy, M A I; Hassaballa, S E; Rashed, U M; ElSabbagh, M M; Soliman, H M; Saudy, A H

    2015-12-01

    For the generation of low-energy electron beam, the design and characteristics of channel spark discharge (CSD) operating at a low voltage are presented in this paper. The discharge voltage, discharge current, X-ray emissions, and electron beam current were experimentally determined. The effects of the applied voltage, working gas pressure, and external capacitance on the CSD and beam parameters were measured. At an applied voltage of 11 kV, an oxygen gas pressure of 25 mTorr, and an external capacitance of 16.45 nF, the maximum measured current was 900 A. The discharge current increased with the increase in the pressure and capacitance, while its periodic time decreased with the increase in the pressure. Two types of the discharge were identified and recorded: the hollow cathode discharge and the conduction discharge. A Faraday cup was used to measure the beam current. The maximum measured beam current was 120 A, and the beam signal exhibited two peaks. The increase in both the external capacitance and the applied discharge voltage increased the maximum electron beam current. The electron-beam pulse time decreased with the increase in the gas pressure at a constant voltage and increased with the decrease in the applied discharge voltage. At an applied voltage of 11 kV and an oxygen gas pressure of 15 mTorr, the maximum beam energy was 2.8 keV. The X-ray signal intensity decreased with the increase in the gas pressure and increased with the increase in the capacitance. PMID:26724026

  4. Generation of a pulsed low-energy electron beam using the channel spark device

    NASA Astrophysics Data System (ADS)

    Elgarhy, M. A. I.; Hassaballa, S. E.; Rashed, U. M.; ElSabbagh, M. M.; Soliman, H. M.; Saudy, A. H.

    2015-12-01

    For the generation of low-energy electron beam, the design and characteristics of channel spark discharge (CSD) operating at a low voltage are presented in this paper. The discharge voltage, discharge current, X-ray emissions, and electron beam current were experimentally determined. The effects of the applied voltage, working gas pressure, and external capacitance on the CSD and beam parameters were measured. At an applied voltage of 11 kV, an oxygen gas pressure of 25 mTorr, and an external capacitance of 16.45 nF, the maximum measured current was 900 A. The discharge current increased with the increase in the pressure and capacitance, while its periodic time decreased with the increase in the pressure. Two types of the discharge were identified and recorded: the hollow cathode discharge and the conduction discharge. A Faraday cup was used to measure the beam current. The maximum measured beam current was 120 A, and the beam signal exhibited two peaks. The increase in both the external capacitance and the applied discharge voltage increased the maximum electron beam current. The electron-beam pulse time decreased with the increase in the gas pressure at a constant voltage and increased with the decrease in the applied discharge voltage. At an applied voltage of 11 kV and an oxygen gas pressure of 15 mTorr, the maximum beam energy was 2.8 keV. The X-ray signal intensity decreased with the increase in the gas pressure and increased with the increase in the capacitance.

  5. Generation of a pulsed low-energy electron beam using the channel spark device

    SciTech Connect

    Elgarhy, M. A. I. Hassaballa, S. E.; Rashed, U. M.; ElSabbagh, M. M.; Saudy, A. H.; Soliman, H. M.

    2015-12-15

    For the generation of low-energy electron beam, the design and characteristics of channel spark discharge (CSD) operating at a low voltage are presented in this paper. The discharge voltage, discharge current, X-ray emissions, and electron beam current were experimentally determined. The effects of the applied voltage, working gas pressure, and external capacitance on the CSD and beam parameters were measured. At an applied voltage of 11 kV, an oxygen gas pressure of 25 mTorr, and an external capacitance of 16.45 nF, the maximum measured current was 900 A. The discharge current increased with the increase in the pressure and capacitance, while its periodic time decreased with the increase in the pressure. Two types of the discharge were identified and recorded: the hollow cathode discharge and the conduction discharge. A Faraday cup was used to measure the beam current. The maximum measured beam current was 120 A, and the beam signal exhibited two peaks. The increase in both the external capacitance and the applied discharge voltage increased the maximum electron beam current. The electron-beam pulse time decreased with the increase in the gas pressure at a constant voltage and increased with the decrease in the applied discharge voltage. At an applied voltage of 11 kV and an oxygen gas pressure of 15 mTorr, the maximum beam energy was 2.8 keV. The X-ray signal intensity decreased with the increase in the gas pressure and increased with the increase in the capacitance.

  6. Radiation-Thermal Sintering of Zirconia Powder Compacts Under Conditions of Bilateral Heating Using Beams of Low-Energy Electrons

    NASA Astrophysics Data System (ADS)

    Ghyngazov, S. A.; Frangulyan, T. S.; Chernyavskii, A. V.; Goreev, A. K.; Naiden, E. P.

    2015-06-01

    Comparative experiments on sintering zirconia ceramics are performed using colliding beams of low-energy electrons and under conditions of thermal heating. The density and microhardness of ceramic materials manufactured via different processes are determined. The use of a regime of bilateral heating by high-intensity,low-energy electron beams is shown to intensify the sintering process and yield material specimens with improved characteristics compared to those formed by thermal sintering.

  7. Electrical and optoelectrical modification of cadmium sulfide nanobelts by low-energy electron beam irradiation.

    PubMed

    Zhang, Lijie; Liu, Manman; Zhao, Mei; Dong, Youqing; Zou, Chao; Yang, Keqin; Yang, Yun; Huang, Shaoming; Zhu, Da-Ming

    2016-09-30

    In this report, we describe a method for modifying electrical and optoelectrical properties of CdS nanobelts using low-energy (lower than 10 keV) e-beam irradiation in a scanning electron microscope. The electrical conductivity of the nanobelts was dramatically improved via the irradiation of e-beams. The modified conductivity of the nanobelts depends on the energy of the e-beam; it exhibits a larger photocurrent and higher external quantum efficiency but slower time-response than that before the modification. A possible mechanism about the modification is the increase of electron accumulation (injected electrons) in the nanobelts due to e-beam irradiation. In addition, the optoelectrical modification could be caused by the trapped electrons in the nanobelts and the decrease of contact resistance between the nanobelts and metal electrodes induced by e-beam irradiation. The results of this work are significant for the in situ study of semiconductor nanostructures in the electron microscope. Besides, the method of electrical and optoelectrical modification presented here has potential application in electronics and optoelectronics. PMID:27561004

  8. Improved design of proton source and low energy beam transport line for European Spallation Source

    NASA Astrophysics Data System (ADS)

    Neri, L.; Celona, L.; Gammino, S.; Mascali, D.; Castro, G.; Torrisi, G.; Cheymol, B.; Ponton, A.; Galatà, A.; Patti, G.; Gozzo, A.; Lega, L.; Ciavola, G.

    2014-02-01

    The design update of the European Spallation Source (ESS) accelerator is almost complete and the construction of the prototype of the microwave discharge ion source able to provide a proton beam current larger than 70 mA to the 3.6 MeV Radio Frequency Quadrupole (RFQ) started. The source named PS-ESS (Proton Source for ESS) was designed with a flexible magnetic system and an extraction system able to merge conservative solutions with significant advances. The ESS injector has taken advantage of recent theoretical updates and new plasma diagnostics tools developed at INFN-LNS (Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare). The design strategy considers the PS-ESS and the low energy beam transport line as a whole, where the proton beam behaves like an almost neutralized non-thermalized plasma. Innovative solutions have been used as hereinafter described. Thermo-mechanical optimization has been performed to withstand the chopped beam and the misaligned focused beam over the RFQ input collimator; the results are reported here.

  9. Improved design of proton source and low energy beam transport line for European Spallation Source

    SciTech Connect

    Neri, L. Celona, L.; Gammino, S.; Mascali, D.; Castro, G.; Ciavola, G.; Torrisi, G.; Cheymol, B.; Ponton, A.; Galatà, A.; Patti, G.; Gozzo, A.; Lega, L.

    2014-02-15

    The design update of the European Spallation Source (ESS) accelerator is almost complete and the construction of the prototype of the microwave discharge ion source able to provide a proton beam current larger than 70 mA to the 3.6 MeV Radio Frequency Quadrupole (RFQ) started. The source named PS-ESS (Proton Source for ESS) was designed with a flexible magnetic system and an extraction system able to merge conservative solutions with significant advances. The ESS injector has taken advantage of recent theoretical updates and new plasma diagnostics tools developed at INFN-LNS (Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare). The design strategy considers the PS-ESS and the low energy beam transport line as a whole, where the proton beam behaves like an almost neutralized non-thermalized plasma. Innovative solutions have been used as hereinafter described. Thermo-mechanical optimization has been performed to withstand the chopped beam and the misaligned focused beam over the RFQ input collimator; the results are reported here.

  10. 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

  11. Characteristics of Al2O3 gate dielectrics partially fluorinated by a low energy fluorine beam

    NASA Astrophysics Data System (ADS)

    Kim, Sung Woo; Park, Byoung Jae; Kang, Se Koo; Kong, Bo Hyun; Cho, Hyung Koun; Yeom, Geun Young; Heo, Sungho; Hwang, Hyunsang

    2008-11-01

    The partial fluorination of Al2O3 gate dielectrics was examined by exposing an oxide-nitride-aluminum oxide (ONA) stack to a low energy fluorine beam, and its effect on the properties of the ONA was investigated. Exposing ONA to about 10 eV fluorine beam resulted in a 5-nm-thick AlOxFy layer on the ONA by replacing some Al-O to Al-F. The electrical properties such as leakage current and memory window characteristics were improved after fluorination of the ONA, possibly due to the improved charge trapping characteristics through the formation of an AlOxFy layer on the Al2O3 without changing the blocking layer thickness.

  12. Recent Activities at the Low-Energy Beam and Ion Trap Facility at NSCL

    NASA Astrophysics Data System (ADS)

    Bustabad, Scott; Bollen, Georg; Brodeur, Maxime; Lincoln, David; Novario, Samuel; Redshaw, Matthew; Ringle, Ryan; Schwarz, Stefan; Valverde, Adrian

    2013-10-01

    The Low-Energy Beam and Ion Trap (LEBIT) facility, for high precision Penning trap mass measurements, has been relocated and upgraded for the expansion of the thermalized beam program at NSCL. I will summarize the changes to the facility and will focus on recent atomic mass measurements of candidates for neutrinoless double- β decay experiments including 82Se and 48Ca. I will also present the first results from the recent successful LEBIT commissioning experiment and will conclude by discussing the exciting future opportunities with the upgraded facility. This work was supported by Michigan State University, the National Science Foundation under Contract No. PHY-1102511, and the Office of Science US Dept of Energy under Grant 03ER-41268.

  13. High intensity ion guides and purification techniques for low energy radioactive ion beams

    NASA Astrophysics Data System (ADS)

    Grévy, S.

    2016-06-01

    This report gives an overview of the different devices which can be used for the purification of high intensity low energy radioactive ion beams: high resolution magnetic separators (HRS), multi-reflection time-of-flight mass separators (MR-TOF-MS) and Penning traps (PT). An overview of HRS, existing or in development, and the methods to increase the resolving power are presented. The MR-TOF-MS of ISOLTRAP and other projects having been presented during this conference, only the main characteristics of such devices are discussed. Concerning the PT, intensively used to measure masses with high precisions, we will present the PIPERADE project which aims to provide pure beams of exotic nuclei with unprecedent intensities at the future DESIR/SPIRAL2 facility.

  14. 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.

  15. The water equivalence of solid phantoms for low energy photon beams

    SciTech Connect

    Hill, Robin; Kuncic, Zdenka; Baldock, Clive

    2010-08-15

    Purpose: To compare and evaluate the dosimetric water equivalence of several commonly used solid phantoms for low energy photon beams. Methods: A total of ten different solid phantom materials was used in the study. The PENELOPE Monte Carlo code was used to calculate depth doses and beam profiles in all the phantom materials as well as the dose to a small water voxel at the surface of the solid phantom. These doses were compared to the corresponding doses calculated in a water phantom. The primary photon beams used ranged in energy from 50 to 280 kVp. Results: A number of phantom materials had excellent agreement in dose compared to water for all the x-ray beam energies studied. RMI457 Solid Water, Virtual Water, PAGAT, A150, and Plastic Water DT all had depth doses that agreed with those in water to within 2%. For these same phantom materials, the dose changes in the water voxel at the surface of the solid phantom were within 2%, except for A150, which agreed to within 2.7%. By comparison, the largest differences in depth doses occurred for Plastic Water (-21.7%) and polystyrene (17.6%) for the 50 kVp energy photon beam and 8 cm diameter field size. Plastic Water gave the largest difference in the normalized beam profiles with differences of up to 3.5% as compared to water. Surface dose changes, due to the presence of the solid phantom acting as the backscatter material, were found to be up to 9.1% for polystyrene with significant differences also found for Plastic Water, PMMA, and RW3 phantoms. Conclusions: The following solid phantoms can be considered water equivalent and are recommended for relative dosimetry of low energy photon beams: A150, PAGAT, Plastic Water DT, RMI457 Solid Water, and Virtual Water. However, the following solid phantoms give significant differences, compared to water, in depth doses, profiles, and/or in surface doses due to backscatter changes: Plastic Water, PMMA, polystyrene, PRESAGE, and RW3.

  16. Recent Performance of the SNS H- ion source and low-energy beam transport system

    SciTech Connect

    Stockli, Martin P; Ewald, Kerry D; Han, Baoxi; Murray Jr, S N; Pennisi, Terry R; Piller, Chip; Santana, Manuel; Tang, Johnny Y; Welton, Robert F

    2014-01-01

    Recent measurements of the H beam current show that SNS is injecting about 55 mA into the RFQ compared to 45 mA in 2010. Since 2010, the H beam exiting the RFQ dropped from 40 mA to 34 mA, which is sufficient for 1 MW of beam power. To minimize the impact of the RFQ degradation, the service cycle of the best performing source was extended to 6 weeks. The only degradation is fluctuations in the electron dump voltage towards the end of some service cycles, a problem that is being investigated. Very recently, the RFQ was retuned, which partly restored its transmission. In addition, the electrostatic low-energy beam transport system was reengineered to double its heat sinking and equipped with a thermocouple that monitors the temperature of the ground electrode between the two Einzel lenses. The recorded data show that emissions from the source at high voltage dominate the heat load. Emissions from the partly Cs-covered first lens cause the temperature to peak several hours after starting up. On rare occasions, the temperature can also peak due to corona discharges between the center ground electrode and one of the lenses.

  17. Graphene treatment using a very low energy Ar+ ion beam for residue removal.

    PubMed

    Min, Kyoung Seok; Kim, Ki Seok; Kim, Kyoung Nam; Mishra, Anurag; Yeom, Geun Young

    2014-12-01

    The effect of Ar+ ion energy on the removal of the polymethyl methacrylate (PMMA) residue remaining on the chemical vapor deposited (CVD) graphene surface without damaging the graphene surface was investigated. Stable and low energy Ar+ ion beams having a mono-energetic energy distribution with a peak energy of 7.5 eV or 11.5 eV could be formed by using a two-grid magnetically enhanced ICP ion gun with and without the application of 25 Gauss axial magnetic field, respectively, while controlling the Ar gas flow rate. When the CVD graphene treatment was performed with the Ar+ ions having the ion energy peak at 7.5 eV (with the magnetic field) and 11.5 eV (without the magnetic field), the blue shift of Raman G peak from p-type doped to intrinsic graphene indicating the removal of residue on the graphene surface could be observed for both conditions, however, the graphene treated at 11.5 eV (without the magnetic field) showed the increase of the defect while that treated at 7.5 eV (with the magnetic field) showed no significant change of the defect. It is believed that, for the treatment of CVD graphene, possibly due to the low binding energy area such as grain boundaries and domains in the CVD graphene, low energy ions with less than the energy of 10 eV is required not to damage the graphene surface, and a magnetically enhanced ICP ion gun which can provide stable and low energy Ar+ ions with a mono-energetic ion energy distribution with a peak of 7.5 eV can be applicable to the residue removal on the graphene surface. PMID:25971019

  18. Characterization of hydrogen binding to tungsten and beryllium surfaces using low energy ion beam analysis

    NASA Astrophysics Data System (ADS)

    Kolasinski, Robert; Whaley, Josh

    2015-11-01

    In this study, we use low energy ion beam analysis to determine how hydrogen interacts with tungsten and beryllium surfaces. The goal of this work is to provide insight into processes that contribute to recycling from plasma-facing surfaces in magnetic fusion devices. Here we have applied low energy ion scattering (LEIS) to enable detection of adsorbed hydrogen at sub-monolayer resolution and to provide isotopic sensitivity. We probe the surfaces of interest with He + and Ne + at energies less than 5 keV to determine the structure and composition of the first few atomic layers. This approach enables us to examine how hydrogen surface concentrations evolve in real time, providing insight into adsorption kinetics. In addition, we have developed a means of determining the hydrogen binding configuration at different temperatures by exploiting mechanisms of ion channeling along surfaces. Using these methods, we have been able to identify hydrogen binding configurations for the W(100) +H, W(110) +H, and Be(0001) +H adsorption systems. We also report on our efforts to more accurately and efficiently model atomic collisions during scattering, key steps needed to extract structural information from LEIS signals. 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. DOE's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  19. Evaluation of low energy electron beam dose application by means of a portable optical device

    NASA Astrophysics Data System (ADS)

    Reitzig, Manuela; Winkler, Martin; Härtling, Thomas; Röder, Olaf; Opitz, Jörg

    2014-11-01

    We present our recent development concerning the evaluation of a low energy dose application to electron beam responding materials with a simple portable optical device. Electron beam irradiation is a promising option to sterilize sensitive and high performance products or surfaces at a low temperature and without moisture. Especially in the fields of the food industry and medicine, regulations regarding sterility are increasingly tightened. Because of this, a secure proof for electron-beam-assisted sterilization is required. However, no nondestructive and in situ method exists up until now. Our approach to provide a secure proof of sterilization is to place a suitable marker material based on rare-earth-doped phosphors inside or on the top of the packaging material of the respective product. Upon electron irradiation the marker material changes its luminescence properties as a function of the applied energy dose. We verified the energy dependence by means of time-resolved measurements of the luminescence decay of an upconversion phosphor with a portable optical device. In our experimental realization, short laser pulses in the near-infrared range are triggered by a microcontrol unit (MCU) and excite the marker material. The light emitted by the marker is collected in the range between 400 and 1100 nm via a silicon photodiode, processed by the MCU, and analyzed in a Labview program via a single-exponential fit. As a main result, we observe an increasing reduction of the luminescence lifetime with higher dose applications.

  20. Synthesis Of Noble Metal Nanoparticle Composite Glasses Using Low Energy Ion Beam Mixing

    SciTech Connect

    Varma, Ranjana S.; Kothari, D. C.; Mahadkar, A. G.; Kulkarni, N. A.; Kanjilal, D.; Kumar, P.

    2010-12-01

    Carbon coated thin films of Cu or Au on fused silica glasses have been irradiated using 100 keV Ar{sup +} ions at different fluences ranging from 1x10{sup 13} to 1x10{sup 16} ion/cm{sup 2}. In this article, we explore a route to form noble metal nanoparticles in amorphous glass matrices without post irradiation annealing using low energy ion beam mixing where nuclear energy loss process is dominant. Optical and structural properties were studied using UV-Vis-NIR absorbance spectroscopy and Glancing angle X-ray Diffraction (GXRD). Results showed that Cu and Au nanoparticles are formed at higher fluence of 1x10{sup 16} ion/cm{sup 2} used in this work without annealing. The diameters of metal nanoparticles obtained from UV-Vis NIR and GXRD are in agreement.

  1. Experiments with highly ionized low-energy tandem accel-decel beams

    SciTech Connect

    Jones, K.W.; Johnson, B.M.; Meron, M.; Da-Hai, W.; Thieberger, P.; Barrette, J.; Schuch, R.; Schmidt-Boecking, H.; Tserruya, I.; Kruse, T.H.

    1982-01-01

    The present status of the production of low-energy highly ionized beams by the 4-stage tandem accel-decel method is surveyed, and their use in three atomic physics experiments is summarized. The experiments are: the measurement of the charge state dependence of K-x-ray production in S/sup +q/-Ar collisions at 10 MeV, the impact-parameter dependence of quasimolecular x rays in S/sup +15/-Ar collisions again at 10 MeV, and the determination of charge transfer cross sections in S/sup +q/ + Ar, He collisions. The results of the three experiments give evidence that the 4-stage accel-decel ion production technique is extremely powerful and useful.

  2. Low-energy beam test results of a calorimeter prototype for the CREAM experiment

    NASA Astrophysics Data System (ADS)

    Bagliesi, M. G.; Lomtadze, T.; Maestro, P.; Marrocchesi, P. S.; Meucci, M.; Millucci, V.; Morsani, F.; Valle, G.; Ahn, H. S.; Ganel, O.; Kim, K. C.; Lee, M. H.; Lutz, L.; Seo, E. S.

