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Sample records for mev proton accelerator

  1. Flare vs. Shock Acceleration of >100 MeV Protons in Large Solar Particle Events

    NASA Astrophysics Data System (ADS)

    Cliver, Edward W.

    2016-05-01

    Recently several studies have presented correlative evidence for a significant-to-dominant role for a flare-resident process in the acceleration of high-energy protons in large solar particle events. In one of these investigations, a high correlation between >100 MeV proton fluence and 35 GHz radio fluence is obtained by omitting large proton events associated with relatively weak flares; these outlying events are attributed to proton acceleration by shock waves driven by coronal mass ejections (CMEs). We argue that the strong CMEs and associated shocks observed for proton events on the main sequence of the scatter plot are equally likely to accelerate high-energy protons. In addition, we examine ratios of 0.5 MeV electron to >100 MeV proton intensities in large SEP events, associated with both well-connected and poorly-connected solar eruptions, to show that scaled-up versions of the small flares associated with classical impulsive SEP events are not significant accelerators of >100 MeV protons.

  2. Calculations of neutron shielding data for 10-100 MeV proton accelerators.

    PubMed

    Chen, C C; Sheu, R J; Jian, S H

    2005-01-01

    The characteristics of neutron sources and their attenuation in concrete were investigated in detail for protons with energies ranging from 10 to 100 MeV striking on target materials of C, N, Al, Fe, Cu and W. A two-step approach was adopted: thick-target double-differential neutron yields were first calculated from the (p, xn) cross sections recommended in the ICRU Report 63; further, transport simulations of those neutrons in concrete were performed by using the FLUKA Monte Carlo code. The purpose of this study is to provide reasonably accurate parameters for shielding design for 10-100 MeV proton accelerators. Source terms and the corresponding attenuation lengths in concrete for several target materials are given as a function of proton energies and neutron emission angles.

  3. Equation of State Measurements of Dense Plasmas Heated by Laser Accelerated MeV Protons

    NASA Astrophysics Data System (ADS)

    Dyer, Gilliss; Bernstein, Aaron; Cho, Byoung-Ick; Grigsby, Will; Dalton, Allen; Shepherd, Ronnie; Ping, Yuan; Chen, Hui; Widmann, Klaus; Ozterhoz, Jens; Ditmire, Todd

    2008-04-01

    Using a fast proton beam generated with an ultra intense laser we have generated and measured the equation of state of solid density plasma at temperatures near 20 eV, a regime in which there have been few previous experimental measurements. The laser accelerated a directional, short pulse of MeV protons, which isochorically heated a solid slab of aluminum. Using two simultaneous, temporally resolved measurements we observed the thermal emission and expansion of the heated foil with picosecond time resolution. With these data we were able to confirm, to within 10%, the SESAME equation-of-state table in this dense plasma region.

  4. Comparing Solar-Flare Acceleration of >-20 MeV Protons and Electrons Above Various Energies

    NASA Technical Reports Server (NTRS)

    Shih, Albert Y.

    2010-01-01

    A large fraction (up to tens of percent) of the energy released in solar flares goes into accelerated ions and electrons, and studies indicate that these two populations have comparable energy content. RHESSI observations have shown a striking close linear correlation between the 2.223 MeV neutron-capture gamma-ray line and electron bremsstrahlung emission >300 keV, indicating that the flare acceleration of >^20 MeV protons and >300 keV electrons is roughly proportional over >3 orders of magnitude in fluence. We show that the correlations of neutron-capture line fluence with GOES class or with bremsstrahlung emission at lower energies show deviations from proportionality, primarily for flares with lower fluences. From analyzing thirteen flares, we demonstrate that there appear to be two classes of flares with high-energy acceleration: flares that exhibit only proportional acceleration of ions and electrons down to 50 keV and flares that have an additional soft, low-energy bremsstrahlung component, suggesting two separate populations of accelerated electrons. We use RHESSI spectroscopy and imaging to investigate a number of these flares in detail.

  5. Research program for the 660 MeV proton accelerator driven MOX-plutonium subcritical assembly

    NASA Astrophysics Data System (ADS)

    Barashenkov, V. S.; Buttsev, V. S.; Buttseva, G. L.; Dudarev, S. Ju.; Polanski, A.; Puzynin, I. V.; Sissakian, A. N.

    2000-07-01

    This paper presents the research program of the Experimental Accelerator Driven System (ADS), which employs a subcritical assembly and a 660 MeV proton accelerator operating in the Laboratory of Nuclear Problems at the Joint Institute for Nuclear Research in Dubna. Mixed-oxide (MOX) fuel (25% PuO2+75% UO2) designed for the BN-600 reactor use will be adopted for the core of the assembly. The present conceptual design of the experimental subcritical assembly is based on a core nominal unit capacity of 15 kW (thermal). This corresponds to the multiplication coefficient keff=0.945, energetic gain G=30, and accelerator beam power of 0.5 kW.