    2003-09-01

    CREAM (Cosmic Ray Energetics And Mass) is an experiment under construction for a direct measurement of high energy cosmic rays (1012 to > 5 · 1014 eV) over the elemental range from proton to iron. The first flight of CREAM is intended to demonstrate the new Ultra Long Duration Balloon (ULDB) capability under development by NASA. A prototype of a tungsten-SciFi imaging calorimeter designed for CREAM has been tested at CERN with electron beam energies ranging from 5 to 100 GeV. Although the calorimeter module is optimized for cosmic-ray spectral measurements in the multi-TeV region, the response of its electromagnetic section to low energy electrons has been studied with this dedicated prototype. Results show good agreement with the expected behaviour in terms of linearity and energy resolution.

  3. Correlation measurements in nuclear {beta}-decay using traps and polarized low energy beams

    SciTech Connect

    Naviliat-Cuncic, Oscar

    2013-05-06

    Precision measurements in nuclear {beta}-decay provide sensitive means to test discrete symmetries in the weak interaction and to determine some of the fundamental constants in semi-leptonic decays, like the coupling of the lightest quarks to charged weak bosons. The main motivation of such measurements is to find deviations from Standard Model predictions as possible indications of new physics. In this contribution I will focus on two topics related to precision measurements in nuclear {beta}-decay: i) the determination of the V{sub ud} element of the Cabibbo-Kobayashi-Maskawa quark mixing matrix from nuclear mirror transitions and ii) the search for exotic scalar or tensor contributions from {beta}{nu} angular correlations. The purpose is to underline the role being played by experimental techniques based on the confinement of radioactive species with atom and ion traps as well as the plans to use low energy polarized beams.

  4. Surface modification and metallization of polycarbonate using low energy ion beam

    NASA Astrophysics Data System (ADS)

    Reheem, A. M. Abdel; Maksoud, M. I. A. Abdel; Ashour, A. H.

    2016-08-01

    The low energy argon ion is used for irradiation polycarbonate samples using cold cathode ion source. The surface of the PC substrates is examined using SEM, UV-spectroscopy and FTIR. It was found that the energy band gap decrease by increase argon ion fluence. Copper films are deposited onto polycarbonate (PC) substrates after irradiation by argon ion beam. The structure, surface morphology and the optical band gap are investigated using XRD, SEM and UV spectroscopy. It can be seen that the intensity increases with deposition time and band gap decreases from 3.45 eV for the pristine PC to ∼1.7 eV for copper thin film.

  5. Monte Carlo dose calculation improvements for low energy electron beams using eMC.

    PubMed

    Fix, Michael K; Frei, Daniel; Volken, Werner; Neuenschwander, Hans; Born, Ernst J; Manser, Peter

    2010-08-21

    The electron Monte Carlo (eMC) dose calculation algorithm in Eclipse (Varian Medical Systems) is based on the macro MC method and is able to predict dose distributions for high energy electron beams with high accuracy. However, there are limitations for low energy electron beams. This work aims to improve the accuracy of the dose calculation using eMC for 4 and 6 MeV electron beams of Varian linear accelerators. Improvements implemented into the eMC include (1) improved determination of the initial electron energy spectrum by increased resolution of mono-energetic depth dose curves used during beam configuration; (2) inclusion of all the scrapers of the applicator in the beam model; (3) reduction of the maximum size of the sphere to be selected within the macro MC transport when the energy of the incident electron is below certain thresholds. The impact of these changes in eMC is investigated by comparing calculated dose distributions for 4 and 6 MeV electron beams at source to surface distance (SSD) of 100 and 110 cm with applicators ranging from 6 x 6 to 25 x 25 cm(2) of a Varian Clinac 2300C/D with the corresponding measurements. Dose differences between calculated and measured absolute depth dose curves are reduced from 6% to less than 1.5% for both energies and all applicators considered at SSD of 100 cm. Using the original eMC implementation, absolute dose profiles at depths of 1 cm, d(max) and R50 in water lead to dose differences of up to 8% for applicators larger than 15 x 15 cm(2) at SSD 100 cm. Those differences are now reduced to less than 2% for all dose profiles investigated when the improved version of eMC is used. At SSD of 110 cm the dose difference for the original eMC version is even more pronounced and can be larger than 10%. Those differences are reduced to within 2% or 2 mm with the improved version of eMC. In this work several enhancements were made in the eMC algorithm leading to significant improvements in the accuracy of the dose

  6. Optical transition radiation used in the diagnostic of low energy and low current electron beams in particle accelerators

    SciTech Connect

    Silva, T. F.; Bonini, A. L.; Lima, R. R.; Maidana, N. L.; Malafronte, A. A.; Pascholati, P. R.; Vanin, V. R.; Martins, M. N.

    2012-09-15

    Optical transition radiation (OTR) plays an important role in beam diagnostics for high energy particle accelerators. Its linear intensity with beam current is a great advantage as compared to fluorescent screens, which are subject to saturation. Moreover, the measurement of the angular distribution of the emitted radiation enables the determination of many beam parameters in a single observation point. However, few works deals with the application of OTR to monitor low energy beams. In this work we describe the design of an OTR based beam monitor used to measure the transverse beam charge distribution of the 1.9-MeV electron beam of the linac injector of the IFUSP microtron using a standard vision machine camera. The average beam current in pulsed operation mode is of the order of tens of nano-Amps. Low energy and low beam current make OTR observation difficult. To improve sensitivity, the beam incidence angle on the target was chosen to maximize the photon flux in the camera field-of-view. Measurements that assess OTR observation (linearity with beam current, polarization, and spectrum shape) are presented, as well as a typical 1.9-MeV electron beam charge distribution obtained from OTR. Some aspects of emittance measurement using this device are also discussed.

  7. Optical transition radiation used in the diagnostic of low energy and low current electron beams in particle accelerators.

    PubMed

    Silva, T F; Bonini, A L; Lima, R R; Maidana, N L; Malafronte, A A; Pascholati, P R; Vanin, V R; Martins, M N

    2012-09-01

    Optical transition radiation (OTR) plays an important role in beam diagnostics for high energy particle accelerators. Its linear intensity with beam current is a great advantage as compared to fluorescent screens, which are subject to saturation. Moreover, the measurement of the angular distribution of the emitted radiation enables the determination of many beam parameters in a single observation point. However, few works deals with the application of OTR to monitor low energy beams. In this work we describe the design of an OTR based beam monitor used to measure the transverse beam charge distribution of the 1.9-MeV electron beam of the linac injector of the IFUSP microtron using a standard vision machine camera. The average beam current in pulsed operation mode is of the order of tens of nano-Amps. Low energy and low beam current make OTR observation difficult. To improve sensitivity, the beam incidence angle on the target was chosen to maximize the photon flux in the camera field-of-view. Measurements that assess OTR observation (linearity with beam current, polarization, and spectrum shape) are presented, as well as a typical 1.9-MeV electron beam charge distribution obtained from OTR. Some aspects of emittance measurement using this device are also discussed. PMID:23020369

  8. Poster — Thur Eve — 22: A water calorimeter for low-energy particle beams

    SciTech Connect

    Renaud, J; Sarfehnia, A; Seuntjens, J; Rossomme, S; Vynckier, S

    2014-08-15

    In this work, the feasibility of absolute dose to water measurements in low-energy electron beams using a water calorimeter specifically developed for shallow measurements is established. The calorimeter design consists of a cylindrical glass vessel encased in a block of expanded polystyrene. The vessel has a front window thickness of 1.1 mm, a 4 cm radius, and is 2.5 cm in depth. The vessel-block assembly sits inside a thermally-insulated box and is air-cooled to an operating temperature of 4 °C. Radiation-induced thermal gradients were simulated in a geometric model of the calorimeter using a finite element analysis software package. 52 absorbed dose to water measurements were performed in a 6 and 8 MeV electron beam (z{sub max} of 1.32 and 1.76 cm, respectively) for 60 seconds at a repetition rate of 400 MU/min and an SSD of 120 cm. Within the vessel, the depth of measurement was set to 1.08 cm relative to the inner front window. The average measured dose to water was 59.6 ± 0.2 cGy/100 MU (6 MeV), and 63.7 ± 0.3 cGy/100 MU (8 MeV). The associated heat transfer corrections were determined to be 1.026 ± 0.003 and 1.017 ± 0.004 for the 6 and 8 MeV beams, respectively. The most significant source of uncertainty in this study was the repeatability (type A, 0.42%). It is expected that performing fewer consecutive measurements under higher dose rate conditions will improve the stability of the thermal background, thereby improving the repeatability and reducing the overall standard uncertainty.

  9. Research and development of H- ion source and low energy beam transport for a kaon-neutrino factory.

    PubMed

    Ji, Q; Staples, J; Sy, A; Schenkel, T; Li, D

    2012-02-01

    A baseline H(-) ion source and low energy beam transport (LEBT) system have been identified for Project X. The filament-discharge H(-) ion source has been fabricated by D-Pace, Inc. and is now in operation at LBNL. The source is capable of delivering over 10 mA of H(-) beam in cw operation with normalized 4 rms emittances less than 0.7 π mm mrad. A two-solenoid magnetic lens LEBT system has been design. The design has been validated with simulations of beam transport for 5 mA 30 keV H(-) beams using various simulation codes. PMID:22380227

  10. Investigation of Mn-implanted n-Si by low-energy ion beam deposition

    NASA Astrophysics Data System (ADS)

    Liu, Lifeng; Chen, Nuofu; Song, Shulin; Yin, Zhigang; Yang, Fei; Chai, Chunlin; Yang, Shaoyan; Liu, Zhikai

    2005-01-01

    Mn ions were implanted to n-type Si(0 0 1) single crystal by low-energy ion beam deposition technique with an energy of 1000 eV and a dose of 7.5×10 17 cm -2. The samples were held at room temperature and at 300 °C during implantation. Auger electron spectroscopy depth profiles of samples indicate that the Mn ions reach deeper in the sample implanted at 300 °C than in the sample implanted at room temperature. X-ray diffraction measurements show that the structure of the sample implanted at room temperature is amorphous while that of the sample implanted at 300 °C is crystallized. There are no new phases found except silicon both in the two samples. Atomic force microscopy images of samples indicate that the sample implanted at 300 °C has island-like humps that cover the sample surface while there is no such kind of characteristic in the sample implanted at room temperature. The magnetic properties of samples were investigated by alternating gradient magnetometer (AGM). The sample implanted at 300 °C shows ferromagnetic behavior at room temperature.

  11. Characterization of a Gafchromic film for the two-dimensional profile measurement of low-energy heavy-ion beams

    NASA Astrophysics Data System (ADS)

    Yuri, Yosuke; Narumi, Kazumasa; Yuyama, Takahiro

    2016-08-01

    The feasibility of the transverse intensity distribution measurement of low-energy (keV/u range) heavy-ion beams using radiochromic films is experimentally explored. We employ a Gafchromic radiochromic film, HD-V2, whose active layer is not laminated by a surface-protection layer. The coloration response of films irradiated with several ion beams is characterized in terms of optical density (OD) by reading the films with a general-purpose scanner. To explore the energy dependence of the film response widely, the kinetic energy of the beams is varied from 1.5 keV/u to 27 MeV/u. We have found that the coloration of HD-V2 films is induced by irradiation with low-energy ion beams of the order of 10 keV/u. The range of the beams is considerably shorter than the thickness of the film's active layer. The dependence of OD response on ion species is also discussed. We demonstrate that the Gafchromic film used here is useful for measuring the intensity distribution of such low-energy ion beams.

  12. High current density ion beam obtained by a transition to a highly focused state in extremely low-energy region

    NASA Astrophysics Data System (ADS)

    Hirano, Y.; Kiyama, S.; Fujiwara, Y.; Koguchi, H.; Sakakita, H.

    2015-11-01

    A high current density (≈3 mA/cm2) hydrogen ion beam source operating in an extremely low-energy region (Eib ≈ 150-200 eV) has been realized by using a transition to a highly focused state, where the beam is extracted from the ion source chamber through three concave electrodes with nominal focal lengths of ≈350 mm. The transition occurs when the beam energy exceeds a threshold value between 145 and 170 eV. Low-level hysteresis is observed in the transition when Eib is being reduced. The radial profiles of the ion beam current density and the low temperature ion current density can be obtained separately using a Faraday cup with a grid in front. The measured profiles confirm that more than a half of the extracted beam ions reaches the target plate with a good focusing profile with a full width at half maximum of ≈3 cm. Estimation of the particle balances in beam ions, the slow ions, and the electrons indicates the possibility that the secondary electron emission from the target plate and electron impact ionization of hydrogen may play roles as particle sources in this extremely low-energy beam after the compensation of beam ion space charge.

  13. High current density ion beam obtained by a transition to a highly focused state in extremely low-energy region.

    PubMed

    Hirano, Y; Kiyama, S; Fujiwara, Y; Koguchi, H; Sakakita, H

    2015-11-01

    A high current density (≈3 mA/cm(2)) hydrogen ion beam source operating in an extremely low-energy region (E(ib) ≈ 150-200 eV) has been realized by using a transition to a highly focused state, where the beam is extracted from the ion source chamber through three concave electrodes with nominal focal lengths of ≈350 mm. The transition occurs when the beam energy exceeds a threshold value between 145 and 170 eV. Low-level hysteresis is observed in the transition when E(ib) is being reduced. The radial profiles of the ion beam current density and the low temperature ion current density can be obtained separately using a Faraday cup with a grid in front. The measured profiles confirm that more than a half of the extracted beam ions reaches the target plate with a good focusing profile with a full width at half maximum of ≈3 cm. Estimation of the particle balances in beam ions, the slow ions, and the electrons indicates the possibility that the secondary electron emission from the target plate and electron impact ionization of hydrogen may play roles as particle sources in this extremely low-energy beam after the compensation of beam ion space charge. PMID:26628125

  14. High current density ion beam obtained by a transition to a highly focused state in extremely low-energy region

    SciTech Connect

    Hirano, Y. E-mail: hirano.yoichi@phys.cst.nihon-u.ac.jp; Kiyama, S.; Koguchi, H.; Fujiwara, Y.; Sakakita, H.

    2015-11-15

    A high current density (≈3 mA/cm{sup 2}) hydrogen ion beam source operating in an extremely low-energy region (E{sub ib} ≈ 150–200 eV) has been realized by using a transition to a highly focused state, where the beam is extracted from the ion source chamber through three concave electrodes with nominal focal lengths of ≈350 mm. The transition occurs when the beam energy exceeds a threshold value between 145 and 170 eV. Low-level hysteresis is observed in the transition when E{sub ib} is being reduced. The radial profiles of the ion beam current density and the low temperature ion current density can be obtained separately using a Faraday cup with a grid in front. The measured profiles confirm that more than a half of the extracted beam ions reaches the target plate with a good focusing profile with a full width at half maximum of ≈3 cm. Estimation of the particle balances in beam ions, the slow ions, and the electrons indicates the possibility that the secondary electron emission from the target plate and electron impact ionization of hydrogen may play roles as particle sources in this extremely low-energy beam after the compensation of beam ion space charge.

  15. RAPD and SSR Polymorphisms in Mutant Lines of Transgenic Wheat Mediated by Low Energy Ion Beam

    NASA Astrophysics Data System (ADS)

    Wang, Tiegu; Huang, Qunce; Feng, Weisen

    2007-10-01

    Two types of markers-random amplified polymorphic DNA (RAPD) and simple sequence repeat DNA (SSR)-have been used to characterize the genetic diversity among nine mutant lines of transgenic wheat intermediated by low energy ion beam and their four receptor cultivars. The objectives of this study were to analyze RAPD-based and SSR-based genetic variance among transgenic wheat lines and with their receptors, and to find specific genetic markers of special traits of transgenic wheat lines. 170 RAPD primers were amplified to 733 fragments in all the experimental materials. There were 121 polymorphic fragments out of the 733 fragments with a ratio of polymorphic fragments of 16.5%. 29 SSR primer pairs were amplified to 83 fragments in all the experiment materials. There were 57 polymorphic fragments out of the 83 fragments with a ratio of polymorphic fragments of 68.7%. The dendrograms were prepared based on a genetic distance matrix using the UPGMA (Unweighted Pair-group Method with Arithmetic averaging) algorithm, which corresponded well to the results of the wheat pedigree analysis and separated the 13 genotypes into four groups. Association analysis between RAPD and SSR markers with the special traits of transgenic wheat mutant lines discovered that three RAPD markers, s1, opt-16, and f14, were significantly associated with the muticate trait, while three SSR markers, Rht8 (Xgwm261), Rht-B1b, and Rht-D1b, highly associated with the dwarf trait. These markers will be useful for marker-assistant breeding and can be used as candidate markers for further gene mapping and cloning.

  16. Common features of particle beams and x-rays generated in a low energy dense plasma focus device

    SciTech Connect

    Behbahani, R. A.; Xiao, C.

    2015-02-15

    Features of energetic charged particle beams and x-ray emission in a low energy (1–2 kJ) plasma focus (DPF) device are described and the possible mechanism are explained based on circuit analyses and energy balance in the DPF system. In particular, the resistance and the voltage across the plasma column are estimated to explain the mechanisms of the generation of particle beams and hard x-ray. The analysis shows that the total inductance of a DPF might have played a role for enhancement of the particle beams and x-ray emissions during the phase of anomalous resistance.

  17. Semiconductor-based heterostructure formation using low energy ion beams: Ion beam deposition (IBD) and combined ion and molecular beam deposition (CIMD)

    SciTech Connect

    Herbots, N.; Hellman, O.C.; Cullen, P.A.; Vancauwenberghe, O.

    1988-09-15

    In our previous work, we investigated the use of ion beam deposition (IBD) to grow epitaxial films at temperatures lower than those used in thermal processing (less than 500/sup 0/C). Presently, we have applied IBD to the growth of dense (6.4 x 10/sup 22/ atom/cm/sup 3/) silicon dioxide thin films at 400/sup 0/C. Through these experiments we have found several clues to the microscopic processes leading to the formation of thin film phases by low energy ions. Using Monte-Carlo simulations, we have found that low energy collision cascades in silicon have unique features such as a high probability of relocation events that refill vacancies as they are created. Our results show that the combination of a low defect density in low energy collision cascades with the high mobility of interstitials in covalent materials can be used to athermally generate atomic displacements tha can lead to ordering. These displacements can lead to epitaxial ordering at substrate temperatures below the minimum temperature necessary for molecular beam epitaxy (550/sup 0/C). It can also lead to the formation of high quality silicon dioxide at temperatures well below that of thermal oxidation in silicon (i.e. <850/sup 0/C). A growth model which we derive from these observations provides a fundamental understanding of how atomic collisions can be used to induce epitaxy or compound formation at low temperatures.

  18. Simulation studies for operating electron beam ion trap at very low energy for disentangling edge plasma spectra

    SciTech Connect

    Jin Xuelong; Fei Zejie; Xiao Jun; Lu Di; Hutton, Roger; Zou Yaming

    2012-07-15

    Electron beam ion traps (EBITs) are very useful tools for disentanglement studies of atomic processes in plasmas. In order to assist studies on edge plasma spectroscopic diagnostics, a very low energy EBIT, SH-PermEBIT, has been set up at the Shanghai EBIT lab. In this work, simulation studies for factors which hinder an EBIT to operate at very low electron energies were made based on the Tricomp (Field Precision) codes. Longitudinal, transversal, and total kinetic energy distributions were analyzed for all the electron trajectories. Influences from the electron current and electron energy on the energy depression caused by the space charge are discussed. The simulation results show that although the energy depression is most serious along the center of the electron beam, the electrons in the outer part of the beam are more likely to be lost when an EBIT is running at very low energy. Using the simulation results to guide us, we successfully managed to reach the minimum electron beam energy of 60 eV with a beam transmission above 57% for the SH-PermEBIT. Ar and W spectra were measured from the SH-PermEBIT at the apparent electron beam energies (read from the voltage difference between the electron gun cathode and the central drift tube) of 60 eV and 1200 eV, respectively. The spectra are shown in this paper.

  19. Simulation studies for operating electron beam ion trap at very low energy for disentangling edge plasma spectra

    NASA Astrophysics Data System (ADS)

    Jin, Xuelong; Fei, Zejie; Xiao, Jun; Lu, Di; Hutton, Roger; Zou, Yaming

    2012-07-01

    Electron beam ion traps (EBITs) are very useful tools for disentanglement studies of atomic processes in plasmas. In order to assist studies on edge plasma spectroscopic diagnostics, a very low energy EBIT, SH-PermEBIT, has been set up at the Shanghai EBIT lab. In this work, simulation studies for factors which hinder an EBIT to operate at very low electron energies were made based on the Tricomp (Field Precision) codes. Longitudinal, transversal, and total kinetic energy distributions were analyzed for all the electron trajectories. Influences from the electron current and electron energy on the energy depression caused by the space charge are discussed. The simulation results show that although the energy depression is most serious along the center of the electron beam, the electrons in the outer part of the beam are more likely to be lost when an EBIT is running at very low energy. Using the simulation results to guide us, we successfully managed to reach the minimum electron beam energy of 60 eV with a beam transmission above 57% for the SH-PermEBIT. Ar and W spectra were measured from the SH-PermEBIT at the apparent electron beam energies (read from the voltage difference between the electron gun cathode and the central drift tube) of 60 eV and 1200 eV, respectively. The spectra are shown in this paper.

  20. Optical and chemical behaviors of CR-39 and Makrofol plastics under low-energy electron beam irradiation

    NASA Astrophysics Data System (ADS)

    El-Saftawy, Ashraf Ali; Abd El Aal, Saad Ahmed; Hassan, Nabil Mohamed; Abdelrahman, Moustafa Mohamed

    2016-07-01

    In this study, CR-39 and Makrofol plastic nuclear track detectors were irradiated with low-energy electron beams to study the effect of the induced changes on their optical and chemical properties. Surface chemical changes were recorded by Fourier transform infrared (FTIR) spectroscopy, which showed successive degradation and crosslinking for CR-39 and decomposition for Makrofol. The optical band gap was determined by UV–vis spectroscopy. Also, the parameters of carbon cluster formation and disordering (Urbach’s energy) occurring on plastic surfaces were examined. The intrinsic viscosity changes were investigated as well. As a result, low-energy electron beams were found to be useful for the control of many properties of the surfaces of the investigated detectors.

  1. A Sensitivity Enhanced MWCNT/PDMS Tactile Sensor Using Micropillars and Low Energy Ar⁺ Ion Beam Treatment.

    PubMed

    Azkar Ul Hasan, Syed; Jung, Youngdo; Kim, Seonggi; Jung, Cho-Long; Oh, Sunjong; Kim, Junhee; Lim, Hyuneui

    2016-01-01

    High sensitive flexible and wearable devices which can detect delicate touches have attracted considerable attentions from researchers for various promising applications. This research was aimed at enhancing the sensitivity of a MWCNT/PDMS piezoresistive tactile sensor through modification of its surface texture in the form of micropillars on MWCNT/PDMS film and subsequent low energy Ar⁺ ion beam treatment of the micropillars. The introduction of straight micropillars on the MWCNT/PDMS surface increased the sensitivity under gentle touch. Low energy ion beam treatment was performed to induce a stiff layer on the exposed surface of the micropillar structured MWCNT/PDMS film. The low energy ion bombardment stabilized the electrical properties of the MWCNT/PDMS surface and tuned the curvature of micropillars according to the treatment conditions. The straight micropillars which were treated by Ar⁺ ion with an incident angle of 0° demonstrated the enhanced sensitivity under normal pressure and the curved micropillars which were treated with Ar⁺ ion with an incident angle of 60° differentiated the direction of an applied shear pressure. The ion beam treatment on micropillar structured MWCNT/PDMS tactile sensors can thus be applied to reliable sensing under gentle touch with directional discrimination. PMID:26771616

  2. A Sensitivity Enhanced MWCNT/PDMS Tactile Sensor Using Micropillars and Low Energy Ar+ Ion Beam Treatment

    PubMed Central

    Hasan, Syed Azkar Ul; Jung, Youngdo; Kim, Seonggi; Jung, Cho-Long; Oh, Sunjong; Kim, Junhee; Lim, Hyuneui

    2016-01-01

    High sensitive flexible and wearable devices which can detect delicate touches have attracted considerable attentions from researchers for various promising applications. This research was aimed at enhancing the sensitivity of a MWCNT/PDMS piezoresistive tactile sensor through modification of its surface texture in the form of micropillars on MWCNT/PDMS film and subsequent low energy Ar+ ion beam treatment of the micropillars. The introduction of straight micropillars on the MWCNT/PDMS surface increased the sensitivity under gentle touch. Low energy ion beam treatment was performed to induce a stiff layer on the exposed surface of the micropillar structured MWCNT/PDMS film. The low energy ion bombardment stabilized the electrical properties of the MWCNT/PDMS surface and tuned the curvature of micropillars according to the treatment conditions. The straight micropillars which were treated by Ar+ ion with an incident angle of 0° demonstrated the enhanced sensitivity under normal pressure and the curved micropillars which were treated with Ar+ ion with an incident angle of 60° differentiated the direction of an applied shear pressure. The ion beam treatment on micropillar structured MWCNT/PDMS tactile sensors can thus be applied to reliable sensing under gentle touch with directional discrimination. PMID:26771616

  3. Thermal hydraulic studies of spallation target for one-way coupled Indian accelerator driven systems with low energy proton beam

    NASA Astrophysics Data System (ADS)

    Mantha, V.; Mohanty, A. K.; Satyamurthy, P.

    2007-02-01

    BARC has recently proposed a one-way coupled ADS reactor. This reactor requires typically 1 GeV proton beam with 2 mA of current. Approximately 8 kW of heat is deposited in the window of the target. Circulating liquid metal target (lead/lead-bismuth{eutectic) has to extract this heat and this is a critical R&D problem to be solved. At present there are very few accelerators, which can give few mA and high-energy proton beam. However, accelerators with low energy and hundreds of micro-ampere current are commercially available. In view of this, it is proposed in this paper to simulate beam window heating of 8 kW in the target with low-energy proton beam. Detailed thermal analysis in the spallation and window region has been carried out to study the capability of heat extraction by circulating LBE for a typical target loop with a proton beam of 30 MeV energy and current of 0.267 mA. The heat deposition study is carried out using FLUKA code and flow analysis by CFD code. The detailed analysis of this work is presented in this paper.

  4. SIMULATION OF A WIDE-BAND LOW-ENERGY NEUTRINO BEAM FOR VERY LONG BASELINE NEUTRINO OSCILLATION EXPERIMENTS.

    SciTech Connect

    BISHAI, M.; HEIM, J.; LEWIS, C.; MARINO, A.D.; VIREN, B.; YUMICEVA, F.

    2006-08-01

    We present simulations of a wide-band low-energy neutrino beam for a future very long baseline neutrino oscillation (VLBNO) program using the proton beam from the Main Injector (MI) proton accelerator at Fermi National Accelerator Laboratory (Fermilab). The target and horn designs previously developed for Brookhaven Laboratory's Alternating Gradient Synchrotron (AGS) VLBNO program are used without modifications. The neutrino flux distributions for various MI proton beam energies and new high-intensity neutrino beam-line designs possible at Fermilab are presented. The beam-line siting and design parameters are chosen to match the requirements of an on-axis beam from Fermilab to one of the two possible sites for the future Deep Underground Science and Engineering Laboratory (DUSEL). A preliminary estimate of the observable event rates and spectra at a detector located in DUSEL for different beam configurations has been performed. Our preliminary conclusions are that a 40-60 GeV 0.5 to 1 MW beam from the Fermilab Main Injector to a DUSEL site has the potential to reach the desired intensity for the next generation of neutrino oscillation experiments. Recent studies indicate that the Fermilab MI can reach a beam power of 0.5 MW at 60 GeV with incremental upgrades to the existing accelerator complex.

  5. Research of transportation efficiency of low-energy high- current electron beam in plasma channel in external magnetic field

    NASA Astrophysics Data System (ADS)

    Vagin, E. S.; Grigoriev, V. P.

    2015-11-01

    Effective high current (5-20 kA) and low energy (tens of keV) electrons beam transportation is possible only with almost complete charging neutralization. It is also necessary to use quite high current neutralization for elimination beam self-pinching effect. The research is based on the self-consistent mathematical model that takes into account beam and plasma particles dynamic, current and charge neutralization of electron beam and examines the transportation of electron beam into a chamber with low-pressure plasma in magnetic field. A numerical study was conducted using particle in cell (PIC) method. The study was performed with various system parameters: rise time and magnitude of the beam current, gas pressure and plasma density and geometry of the system. Regularities of local virtual cathode field generated by the beam in the plasma channel, as well as ranges of parameters that let transportation beam with minimal losses, depending on the external magnetic field were determined through a series of numerical studies. In addition, the assessment of the impact of the plasma ion mobility during the transition period and during steady beam was performed.

  6. First test experiment to produce the slowed-down RI beam with the momentum-compression mode at RIBF

    NASA Astrophysics Data System (ADS)

    Sumikama, T.; Ahn, D. S.; Fukuda, N.; Inabe, N.; Kubo, T.; Shimizu, Y.; Suzuki, H.; Takeda, H.; Aoi, N.; Beaumel, D.; Hasegawa, K.; Ideguchi, E.; Imai, N.; Kobayashi, T.; Matsushita, M.; Michimasa, S.; Otsu, H.; Shimoura, S.; Teranishi, T.

    2016-06-01

    The 82Ge beam has been produced by the in-flight fission reaction of the 238U primary beam with 345 MeV/u at the RIKEN RI beam factory, and slowed down to about 15 MeV/u using the energy degraders. The momentum-compression mode was applied to the second stage of the BigRIPS separator to reduce the momentum spread. The energy was successfully reduced down to 13 ± 2.5 MeV/u as expected. The focus was not optimized at the end of the second stage, therefore the beam size was larger than the expectation. The transmission of the second stage was half of the simulated value mainly due to out of focus. The two-stage separation worked very well for the slowed-down beam with the momentum-compression mode.

  7. Beam dynamics in an ultra-low energy storage rings (review of existing facilities and feasibility studies for future experiments)

    NASA Astrophysics Data System (ADS)

    Papash, A. I.; Smirnov, A. V.; Welsch, C. P.

    2014-03-01

    Storage rings operating at ultra-low energies and in particular electrostatic storage rings have proven to be invaluable tools for atomic and molecular physics. Due to the mass independence of the electrostatic rigidity, these machines are able to store a wide range of different particles, from light ions to heavy singly charged bio-molecules. However, earlier measurements showed strong limitations on beam intensity, fast decay of ion current, reduced life time etc. The nature of these effects was not fully understood. Also a large variety of experiments in future generation ultra-low energy storage and decelerator facilities including in-ring collision studies with a reaction microscope require a comprehensive investigation of the physical processes involved into the operation of such rings. In this paper, we present review of non-linear and long term beam dynamics studies on example of the ELISA, AD Recycler, TSR and USR rings using the computer codes BETACOOL, OPERA-3D and MAD-X. The results from simulations were benchmarked against experimental data of beam losses in the ELISA storage ring. We showed that decay of beam intensity in ultra-low energy rings is mainly caused by ion losses on ring aperture due to multiple scattering on residual gas. Beam is lost on ring aperture due to small ring acceptance. Rate of beam losses increases at high intensities because of the intra-beam scattering effect adds to vacuum losses. Detailed investigations into the ion kinetics under consideration of the effects from electron cooling and multiple scattering of the beam on a supersonic gas jet target have been carried out as well. The life time, equilibrium momentum spread and equilibrium lateral spread during collisions with this internal gas jet target were estimated. In addition, the results from experiments at the TSR ring, where low intensity beam of CF+ ions at 93 keV/u has been shrunk to extremely small dimensions have been reproduced. Based on these simulations

  8. Dosimetry of low energy proton beams for use in spacecraft parts testing

    NASA Technical Reports Server (NTRS)

    Miller, C. G.

    1975-01-01

    Thermoluminescent Dosimeters tes (TLD) were used to measure proton fluences consisting of 5MeV or lower energies. The results were at variance with the corresponding gamma measurements. The results of experiments on low energy proton dosimetry using LiF-in-teflon microrods (TLD-700 or LiF-7), are presented.

  9. Ion energy distribution functions of low energy beams formed by wire extraction electrodes

    SciTech Connect

    Tokumura, S.; Kasuya, T.; Vasquez, M. Jr.; Maeno, S.; Wada, M.

    2012-02-15

    The two-electrode extractor system made of 0.1 mm diameter tungsten wires separated by 0.7 mm has formed an argon ion beam with 50 V extraction potential. Energy spreads of the extracted beams were typically less than 2 eV when the beam current density was low. The beam intensity rapidly decreased as the distance between the extractor and the beam detector increased, indicating space charge limited transport of the beam. Problems associated with the emittance measurements are also discussed.

  10. Space Charge Correction on Emittance Measurement of Low Energy Electron Beams

    SciTech Connect

    Treado, Colleen J.; /Massachusetts U., Amherst

    2012-09-07

    The goal of any particle accelerator is to optimize the transport of a charged particle beam along a set path by confining the beam to a small region close to the design trajectory and directing it accurately along the beamline. To do so in the simplest fashion, accelerators use a system of magnets that exert approximately linear electromagnetic forces on the charged beam. These electromagnets bend the beam along the desired path, in the case of bending magnets, and constrain the beam to the desired area through alternating focusing and defocusing effects, in the case of quadrupole magnets. We can model the transport of such a beam through transfer matrices representing the actions of the various beamline elements. However, space charge effects, produced from self electric fields within the beam, defocus the beam and must be accounted for in the calculation of beam emittance. We present below the preliminary results of a MATLAB code built to model the transport of a charged particle beam through an accelerator and measure the emittance under the influence of space charge effects. We demonstrate the method of correctly calculating the emittance of a beam under space charge effects using a least square fit to determine the initial properties of the beam given the beam size measured at a specific point after transport.

  11. Extraction and low energy beam transport from a surface ion source at the TRIUMF-ISAC facility

    NASA Astrophysics Data System (ADS)

    Sen, A.; Ames, F.; Bricault, P.; Lassen, J.; Laxdal, A.; Mjos, A.

    2016-06-01

    A large fraction of radioactive beams produced and delivered at TRIUMF's isotope separator and accelerator facility, ISAC, are using either a surface ion source or a resonant ionization laser ion source, which share a common design. To characterize the operation of the ion sources, simulations were performed to determine the ion beam optics and beam envelope properties of the extracted beam. Furthermore ion-optics calculations were performed to determine the transmission parameters through the mass separator magnet. Emittances are measured in the ISAC low energy beam line right after the mass separator. The recent addition of a channeltron to the Allison emittance meter scanner now allows us to measure emittances for ion beams with intensities as low as 105 ions/s. This is particularly useful for establishing high resolution, high throughput mass separator tunes for radioactive isotope beams. This paper discusses emittance measurements of low intensity beams, typical emittance scans for the surface ion source and the resonant laser ionized source for different source parameters. The observed results are compared to the simulations and discussed.

  12. Key elements of space charge compensation on a low energy high intensity beam injector

    SciTech Connect

    Peng Shixiang; Lu Pengnan; Ren Haitao; Zhao Jie; Chen Jia; Xu Yuan; Guo Zhiyu; Chen Jia'er; Zhao Hongwei; Sun Liangting

    2013-03-15

    Space charge effect (SCE) along the beam line will decrease beam quality. Space charge compensation (SCC) with extra gas injection is a high-efficiency method to reduce SCE. In this paper, we will report the experimental results on the beam profile, potential distribution, beam emittance, and beam transmission efficiency of a 35 keV/90 mA H{sup +} beam and a 40 keV/10 mA He{sup +} beam compensated by Ar/Kr. The influence of gas type, gas flow, and injection location will be discussed. Emphasis is laid on the consideration of SCC when designing and commissioning a high intensity ion beam injector. Based on measured data, a new definition of space charge compensation degree is proposed.

  13. Key elements of space charge compensation on a low energy high intensity beam injector.

    PubMed

    Peng, Shixiang; Lu, Pengnan; Ren, Haitao; Zhao, Jie; Chen, Jia; Xu, Yuan; Guo, Zhiyu; Chen, Jia'er; Zhao, Hongwei; Sun, Liangting

    2013-03-01

    Space charge effect (SCE) along the beam line will decrease beam quality. Space charge compensation (SCC) with extra gas injection is a high-efficiency method to reduce SCE. In this paper, we will report the experimental results on the beam profile, potential distribution, beam emittance, and beam transmission efficiency of a 35 keV∕90 mA H(+) beam and a 40 keV∕10 mA He(+) beam compensated by Ar∕Kr. The influence of gas type, gas flow, and injection location will be discussed. Emphasis is laid on the consideration of SCC when designing and commissioning a high intensity ion beam injector. Based on measured data, a new definition of space charge compensation degree is proposed. PMID:23556812

  14. Low energy highly charged ion beam facility at Inter University Accelerator Centre: Measurement of the plasma potential and ion energy distributions

    SciTech Connect

    Sairam, T. Bhatt, Pragya; Safvan, C. P.; Kumar, Ajit; Kumar, Herendra

    2015-11-15

    A deceleration lens coupled to one of the beam lines of the electron cyclotron resonance based low energy beam facility at Inter University Accelerator Centre is reported. This system is capable of delivering low energy (2.5 eV/q–1 keV/q) highly charged ion beams. The presence of plasma potential hinders the measurements of low energies (<50 eV), therefore, plasma potential measurements have been undertaken using a retarding plate analyzer in unison with the deceleration assembly. The distributions of the ion energies have been obtained and the effect of different source parameters on these distributions is studied.

  15. An ultra-low energy (30-200 eV) ion-atomic beam source for ion-beam-assisted deposition in ultrahigh vacuum.

    PubMed

    Mach, Jindrich; Samoril, Tomás; Voborný, Stanislav; Kolíbal, Miroslav; Zlámal, Jakub; Spousta, Jirí; Dittrichová, Libuse; Sikola, Tomás

    2011-08-01

    The paper describes the design and construction of an ion-atomic beam source with an optimized generation of ions for ion-beam-assisted deposition under ultrahigh vacuum (UHV) conditions. The source combines an effusion cell and an electron impact ion source and produces ion beams with ultra-low energies in the range from 30 eV to 200 eV. Decreasing ion beam energy to hyperthermal values (≈10(1) eV) without loosing optimum ionization conditions has been mainly achieved by the incorporation of an ionization chamber with a grid transparent enough for electron and ion beams. In this way the energy and current density of nitrogen ion beams in the order of 10(1) eV and 10(1) nA/cm(2), respectively, have been achieved. The source is capable of growing ultrathin layers or nanostructures at ultra-low energies with a growth rate of several MLs/h. The ion-atomic beam source will be preferentially applied for the synthesis of GaN under UHV conditions. PMID:21895238

  16. Characteristics of low-energy ion beams extracted from a wire electrode geometry

    SciTech Connect

    Vasquez, M. Jr.; Tokumura, S.; Kasuya, T.; Maeno, S.; Wada, M.

    2012-02-15

    Beams of argon ions with energies less than 50 eV were extracted from an ion source through a wire electrode extractor geometry. A retarding potential energy analyzer (RPEA) was constructed in order to characterize the extracted ion beams. The single aperture RPEA was used to determine the ion energy distribution function, the mean ion energy and the ion beam energy spread. The multi-cusp hot cathode ion source was capable of producing a low electron temperature gas discharge to form quiescent plasmas from which ion beam energy as low as 5 eV was realized. At 50 V extraction potential and 0.1 A discharge current, the ion beam current density was around 0.37 mA/cm{sup 2} with an energy spread of 3.6 V or 6.5% of the mean ion energy. The maximum ion beam current density extracted from the source was 0.57 mA/cm{sup 2} for a 50 eV ion beam and 1.78 mA/cm{sup 2} for a 100 eV ion beam.

  17. High-Brightness Beam Generation and Characterization at the Advanced Photon Source Low-Energy Undulator Test Line Linac*

    NASA Astrophysics Data System (ADS)

    Lewellen, John; Biedron, Sandra; Borland, Michael; Hahne, Michael; Harkay, Katherine; Lumpkin, Alex; Milton, Stephen; Sereno, Nicholas; Travish, Gil

    2000-04-01

    Improvements to the Advanced Photon Source injector linac have been made to allow for the production and characterization of high-brightness beams in support of fourth-generation light source research. In particular, effort has been directed at generating beams suitable for use in the low-energy undulator test line (LEUTL) free-electron laser (FEL). We describe the enhancements to the linac operational and diagnostic capabilities that enabled self-amplified spontaneous emission (SASE) operation of the FEL at 530 nm. Electron beam measurement techniques and recent results will be discussed. Beam properties are measured under the same operational conditions as those used for FEL studies. The nominal FEL beam parameters are as follows: 217 MeV beam energy; less than 0.15 mm-mrad normalized emittance; 100 A peak current from a 0.7-nC charge at a 7-psec bunch. * Work supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38

  18. The optimization of incident angles of low-energy oxygen ion beams for increasing sputtering rate on silicon samples

    NASA Astrophysics Data System (ADS)

    Sasaki, T.; Yoshida, N.; Takahashi, M.; Tomita, M.

    2008-12-01

    In order to determine an appropriate incident angle of low-energy (350-eV) oxygen ion beam for achieving the highest sputtering rate without degradation of depth resolution in SIMS analysis, a delta-doped sample was analyzed with incident angles from 0° to 60° without oxygen bleeding. As a result, 45° incidence was found to be the best analytical condition, and it was confirmed that surface roughness did not occur on the sputtered surface at 100-nm depth by using AFM. By applying the optimized incident angle, sputtering rate becomes more than twice as high as that of the normal incident condition.