  6. Characterization of MeV proton acceleration from double pulse irradiation of foil targets

    NASA Astrophysics Data System (ADS)

    Kerr, S.; Mo, M. Z.; Masud, R.; Tiedje, H. F.; Tsui, Y.; Fedosejevs, R.; Link, A.; Patel, P.; McLean, H. S.; Hazi, A.; Chen, H.; Ceurvorst, L.; Norreys, P.

    2014-10-01

    We report on the experimental characterization of proton acceleration from double-pulse irradiation of um-scale foil targets. Temporally separated sub-picosecond pulses have been shown to increase the conversion efficiency of laser energy to MeV protons. Here, two 700 fs, 1 ω pulses were separated by 1 to 5 ps; total beam energy was 100 J, with 5-20% of the total energy contained within the first pulse. In contrast to the ultraclean beams used in previous experiments, prepulse energies on the order of 10 mJ were present in the current experiments which appear to have a moderating effect on the enhancement. Proton beam measurements were made with radiochromic film stacks, as well as magnetic spectrometers. The effect on electron generation was measured using Kα emission from buried Cu tracer layers, while specular light diagnostics (FROG, reflection spectralon) indicated the laser coupling efficiency into the target. The results obtained will be presented and compared to PIC simulations. Work by LLNL was performed under the auspices of U.S. DOE under contract DE-AC52-07NA27344.

  7. Filamentation control and collimation of laser accelerated MeV protons

    NASA Astrophysics Data System (ADS)

    Ramakrishna, B.; Tayyab, M.; Bagchi, S.; Mandal, T.; Upadhyay, A.; Weng, S. M.; Murakami, M.; Cowan, T. E.; Chakera, J. A.; Naik, P. A.; Gupta, P. D.

    2015-12-01

    We demonstrate experimentally that the proton beam filamentation in dense plasma can be controlled in multi-layered (Al-CH-Al) sandwich targets. We observe up to three-fold reduction in the MeV proton beam divergence (~12°) from these targets as a result of decrease in filamentary structures in the proton beam profile. Strong self-generated resistive magnetic fields in targets with a high-Z transport layer are mainly responsible for this observed effect. Enhancement in the proton flux and energy is also observed from these targets. Supported by a matching 2D particle-in-cell (PIC) simulation and theoretical considerations, we suggest that these targets can be very effectively implemented to collimate proton beams useful for ion oncology applications or advanced fast igniter approach of inertial confinement fusion (ICF).

  8. Neutron yield and induced radioactivity: a study of 235-MeV proton and 3-GeV electron accelerators.

    PubMed

    Hsu, Yung-Cheng; Lai, Bo-Lun; Sheu, Rong-Jiun

    2016-01-01

    This study evaluated the magnitude of potential neutron yield and induced radioactivity of two new accelerators in Taiwan: a 235-MeV proton cyclotron for radiation therapy and a 3-GeV electron synchrotron serving as the injector for the Taiwan Photon Source. From a nuclear interaction point of view, neutron production from targets bombarded with high-energy particles is intrinsically related to the resulting target activation. Two multi-particle interaction and transport codes, FLUKA and MCNPX, were used in this study. To ensure prediction quality, much effort was devoted to the associated benchmark calculations. Comparisons of the accelerators' results for three target materials (copper, stainless steel and tissue) are presented. Although the proton-induced neutron yields were higher than those induced by electrons, the maximal neutron production rates of both accelerators were comparable according to their respective beam outputs during typical operation. Activation products in the targets of the two accelerators were unexpectedly similar because the primary reaction channels for proton- and electron-induced activation are (p,pn) and (γ,n), respectively. The resulting residual activities and remnant dose rates as a function of time were examined and discussed.

  9. Proton-Proton Scattering at 105 Mev and 75 Mev

    DOE R&D Accomplishments Database

    Birge, R. W.; Kruse, U. E.; Ramsey, N. F.

    1951-01-31

    The scattering of protons by protons provides an important method for studying the nature of nuclear forces. Recent proton-proton scattering experiments at energies as high as thirty Mev{sup 1} have failed to show any appreciable contribution to the cross section from higher angular momentum states, but it is necessary to bring in tensor forces to explain the magnitude of the observed cross section.

  10. Acceleration of protons to above 6 MeV using H{sub 2}O 'snow' nanowire targets

    SciTech Connect

    Pomerantz, I.; Schleifer, E.; Nahum, E.; Eisenmann, S.; Botton, M.; Gordon, D.; Sprangel, P.; Zigler, A.

    2012-07-09

    A scheme is presented for using H{sub 2}O 'snow' nanowire targets for the generation of fast protons. This novel method may relax the requirements for very high laser intensities, thus reducing the size and cost of laser based ion acceleration system.