  19. The role of low-energy electrons in focused electron beam induced deposition: four case studies of representative precursors

    PubMed Central

    Thorman, Rachel M; Kumar T. P., Ragesh; Fairbrother, D Howard

    2015-01-01

    Summary Focused electron beam induced deposition (FEBID) is a single-step, direct-write nanofabrication technique capable of writing three-dimensional metal-containing nanoscale structures on surfaces using electron-induced reactions of organometallic precursors. Currently FEBID is, however, limited in resolution due to deposition outside the area of the primary electron beam and in metal purity due to incomplete precursor decomposition. Both limitations are likely in part caused by reactions of precursor molecules with low-energy (<100 eV) secondary electrons generated by interactions of the primary beam with the substrate. These low-energy electrons are abundant both inside and outside the area of the primary electron beam and are associated with reactions causing incomplete ligand dissociation from FEBID precursors. As it is not possible to directly study the effects of secondary electrons in situ in FEBID, other means must be used to elucidate their role. In this context, gas phase studies can obtain well-resolved information on low-energy electron-induced reactions with FEBID precursors by studying isolated molecules interacting with single electrons of well-defined energy. In contrast, ultra-high vacuum surface studies on adsorbed precursor molecules can provide information on surface speciation and identify species desorbing from a substrate during electron irradiation under conditions more representative of FEBID. Comparing gas phase and surface science studies allows for insight into the primary deposition mechanisms for individual precursors; ideally, this information can be used to design future FEBID precursors and optimize deposition conditions. In this review, we give a summary of different low-energy electron-induced fragmentation processes that can be initiated by the secondary electrons generated in FEBID, specifically, dissociative electron attachment, dissociative ionization, neutral dissociation, and dipolar dissociation, emphasizing the

  20. Chemical composition, morphology and optical properties of zinc sulfide coatings deposited by low-energy electron beam evaporation

    NASA Astrophysics Data System (ADS)

    Ragachev, A. V.; Yarmolenko, M. A.; Rogachev, A. A.; Gorbachev, D. L.; Zhou, Bing

    2014-06-01

    The research determines the features of formation, morphology, chemical composition and optical properties of the coatings deposited by the method, proposed for the first time, of the exposure of mechanical mixture of zinc and sulfur powders to low-energy electron beam evaporation. The findings show that the deposited coatings are characterized by high chemical and structural homogeneity in thickness. The study considers the influence of substrate temperature and thickness of the deposited layer on the morphology and the width of the formed ZnS thin layers band gap. Also was shown the possibility to form ZnS coatings with this method using the mixture of zinc and copper sulfide powders.

  1. Design and characterization of a movable emittance meter for low-energy electron beams

    SciTech Connect

    Catani, Luciano; Chiadroni, Enrica; Cianchi, Alessandro; Tazzari, Sergio; Boscolo, Manuela; Castellano, Michele; Di Pirro, Giampiero; Ferrario, Massimo; Fusco, Valeria; Filippetto, Daniele; Palumbo, Luigi; Vaccarezza, Cristina; Vicario, Carlo; Ronsivalle, Concetta

    2006-09-15

    In order to characterize and optimize the beam emittance compensation scheme [L. Serafini and J. B. Rosenzweig, Phys. Rev. E 55, 7565 (1997)] of the Sorgente Pulsata Autoamplificata di Radiazione Coerente project [D. Alesini et al., Nucl. Instrum. Methods Phys. Res. A 507, 345 (2003)] high brightness preinjector a system to accurately measure the beam rms emittance evolution downstream of the rf gun has been developed. Since in a space charge dominated beam the quadrupole-scan method is not applicable, a movable emittance measurement device has been built based on the pepper-pot technique. The device consists of a double system of horizontal and vertical slit arrays and a downstream screen, all installed on a longitudinally movable support equipped with bellows and spanning the {approx_equal}1.2 m long drift space between gun and first accelerating section. The system allows the measuring of the beam rms emittance all along the spanned region so as to accurately reconstruct its evolution along the beam trajectory. More than a simple improvement over more conventional beam emittance measurement tools this device defines a new strategy for characterizing high performance photoinjectors as it allows a detailed analysis of the beam behavior over a section of the accelerator where crucial beam shaping takes place. Numerical simulations of the measurement, mainly based on PARMELA [J. Billen, PARMELA Report No. LA-UR 96-1835, 1996 (unpublished)], have been used to estimate the achievable accuracy and to optimize the experimental setup. Wake field effects induced by the beam propagation through the bellows have also been investigated with HOMDYN [M. Ferrario et al., LCLS Report No. SLAC-PUB 84000, 1999 (unpublished)]. A series of laboratory tests to evaluate its performance has been carried out at LNF in Frascati. The system was then moved to DESY Zeuthen and installed on the Photo Injector Test Facility PITZ, for further testing with beam. Design criteria and tests

  2. Design of a compact Faraday cup for low energy, low intensity ion beams

    NASA Astrophysics Data System (ADS)

    Cantero, E. D.; Sosa, A.; Andreazza, W.; Bravin, E.; Lanaia, D.; Voulot, D.; Welsch, C. P.

    2016-01-01

    Beam intensity is one of the key parameters in particle accelerators, in particular during machine commissioning, but also during operation for experiments. At low beam energies and low intensities a number of challenges arise in its measurement as commonly used non-invasive devices are no longer sensitive enough. It then becomes necessary to stop the beam in order to measure its absolute intensity. A very compact Faraday cup for determining ion beam currents from a few nanoamperes down to picoamperes for the HIE-ISOLDE post-accelerator at CERN has been designed, built and tested with beam. It has a large aperture diameter of 30 mm and a total length of only 16 mm, making it one of the most compact designs ever used. In this paper we present the different steps that were involved in the design and optimization of this device, including beam tests with two early prototypes and the final monitor. We also present an analysis of the losses caused by secondary particle emission for different repelling electrode voltages and beam energies. Finally, we show that results obtained from an analytical model for electron loss probability combined with Monte Carlo simulations of particles trajectories provide a very good agreement with experimental data.

  3. Effect of strong solenoidal focusing on beam emittance of low-energy intense proton beam in the SARAF LEBT

    NASA Astrophysics Data System (ADS)

    Shor, A.; Weissman, L.

    2016-07-01

    Influence of strong solenoidal beam focusing on beam emittance was studied at the SARAF LEBT beam line using 5 mA 20 keV proton quasi-DC beams. The measurements show that within the experimental uncertainties, emittance does not change over the whole focusing range. Detailed beam dynamics simulations were performed to achieve better understanding of the experimental results. The experimental and simulation results are fully consistent with the assumption of nearly full space charge neutralization for the quasi-DC proton beam.

  4. Structured organic materials and devices using low-energy particle beams

    DOEpatents

    Vardeny, Z. Valy; Li, Sergey; Delong, Matthew C.; Jiang, Xiaomei

    2005-09-13

    Organic materials exposed to an electron beam for patterning a substrate (1) to make an optoelectronic organic device which includes a source, a drain, gate dielectric layer (4), and a substrate for emitting light.

  5. Monte Carlo simulation of a collimation system for low-energy beamline of ELI-NP Gamma Beam System

    NASA Astrophysics Data System (ADS)

    Cardarelli, P.; Gambaccini, M.; Marziani, M.; Bagli, E.; Petrillo, V.; Bacci, A.; Curatolo, C.; Drebot, I.; Vaccarezza, C.

    2015-07-01

    ELI-nuclear physics (NP) Gamma Beam System (GBS) is an intense and monochromatic gamma beam source based on inverse Compton interaction, currently being built in Bucharest, Romania. The gamma beam produced, with energy ranging from 0.2 to 20 MeV, energy bandwidth 0.5% and flux of about 108photons/s, will be devoted to investigate a broad range of applications such as nuclear physics, astrophysics, material science and life sciences. The radiation produced by an inverse Compton interaction is not intrinsically monochromatic. In fact, the energy of the photons produced is related to the emission angle, therefore the energy bandwidth can be modified adjusting the collimation of the gamma beam. In order to define the optimal layout and evaluate the performance of a collimation system for the ELI-NP-GBS low-energy beamline (0.2-3.5 MeV), a detailed Monte Carlo simulation activity has been carried out. The simulation, using Geant4 and MCNPX codes, included the transport of the gamma beam from the interaction point to the experimental area passing through vacuum pipes, vacuum chambers, collimation system and relative shielding. The effectiveness of the collimation system, in obtaining the required energy distribution and avoiding the contamination due to secondary radiation production, was evaluated. Also, the background radiation generated by collimation and the shielding layout have been studied.

  6. Isobar separation by time-of-flight mass spectrometry for low-energy radioactive ion beam facilities

    NASA Astrophysics Data System (ADS)

    Plaß, Wolfgang R.; Dickel, Timo; Czok, Ulrich; Geissel, Hans; Petrick, Martin; Reinheimer, Katrin; Scheidenberger, Christoph; Yavor, Mikhail I.

    2008-10-01

    A multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) system for low-energy radioactive ion beam facilities has been developed, which can be used for (i) isobar separation and (ii) direct mass measurements of very short-lived nuclei with half-lives of about 1 ms or longer, and (iii) for identification and diagnosis of the ion beam by mass spectrometry. The system has been designed and simulated, and individual subsystems have been built and characterized experimentally. An injection trap for cooling and bunching of the ion beam has been developed, and cooling times of less than one millisecond have been achieved. The performance of the MR-TOF-MS was characterized using the isobaric doublet of carbon monoxide and nitrogen molecular ions. A mass resolving power of 105 (FWHM) has been obtained even with an uncooled ion population. The separator capabilities of the MR-TOF-MS have been demonstrated by removing either carbon monoxide or nitrogen ions from the beam in a Bradbury-Nielsen Gate after a flight time of 320 μs. The separation power achieved is thus at least 7000 (FWHM) and increases for longer time-of-flight. An energy buncher stage has been designed that compresses the energy spread of the beam after the separation and facilitates efficient injection of the selected ions into an accumulation trap prior to transfer of the ions to experiments downstream of the MR-TOF-MS.

  7. Investigation of the mechanism of impurity assisted nanoripple formation on Si induced by low energy ion beam erosion

    SciTech Connect

    Koyiloth Vayalil, Sarathlal; Gupta, Ajay; Roth, Stephan V.; Ganesan, V.

    2015-01-14

    A detailed mechanism of the nanoripple pattern formation on Si substrates generated by the simultaneous incorporation of pure Fe impurities at low energy (1 keV) ion beam erosion has been studied. To understand and clarify the mechanism of the pattern formation, a comparative analysis of the samples prepared for various ion fluence values using two complimentary methods for nanostructure analysis, atomic force microscopy, and grazing incidence small angle x-ray scattering has been done. We observed that phase separation of the metal silicide formed during the erosion does not precede the ripple formation. It rather concurrently develops along with the ripple structure. Our work is able to differentiate among various models existing in the literature and provides an insight into the mechanism of pattern formation under ion beam erosion with impurity incorporation.

  8. An RF driven H{sup {minus}} source and a low energy beam injection system for RFQ operation

    SciTech Connect

    Leung, K.N.; Bachman, D.A.; Chan, C.F.; McDonald, D.S.

    1992-12-31

    An RF driven H{sup {minus}} source has been developed at LBL for use in the Superconducting Super Collider (SSC). To date, an H{sup {minus}} current of {approx}40 mA can be obtained from a 5.6-cm-diam aperture with the source operated at a pressure of about 12 m Torr and 50 kW of RF power. In order to match the accelerated H{sup {minus}} beam into the SSC RFQ, a low-energy H{sup {minus}} injection system has been designed. This injector produces an outgoing H{sup {minus}} beam free of electron contamination, with small radius, large convergent angle and small projectional emittance.

  9. Reaction studies with low-energy weakly-bound beams at INFN-LNS

    NASA Astrophysics Data System (ADS)

    Di Pietro, A.; Fernandez-Garcia, J. P.; Figuera, P.; Fisichella, M.; Lattuada, M.; Torresi, D.; Zadro, M.

    2016-05-01

    The reaction dynamics of collisions involving halo or weakly bound nuclei, at energies around the Coulomb barrier, can be strongly affected by the structure of such nuclei. Very strong entrance channel effects have been observed on various reaction pocess such as, elastic scattering, fusion and direct reactions when comparing collision induced by the 6He and 11Be halo nuclei with the ones induced by their cores 4He and 10Be. Collisions induced by the stable weakly bound nuclei 6Li, 7Li show also some peculiarities in comparison to the ones induced by well bound nuclei; coupling with the break-up channel is in fact very important in reproducing low energy data. In this contribution an overview of our present understanding of the discussed topic will be given along with the discussion of some new preliminary results.

  10. MODULATION OF LOW ENERGY BEAM TO GENERATE PREDEFINED BUNCH TRAINS FOR THE NSLS-II TOP-OFF INJECTION

    SciTech Connect

    Wang, G.M.; Cheng, W.X.; Shaftan, T.; Fliller, R.; Heese, R.; Rose, J.

    2011-03-28

    The NSLS II linac will produce a bunch train, 80-150 bunches long with 2 ns bunch spacing. Having the ability to tailor the bunch train can lead to the smaller bunch to bunch charge variation in the storage ring. A stripline is planned to integrate into the linac baseline to achieve this tailoring. The stripline must have a fast field rise and fall time to tailor each bunch. The beam dynamics is minimally affected by including the extra space for the stripline. This paper discusses the linac beam dynamics with stripline, and the optimal design of the stripline. A stripline is to be integrated in the linac to match the storage ring uniform bunch charge requirement, which simplifies the gun pulser electronics and looses the edge uniform requirement. It is located at low energy to lower the stripline power supply requirement and limit the dumped electron radiation. By turning off the stripline, the beam dynamics through linac is comparable with the baseline design. More advanced ideas can be explored. If a DC corrector along with the stripline is used, the core bunch trains gets kick from the stripline while the head and the tail of bunch train just gets a DC kick. The stripline power supply waveform is a single flat top waveform with fast rise and drop and the pulse length is {approx}200 ns long or 100 bunches, which may be easier from the power supply view point. We are also considering the bunch by bunch charge manipulation to match the storage ring uniform bunch charge distribution requirement. By modulating the flat top waveform at 250 MHz with adjustable amplitude, each the bunch center is either at 45 degree or 135 degree. Only the head or tail of the bunch is trimmed out. Although each bunch center deviation from idea center is very different at low energy, it is gradually minimized with beam energy increase.

  11. Laboratory degradation of Kapton in a low energy oxygen ion beam

    NASA Technical Reports Server (NTRS)

    Ferguson, D. C.

    1984-01-01

    An atomic oxygen ion beam, accelerated from a tunable microwave resonant cavity, was used at Lewis Research Center to bombard samples of the widely used polyimide Kapton. The Kapton experienced degradation and mass loss at high rates, which may be comparable to those found in Space Shuttle operations if the activation energy supplied by the beam enabled surface reactions with the ambient oxygen. The simulation reproduced the directionality (ram-wake dependence) of the degradation, the change in optical properties of the degraded materials, and the structure seen in scanning electron micrographs of samples returned on the Shuttle Trails with a substituted argon ion beam produced no rapid degradation. Energy Dispersive X-ray Analysis (EDAX) showed significant surface composition changes in all bombarded samples. Mass loss rates and surface composition changes are discussed in terms of the possible oxidation chemistry of the interaction. Finally, the question of how the harmful degradation of materials in low Earth orbit can be minimized is addressed.

  12. Laboratory degradation of Kapton in a low energy oxygen ion beam

    NASA Technical Reports Server (NTRS)

    Ferguson, D. C.

    1983-01-01

    An atomic oxygen ion beam, accelerated from a tunable microwave resonant cavity, was used at Lewis Research Center to bombard samples of the widely used polyimide Kapton. The Kapton experienced degradation and mass loss at high rates, which may be comparable to those found in Space Shuttle operations if the activation energy supplied by the beam enabled surface reactions with the ambient oxygen. The simulation reproduced the directionality (ram-wake dependence) of the degradiation, the change in optical properties of the degraded materials, and the structure seen in scanning electron micrographs of samples returned on the Shuttle Trails with a substituted argon ion beam produced no rapid degradation. Energy Dispersive X-ray Analysis (EDAX) showed significant surface composition changes in all bombarded samples. Mass loss rates and surface composition changes are discussed in terms of the possible oxidation chemistry of the interaction. Finally, the question of how the harmful degradation of materials in low earth orbit can be minimized is addressed.

  13. Feasibility of a 90° electric sector energy analyzer for low energy ion beam characterization

    SciTech Connect

    Mahinay, C. L. S. Ramos, H. J.; Wada, M.

    2015-02-15

    A simple formula to calculate refocusing by locating the output slit at a specific distance away from the exit of 90° ion deflecting electric sector is given. Numerical analysis is also performed to calculate the ion beam trajectories for different values of the initial angular deviation of the beam. To validate the theory, a compact (90 mm × 5.5 mm × 32 mm) 90° sector ESA is fabricated which can fit through the inner diameter of a conflat 70 vacuum flange. Experimental results show that the dependence of resolution upon the distance between the sector exit and the Faraday cup agrees with the theory. The fabricated 90° sector electrostatic energy analyzer was then used to measure the space resolved ion energy distribution functions of an ion beam with the energy as low as 600 eV.

  14. Feasibility of a 90° electric sector energy analyzer for low energy ion beam characterization.

    PubMed

    Mahinay, C L S; Wada, M; Ramos, H J

    2015-02-01

    A simple formula to calculate refocusing by locating the output slit at a specific distance away from the exit of 90° ion deflecting electric sector is given. Numerical analysis is also performed to calculate the ion beam trajectories for different values of the initial angular deviation of the beam. To validate the theory, a compact (90 mm × 5.5 mm × 32 mm) 90° sector ESA is fabricated which can fit through the inner diameter of a conflat 70 vacuum flange. Experimental results show that the dependence of resolution upon the distance between the sector exit and the Faraday cup agrees with the theory. The fabricated 90° sector electrostatic energy analyzer was then used to measure the space resolved ion energy distribution functions of an ion beam with the energy as low as 600 eV. PMID:25725835

  15. Luminescence evolution of ZnO single crystal under low-energy electron beam irradiation

    SciTech Connect

    Dierre, B.; Sekiguchi, T.; Yuan, X. L.

    2008-08-15

    The effects of electron beam irradiation on the luminescence of ZnO single crystals were investigated by cathodoluminescence. We have found that the evolution of the intensity during the e-beam irradiation depends on the surface polarity. For O-face, the ultraviolet (UV) emission decreases exponentially and approaches an asymptotic value. For Zn-face, it first increases and then decreases. The decrease components are similar in both faces. If we halt the e-beam irradiation, the UV intensity recovers partially. These results suggest that the decrease in the UV evolution is related to metastable bulk defect reactions at the subsurface region while the increase is related to surface reaction such as electron-stimulated desorption.

  16. AREAL low energy electron beam applications in life and materials sciences

    NASA Astrophysics Data System (ADS)

    Tsakanov, V. M.; Aroutiounian, R. M.; Amatuni, G. A.; Aloyan, L. R.; Aslanyan, L. G.; Avagyan, V. Sh.; Babayan, N. S.; Buniatyan, V. V.; Dalyan, Y. B.; Davtyan, H. D.; Derdzyan, M. V.; Grigoryan, B. A.; Grigoryan, N. E.; Hakobyan, L. S.; Haroutyunian, S. G.; Harutiunyan, V. V.; Hovhannesyan, K. L.; Khachatryan, V. G.; Martirosyan, N. W.; Melikyan, G. S.; Petrosyan, A. G.; Petrosyan, V. H.; Sahakyan, A. A.; Sahakyan, V. V.; Sargsyan, A. A.; Simonyan, A. S.; Tatikyan, S. Sh.; Tsakanova, G. V.; Tsovyan, E.; Vardanyan, A. S.; Vardanyan, V. V.; Yeremyan, A. S.; Yeritsyan, H. N.; Zanyan, G. S.

    2016-09-01

    The AREAL laser-driven RF gun provides 2-5 MeV energy ultrashort electron pulses for experimental study in life and materials sciences. We report the first experimental results of the AREAL beam application in the study of molecular-genetic effects, silicon-dielectric structures, ferroelectric nanofilms, and single crystals for scintillators.

  17. Recent performance of the SNS H{sup −} ion source and low-energy beam transport system

    SciTech Connect

    Stockli, Martin P. Ewald, K. D.; Han, B. X.; Murray, S. N.; Pennisi, T. R.; Piller, C.; Santana, M.; Tang, J.; Welton, R.