  11. Shielding data for 100 250 MeV proton accelerators: Double differential neutron distributions and attenuation in concrete

    NASA Astrophysics Data System (ADS)

    Agosteo, S.; Magistris, M.; Mereghetti, A.; Silari, M.; Zajacova, Z.

    2007-12-01

    Double differential distributions of neutrons produced by 100, 150, 200 and 250 MeV protons stopped in a thick iron target were simulated with the FLUKA Monte Carlo code at four emission angles: forward, 45°, transverse and 135° backwards. The attenuation in ordinary concrete of the dose equivalent due to secondary neutrons, protons, photons and electrons was calculated. Some of the resulting attenuation curves are best fitted by a double-exponential function rather than a single-exponential. The effect of various approximations introduced in the simulations is thoroughly discussed. The contribution to the total ambient dose equivalent from photons and protons is usually limited to a few percent, except in the backward direction where photons contribute more than 10% and up to 35% to the total dose for a shield thickness of 1-2 m. Source terms and attenuation lengths are given as a function of energy and emission angle, along with fit to the Monte Carlo data. An extensive comparison is made of values obtained in the present work with published experimental and computational data.

  12. Berkeley Proton Linear Accelerator

    DOE R&D Accomplishments Database

    Alvarez, L. W.; Bradner, H.; Franck, J.; Gordon, H.; Gow, J. D.; Marshall, L. C.; Oppenheimer, F. F.; Panofsky, W. K. H.; Richman, C.; Woodyard, J. R.

    1953-10-13

    A linear accelerator, which increases the energy of protons from a 4 Mev Van de Graaff injector, to a final energy of 31.5 Mev, has been constructed. The accelerator consists of a cavity 40 feet long and 39 inches in diameter, excited at resonance in a longitudinal electric mode with a radio-frequency power of about 2.2 x 10{sup 6} watts peak at 202.5 mc. Acceleration is made possible by the introduction of 46 axial "drift tubes" into the cavity, which is designed such that the particles traverse the distance between the centers of successive tubes in one cycle of the r.f. power. The protons are longitudinally stable as in the synchrotron, and are stabilized transversely by the action of converging fields produced by focusing grids. The electrical cavity is constructed like an inverted airplane fuselage and is supported in a vacuum tank. Power is supplied by 9 high powered oscillators fed from a pulse generator of the artificial transmission line type.

  13. Cascaded proton acceleration by collisionless electrostatic shock

    SciTech Connect

    Xu, T. J.; Shen, B. F. E-mail: zhxm@siom.ac.cn; Zhang, X. M. E-mail: zhxm@siom.ac.cn; Yi, L. Q.; Wang, W. P.; Zhang, L. G.; Xu, J. C.; Zhao, X. Y.; Shi, Y.; Liu, C.; Pei, Z. K.

    2015-07-15

    A new scheme for proton acceleration by cascaded collisionless electrostatic shock (CES) is proposed. By irradiating a foil target with a moderate high-intensity laser beam, a stable CES field can be induced, which is employed as the accelerating field for the booster stage of proton acceleration. The mechanism is studied through simulations and theoretical analysis, showing that a 55 MeV seed proton beam can be further accelerated to 265 MeV while keeping a good energy spread. This scheme offers a feasible approach to produce proton beams with energy of hundreds of MeV by existing available high-intensity laser facilities.

  14. ACCELERATING POLARIZED PROTONS TO HIGH ENERGY.

    SciTech Connect

    BAI, M.; AHRENS, L.; ALEKSEEV, I.G.; ALESSI, J.; BEEBE-WANG, J.; BLASKIEWICZ, M.; BRAVAR, A.; BRENNAN, J.M.; BRUNO, D.; BUNCE, G.; ET AL.

    2006-10-02

    The Relativistic Heavy Ion Collider (RHIC) is designed to provide collisions of high energy polarized protons for the quest of understanding the proton spin structure. Polarized proton collisions at a beam energy of 100 GeV have been achieved in RHIC since 2001. Recently, polarized proton beam was accelerated to 250 GeV in RHIC for the first time. Unlike accelerating unpolarized protons, the challenge for achieving high energy polarized protons is to fight the various mechanisms in an accelerator that can lead to partial or total polarization loss due to the interaction of the spin vector with the magnetic fields. We report on the progress of the RHIC polarized proton program. We also present the strategies of how to preserve the polarization through the entire acceleration chain, i.e. a 200 MeV linear accelerator, the Booster, the AGS and RHIC.

  15. Shielding data for 100 250 MeV proton accelerators: Attenuation of secondary radiation in thick iron and concrete/iron shields

    NASA Astrophysics Data System (ADS)

    Agosteo, S.; Magistris, M.; Mereghetti, A.; Silari, M.; Zajacova, Z.