    2014-02-15

    Recent measurements of the H{sup −} beam current show that SNS is injecting about 55 mA into the RFQ compared to ∼45 mA in 2010. Since 2010, the H{sup −} beam exiting the RFQ dropped from ∼40 mA to ∼34 mA, which is sufficient for 1 MW of beam power. To minimize the impact of the RFQ degradation, the service cycle of the best performing source was extended to 6 weeks. The only degradation is fluctuations in the electron dump voltage towards the end of some service cycles, a problem that is being investigated. Very recently, the RFQ was retuned, which partly restored its transmission. In addition, the electrostatic low-energy beam transport system was reengineered to double its heat sinking and equipped with a thermocouple that monitors the temperature of the ground electrode between the two Einzel lenses. The recorded data show that emissions from the source at high voltage dominate the heat load. Emissions from the partly Cs-covered first lens cause the temperature to peak several hours after starting up. On rare occasions, the temperature can also peak due to corona discharges between the center ground electrode and one of the lenses.

  18. Space-charge compensation measurements in electron cyclotron resonance ion source low energy beam transport lines with a retarding field analyzer

    SciTech Connect

    Winklehner, D.; Leitner, D. Cole, D.; Machicoane, G.; Tobos, L.

    2014-02-15

    In this paper we describe the first systematic measurement of beam neutralization (space charge compensation) in the ECR low energy transport line with a retarding field analyzer, which can be used to measure the potential of the beam. Expected trends for the space charge compensation levels such as increase with residual gas pressure, beam current, and beam density could be observed. However, the overall levels of neutralization are consistently low (<60%). The results and the processes involved for neutralizing ion beams are discussed for conditions typical for ECR injector beam lines. The results are compared to a simple theoretical beam plasma model as well as simulations.

  19. 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.

  20. Characterization of low-energy photon-emitting brachytherapy sources and kilovoltage x-ray beams using spectrometry

    NASA Astrophysics Data System (ADS)

    Moga, Jacqueline D.

    Low-energy photon sources are used in therapeutic radiation oncology for brachytherapy with low dose-rate (LDR) sources and for superficial and orthovoltage therapy with kilovolt-age x-ray beams. Current dosimetry methods for these sources utilize energy-integrating devices, such as thermoluminescent dosimeters and ionization chambers. This thesis work investigates the dosimetry of LDR brachytherapy sources and kilovoltage x-ray beams using spectrometry, which preserves the energy-specific source output. Several LDR brachytherapy source models were measured with a reverse-electrode germanium (REGe) detector. The measured spectra were corrected for MCNP5-calculated detector response using a deconvolution algorithm (Beach, 2005). The peak areas determined from the corrected spectra were used to calculate the dose-rate constant (Chen and Nath, 2001) and the air-kerma strength. Dose-rate constant results agreed well with the published values (Rivard et al., 2004; Chen and Nath, 2007). Air-kerma strength results were systematically 2%--5% low compared to calibration values and primary air-kerma strength measurements. The spectrometry methods for LDR brachytherapy sources offer a promising alternative to existing experimental techniques, but further work is necessary to improve agreement with the current air-kerma strength standard methodology. Spectra of 20kVp---250kVp x-ray beams were measured with a low-energy germanium detector (LEGe). The LEGe spectrometry system was modeled in MCNP5 to calculate a detector response function. Backward stripping, which showed less variability than deconvolution, was used for correcting the measured x-ray spectra. The corrected experimental spectra were compared to spectra from: (1) Monte Carlo simulations of the full x-ray tube with EGSnrc, (2) the SpekCalc program (Poludniowski et al., 2009), and (3) the Gesellschaft fur Strahlen-und Umweltforschung mbH Munchen (GSF) Report 560. Agreement was best for the UW60-M through UW150-M

  1. Making AlN(x) Tunnel Barriers Using a Low-Energy Nitrogen-Ion Beam

    NASA Technical Reports Server (NTRS)

    Kaul, Anupama; Kleinsasser, Alan; Bumble, Bruce; LeDuc, Henry; Lee, Karen

    2005-01-01

    A technique based on accelerating positive nitrogen ions onto an aluminum layer has been demonstrated to be effective in forming thin (<2 nm thick) layers of aluminum nitride (AlN(x)) for use as tunnel barriers in Nb/Al-AlN(x)/Nb superconductor/insulator/ superconductor (SIS) Josephson junctions. AlN(x) is the present material of choice for tunnel barriers because, to a degree greater than that of any other suitable material, it offers the required combination of low leakage current at high current density and greater thermal stability. While ultra-thin AlN films with good thickness and stoichiometry control are easily formed using techniques such as reactive molecular beam epitaxy and chemical vapor deposition, growth temperatures of 900 C are necessary for the dissociative adsorption of nitrogen from either nitrogen (N2) or ammonia (NH3). These growth temperatures are prohibitively high for the formation of tunnel barriers on Nb films because interfacial reactions at temperatures as low as 200 to 300 C degrade device properties. Heretofore, deposition by reactive sputtering and nitridation of thin Al layers with DC and RF nitrogen plasmas have been successfully used to form AlN barriers in SIS junctions. However, precise control over critical current density Jc has proven to be a challenge, as is attaining adequate process reproducibility from system to system. The present ion-beam technique is an alternative to the plasma or reactive sputtering techniques as it provides a highly controlled arrival of reactive species, independent of the electrical conditions of the substrate or vacuum chamber. Independent and accurate control of parameters such as ion energy, flux, species, and direction promises more precise control of film characteristics such as stoichiometry and thickness than is the case with typical plasma processes. In particular, the background pressure during ion-beam nitride growth is 2 or 3 orders of magnitude lower, minimizing the formation of

  2. Research on the Distant Hybrids of Wheat Obtained via Low-Energy Ion-Beam Implantation

    NASA Astrophysics Data System (ADS)

    Chang, Shouwei; Cheng, Yuhong; Qin, Guangyong; Su, Mingjie

    2003-06-01

    The whole DNA of soybean was implanted into four varieties of wheat of Zhongyu 5, Huaiyin 9628, Wenyou 1, Jimai 5 respectively via ion-beam mediation. There were 5 plants obtained whose protein content was higher than 18.5%, the highest one was 21.44%. There were 3 plants obtained whose protein content was lower than 11.5%, the lowest one was 10.96%. We can see that the whole DNA of soybean transformed into wheat via ion beam implantation can induce the increase in wheat protein content dramatically. The result also shows that the transformation efficiency of different gene types of wheat receptor varies greatly that the implanting time has a certain effect on the efficiency of transformation.

  3. Transfer reactions using a low-energy {sup 11}Be beam

    SciTech Connect

    Johansen, Jacob

    2011-10-28

    A series of experiments have been performed to investigate neutron rich beryllium isotopes. Scattering as well as one neutron transfer reactions have been studied using a {sup 11}Be beam on deuteron targets. Bound states of {sup 10,11,12}Be have been studied and reaction cross sections have been calculated. The elastic scattering cross section has shown remarkable structure due to the halo structure of {sup 11}Be.

  4. Closely spaced nanomagnets by dual e-beam exposure for low-energy nanomagnet logic

    SciTech Connect

    Shah, Faisal A.; Csaba, Gyorgy; Butler, Katherine; Bernstein, Gary H.

    2013-05-07

    The effect of nanomagnet spacing on required clock field has been studied by micromagnetic simulation for supermalloy (Ni{sub 79}Fe{sub 16}Mo{sub 5}) dots with dimensions 90 Multiplication-Sign 60 Multiplication-Sign 20 nm{sup 3} and 120 Multiplication-Sign 60 Multiplication-Sign 20 nm{sup 3}. Reduction of the inter-magnet spacing for both dimensions has resulted in reduction of the required clock field in the simulation. A dual e-beam exposure technique has been developed to allow fabrication of ultra dense features using conventional poly(methylmethacrylate) e-beam resist. Nanomagnet logic (NML) datalines of supermalloy dots with {approx}10 nm and {approx}15 nm spacing have been fabricated using dual e-beam exposure with a 3{sigma} overlay accuracy of {approx}4 nm. Fabricated NML datalines have been characterized using magnetic force microscopy for various clock fields. Datalines of both spacing have shown proper NML functionality with a clock field as low as 60 mT.

  5. Systematic investigations of low energy Ar ion beam sputtering of Si and Ag

    NASA Astrophysics Data System (ADS)

    Feder, R.; Frost, F.; Neumann, H.; Bundesmann, C.; Rauschenbach, B.

    2013-12-01

    Ion beam sputter deposition (IBD) delivers some intrinsic features influencing the growing film properties, because ion properties and geometrical process conditions generate different energy and spatial distributions of the sputtered and scattered particles. Even though IBD has been used for decades, the full capabilities are not investigated systematically and specifically used yet. Therefore, a systematic and comprehensive analysis of the correlation between the properties of the ion beam, the generated secondary particles and backscattered ions and the deposited films needs to be done.A vacuum deposition chamber has been set up which allows ion beam sputtering of different targets under variation of geometrical parameters (ion incidence angle, position of substrates and analytics in respect to the target) and of ion beam parameters (ion species, ion energy) to perform a systematic and comprehensive analysis of the correlation between the properties of the ion beam, the properties of the sputtered and scattered particles, and the properties of the deposited films. A set of samples was prepared and characterized with respect to selected film properties, such as thickness and surface topography. The experiments indicate a systematic influence of the deposition parameters on the film properties as hypothesized before. Because of this influence, the energy distribution of secondary particles was measured using an energy-selective mass spectrometer. Among others, experiments revealed a high-energetic maximum for backscattered primary ions, which shifts with increasing emission angle to higher energies. Experimental data are compared with Monte Carlo simulations done with the well-known Transport and Range of Ions in Matter, Sputtering version (TRIM.SP) code [J.P. Biersack, W. Eckstein, Appl. Phys. A: Mater. Sci. Process. 34 (1984) 73]. The thicknesses of the films are in good agreement with those calculated from simulated particle fluxes. For the positions of the

  6. Self-trapping of low-energy infrared femtosecond beams in lithium niobate

    SciTech Connect

    Pettazzi, Federico; Alonzo, Massimo; Centini, Marco; Fazio, Eugenio; Petris, Adrian; Vlad, Valentin I.; Chauvet, Mathieu

    2007-12-15

    In this paper we report self-trapping of subnanojoule femtosecond near-infrared beams in photonic-grade undoped bulk lithium niobate under application of an external dc electric field. We show that the phenomenon occurs thanks to the photorefractive effect induced by a weak second-harmonic component generated under large velocity mismatch. It offers a way to extend lithium niobate's photorefractive response to the near-infrared spectrum for peak intensity lower than 1 GW/cm{sup 2}, which is three orders of magnitude lower than reported in the literature.

  7. Low energy oxygen ion beam modification of the surface morphology and chemical structure of polyurethane fibers

    NASA Astrophysics Data System (ADS)

    Wong, K. H.; Zinke-Allmang, M.; Wan, W. K.; Zhang, J. Z.; Hu, P.

    2006-01-01

    Energetic O+ ions were implanted into polyurethane (PU) fiber filaments, at 60 and 100 keV with doses of 5 × 1014 and 1 × 1015 ions/cm2, to modify the near-surface fiber morphology. The implantations were performed at room temperature and at -197 °C, a temperature well below the glass transition temperature for this system. At room temperature, the lower energy implantation heats the fibers primarily near their surface, causing the fiber surface to smoothen and to develop a flattened shape. At the higher energy, the ion beam deposits its energy closer to the fiber core, heating the fiber more uniformly and causing them to re-solidify slowly. This favors a cylindrical equilibrium shape with a smooth fiber surface and no crack lines. The average fiber diameter reduced during 100 keV implantation from 3.1 to 2.3 μm. At -197 °C, the ion implantation does not provide enough heat to cause notable physical modifications, but the fibers crack and break during subsequent warming to room temperature. The dose dependence of the crack formation along the fiber intersections is presented. The ion beams further cause near-surface chemical modifications in the fibers, particularly introducing two new chemical functional groups (C-(Cdbnd O)-C and C-N-C).

  8. 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.

  9. A permanent magnet electron beam spread system used for a low energy electron irradiation accelerator

    NASA Astrophysics Data System (ADS)

    Huang, Jiang; Xiong, Yong-Qian; Chen, De-Zhi; Liu, Kai-Feng; Yang, Jun; Li, Dong; Yu, Tiao-Qin; Fan, Ming-Wu; Yang, Bo

    2014-10-01

    The development of irradiation processing industry brings about various types of irradiation objects and expands the irradiation requirements for better uniformity and larger areas. This paper proposes an innovative design of a permanent magnet electron beam spread system. By clarifying its operation principles, the author verifies the feasibility of its application in irradiation accelerators for industrial use with the examples of its application in electron accelerators with energy ranging from 300 keV to 1 MeV. Based on the finite element analyses of electromagnetic fields and the charged particle dynamics, the author also conducts a simulation of electron dynamics in magnetic field on a computer. The results indicate that compared with the traditional electron beam scanning system, this system boosts the advantages of a larger spread area, non-power supply, simple structure and low cost, etc., which means it is not only suitable for the irradiation of objects with the shape of tubes, strips and panels, but can also achieve a desirable irradiation performance on irregular constructed objects of large size.

  10. Sub-5 nm graphene nanopore fabrication by nitrogen ion etching induced by a low-energy electron beam

    NASA Astrophysics Data System (ADS)

    Fox, Daniel S.; Maguire, Pierce; Zhou, Yangbo; Rodenburg, Cornelia; O’Neill, Arlene; Coleman, Jonathan N.; Zhang, Hongzhou

    2016-05-01

    A flexible and efficient method to fabricate nanopores in graphene has been developed. A focused, low-energy (5 keV) electron beam was used to locally activate etching of a graphene surface in a low pressure (0.3 Pa) N2 environment. Nanopores with sub-5 nm diameters were fabricated. The lattice structure of the graphene was observed to recover within 20 nm of the nanopore edge. Nanopore growth rates were investigated systematically. The effects of nitrogen pressure, electron beam dwell time and beam current were characterised in order to understand the etching mechanism and enable optimisation of the etching parameters. A model was developed which describes how the diffusion of ionised nitrogen affects the nanopore growth rate. Etching of other two-dimensional materials was attempted as demonstrated with MoS2. The lack of etching observed supports our model of a chemical reaction-based mechanism. The understanding of the etching mechanism will allow more materials to be etched by selection of an appropriate ion species.

  11. Sub-5 nm graphene nanopore fabrication by nitrogen ion etching induced by a low-energy electron beam.

    PubMed

    Fox, Daniel S; Maguire, Pierce; Zhou, Yangbo; Rodenburg, Cornelia; O'Neill, Arlene; Coleman, Jonathan N; Zhang, Hongzhou

    2016-05-13

    A flexible and efficient method to fabricate nanopores in graphene has been developed. A focused, low-energy (5 keV) electron beam was used to locally activate etching of a graphene surface in a low pressure (0.3 Pa) N2 environment. Nanopores with sub-5 nm diameters were fabricated. The lattice structure of the graphene was observed to recover within 20 nm of the nanopore edge. Nanopore growth rates were investigated systematically. The effects of nitrogen pressure, electron beam dwell time and beam current were characterised in order to understand the etching mechanism and enable optimisation of the etching parameters. A model was developed which describes how the diffusion of ionised nitrogen affects the nanopore growth rate. Etching of other two-dimensional materials was attempted as demonstrated with MoS2. The lack of etching observed supports our model of a chemical reaction-based mechanism. The understanding of the etching mechanism will allow more materials to be etched by selection of an appropriate ion species. PMID:27040079

  12. Low-energy mass-selected ion beam production of fragments produced from hexamethyldisilane for SiC film formation

    NASA Astrophysics Data System (ADS)

    Yoshimura, Satoru; Sugimoto, Satoshi; Kiuchi, Masato

    2016-03-01

    We have proposed an experimental methodology which makes it possible to deposit silicon carbide (SiC) films on Si substrates with a low-energy mass-selected ion beam system using hexamethyldisilane (HMD) as a gas source. In this study, one of the fragment ions produced from HMD, SiCH4+, was mass-selected. The ion energy was approximately 100 eV. Then, the SiCH4+ ions were irradiated to a Si(100) substrate. When the temperature of the Si substrate was set at 800 °C during the ion irradiation, the X-ray diffraction and Raman spectroscopy of the substrate following the completion of ion irradiation experiment demonstrated the occurrence of 3C-SiC deposition.

  13. Measurement of the beam-recoil polarization in low-energy virtual Compton scattering from the proton

    NASA Astrophysics Data System (ADS)

    Doria, L.; Janssens, P.; Achenbach, P.; Ayerbe Gayoso, C.; Baumann, D.; Bensafa, I.; Benali, M.; Beričič, J.; Bernauer, J. C.; Böhm, R.; Bosnar, D.; Correa, L.; D'Hose, N.; Defaÿ, X.; Ding, M.; Distler, M. O.; Fonvieille, H.; Friedrich, J.; Friedrich, J. M.; Laveissière, G.; Makek, M.; Marroncle, J.; Merkel, H.; Mihovilovič, M.; Müller, U.; Nungesser, L.; Pasquini, B.; Pochodzalla, J.; Postavaru, O.; Potokar, M.; Ryckbosch, D.; Sánchez Majos, S.; Schlimme, B. S.; Seimetz, M.; Širca, S.; Tamas, G.; Van de Vyver, R.; Van Hoorebeke, L.; Van Overloop, A.; Walcher, Th.; Weinriefer, M.; A1 Collaboration

    2015-11-01

    Double-polarization observables in the reaction e ⃗p →e'p ⃗'γ have been measured at Q2=0.33 (GeV/c ) 2 . The experiment was performed at the spectrometer setup of the A1 Collaboration using the 855 MeV polarized electron beam provided by the Mainz Microtron (MAMI) and a recoil proton polarimeter. From the double-polarization observables the structure function PLT ⊥ is extracted for the first time, with the value (-15.4 ±3 .3(stat .)-2.4+1.5(syst.)) GeV-2 , using the low-energy theorem for virtual Compton scattering. This structure function provides a hitherto unmeasured linear combination of the generalized polarizabilities of the proton.

  14. A field-assisted moderator for low-energy positron beams

    NASA Astrophysics Data System (ADS)

    Beling, C. D.; Simpson, R. I.; Charlton, M.; Jacobsen, F. M.; Griffith, T. C.; Moriarty, P.; Fung, S.

    1987-01-01

    A new positron field-assisted (FA) moderator based on the drift of positrons across a cooled silicon crystal is proposed. Using estimates for both the β + implantation profile and attainable drift velocities, the efficiency of drift to a slow e+ emitting surface is calculated using a diffusion equation which incorporates terms describing positron drift and annihilation. It is conjectured that efficiencies of up to 10% can be achieved. The use of epitaxially grown metallic suicide contacts to facilitate the application of the electric field is described and the consequences of using such contacts are fully discussed. Applications of the FA transmission mode moderator described here to produce timed brightness enhanced beams are briefly discussed.

  15. Mechanical properties of silicon oxynitride thin films prepared by low energy ion beam assisted deposition

    NASA Astrophysics Data System (ADS)

    Shima, Yukari; Hasuyama, Hiroki; Kondoh, Toshiharu; Imaoka, Yasuo; Watari, Takanori; Baba, Koumei; Hatada, Ruriko

    1999-01-01

    Silicon oxynitride (SiO xN y) films (0.1-0.7 μm) were produced on Si (1 0 0), glass and 316L stainless steel substrates by ion beam assisted deposition (IBAD) using Si evaporation and the concurrent bombardment with a mixture of 200 eV N 2 and Ar, or O 2 and Ar ions. Adhesion was evaluated by pull-off tests. Film hardness was measured by a nanoindentation system with AFM. The measurement of internal stress in the films was carried out by the Stoney method. The film structure was examined by GXRD. XPS was employed to measure the composition of films and to analyze the chemical bonds. The dependence of mechanical properties on the film thickness and the processing temperature during deposition was studied. Finally, the relations between the mechanical properties of the films and the correlation with corrosion-protection ability of films are discussed and summarized.

  16. 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.

  17. Performance of beta tool for low-energy electron-beam proximity-projection lithography (LEEPL)

    NASA Astrophysics Data System (ADS)

    Yoshida, Akira; Kasahara, Haruo; Higuchi, Akira; Nozue, Hiroshi; Endo, Akihiro; Shimazu, Nobuo

    2003-06-01

    The two LEEPL beta-tools were completed in earlier 2002 and have been evaluated for the performance. 50nm CH patterns and 70nm L/S patterns are attained and the CD uniformity of 70nm L/S patterns with 37 shots on a 200mm wafer is under 4nm with the LEEPL beta-tools. In addition, it is proven that the fine tuning deflector can correct a mask and a wafer distortion by giving a minute angle to the electron beam. The mask distortion with respect to orthogonality and magnification is decreased on a wafer by 1/5. By means of this fine tuning deflector, Mix & Match accuracy with any other lithography tools will be better and difficulty of 1X stencil mask fabrication wil be easier. Referring to the data which has been obtained with the evaluation of the LEEPL beta-tools, the first LEEPL production tool dubbed "LEEPL-3000" is under construction to realize the satisfactory ability for 65nm node device fabrication. The shipping of the first LEEPL-3000 is scheduled in earlier 2003 and it is earlier than any other Next Generation Lithography technologies.