    2008-08-01

    Double differential distributions of neutrons produced by 100, 150, 200 and 250 MeV protons stopped in a thick iron target were calculated with the FLUKA Monte Carlo code at four emission angles: forward, 45°, transverse and 135° backwards. The attenuation in thick iron shields of the dose equivalent due to neutrons, protons, photons and electrons was also calculated. The contribution to the total ambient dose equivalent from photons and protons is limited to a few percent at maximum. Source terms and attenuation lengths are given as a function of energy and emission angle, along with fits to the Monte Carlo data, for shallow depth and deep penetration in the shield. A brief discussion of simulations performed with composite iron/concrete shields is also given, showing the need for further investigations.

  16. Large Scale Accelerator Production of 225Ac: Effective Cross sections for 78-192 MeV Protons Incident on 232Th Targets

    DOE PAGES

    Griswold, Justin R; Medvedev, Dmitri G.; Engle, Jonathan W.; ...

    2016-09-28

    Actinium-225 and 213Bi have been used successfully in targeted alpha therapy (TAT) in preclinical and clinical research. This paper is a continuation of research activities aiming to expand the availability of 225Ac. The high energy proton spallation reaction on natural thorium metal target has been utilized to produce millicurie quantities of 225Ac. The results of sixteen irradiation experiments of Th metal at beam energies between 78 and 200 MeV are summarized in this work. Irradiations have been conducted at Brookhaven National Laboratory (BNL) and Los Alamos National Laboratory (LANL), while target dissolution and processing was carried out at Oak Ridgemore » National Laboratory (ORNL). Excitation functions for actinium and thorium isotopes as well as for some of the fission products are presented. The cross sections for production of 225Ac range from 3.6 to 16.7 mb in the incident proton energy range of 78 to 192 MeV. Based on these data, production of Curie quantities of 225Ac is possible by irradiating a 5.0 g cm-2232Th target for 10 days in either BNL or LANL proton irradiation facilities.« less

  17. Large scale accelerator production of (225)Ac: Effective cross sections for 78-192MeV protons incident on (232)Th targets.

    PubMed

    Griswold, J R; Medvedev, D G; Engle, J W; Copping, R; Fitzsimmons, J M; Radchenko, V; Cooley, J C; Fassbender, M E; Denton, D L; Murphy, K E; Owens, A C; Birnbaum, E R; John, K D; Nortier, F M; Stracener, D W; Heilbronn, L H; Mausner, L F; Mirzadeh, S

    2016-12-01

    Actinium-225 and (213)Bi have been used successfully in targeted alpha therapy (TAT) in preclinical and clinical research. This paper is a continuation of research activities aiming to expand the availability of (225)Ac. The high-energy proton spallation reaction on natural thorium metal targets has been utilized to produce millicurie quantities of (225)Ac. The results of sixteen irradiation experiments of thorium metal at beam energies between 78 and 192MeV are summarized in this work. Irradiations have been conducted at Brookhaven National Laboratory (BNL) and Los Alamos National Laboratory (LANL), while target dissolution and processing was carried out at Oak Ridge National Laboratory (ORNL). Excitation functions for actinium and thorium isotopes, as well as for some of the fission products, are presented. The cross sections for production of (225)Ac range from 3.6 to 16.7mb in the incident proton energy range of 78-192MeV. Based on these data, production of curie quantities of (225)Ac is possible by irradiating a 5.0gcm(-2 232)Th target for 10 days in either BNL or LANL proton irradiation facilities.

  18. [Proton therapy and particle accelerators].

    PubMed

    Fukumoto, Sadayoshi

    2012-01-01

    Since the high energy accelerator plan was changed from a 40 GeV direct machine to a 12GeV cascade one, a 500 MeV rapid cycling booster synchrotron was installed between the injector linac and the 12 GeV main ring at KEK, National Lab. for High Energy Physics. The booster beams were used not only for injection to the main ring but also for medical use. Their energy was reduced to 250 MeV by a graphite block for clinical trial of cancer therapy. In 1970's, pi(-) or heavy ions were supposed to be promising. Although advantage of protons with Bragg Peak was pointed out earlier, they seemed effective only for eye melanoma at that time. In early 1980's, it was shown that they were effective for deep-seated tumor by Tsukuba University with KEK beams. The first dedicated facility was built at Loma Linda University Medical Center. Its synchrotron was made by Fermi National Accelerator Lab. Since a non-resonant accelerating rf cavity was installed, operation of the synchrotron became much easier. Later, innovation of the cyclotron was achieved. Its weight was reduced from 1,000 ton to 200 ton. Some of the cyclotrons are equipped with superconducting coils.