  18. High and low energy gamma beam dump designs for the gamma beam delivery system at ELI-NP

    NASA Astrophysics Data System (ADS)

    Yasin, Zafar; Matei, Catalin; Ur, Calin A.; Mitu, Iani-Octavian; Udup, Emil; Petcu, Cristian

    2016-03-01

    The Extreme Light Infrastructure - Nuclear Physics (ELI-NP) is under construction in Magurele, Bucharest, Romania. The facility will use two 10 PW lasers and a high intensity, narrow bandwidth gamma beam for stand-alone and combined laser-gamma experiments. The accurate estimation of particle doses and their restriction within the limits for both personel and general public is very important in the design phase of any nuclear facility. In the present work, Monte Carlo simulations are performed using FLUKA and MCNPX to design 19.4 and 4 MeV gamma beam dumps along with shielding of experimental areas. Dose rate contour plots from both FLUKA and MCNPX along with numerical values of doses in experimental area E8 of the facility are performed. The calculated doses are within the permissible limits. Furthermore, a reasonable agreement between both codes enhances our confidence in using one or both of them for future calculations in beam dump designs, radiation shielding, radioactive inventory, and other calculations releated to radiation protection. Residual dose rates and residual activity calculations are also performed for high-energy beam dump and their effect is negligible in comparison to contributions from prompt radiation.

  19. Low-energy broad-beam photon shielding data for constituents of concrete.

    PubMed

    Ogundare, Folorunso O; Ogundele, Samuel A; Akerele, Olumide O; Balogun, Fatai A

    2012-01-01

    The ability of concrete to attenuate ionizing radiation intensity is assessed using its linear or mass attenuation coefficient. In this work, the broad-beam linear and mass attenuation coefficients of different types of soils and cements used for making concrete were measured at different photon energies (60-1333 keV), nearly spanning the diagnostic photon energy range, using a NaI detector. The mass attenuation coefficients of cement decreased from 0.133 ± 0.002 at 60 keV to 0.047 ± 0.003 at 1332.5 keV. For soils, the mass attenuation coefficient of those collected from the beach was the highest, decreasing from 0.176 ± 0.003 cm²/g at 60 keV to 0.054 ± 0.001 cm²/g at 1332.5 keV. Land soils had the least value, decreasing from 0.124 ± 0.002 cm²/g at 60 keV to 0.044 ± 0.003 cm²/g at 1332.5 keV. Limestone had smaller mass attenuation coefficients than the cement produced using it. The implication of the above is that for making concrete, beach sand should be preferred as the sand component of the concrete. Models of the form μ(L) = A(E) exp[B(E)ρ] and μ(m) = αln(E)+β are proposed for fitting the linear attenuation coefficient and mass attenuation coefficient data, respectively. PMID:22402377

  20. Low energy electron beam irradiation effect on optical properties of nanopillar MQW InGaN/GaN structures

    SciTech Connect

    Yakimov, E. B.; Vergeles, P. S.; Polyakov, A. Y.; Jeon, Dae-Woo; Lee, In-Hwan

    2014-02-21

    The low energy electron beam irradiation (LEEBI) effect on optical properties of planar and nanopillar InGaN/GaN muliple quantum well light emitting structures was studied by the cathodoluminescence (CL) method. On the planar structures LEEBI leads to a formation of new InGaN-related emission bands red shifted in comparison with initial one at small irradiation doses and blue shifted at doses higher than 0.5 C/cm{sup 2}. It was observed that after dry etching used for the nanopillar formation the main InGaN-related emission line moves from 2.92 to 2.98 eV that can be explained by a strain relaxation in the quantum wells. The optical properties of nanopilars start to change under LEEBI at a dose of about one order of magnitude lower than that for planar structures. At high irradiation doses the behavior of both structures under LEEBI is similar. The results obtained were explained by the formation and reconstruction of quantum dots inside the quantum wells due to a point defect generation and redistribution stimulated by the electron beam irradiation.

  1. 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.

  2. 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

  3. The effect of low-energy electrons on the response of ion chambers to ionizing photon beams

    NASA Astrophysics Data System (ADS)

    La Russa, Daniel J.

    Cavity ionization chambers are one of the most popular and widely used devices for quantifying ionizing photon beams. This popularity originates from the precision of these devices and the relative ease with which ionization measurements are converted to quantities of interest in therapeutic radiology or radiation protection, collectively referred to as radiation dosimetry. The formalisms used for these conversions, known as cavity theory, make several assumptions about the electron spectrum in the low-energy range resulting from the incident photon beam. These electrons often account for a significant fraction of the ion chamber response. An inadequate treatment of low-energy electrons can therefore significantly effect calculated quantities of interest. This thesis sets out to investigate the effect of low-energy electrons on (1) the use of Spencer-Attix cavity theory with 60Co beams; and (2) the standard temperature-pressure correction factor, P TP, used to relate the measured ionization to a set of reference temperature and pressure conditions for vented ion chambers. Problems with the PTP correction are shown to arise when used with kilovoltage x rays, where ionization measurements are due primarily to electrons that do not have enough energy to cross the cavity. A combination of measurements and Monte Carlo calculations using the EGSnrc Monte Carlo code demonstrate the breakdown of PTP in these situations when used with non-air-equivalent chambers. The extent of the breakdown is shown to depend on cavity size, energy of the incident photons, and the composition of the chamber. In the worst case, the standard P TP factor overcorrects the response of an aluminum chamber by ≈12% at an air density typical of Mexico City. The response of a more common graphite-walled chamber with similar dimensions at the same air density is undercorrected by ≈ 2%. The EGSnrc Monte Carlo code is also used to investigate Spencer-Attix cavity theory as it is used in the

  4. Investigation of the Direct Charge Transfer in Low Energy D2+ + H Collisions using Merged-Beams Technique

    NASA Astrophysics Data System (ADS)

    Romano, S. L.; Guillen, C. I.; Andrianarijaona, V. M.; Havener, C. C.

    2011-10-01

    The hydrogen - hydrogen (deuterium) molecular ion is the most fundamental ion-molecule two-electron system. Charge transfer (CT) for H2+ on H, which is one of the possible reaction paths for the (H-H2)+ system, is of special interest because of its contribution to H2 formation in the early universe, its exoergicity, and rich collision dynamics. Due to technical difficulty in making an atomic H target, the direct experimental investigations of CT for H2+ on H are sparse and generally limited to higher collision energies. The measurements of the absolute cross section of different CT paths for H2+ on H over a large range of collision energy are needed to benchmark theoretical calculations, especially the ones at low energies. The rate coefficient of CT at low energy is not known but may be comparable to other reaction rate coefficients in cold plasmas with H, H+, H2+, and H3+ as constituents. For instance, CT for H2+ on H and the following H3+ formation reaction H2+ + H2 → H + H3+ are clearly rate interdependent although it was always assumed that every ionization of H2 will lead to the formation of H3+. CT proceeds through dynamically coupled electronic, vibrational and rotational degrees of freedom. One can depict three paths, electronic CT, CT with nuclear substitution, and CT with dissociation. Electronic CT and CT with nuclear substitution in the H2+ on H collisions are not distinguishable by any quantum theory. Here we use the isotopic system (D2+ - H) to measure without ambiguity the electronic CT cross section by observing the H+ products. Using the ion-atom merged-beam apparatus at Oak Ridge National Laboratory, the absolute direct CT cross sections for D2+ + H from keV/u to meV/u collision energies have been measured. The molecular ions are extracted from an Electron-Cyclotron Resonance (ECR) ion source with a vibrational state distribution which is most likely determined by Frank-Condon transitions between ground state D2 and D2+. A ground-state H beam

  5. Design of a high-current low-energy beam transport line for an intense D-T/D-D neutron generator

    NASA Astrophysics Data System (ADS)

    Lu, Xiaolong; Wang, Junrun; Zhang, Yu; Li, Jianyi; Xia, Li; Zhang, Jie; Ding, Yanyan; Jiang, Bing; Huang, Zhiwu; Ma, Zhanwen; Wei, Zheng; Qian, Xiangping; Xu, Dapeng; Lan, Changlin; Yao, Zeen

    2016-03-01

    An intense D-T/D-D neutron generator is currently being developed at the Lanzhou University. The Cockcroft-Walton accelerator, as a part of the neutron generator, will be used to accelerate and transport the high-current low-energy beam from the duoplasmatron ion source to the rotating target. The design of a high-current low-energy beam transport (LEBT) line and the dynamics simulations of the mixed beam were carried out using the TRACK code. The results illustrate that the designed beam line facilitates smooth transportation of a deuteron beam of 40 mA, and the number of undesired ions can be reduced effectively using two apertures.

  6. Electron stripping processes of H- ion beam in the 80 kV high voltage extraction column and low energy beam transport line at LANSCE

    NASA Astrophysics Data System (ADS)

    Draganic, I. N.

    2016-02-01

    Basic vacuum calculations were performed for various operating conditions of the Los Alamos National Neutron Science H- Cockcroft-Walton (CW) injector and the Ion Source Test Stand (ISTS). The vacuum pressure was estimated for both the CW and ISTS at five different points: (1) inside the H- ion source, (2) in front of the Pierce electrode, (3) at the extraction electrode, (4) at the column electrode, and (5) at the ground electrode. A static vacuum analysis of residual gases and the working hydrogen gas was completed for the normal ion source working regime. Gas density and partial pressure were estimated for the injected hydrogen gas. The attenuation of H- beam current and generation of electron current in the high voltage acceleration columns and low energy beam transport lines were calculated. The interaction of H- ions on molecular hydrogen (H2) is discussed as a dominant collision process in describing electron stripping rates. These results are used to estimate the observed increase in the ratio of electrons to H- ion beam in the ISTS beam transport line.

  7. Electron stripping processes of H⁻ ion beam in the 80 kV high voltage extraction column and low energy beam transport line at LANSCE.

    PubMed

    Draganic, I N

    2016-02-01

    Basic vacuum calculations were performed for various operating conditions of the Los Alamos National Neutron Science H(-) Cockcroft-Walton (CW) injector and the Ion Source Test Stand (ISTS). The vacuum pressure was estimated for both the CW and ISTS at five different points: (1) inside the H(-) ion source, (2) in front of the Pierce electrode, (3) at the extraction electrode, (4) at the column electrode, and (5) at the ground electrode. A static vacuum analysis of residual gases and the working hydrogen gas was completed for the normal ion source working regime. Gas density and partial pressure were estimated for the injected hydrogen gas. The attenuation of H(-) beam current and generation of electron current in the high voltage acceleration columns and low energy beam transport lines were calculated. The interaction of H(-) ions on molecular hydrogen (H2) is discussed as a dominant collision process in describing electron stripping rates. These results are used to estimate the observed increase in the ratio of electrons to H(-) ion beam in the ISTS beam transport line. PMID:26931993

  8. Development of ion transportation, extraction and neutralization systems for atomic beam resonance method

    NASA Astrophysics Data System (ADS)

    Nagae, Daisuke; Asahi, Koichiro; Miyoshi, Hisanori; Shimada, Kenzi; Yoshimi, Akihiro; Ueno, Hideki; Murata, Jiro; Uchida, Makoto; Kameda, Daisuke; Kato, Go; Emori, Shoken; Kijima, Go; Oshima, Sachiko; Takemura, Makoto; Arai, Takemasa; Kobayashi, Yoshio; Haseyama, Tomohito; Schmidt-Ott, W. D.

    2005-11-01

    A device that produces a low-energy and largely spin polarized RI beam based on the atomic beam resonance method (RIABR) has been developed. We have performed measurements of stopping and drifting an incoming RI ion beam in a gas chamber, extraction of the ions into a vacuum region, and neutralization of the extracted low-energy ion beam. The drift efficiency of RI ions in a gas and the extraction efficiency at a Laval-type glass nozzle were found to be 0.72±0.04 and 0.033, respectively. The result of the experiment for the neutralization is also discussed.

  9. SIM.RI(I)-K3 comparison of calibration coefficients at radiotherapy level for orthovoltage x-ray beams

    NASA Astrophysics Data System (ADS)

    O'Brien, M.; McCaffrey, J.; Shen, H.; Saraví, M.; Stefanic, A.; Montaño Ortiz, G.; Carlos, M.; da Silva, C.; Álvarez, J.; Tovar, V.

    2015-01-01

    Air-kerma calibration coefficients were compared at the radiotherapy level for orthovoltage x ray beams in the SIM.RI(I)-K3 comparison for members of the Sistema Interamericano de Metrología (SIM). Five SIM laboratories participated in the comparison: NIST, NRC, ININ, CNEA and LNMRI, the NIST being the pilot laboratory. Results from the comparison are linked to the BIPM.RI(I)-K3 key comparison reference value through the NIST-BIPM comparison made in 2003 and will meet requirements of the Mutual Recognition Arrangement (MRA) to support several CMCs (calibration and measurement capability claims) of the participants. The comparison began in October of 2007 and the measurements were completed in September 2008. The results reveal the degree to which the participating calibration facility can demonstrate proficiency in transferring air-kerma calibrations under the conditions of the said facility at the time of the measurements. The evaluation of the degrees of equivalence was performed as described in the comparison protocol. The comparison of the calibration coefficients for the four chambers is based on the average ratios of the calibration coefficients measured at the NIST and at each participating laboratory. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  10. Status of Beam Line Detectors for the BigRIPS Fragment Separator at RIKEN RI Beam Factory: Issues on High Rates and Resolution

    NASA Astrophysics Data System (ADS)

    Sato, Yuki; Fukuda, Naoki; Takeda, Hiroyuki; Kameda, Daisuke; Suzuki, Hiroshi; Shimizu, Yohei; Ahn, DeukSoon; Murai, Daichi; Inabe, Naohito; Shimaoka, Takehiro; Tsubota, Masakatsu; Kaneko, Junichi H.; Chayahara, Akiyoshi; Umezawa, Hitoshi; Shikata, Shinichi; Kumagai, Hidekazu; Murakami, Hiroyuki; Sato, Hiromi; Yoshida, Koichi; Kubo, Toshiyuki

    A multiple sampling ionization chamber (MUSIC) and parallel-plate avalanche counters (PPACs) were installed within the superconducting in-flight separator, named BigRIPS, at the RIKEN Nishina Center for particle identification of RI beams. The MUSIC detector showed negligible charge collection inefficiency from recombination of electrons and ions, up to a 99-kcps incidence rate for high-energy heavy ions. For the PPAC detectors, the electrical discharge durability for incident heavy ions was improved by changing the electrode material. Finally, we designed a single crystal diamond detector, which is under development for TOF measurements of high-energy heavy ions, that has a very fast response time (pulse width <1 ns).

  11. Weak-coupling structure of proton resonant states in 23Al studied with RI beam at CNS

    NASA Astrophysics Data System (ADS)

    He, J. J.; Kubono, S.; Teranishi, T.; Notani, M.; Michimasa, S.; Baba, H.; Nishimura, S.; Nishimura, M.; Yanagisawa, Y.; Hokoiwa, N.; Kibe, M.; Gono, Y.; Moon, J. Y.; Lee, J. H.; Lee, C. S.; Iwasaki, H.; Kato, S.

    2006-07-01

    Proton resonances in 23Al have been investigated for the first time by the resonant elastic and inelastic scattering of 22Mg+p by using a 4.38 MeV/nucleon 22Mg beam bombarding a thick Hydrogen target. The low-energy 22Mg beam was separated by the CNS radioactive ion beam separator (CRIB). A new resonant state due to elastic scattering was observed at Ex = 3.00 MeV with a Jπ = (3/2+) assignment. Other three excited states due to resonant inelastic scattering at 3.14, 3.26 and 3.95 MeV were identified and all mainly decay to the first excited state in 22Mg by the proton emissions. The newly observed 3.95-MeV state probably has a spin-parity of Jπ = (7/2+). The resonant properties were determined from an R-matrix analysis of the excitation functions. The weak-coupling structure in 23Al is discussed in conjunction with a shell-model calculation.

  12. Is low-energy-ion bombardment generated X-ray emission a secondary mutational source to ion-beam-induced genetic mutation?

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

    Low-energy ion beam biotechnology has achieved tremendous successes in inducing crop mutation and gene transfer. However, mechanisms involved in the related processes are not yet well understood. In ion-beam-induced mutation, ion-bombardment-produced X-ray has been proposed to be one of the secondary mutation sources, but the speculation has not yet been experimentally tested. We carried out this investigation to test whether the low-energy ion-beam-produced X-ray was a source of ion-beam-induced mutation. In the investigation, X-ray emission from 29-keV nitrogen- or argon- ion beam bombarded bacterial Escherichia coli (E. coli) cells held in a metal or plastic sample holder was in situ detected using a highly sensitive X-ray detector. The ion beam bombarded bacterial cells held in different material holders were observed for mutation induction. The results led to a conclusion that secondary X-ray emitted from ion-beam-bombarded biological living materials themselves was not a, or at least a negligible, mutational source, but the ion-beam-induced X-ray emission from the metal that made the sample holder could be a source of mutation.

  13. 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

  14. Evolution of the CaF2:Tm (TLD-300) glow curve as an indicator of beam quality for low-energy photon beams

    NASA Astrophysics Data System (ADS)

    Muñoz, I. D.; Avila, O.; Gamboa-deBuen, I.; Brandan, M. E.

    2015-03-01

    We study the high- to low- temperature signal ratio (HLTR) of the CaF2:Tm glow curve as a function of beam quality for low-energy photon beams with effective energy between 15.2 and 33.6 keV, generated with W, Mo and Rh anodes. CaF2:Tm dosemeters (TLD-300) were exposed to x-rays and 60Co gamma-rays. Glow curves were deconvoluted into 7 peaks, using computerized glow curve deconvolution and HLTR was evaluated. Air kerma and dose in water were between 2.1-15.0 mGy and 49.8-373.8 mGy, respectively. All peaks in the glow curve showed a linear response with respect to air kerma and dose in water. HLTR values decreased monotonically between 1.029  ±  0.010 (at 15.2 keV) and 0.821  ±  0.011 (33.6 keV), and no effects due to the use of different anode/filter combinations were observed. The results indicate a relatively high value of HLTR (about 1 for 17 keV effective energy, or 3 keV μm-1 track-average LET) and a measurable dependence on the photon beam quality. Comparison of these photon data with HLTR for ions shows good quantitative agreement. The reported evolution of the CaF2:Tm glow curve could facilitate the estimation of the effective energy of unknown photon fields by this technique.

  15. Electron density profile measurements at a self-focusing ion beam with high current density and low energy extracted through concave electrodes

    SciTech Connect

    Fujiwara, Y. Nakamiya, A.; Sakakita, H.; Hirano, Y.; Kiyama, S.; Koguchi, H.

    2014-02-15

    The self-focusing phenomenon has been observed in a high current density and low energy ion beam. In order to study the mechanism of this phenomenon, a special designed double probe to measure the electron density and temperature is installed into the chamber where the high current density ion beam is injected. Electron density profile is successfully measured without the influence of the ion beam components. Estimated electron temperature and density are ∼0.9 eV and ∼8 × 10{sup 8} cm{sup −3} at the center of ion beam cross section, respectively. It was found that a large amount of electrons are spontaneously accumulated in the ion beam line in the case of self-forcing state.

  16. SU-F-19A-06: Experimental Investigation of the Energy Dependence of TLD Sensitivity in Low-Energy Photon Beams

    SciTech Connect

    Chen, Z; Nath, R

    2014-06-15

    Purpose: To measure the energy dependence of TLD sensitivity in lowenergy photon beams with equivalent mono-energetic energy matching those of 103Pd, 125I and 131Cs brachytherapy sources. Methods: A Pantek DXT 300 x-ray unit (Precision X-ray, Branford, CT), with stable digital voltage control down to 20 kV, was used to establish three lowenergy photon beams with narrow energy spread and equivalent monoenergetic energies matching those of 103Pd, 125I and 131Cs brachytherapy sources. The low-energy x-ray beams and a reference 6 MV photon beam were calibrated according to the AAPM TG-61 and TG-51 protocols, respectively, using a parallel-plate low-energy chamber and a Farmer cylindrical chamber with NIST traceable calibration factors. The dose response of model TLD-100 micro-cubes (1×1×1 mm{sup 3}) in each beam was measured for five different batches of TLDs (each contained approximately 100 TLDs) that have different histories of irradiation and usage. Relative absorbed dose sensitivity was determined as the quotient of the slope of dose response for a beam-of-interest to that of the reference beam. Results: Equivalent mono-energetic photon energies of the low-energy beams established for 103Pd, 125I and 131Cs sources were 20.5, 27.5, and 30.1 keV, respectively. Each beam exhibited narrow spectral spread with energyhomogeneity index close to 90%. The relative absorbed-dose sensitivity was found to vary between different batches of TLD with maximum differences of up to 8%. The mean and standard deviation determined from the five TLD batches was 1.453 ± 0.026, 1.541 ± 0.035 and 1.529 ± 0.051 for the simulated 103P, 125I and 131Cs beams, respectively. Conclusion: Our measured relative absorbed-dose sensitivities are greater than the historically measured value of 1.41. We find that the relative absorbed-dose sensitivity of TLD in the 103P beam is approximately 5% lower than that of 125I and 131Cs beams. Comparison of our results with other studies will be presented.