  19. Characterization of moderator assembly dimension for accelerator boron neutron capture therapy of brain tumors using {sup 7}Li(p,n) neutrons at proton energy of 2.5 MeV

    SciTech Connect

    Tanaka, Kenichi; Kobayashi, Tooru; Bengua, Gerard; Nakagawa, Yoshinobu; Endo, Satoru; Hoshi, Masaharu

    2006-06-15

    The characteristics of moderator assembly dimension are investigated for the usage of {sup 7}Li(p,n) neutrons by 2.5 MeV protons in boron newtron capture therapy (BNCT) of brain tumors in the present study. The indexes checked are treatable protocol depth (TPD), which is the greatest depth of the region satisfying the dose requirements in BNCT protocol, proton current necessary to complete BNCT by 1 h irradiation, and the heat flux deposited in the Li target which should be removed. Assumed materials are D{sub 2}O for moderator, and mixture of polyethylene and LiF with 50 wt % for collimator. Dose distributions have been computed with MCNP 4B and 4C codes. Consequently, realized TPD does not show a monotonical tendency for the Li target diameter. However, the necessary proton current and heat flux in the Li target decreases as the Li target diameter increases, while this trend reverses at around 10 cm of the Li target diameter for the necessary proton current in the condition of this study. As to the moderator diameter, TPD does not exhibit an apparent dependence. On the other hand, necessary proton current and heat flux decrease as the moderator diameter increases, and this tendency saturates at around 60 cm of the moderator diameter in this study. As to the collimator, increase in inner diameter is suitable from the viewpoint of increasing TPD and decreasing necessary proton current and heat flux, while these indexes do not show apparent difference for collimator inner diameters over 14 cm for the parameters treated here. The practical viewpoint in selecting the parameters of moderator assembly dimension is to increase TPD, within the technically possible condition of accelerated proton current and heat removal from the Li target. In this process, the values for which the resultant characteristics mentioned above saturate or reverse would be important factors.

  20. Shielding measurements for a 230 MeV proton beam

    SciTech Connect

    Siebers, J.V.

    1990-01-01

    Energetic secondary neutrons produced as protons interact with accelerator components and patients dominate the radiation shielding environment for proton radiotherapy facilities. Due to the scarcity of data describing neutron production, attenuation, absorbed dose, and dose equivalent values, these parameters were measured for 230 MeV proton bombardment of stopping length Al, Fe, and Pb targets at emission angles of 0{degree}, 22{degree}, 45{degree}, and 90{degree} in a thick concrete shield. Low pressure tissue-equivalent proportional counters with volumes ranging from 1 cm{sup 3} to 1000 cm{sup 3} were used to obtain microdosimetric spectra from which absorbed dose and radiation quality are deduced. Does equivalent values and attenuation lengths determined at depth in the shield were found to vary sharply with angle, but were found to be independent of target material. Neutron dose and radiation length values are compared with Monte Carlo neutron transport calculations performed using the Los Alamos High Energy Transport Code (LAHET). Calculations used 230 MeV protons incident upon an Fe target in a shielding geometry similar to that used in the experiment. LAHET calculations overestimated measured attenuation values at 0{degree}, 22{degree}, and 45{degree}, yet correctly predicted the attenuation length at 90{degree}. Comparison of the mean radiation quality estimated with the Monte Carlo calculations with measurements suggest that neutron quality factors should be increased by a factor of 1.4. These results are useful for the shielding design of new facilities as well as for testing neutron production and transport calculations.

  1. Medical Application of the SARAF-Proton/Deuteron 40 MeV Superconducting Linac

    NASA Astrophysics Data System (ADS)

    Halfon, Shlomi

    2007-11-01

    The Soreq Applied Research Accelerator Facility (SARAF) is based on a superconducting linear accelerator currently being built at the Soreq research center (Israel). The SARAF is planned to generate a 2 mA 4 MeV proton beam during its first year of operation and up to 40 MeV proton or deuteron beam in 2012. The high intensity beam, together with the linac ability to adjust the ion energy provides opportunities for medical research, such as Boron Neutron Capture Therapy (BNCT) and the production of medical radioisotopes, for instance 103Pd for prostate brachytherapy.

  2. Proton Therapy - Accelerating Protons to Save Lives

    SciTech Connect

    Keppel, Cynthia

    2011-10-25

    In 1946, physicist Robert Wilson first suggested that protons could be used as a form of radiation therapy in the treatment of cancer because of the sharp drop-off that occurs on the distal edge of the radiation dose. Research soon confirmed that high-energy protons were particularly suitable for treating tumors near critical structures, such as the heart and spinal column. The precision with which protons can be delivered means that more radiation can be deposited into the tumor while the surrounding healthy tissue receives substantially less or, in some cases, no radiation. Since these times, particle accelerators have continuously been used in cancer therapy and today new facilities specifically designed for proton therapy are being built in many countries. Proton therapy has been hailed as a revolutionary cancer treatment, with higher cure rates and fewer side effects than traditional X-ray photon radiation therapy. Proton therapy is the modality of choice for treating certain small tumors of the eye, head or neck. Because it exposes less of the tissue surrounding a tumor to the dosage, proton therapy lowers the risk of secondary cancers later in life - especially important for young children. To date, over 80,000 patients worldwide have been treated with protons. Currently, there are nine proton radiation therapy facilities operating in the United States, one at the Hampton University Proton Therapy Institute. An overview of the treatment technology and this new center will be presented.