  17. Magnetron sputtering system for coatings deposition with activation of working gas mixture by low-energy high-current electron beam

    NASA Astrophysics Data System (ADS)

    Gavrilov, N. V.; Kamenetskikh, A. S.; Men'shakov, A. I.; Bureyev, O. A.

    2015-11-01

    For the purposes of efficient decomposition and ionization of the gaseous mixtures in a system for coatings deposition using reactive magnetron sputtering, a low-energy (100-200 eV) high-current electron beam is generated by a grid-stabilized plasma electron source. The electron source utilizes both continuous (up to 20 A) and pulse-periodic mode of discharge with a self-heated hollow cathode (10-100 A; 0.2 ms; 10-1000 Hz). The conditions for initiation and stable burning of the high-current pulse discharge are studied along with the stable generation of a low-energy electron beam within the gas pressure range of 0.01 - 1 Pa. It is shown that the use of the electron beam with controllable parameters results in reduction of the threshold values both for the pressure of gaseous mixture and for the fluxes of molecular gases. Using such a beam also provides a wide range (0.1-10) of the flux density ratios of ions and sputtered atoms over the coating surface, enables an increase in the maximum pulse density of ion current from plasma up to 0.1 A, ensures an excellent adhesion, optimizes the coating structure, and imparts improved properties to the superhard nanocomposite coatings of (Ti,Al)N/a-Si3N4 and TiC/-a-C:H. Mass-spectrometric measurements of the beam-generated plasma composition proved to demonstrate a twofold increase in the average concentration of N+ ions in the Ar-N2 plasma generated by the high-current (100 A) pulsed electron beam, as compared to the dc electron beam.

  18. A Parallel 3d Model for The Multi-Species Low Energy BeamTransport System of the RIA Prototype ECR Ion Source Venus

    SciTech Connect

    Qiang, J.; Leitner, D.; Todd, D.

    2005-05-16

    The driver linac of the proposed Rare Isotope Accelerator (RIA) requires a great variety of high intensity, high charge state ion beams. In order to design and to optimize the low energy beamline optics of the RIA front end,we have developed a new parallel three-dimensional model to simulate the low energy, multi-species ion beam formation and transport from the ECR ion source extraction region to the focal plane of the analyzing magnet. A multisection overlapped computational domain has been used to break the original transport system into a number of each subsystem, macro-particle tracking is used to obtain the charge density distribution in this subdomain. The three-dimensional Poisson equation is solved within the subdomain and particle tracking is repeated until the solution converges. Two new Poisson solvers based on a combination of the spectral method and the multigrid method have been developed to solve the Poisson equation in cylindrical coordinates for the beam extraction region and in the Frenet-Serret coordinates for the bending magnet region. Some test examples and initial applications will also be presented.

  19. Gene expression profiles in promoted-growth rice seedlings that germinated from the seeds implanted by low-energy N+ beam

    PubMed Central

    Ya, Huiyuan; Chen, Qiufang; Wang, Weidong; Chen, Wanguang; Qin, Guangyong; Jiao, Zhen

    2012-01-01

    The stimulation effect that some beneficial agronomic qualities have exhibited in present-generation plants have also been observed due to ion implantation on plants. However, there is relatively little knowledge regarding the molecular mechanism of the stimulation effects of ion-beam implantation. In order to extend our current knowledge about the functional genes related to this stimulation effect, we have reported a comprehensive microarray analysis of the transcriptome features of the promoted-growth rice seedlings germinating from seeds implanted by a low-energy N+ beam. The results showed that 351 up-regulated transcripts and 470 down-regulated transcripts, including signaling proteins, kinases, plant hormones, transposable elements, transcription factors, non-coding protein RNA (including miRNA), secondary metabolites, resistance proteins, peroxidase and chromatin modification, are all involved in the stimulating effects of ion-beam implantation. The divergences of the functional catalog between the vacuum and ion implantation suggest that ion implantation is the principle cause of the ion-beam implantation biological effects, and revealed the complex molecular networks required to adapt to ion-beam implantation stress in plants, including enhanced transposition of transposable elements, promoted ABA biosynthesis and changes in chromatin modification. Our data will extend the current understanding of the molecular mechanisms and gene regulation of stimulation effects. Further research on the candidates reported in this study should provide new insights into the molecular mechanisms of biological effects induced by ion-beam implantation. PMID:22843621

  20. Low-energy operation of the Livermore electron beam ion traps: Atomic spectroscopy of Si V, S VII, and Ar IX

    SciTech Connect

    Lepson, J K; Beiersdorfer, P

    2004-01-02

    As part of a project to compile a comprehensive catalog of astrophysically relevant emission lines, we used the low-energy capability of the Lawrence Livermore electron beam ion traps to extend the spectroscopy of neon-like ions and the neighboring charge states to silicon, sulfur, and argon. They present wavelength data of Si V and demonstrate the effect of collisional deexcitation of electric dipole forbidden lines on the 2-3 L-shell spectra of Si V, S VII, and Ar IX.

  1. SU-D-19A-01: Can Farmer-Type Ionization Chambers Be Used to Improve the Accuracy of Low-Energy Electron Beam Reference Dosimetry?

    SciTech Connect

    Muir, B R; McEwen, M R

    2014-06-01

    Purpose: To investigate the use of cylindrical Farmer-type ionization chambers to improve the accuracy of low-energy electron beam calibration. Historically, these chamber types have not been used in beams with incident energies less than 10 MeV (R{sub 5} {sub 0} < 4.3 cm) because early investigations suggested large (up to 5 %) fluence perturbation factors in these beams, implying that a significant component of uncertainty would be introduced if used for calibration. More recently, the assumptions used to determine perturbation corrections for cylindrical chambers have been questioned. Methods: Measurements are made with cylindrical chambers in Elekta Precise 4, 8 and 18 MeV electron beams. Several chamber types are investigated that employ graphite walls and aluminum electrodes with very similar specifications (NE2571, NE2505/3, FC65-G). Depth-ionization scans are measured in water in the 8 and 18 MeV beams. To reduce uncertainty from chamber positioning, measurements in the 4 MeV beam are made at the reference depth in Virtual Water™. The variability of perturbation factors is quantified by comparing normalized response of various chambers. Results: Normalized ion chamber response varies by less than 0.7 % for similar chambers at average electron energies corresponding to that at the reference depth from 4 or 6 MeV beams. Similarly, normalized measurements made with similar chambers at the reference depth in the 4 MeV beam vary by less than 0.4 %. Absorbed dose calibration coefficients derived from these results are stable within 0.1 % on average over a period of 6 years. Conclusion: These results indicate that the uncertainty associated with differences in fluence perturbations for cylindrical chambers with similar specifications is only 0.2 %. The excellent long-term stability of these chambers in both photon and electron beams suggests that these chambers might offer the best performance for all reference dosimetry applications.

  2. Use of a wire scanner for monitoring residual gas ionization in Soreq Applied Research Accelerator Facility 20 keV∕u proton∕deuteron low energy beam transport beam line.

    PubMed

    Vainas, B; Eliyahu, I; Weissman, L; Berkovits, D

    2012-02-01

    The ion source end of the Soreq Applied Research Accelerator Facility accelerator consists of a proton∕deuteron ECR ion source and a low energy beam transport (LEBT) beam line. An observed reduction of the radio frequency quadrupole transmission with increase of the LEBT current prompted additional study of the LEBT beam properties. Numerous measurements have been made with the LEBT bream profiler wire biased by a variable voltage. Current-voltage characteristics in presence of the proton beam were measured even when the wire was far out of the beam. The current-voltage characteristic in this case strongly resembles an asymmetric diodelike characteristic, which is typical of Langmuir probes monitoring plasma. The measurement of biased wire currents, outside the beam, enables us to estimate the effective charge density in vacuum. PMID:22380317

  3. Measurements of the Propagation of EM Waves through the Vacuum Chamber of the PEP-II Low Energy Ring for Beam Diagnostics

    SciTech Connect

    Byrd, John Michael; De Santis, S.; Pivi, MTF; /SLAC

    2008-01-23

    We present the results of our measurements of the electron cloud density in the PEP-II low energy ring (LER) by propagating a TE wave into the beam pipe. By connecting a signal generator to a beam position monitor button we can excite a signal above the vacuum chamber cut-off frequency and measure its propagation through the beam pipe with a spectrum analyzer connected to another button about 50 meters away. The measurement can be performed with different beam conditions and also at different settings of the solenoids used to reduce the build up of electrons. The presence of a modulation in the TE wave transmission, synchronous with the beam revolution frequency, which appear to increase in depth when the solenoids are switched off, seem to be directly correlated to the electron cloud density in the region between the two BPM's. In this paper we present and discuss the measurements taken in the Interaction Region 12 straight of the LER during 2006 and the first part of 2007.

  4. Energy deposition evaluation for ultra-low energy electron beam irradiation systems using calibrated thin radiochromic film and Monte Carlo simulations.

    PubMed

    Matsui, S; Mori, Y; Nonaka, T; Hattori, T; Kasamatsu, Y; Haraguchi, D; Watanabe, Y; Uchiyama, K; Ishikawa, M

    2016-05-01

    For evaluation of on-site dosimetry and process design in industrial use of ultra-low energy electron beam (ULEB) processes, we evaluate the energy deposition using a thin radiochromic film and a Monte Carlo simulation. The response of film dosimeter was calibrated using a high energy electron beam with an acceleration voltage of 2 MV and alanine dosimeters with uncertainty of 11% at coverage factor 2. Using this response function, the results of absorbed dose measurements for ULEB were evaluated from 10 kGy to 100 kGy as a relative dose. The deviation between the responses of deposit energy on the films and Monte Carlo simulations was within 15%. As far as this limitation, relative dose estimation using thin film dosimeters with response function obtained by high energy electron irradiation and simulation results is effective for ULEB irradiation processes management. PMID:27250416

  5. IMPACT: a facility to study the interaction of low-energy intense particle beams with dynamic heterogeneous surfaces.

    PubMed

    Allain, J P; Nieto, M; Hendricks, M R; Plotkin, P; Harilal, S S; Hassanein, A

    2007-11-01

    The Interaction of Materials with Particles and Components Testing (IMPACT) experimental facility is furnished with multiple ion sources and in situ diagnostics to study the modification of surfaces undergoing physical, chemical, and electronic changes during exposure to energetic particle beams. Ion beams with energies in the range between 20 and 5000 eV can bombard samples at flux levels in the range of 10(10)-10(15) cm(-2) s(-1); parameters such as ion angle of incidence and exposed area are also controllable during the experiment. IMPACT has diagnostics that allow full characterization of the beam, including a Faraday cup, a beam imaging system, and a retarding field energy analyzer. IMPACT is equipped with multiple diagnostics, such as electron (Auger, photoelectron) and ion scattering spectroscopies that allow different probing depths of the sample to monitor compositional changes in multicomponent and/or layered targets. A unique real-time erosion diagnostic based on a dual quartz crystal microbalance measures deposition from an eroding surface with rates smaller than 0.01 nm/s, which can be converted to a sputter yield measurement. The monitoring crystal can be rotated and placed in the target position so that the deposited material on the quartz crystal oscillator surface can be characterized without transfer outside of the vacuum chamber. PMID:18052463

  6. Key comparison BIPM.RI(I)-K2 of the air-kerma standards of the CMI, Czech Republic and the BIPM in low-energy x-rays

    NASA Astrophysics Data System (ADS)

    Burns, D. T.; Kessler, C.; Sochor, V.

    2016-01-01

    A key comparison has been made between the air-kerma standards of the CMI, Czech Republic and the BIPM in the low-energy x-ray range. The results show the standards to be in agreement at around the level of the standard uncertainty of the comparison of 3.5 parts in 103. The results are analysed and presented in terms of degrees of equivalence, suitable for entry in the BIPM key comparison database. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  7. Individualized eye shields for use in electron beam therapy as well as low-energy photon irradiation

    SciTech Connect

    Asbell, S.O.; Siu, J.; Lightfoot, D.A.; Brady, L.W.

    1980-04-01

    Thin lead eye shields formed with a rubber hammer over smooth wooden mandril and coated with dental acrylic have been used on 25 patients undergoing electron beam treatment for mycosis fungoides or superficial x-ray irradiation with no significant difficulties. The shields may be fabricated in less than two hours and exactly fit the contour and size of the eye. Details of the fabrication process and evaluation of the shielding effectiveness are presented.

  8. Electrostatic energy analyzer measurements of low energy zirconium beam parameters in a plasma sputter-type negative ion source

    SciTech Connect

    Malapit, Giovanni M.; Mahinay, Christian Lorenz S.; Poral, Matthew D.; Ramos, Henry J.

    2012-02-15

    A plasma sputter-type negative ion source is utilized to produce and detect negative Zr ions with energies between 150 and 450 eV via a retarding potential-type electrostatic energy analyzer. Traditional and modified semi-cylindrical Faraday cups (FC) inside the analyzer are employed to sample negative Zr ions and measure corresponding ion currents. The traditional FC registered indistinct ion current readings which are attributed to backscattering of ions and secondary electron emissions. The modified Faraday cup with biased repeller guard ring, cut out these signal distortions leaving only ringings as issues which are theoretically compensated by fitting a sigmoidal function into the data. The mean energy and energy spread are calculated using the ion current versus retarding potential data while the beam width values are determined from the data of the transverse measurement of ion current. The most energetic negative Zr ions yield tighter energy spread at 4.11 eV compared to the least energetic negative Zr ions at 4.79 eV. The smallest calculated beam width is 1.04 cm for the negative Zr ions with the highest mean energy indicating a more focused beam in contrast to the less energetic negative Zr ions due to space charge forces.

  9. Solid water as phantom material for dosimetry of electron backscatter using low-energy electron beams: a Monte Carlo evaluation.

    PubMed

    Chow, James C L; Owrangi, Amir M

    2009-05-01

    This study evaluated the dosimetry of electron backscatter when Solid Water is used to substitute water as phantom in electron radiotherapy. Monte Carlo simulation (EGSnrc-based code) was employed to predict electron energy spectra and depth doses for the 0.5 and 1 cm of Solid Water and water slabs above 3 mm of lead (Pb) layers using electron beams with energies of 4 and 6 MeV. For comparison, Monte Carlo simulations were repeated with Pb layers taken out from the phantoms using the same experimental configuration. Analyses on electron energy spectra for the 4 and 6 MeV electron beams showed that deviations of electron energy distributions between the Solid Water and water phantom were more significant in the high-energy range (i.e., close to the maximal electron energy) than the lower range corresponding to the electron backscatter. These deviations of electron energy spectra varied with depth and were mainly due to the electron fluence or beam attenuation. Dosimetry results from Monte Carlo simulations showed that the Solid Water phantom had lower depth dose compared to water with the same experimental setup. For the 4 MeV electron beams with 0.5 cm of Solid Water, depth doses were 1.8%-3.9% and 2.3%-4.4% lower than those in water, with and without the Pb layer underneath, respectively. Thicker Solid Water of 1 cm resulted in different decreases in depth doses of 1.8%-4.6% (with Pb) and 2.3%-4.4% (without Pb) compared to water. For higher nominal electron beam energy of 6 MeV with 0.5 cm of Solid Water, depth doses decreased 1.7%-2.9% (with Pb) and 1.6%-2.1% (without Pb) compared to water. These decreases in depth doses changed to 1.7%-3.7% (with Pb) and 1.7%-3% (without Pb) when the thickness of Solid Water was increased to 1 cm. The dosimetry data in this study are useful in determining the correction factor when using Solid Water to substitute water for the electron backscatter measurement in electron radiotherapy. PMID:19544774

  10. Solid Water as phantom material for dosimetry of electron backscatter using low-energy electron beams: A Monte Carlo evaluation

    SciTech Connect

    Chow, James C. L.; Owrangi, Amir M.

    2009-05-15

    This study evaluated the dosimetry of electron backscatter when Solid Water is used to substitute water as phantom in electron radiotherapy. Monte Carlo simulation (EGSnrc-based code) was employed to predict electron energy spectra and depth doses for the 0.5 and 1 cm of Solid Water and water slabs above 3 mm of lead (Pb) layers using electron beams with energies of 4 and 6 MeV. For comparison, Monte Carlo simulations were repeated with Pb layers taken out from the phantoms using the same experimental configuration. Analyses on electron energy spectra for the 4 and 6 MeV electron beams showed that deviations of electron energy distributions between the Solid Water and water phantom were more significant in the high-energy range (i.e., close to the maximal electron energy) than the lower range corresponding to the electron backscatter. These deviations of electron energy spectra varied with depth and were mainly due to the electron fluence or beam attenuation. Dosimetry results from Monte Carlo simulations showed that the Solid Water phantom had lower depth dose compared to water with the same experimental setup. For the 4 MeV electron beams with 0.5 cm of Solid Water, depth doses were 1.8%-3.9% and 2.3%-4.4% lower than those in water, with and without the Pb layer underneath, respectively. Thicker Solid Water of 1 cm resulted in different decreases in depth doses of 1.8%-4.6% (with Pb) and 2.3%-4.4% (without Pb) compared to water. For higher nominal electron beam energy of 6 MeV with 0.5 cm of Solid Water, depth doses decreased 1.7%-2.9% (with Pb) and 1.6%-2.1% (without Pb) compared to water. These decreases in depth doses changed to 1.7%-3.7% (with Pb) and 1.7%-3% (without Pb) when the thickness of Solid Water was increased to 1 cm. The dosimetry data in this study are useful in determining the correction factor when using Solid Water to substitute water for the electron backscatter measurement in electron radiotherapy.

  11. Characterization of single crystal films of molybdenum (011) grown by molecular beam epitaxy on sapphire (112¯0) and studied by low-energy electron microscopy

    NASA Astrophysics Data System (ADS)

    Świȩch, W.; Mundschau, M.; Flynn, C. P.

    1999-08-01

    Films of molybdenum grown on the (112¯0) plane of sapphire (Al 2O 3) are characterized using low-energy microscopy and low-energy electron diffraction. Stress fields observed on the Mo surface originate at dislocations and at miscut steps of the buried molybdenum-alumina vicinal interface. As-grown films contain small-angle grain boundaries. These are largely eliminated upon heating to 1700 K as edge dislocations that form the boundaries become extremely mobile. Edge dislocations attract and annihilate one another, and the small-angle grain boundaries disappear. Mobility of edge dislocations is correlated with rapid diffusion of carbon, which apparently pins dislocations up to temperatures that allow diffusion of carbon from dislocations into the bulk. The main contaminants of the Mo surface are carbon, oxygen and carbon monoxide. The most stable impurities are carbides that persist to 1700 K. Oxygen promotes bunching of monatomic steps into groups of two, three and four. Electron beams dissociate CO with energy less than 1 eV and deposit residues of carbon. Fairly ideal single crystal films of Mo produced by annealing exhibit monatomic surface step and terrace structure, and a minimum of dislocations. The quality of surfaces on these films exceeds that of typical single crystal bulk samples and is well suited for fundamental studies in surface science.

  12. Breeding for blast-disease-resistant and high-yield Thai jasmine rice (Oryza sativa L. cv. KDML 105) mutants using low-energy ion beams

    NASA Astrophysics Data System (ADS)

    Mahadtanapuk, S.; Teraarusiri, W.; Phanchaisri, B.; Yu, L. D.; Anuntalabhochai, S.

    2013-07-01

    Low-energy ion beam was applied on mutation induction for plant breeding of blast-disease-resistant Thai jasmine rice (Oryza sativa L. cv. KDML 105). Seeds of the wild-type rice were bombarded in vacuum by nitrogen ion beam at energy of 60-80 keV to a beam fluence range of 2 × 1016-2 × 1017 ions/cm2. The ion-bombarded rice seeds were grown in soil for 2 weeks as transplanted rice in plastic pots at 1 seedling/pot. The seedlings were then screened for blast resistance by Pyricularia grisea inoculation with 106 spores/ml concentrations. The blast-resistant rice mutant was planted up to F6 generation with the consistent phenotypic variation. The high percentage of the blast-disease-resistant rice was analyzed with DNA fingerprint. The HAT-RAPD (high annealing temperature-random amplified polymorphic DNA) marker revealed the modified polymorphism fragment presenting in the mutant compared with wild type (KDML 105). The cDNA fingerprints were investigated and the polymorphism fragment was subcloned into pGEM-T easy vector and then sequenced. The sequence of this fragment was compared with those already contained in the database, and the fragment was found to be related to the Spotted leaf protein 11 (Spl11).