  3. Proton acceleration with a table-top TW laser

    NASA Astrophysics Data System (ADS)

    Seimetz, M.; Bellido, P.; Lera, R.; Ruiz-de la Cruz, A.; Mur, P.; Sánchez, I.; Galán, M.; Sánchez, F.; Roso, L.; Benlloch, J. M.

    2016-11-01

    We report on the recent demonstration of proton acceleration from a purpose-made Ti:Sapphire laser system. In the first successful series of autumn 2015, running at 2 TW peak power and 100 Hz diode pump rate, protons up to 0.7 MeV have been spectrally characterised. Subsequently, at increased laser pulse energy and improved contrast, we have obtained maximum particle energies around 1.7 MeV. These results, achieved in single-shot mode with a variety of thin foil targets, are an important step towards our aim of a stable, compact proton accelerator with high rate capacity.

  4. Accelerator Science: Proton vs. Electron

    ScienceCinema

    Lincoln, Don

    2016-10-19

    Particle accelerators are one of the most powerful ways to study the fundamental laws that govern the universe. However, there are many design considerations that go into selecting and building a particular accelerator. In this video, Fermilab’s Dr. Don Lincoln explains the pros and cons of building an accelerator that collides pairs of protons to one that collides electrons.

  5. Accelerator Science: Proton vs. Electron

    SciTech Connect

    Lincoln, Don

    2016-10-11

    Particle accelerators are one of the most powerful ways to study the fundamental laws that govern the universe. However, there are many design considerations that go into selecting and building a particular accelerator. In this video, Fermilab’s Dr. Don Lincoln explains the pros and cons of building an accelerator that collides pairs of protons to one that collides electrons.

  6. Shock Acceleration of Solar Energetic Protons: The First 10 Minutes

    NASA Technical Reports Server (NTRS)

    Ng, Chee K.; Reames, Donald V.

    2008-01-01

    Proton acceleration at a parallel coronal shock is modeled with self-consistent Alfven wave excitation and shock transmission. 18 - 50 keV seed protons at 0.1% of plasma proton density are accelerated in 10 minutes to a power-law intensity spectrum rolling over at 300 MeV by a 2500km s-1 shock traveling outward from 3.5 solar radius, for typical coronal conditions and low ambient wave intensities. Interaction of high-energy protons of large pitch-angles with Alfven waves amplified by low-energy protons of small pitch angles is key to rapid acceleration. Shock acceleration is not significantly retarded by sunward streaming protons interacting with downstream waves. There is no significant second-order Fermi acceleration.

  7. Low cost/low intensity 50 MeV proton irradiation facility

    SciTech Connect

    Kramer, S.L.; Martin, R.L.

    1985-01-01

    Protons have been proposed as one of the most useful particles for radiation therapy, but have found limited use due to the cost and scarcity of medium energy proton accelerators. However, the highly successful program on the Harvard Cyclotron has increased interest in expanding the number of treatment facilities. In order to demonstrate that high intensity proton accelerators are not required and to gain experience with treating patients using protons, a low cost and low intensity source of 50 MeV protons was developed at Argonne. Although the beam penetration is limited to 22 mm, the beam is capable of treating a major fraction of the ocular melanoma tumors treated at the Harvard Cyclotron. This beam operates parasitically with the Rapid Cycling Synchrotron at Argonne using a source of 50 MeV H/sup 0/ atoms which are produced by stripping in the gas of the 50 MeV H/sup -/ linear accelerator. A stripping fraction of about 3 to 5 x 10/sup -5/ is observed and yields a 0.4 namp beam of protons. Results on the properties and operation of this parasitic beam are presented. 5 refs., 3 figs.

  8. Stochastic acceleration of solar flare protons

    NASA Technical Reports Server (NTRS)

    Barbosa, D. D.

    1978-01-01

    The acceleration of solar flare protons is considered by cyclotron damping of intense Alfven wave turbulence in a magnetic trap. The energy diffusion coefficient is computed for a near-isotropic distribution of super-Alfvenic protons and a steady-state solution for the particle spectrum is found for both transit-time and diffusive losses out of the ends of the trap. The acceleration time to a characteristic energy approximately 20 Mev/nucl can be as short as 10 sec. On the basis of phenomenological arguments an omega/2 frequency dependence for the Alfven wave spectrum is inferred. The correlation time of the turbulence lies in the range .0005 less than tau/corr less than .05s.

  9. RADIATION DAMAGE TO BSCCO-2223 FROM 50 MEV PROTONS

    SciTech Connect

    Zeller, A.F.; Ronningen, R.M.; Godeke, A.; Heilbronn, L.H.; McMahan-Norris, P.; Gupta, R.

    2007-11-27

    The use of HTS materials in high radiation environmentsrequires that the superconducting properties remain constant up to aradiation high dose. BSCCO-2223 samples from two manufacturers wereirradiated with 50 MeV protons at fluences of up to 5 x 1017 protons/cm2.The samples lost approximately 75 percent of their pre-irradiation Ic.This compares with Nb3Sn, which loses about 50 percent at the samedisplacements per atom.

  10. RADIATION DAMAGE TO BSCCO-2223 FROM 50 MEV PROTONS

    SciTech Connect

    Zeller, A.F.; Ronningen, R.M.; Godeke, Arno; Heibronn, L.H; McMahan-Norris, P.; Gupta, R.

    2007-11-01

    The use of HTS materials in high radiation environments requires that the superconducting properties remain constant up to a radiation high dose. BSCCO-2223 samples from two manufacturers were irradiated with 50 MeV protons at fluences of up to 5 x 10{sup 17} protons/cm{sup 2}. The samples lost approximately 75% of their pre-irradiation I{sub c}. This compares with Nb{sub 3}Sn, which loses about 50% at the same displacements per atom.

  11. Possible parameters of proton acceleration using backward traveling wave harmonic

    NASA Astrophysics Data System (ADS)

    Paramonov, V. V.

    2016-12-01

    Analysis shows that, when accelerating protons of intermediate energy range using the field of backward harmonic of the traveling wave, a range of practically accessible parameters of accelerating structure exists, where it is possible to provide simultaneously the stability of longitudinal and transverse particle motion and high rates of acceleration. The focusing effect is provided by the field of slow fundamental harmonic. The calculated characteristics of accelerating structure and the assessment of parameters of the proton linac are obtained in a range of 15-230 MeV.

  12. High-Intensity Proton Accelerator

    SciTech Connect

    Jay L. Hirshfield

    2011-12-27

    Analysis is presented for an eight-cavity proton cyclotron accelerator that could have advantages as compared with other accelerators because of its potentially high acceleration gradient. The high gradient is possible since protons orbit in a sequence of TE111 rotating mode cavities of equally diminishing frequencies with path lengths during acceleration that greatly exceed the cavity lengths. As the cavities operate at sequential harmonics of a basic repetition frequency, phase synchronism can be maintained over a relatively wide injection phase window without undue beam emittance growth. It is shown that use of radial vanes can allow cavity designs with significantly smaller radii, as compared with simple cylindrical cavities. Preliminary beam transport studies show that acceptable extraction and focusing of a proton beam after cyclic motion in this accelerator should be possible. Progress is also reported on design and tests of a four-cavity electron counterpart accelerator for experiments to study effects on beam quality arising from variations injection phase window width. This device is powered by four 500-MW pulsed amplifiers at 1500, 1800, 2100, and 2400 MHz that provide phase synchronous outputs, since they are driven from a with harmonics derived from a phase-locked 300 MHz source.

  13. Measurement of the Wolfenstein parameters for proton-proton and proton-neutron scattering at 500 MeV

    SciTech Connect

    Marshall, J.A.

    1984-07-01

    Using liquid hydrogen and liquid deuterium targets respectively, forward angle (ten degrees to sixty degrees in the center of Mass) free proton-proton and quasielastic proton-proton and proton-neutron triple scattering data at 500 MeV have been obtained using the high resolution spectrometer at the Los Alamos Meson Physics Facility. The data are in reasonable agreement with recent predictions from phase shift analyses, indicating that the proton-nucleon scattering amplitudes are fairly well determined at 500 MeV. 32 references.

  14. Preliminary shielding assessment for the 100 MeV proton linac (KOMAC).

    PubMed

    Lee, Young-Ouk; Cho, Y S; Chang, J

    2005-01-01

    The Proton Engineering Frontier Project is building the Korea Multipurpose Accelerator Complex facilities from 2002 to 2012, which consists of a high-current 100 MeV proton linear accelerator and various beam-lines. This paper provides a preliminary estimate of the shielding required for the 20 mA proton linac and the beam-dump. For an accurate information on secondary neutron production from the guiding magnet and primary heat sink of the beam dump, proton-induced 63Cu and 65Cu cross section data were evaluated and applied to shielding calculations. The required thickness of the concrete was assessed by a simple line-of-sight model for the lateral shielding of the beam-line and the full shielding of the beam dump. Monte Carlo simulations were also performed using the MCNPX code to obtain the source term and attenuation coefficients for the three-dimensional lateral shielding model of the beam-line.

  15. Absolute polarimeter for the proton-beam energy of 200 MeV

    SciTech Connect

    Zelenski, A. N.; Atoian, G.; Bogdanov, A. A.; Nurushev, S. B.; Pylaev, F. S.; Raparia, D.; Runtso, M. F.; Stephenson, E.