  13. Development of a pepper-pot emittance meter for diagnostics of low-energy multiply charged heavy ion beams extracted from an ECR ion source

    NASA Astrophysics Data System (ADS)

    Nagatomo, T.; Tzoganis, V.; Kase, M.; Kamigaito, O.; Nakagawa, T.

    2016-02-01

    Several fluorescent materials were tested for use in the imaging screen of a pepper-pot emittance meter that is suitable for investigating the beam dynamics of multiply charged heavy ions extracted from an ECR ion source. SiO2 (quartz), KBr, Eu-doped CaF2, and Tl-doped CsI crystals were first irradiated with 6.52-keV protons to determine the effects of radiation damage on their fluorescence emission properties. For such a low-energy proton beam, only the quartz was found to be a suitable fluorescent material, since the other materials suffered a decay in fluorescence intensity with irradiation time. Subsequently, quartz was irradiated with heavy 12C4+, 16O4+, and 40Ar11+ ions, but it was found that the fluorescence intensity decreased too rapidly to measure the emittance of these heavy-ion beams. These results suggest that a different energy loss mechanism occurs for heavier ions and for protons.

  14. Development of a pepper-pot emittance meter for diagnostics of low-energy multiply charged heavy ion beams extracted from an ECR ion source.

    PubMed

    Nagatomo, T; Tzoganis, V; Kase, M; Kamigaito, O; Nakagawa, T

    2016-02-01

    Several fluorescent materials were tested for use in the imaging screen of a pepper-pot emittance meter that is suitable for investigating the beam dynamics of multiply charged heavy ions extracted from an ECR ion source. SiO2 (quartz), KBr, Eu-doped CaF2, and Tl-doped CsI crystals were first irradiated with 6.52-keV protons to determine the effects of radiation damage on their fluorescence emission properties. For such a low-energy proton beam, only the quartz was found to be a suitable fluorescent material, since the other materials suffered a decay in fluorescence intensity with irradiation time. Subsequently, quartz was irradiated with heavy (12)C(4+), (16)O(4+), and (40)Ar(11+) ions, but it was found that the fluorescence intensity decreased too rapidly to measure the emittance of these heavy-ion beams. These results suggest that a different energy loss mechanism occurs for heavier ions and for protons. PMID:26932092

  15. 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.

  16. A new experiment to investigate the origin of optical activity using a low energy positron beam of controlled helicity. [molecular biology

    NASA Technical Reports Server (NTRS)

    Gidley, D. W.; Rich, A.; Van House, J. C.; Zitzewitz, P. W.

    1981-01-01

    Previous experiments undertaken in search of a correlation between the origin of optical activity in biological molecules and the helicity of beta particles emitted in nuclear beta decay have not provided any useful results. A description is presented of an experiment in which a low energy polarized positron beam of controlled helicity interacts with an optically active material to form positronium in vacuum. Advantages of the current study compared to the previous experiments are mainly related to a much greater sensitivity. Initially, it will be possible to detect a helicity-dependent asymmetry in triplet positronium formation of 1 part in 10,000. Improvements to better than 1 part in 100,000 should be attainable.

  17. Nuclear Science and Applications with the Next Generation of High-Power Lasers and Brilliant Low-Energy Gamma Beams at ELI-NP

    NASA Astrophysics Data System (ADS)

    Gales, S.; ELI-NP Team

    2015-10-01

    The development of high power lasers and the combination of such novel devices with accelerator technology has enlarged the science reach of many research fields, in particular High Energy, Nuclear and Astrophysics as well as societal applications in Material Science, Nuclear Energy and Medicine. The European Strategic Forum for Research Infrastructures (ESFRI) has selected a proposal based on these new premises called "ELI" for Extreme Light Infrastructure. ELI will be built as a network of three complementary pillars at the frontier of laser technologies. The ELI-NP pillar (NP for Nuclear Physics) is under construction near Bucharest (Romania) and will develop a scientific program using two 10 PW class lasers and a Back Compton Scattering High Brilliance and Intense Low Energy Gamma Beam, a marriage of Laser and Accelerator technology at the frontier of knowledge. In the present paper, the technical and scientific status of the project as well as the applications of the gamma source will be discussed.

  18. Electron capture in very low energy collisions of multicharged ions with H and D in merged beams

    SciTech Connect

    Havener, C.C.; Meyer, F.W.; Phaneuf, R.A.

    1991-01-01

    An ion-atom merged-beams technique is being used to measure total absolute electron-capture cross sections for multicharged ions in collisions with H (or D) in the energy range between 0.1 and 1000 eV/amu. Comparison between experiment and theory over such a large energy range constitutes a critical test for both experiment and theory. Total capture cross-section measurements for O{sup 3+} H(D) and O{sup 5+} + H(D) are presented and compared to state selective and differential cross section calculations. Landau-Zener calculations show that for O{sup 5+} the sharp increase in the measured cross section below 1 eV/amu is partly due to trajectory effects arising from the ion-induced dipole interaction between the reactants. 20 refs., 8 figs.

  19. Amorphous silicon carbonitride diaphragm for environmental-cell transmission electron microscope fabricated by low-energy ion beam induced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Matsutani, Takaomi; Yamasaki, Kayo; Imaeda, Norihiro; Kawasaki, Tadahiro

    2015-12-01

    An amorphous silicon carbonitride (a-SiCN) diaphragm for an environmental-cell transmission electron microscope (E-TEM) was fabricated by low-energy ion beam induced chemical vapor deposition (LEIBICVD) with hexamethyldisilazane (HMDSN). The films were prepared by using gaseous HMDSN and N2+ ions with energies ranging from 300 to 600 eV. The diaphragms were applied to Si (1 0 0) and a Cu grid with 100-μm-diameter holes. With increasing ion energy, these diaphragms became perfectly smooth surfaces (RMS = 0.43 nm at 600 eV), as confirmed by atomic force microscopy and TEM. The diaphragms were amorphous and transparent to 200 kV electrons, and no charge-up was observed. Fourier transform infrared spectra and X-ray photoelectron spectra revealed that the elimination of organic compounds and formation of Si-N and C-N bonds can be promoted in diaphragms by increasing the ion impact energy. The resistance to electron beams and reaction gases in the E-cell was improved when the diaphragm was formed with high ion energy.

  20. Mass Measurement with Rare-RI Rin

    NASA Astrophysics Data System (ADS)

    Ozawa, Akira

    2014-09-01

    Mass measurement with Rare-RI Ring in RIKEN RI Beam Factory (RIBF) will be presented. The main purpose of Rare-RI Ring is to measure the mass for very neutron-rich nuclei, the production rate of which is very small (rare RI) and the life-time of which is predicted to be very short (less than 10 ms). In Rare-RI Ring, mass measurements will be performed based on isochronous mass spectrometry. There are two innovative apparatus in Rare-RI Ring: individual injection, which can realize the injection of 200 A MeV rare RI one-by-one, and a cyclotron-like storage ring, which allows high isochronous magnetic fields with large angular and momentum acceptances (~1%). By these apparatus, we will achieve a 10-6 mass resolution, and will be able to access rare RI, the production rate of which is down to 1 event/day/pnA in RIBF. Construction of Rare-RI Ring has started from the 2012 fiscal year. Construction of the storage ring itself was almost completed. In this fiscal year, we succeeded to store alphas from 241Am source and to check the production of isochronous fields in the storage ring. In this talk, present status of Rare-RI Ring and the possible mass measurement there will be presented.

  1. Atomic Oxygen (ATOX) simulation of Teflon FEP and Kapton H surfaces using a high intensity, low energy, mass selected, ion beam facility

    NASA Technical Reports Server (NTRS)

    Vered, R.; Grossman, E.; Lempert, G. D.; Lifshitz, Y.

    1994-01-01

    A high intensity (greater than 10(exp 15) ions/sq cm) low energy (down to 5 eV) mass selected ion beam (MSIB) facility was used to study the effects of ATOX on two polymers commonly used for space applications (Kapton H and Teflon FEP). The polymers were exposed to O(+) and Ne(+) fluences on 10(exp 15) - 10(exp 19) ions/sq cm, using 30eV ions. A variety of analytical methods were used to analyze the eroded surfaces including: (1) atomic force microscopy (AFM) for morphology measurements; (2) total mass loss measurements using a microbalance; (3) surface chemical composition using x-ray photoelectron spectroscopy (XPS), and (4) residual gas analysis (RGA) of the released gases during bombardment. The relative significance of the collisional and chemical degradation processes was evaluated by comparing the effects of Ne(+) and O(+) bombardment. For 30 eV ions it was found that the Kapton is eroded via chemical mechanisms while Teflon FEP is eroded via collisional mechanisms. AFM analysis was found very powerful in revealing the evolution of the damage from its initial atomic scale (roughness of approx. 1 nm) to its final microscopic scale (roughness greater than 1 micron). Both the surface morphology and the average roughness of the bombarded surfaces (averaged over 1 micron x 1 micron images by the system's computer) were determined for each sample. For 30 eV a non linear increase of the Kapton roughness with the O(+) fluence was discovered (a slow increase rate for fluences phi less than 5 x 10(exp 17) O(+)/sq cm, and a rapid increase rate for phi greater than 5 x 10(exp 17) O(+)/sq cm). Comparative studies on the same materials exposed to RF and DC oxygen plasmas indicate that the specific details of the erosion depend on the simulation facility emphasizing the advantages of the ion beam facility.

  2. Simple model of bulk and surface excitation effects to inelastic scattering in low-energy electron beam irradiation of multi-walled carbon nanotubes

    SciTech Connect

    Kyriakou, Ioanna; Emfietzoglou, Dimitris; Garcia-Molina, Rafael; Abril, Isabel; Kostarelos, Kostas

    2011-09-01

    The effect of bulk and surface excitations to inelastic scattering in low-energy electron beam irradiation of multi-walled carbon nanotubes (MWNTs) is studied using the dielectric formalism. Calculations are based on a semiempirical dielectric response function for MWCNTs determined by means of a many-pole plasmon model with parameters adjusted to available experimental spectroscopic data under theoretical sum-rule constrains. Finite-size effects are considered in the context of electron gas theory via a boundary correction term in the plasmon dispersion relations, thus, allowing a more realistic extrapolation of the electronic excitation spectrum over the whole energy-momentum plane. Energy-loss differential and total inelastic scattering cross sections as a function of electron energy and distance from the surface, valid over the energy range {approx}50-30,000 eV, are calculated with the individual contribution of bulk and surface excitations separated and analyzed for the case of normally incident and escaping electrons. The sensitivity of the results to the various approximations for the spatial dispersion of the electronic excitations is quantified. Surface excitations are shown to have a strong influence upon the shape and intensity of the energy-loss differential cross section in the near surface region whereas the general notion of a spatially invariant inelastic mean free path inside the material is found to be of good approximation.

  3. Simple model of bulk and surface excitation effects to inelastic scattering in low-energy electron beam irradiation of multi-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Kyriakou, Ioanna; Emfietzoglou, Dimitris; Garcia-Molina, Rafael; Abril, Isabel; Kostarelos, Kostas

    2011-09-01

    The effect of bulk and surface excitations to inelastic scattering in low-energy electron beam irradiation of multi-walled carbon nanotubes (MWNTs) is studied using the dielectric formalism. Calculations are based on a semiempirical dielectric response function for MWCNTs determined by means of a many-pole plasmon model with parameters adjusted to available experimental spectroscopic data under theoretical sum-rule constrains. Finite-size effects are considered in the context of electron gas theory via a boundary correction term in the plasmon dispersion relations, thus, allowing a more realistic extrapolation of the electronic excitation spectrum over the whole energy-momentum plane. Energy-loss differential and total inelastic scattering cross sections as a function of electron energy and distance from the surface, valid over the energy range ˜50-30,000 eV, are calculated with the individual contribution of bulk and surface excitations separated and analyzed for the case of normally incident and escaping electrons. The sensitivity of the results to the various approximations for the spatial dispersion of the electronic excitations is quantified. Surface excitations are shown to have a strong influence upon the shape and intensity of the energy-loss differential cross section in the near surface region whereas the general notion of a spatially invariant inelastic mean free path inside the material is found to be of good approximation.

  4. Tailoring medium energy proton beam to induce low energy nuclear reactions in ⁸⁶SrCl₂ for production of PET radioisotope ⁸⁶Y.

    PubMed

    Medvedev, Dmitri G; Mausner, Leonard F; Pile, Philip

    2015-07-01

    This paper reports results of experiments at Brookhaven Linac Isotope Producer (BLIP) aiming to investigate effective production of positron emitting radioisotope (86)Y by the low energy (86)Sr(p,n) reaction. BLIP is a facility at Brookhaven National Laboratory designed for the proton irradiation of the targets for isotope production at high and intermediate proton energies. The proton beam is delivered by the Linear Accelerator (LINAC) whose incident energy is tunable from 200 to 66 MeV in approximately 21 MeV increments. The array was designed to ensure energy degradation from 66 MeV down to less than 20 MeV. Aluminum slabs were used to degrade the proton energy down to the required range. The production yield of (86)Y (1.2+/-0.1 mCi (44.4+/-3.7) MBq/μAh) and ratio of radioisotopic impurities was determined by assaying an aliquot of the irradiated (86)SrCl2 solution by gamma spectroscopy. The analysis of energy dependence of the (86)Y production yield and the ratios of radioisotopic impurities has been used to adjust degrader thickness. Experimental data showed substantial discrepancies in actual energy propagation compared to energy loss calculations. PMID:25813003

  5. Analysis of a Partial Male-Sterile Mutant of Arabidopsis thaliana Isolated from a Low-Energy Argon Ion Beam Mutagenized Pool

    NASA Astrophysics Data System (ADS)

    Xu, Min; Bian, Po; Wu, Yuejin; Yu, Zengliang

    2008-04-01

    A screen for Arabidopsis fertility mutants, mutagenized by low-energy argon ion beam, yielded two partial male-sterile mutants tc243-1 and tc243-2 which have similar phenotypes. tc243-2 was investigated in detail. The segregation ratio of the mutant phenotypes in the M2 pools suggested that mutation behaved as single Mendelian recessive mutations. tc243 showed a series of mutant phenotypes, among which partial male-sterile was its striking mutant characteristic. Phenotype analysis indicates that there are four factors leading to male sterility. a. Floral organs normally develop inside the closed bud, but the anther filaments do not elongate sufficiently to position the locules above the stigma at anthesis. b. The anther locules do not dehisce at the time of flower opening (although limited dehiscence occurs later). c. Pollens of mutant plants develop into several types of pollens at the trinucleated stage, as determined by staining with DAPI (4',6-diamidino-2-phenylindole), which shows a variable size, shape and number of nucleus. d. The viability of pollens is lower than that of the wild type on the germination test in vivo and vitro.

  6. Formation of microcraters and hierarchically-organized surface structures in TiNi shape memory alloy irradiated with a low-energy, high-current electron beam

    SciTech Connect

    Meisner, L. L. Meisner, S. N.; Markov, A. B. Ozur, G. E. Yakovlev, E. V.; Rotshtein, V. P.; Gudimova, E. Yu.

    2015-10-27

    The regularities of surface cratering in TiNi alloy irradiated with a low-energy, high-current electron beam (LEHCEB) in dependence on energy density and number of pulses are studied. LEHCEB processing of TiNi samples was carried out using RITM-SP facility. Energy density E{sub s} was varied from 1 to 5 J/cm{sup 2}, pulse duration was 2.5–3.0 μs, the number of pulses n = 1–128. The dominant role of non-metallic inclusions [mainly, TiC(O)] in the nucleation of microcraters was found. It was revealed that at small number of pulses (n = 2), an increase in energy density leads both to increasing average diameter and density of microcraters. An increase in the number of pulses leads to a monotonic decrease in density of microcraters, and, therefore, that of the proportion of the area occupied by microcraters, as well as a decrease in the surface roughness. The multiple LEHCEB melting of TiNi alloy in crater-free modes enables to form quasi-periodical, hierarchically-organized microsized surface structures.

  7. Formation of microcraters and hierarchically-organized surface structures in TiNi shape memory alloy irradiated with a low-energy, high-current electron beam

    NASA Astrophysics Data System (ADS)

    Meisner, L. L.; Markov, A. B.; Rotshtein, V. P.; Ozur, G. E.; Meisner, S. N.; Yakovlev, E. V.; Gudimova, E. Yu.

    2015-10-01

    The regularities of surface cratering in TiNi alloy irradiated with a low-energy, high-current electron beam (LEHCEB) in dependence on energy density and number of pulses are studied. LEHCEB processing of TiNi samples was carried out using RITM-SP facility. Energy density Es was varied from 1 to 5 J/cm2, pulse duration was 2.5-3.0 μs, the number of pulses n = 1-128. The dominant role of non-metallic inclusions [mainly, TiC(O)] in the nucleation of microcraters was found. It was revealed that at small number of pulses (n = 2), an increase in energy density leads both to increasing average diameter and density of microcraters. An increase in the number of pulses leads to a monotonic decrease in density of microcraters, and, therefore, that of the proportion of the area occupied by microcraters, as well as a decrease in the surface roughness. The multiple LEHCEB melting of TiNi alloy in crater-free modes enables to form quasi-periodical, hierarchically-organized microsized surface structures.

  8. Nuclear Science and Applications with the Next Generation of High-Power Lasers and Brilliant Low-Energy Gamma Beams at ELI-NP

    NASA Astrophysics Data System (ADS)

    Gales, S.

    The development of high power lasers and the combination of such novel devices with accelerator technology has enlarged the science reach of many research fields, in particular Particle and Nuclear Physics, Astrophysics as well as societal applications in Material Science, Nuclear Energy and Medicine. The European Strategic Forum for Research Infrastructures (ESFRI) has selected a proposal based on these new premises called "ELI" for Extreme Light Infrastructure. ELI will be built as a network of three complementary pillars at the frontier of laser technologies. The ELI-NP pillar (NP for Nuclear Physics) is under construction near Bucharest (Romania) and will develop a scientific program using two 10 PW lasers and a Compton back-scattering high-brilliance and intense low-energy gamma beam, a marriage of laser and accelerator technology at the frontier of knowledge. In the present paper, the technical description of the facility, the present status of the project as well as the science, applications and future perspectives will be discussed.

  9. Nuclear Science and Applications with the Next Generation of High-Power Lasers and Brilliant Low-Energy Gamma Beams at ELI-NP

    NASA Astrophysics Data System (ADS)

    Gales, S.

    2015-11-01

    The development of high-power lasers and the combination of such novel devices with accelerator technology has enlarged the science reach of many research fields, in particular high-energy nuclear physics and astrophysics, as well as societal applications in material science, nuclear energy and medicine. The European Strategic Forum for Research Infrastructures (ESFRI) has selected a proposal based on these new premises called "ELI" for Extreme Light Infrastructure. ELI will be built as a network of three complementary pillars at the frontier of laser technologies. The ELI-NP pillar (NP for nuclear physics) is under construction near Bucharest (Romania) and will develop a scientific program using two 10-PW lasers and a Compton back-scattering high-brilliance and intense low-energy gamma beam, a marriage of laser and accelerator technology at the frontier of knowledge. In the present paper, the technical description of the facility, the present status of the project as well as the science, applications and future perspectives will be discussed.

  10. Effects of low energy E-beam irradiation on graphene and graphene field effect transistors and raman metrology of graphene on split gate test structures

    NASA Astrophysics Data System (ADS)

    Rao, Gayathri S.

    2011-12-01

    Apart from its compelling performance in conventional nanoelectronic device geometries, graphene is an appropriate candidate to study certain interesting phenomenon (e.g. the Veselago lens effect) predicted on the basis of its linear electron dispersion relation. A key requirement for the observation of such phenomenon in graphene and for its use in conventional field-effect transistor (FET) devices is the need to minimize defects such as consisting of -- or resulting from -- adsorbates and lattice non-uniformities, and reduce deleterious substrate effects. Consequently the investigation of the origin and interaction of defects in the graphene lattice is essential to improve and tailor graphene-based device performance. In this thesis, optical spectroscopic studies on the influence of low-energy electron irradiation on adsorbate-induced defectivity and doping for substrate supported and suspended graphene were carried out along with spectroscopic and transport measurements on graphene FETs. A comparative investigation of the effects of single-step versus multi-step, low-energy electron irradiation (500 eV) on suspended, substrate supported graphene and on graphene FETs is reported. E-beam irradiation (single-step and multi-step) of substrate-supported graphene resulted in an increase in the Raman ID/IG ratio largely from hydrogenation due to radiolysis of the interfacial water layer between the graphene and the SiO2 substrate and from irradiated surface adsorbates. GFETs subjected to single and multi-step irradiation showed n-doping from CNP (charge neutrality point) shift of ˜ -8 and ˜ -16 V respectively. Correlation of this data with Raman analysis of suspended and supported graphene samples implied a strong role of the substrate and irradiation sequence in determining the level of doping. A correspondingly higher reduction in mobility per incident electron was also observed for GFETs subjected to multi-step irradiation compared to single step, in line with