    2013-12-15

    A polarimeter is upgraded and tested in a 200-MeV polarized-proton beam at the accelerator-collider facility of the Brookhaven National Laboratory. The polarimeter is based on the elastic polarizedproton scattering on a carbon target at an angle of 16.2°, in which case the analyzing power is close to unity and was measured to a very high degree of precision. It is shown that, in the energy range of 190–205 MeV, the absolute polarization can be measured to a precision better than ±0.5%.

  16. Stochastic cooling of 200 MeV protons

    NASA Astrophysics Data System (ADS)

    Lambertson, G.; Bisognano, J.; Flood, W.; Laslett, L. J.; Leemann, C.; Leskovar, B.; Lo, C. C.; Main, R.; Smith, L.; Staples, J.

    1980-07-01

    Vertical and longitudinal cooling was achieved at the FNAL 200 MeV cooling ring. Initial longitudinal cooling times of 20 seconds for 1.5 x 1 million circulating protons are in approximate 20 seconds for 1.5 x 1 million circulating protons are in approximate agreement with calculations based on measured system parameters. The cooling systems have an electronic bandwidth of approxmately 300 MHz, traveling wave pickups and kickers, and a notch filter using flexible cable. The traveling wave structures provide a good signal-to-noise ratio and reduce output power requirements.

  17. Large Scale Accelerator Production of 225Ac: Effective Cross sections for 78-192 MeV Protons Incident on 232Th Targets

    SciTech Connect

    Griswold, Justin R; Medvedev, Dmitri G.; Engle, Jonathan W.; Copping, Roy; Fitzsimmons, Jonathan M.; Radchenko, Valery; Cooley, Jason; Fassbender, Michael; Denton, David L.; Murphy, Karen E.; Owens, Allison C.; Birnbaum, Eva R.; John, Kevin D.; Nortier, Francois M.; Stracener, Daniel W; Heilbronn, Lawrence H.; Mausner, Leonard F.; Mirzadeh, Saed

    2016-09-28

    Actinium-225 and 213Bi have been used successfully in targeted alpha therapy (TAT) in preclinical and clinical research. This paper is a continuation of research activities aiming to expand the availability of 225Ac. The high energy proton spallation reaction on natural thorium metal target has been utilized to produce millicurie quantities of 225Ac. The results of sixteen irradiation experiments of Th metal at beam energies between 78 and 200 MeV are summarized in this work. Irradiations have been conducted at Brookhaven National Laboratory (BNL) and Los Alamos National Laboratory (LANL), while target dissolution and processing was carried out at Oak Ridge National Laboratory (ORNL). Excitation functions for actinium and thorium isotopes as well as for some of the fission products are presented. The cross sections for production of 225Ac range from 3.6 to 16.7 mb in the incident proton energy range of 78 to 192 MeV. Based on these data, production of Curie quantities of 225Ac is possible by irradiating a 5.0 g cm-2232Th target for 10 days in either BNL or LANL proton irradiation facilities.

  18. Gadolinium-148 production cross section measurements for 600-and 800-MEV protons.

    SciTech Connect

    Kelley, K. C.; Devlin, M. J.; Pitcher, E. J.; Mashnik, S. G.; Hertel, N. E.

    2004-01-01

    In a series of experiments at LANSCE's WNR facility, {sup 148}Gd production was measured for 600- and 800-MeV protons on tungsten, tantalum, and gold. These experiments used 3 {mu}m thin W, Ta, and Au foils and 10 {mu}m thin Al activation foils. Gadolinium spallation yields were determined from these foils using alpha spectroscopy and compared with the LANL codes CEM2k+GEM2 and MCNPX. When heavy metal targets, such as tungsten, are bombarded with protons greater than a few hundred MeV many different nuclides are produced. These nuclides are both stable and radioactive and are created by spallation, proton activation, or secondary reactions with neutrons and other nuclear particles made in the target. These products are distributed somewhat heterogeneously throughout a thick target because of the energy dependence of the cross sections and energy loss of the proton beam within the target. From this standpoint, it is difficult to measure nuclide production cross sections for a given energy proton in a thick target. At the Los Alamos Neutron Science Center (LANSCE) accelerator complex, protons are accelerated to 800 MeV and directed to two tungsten targets, Target 4 at the Weapons Neutron Research (WNR) facility and 1L target at the Manuel Lujan Jr. Neutron Scattering Center. DOE requires hazard classification analyses to be performed on these targets and places limits on radionuclide inventories in the target as a means of determining the 'nuclear facility' category level. Presently, WNR's Target 4 is a non-nuclear facility while the Lujan 1L target is classified as a Category 3 nuclear facility. Gadolinium-148 is a radionuclide created from the spallation of tungsten and other heavy elements. Allowable isotopic inventories are particularly low for this isotope because it is an alpha-particle emitter with a 75-year half-life. The activity level of {sup 148}Gd is generally low, but it encompasses almost two-thirds of the total inhalation dose burden in an accident

  19. RF phase stability in the 100-MeV proton linac operation

    NASA Astrophysics Data System (ADS)

    Seol, Kyung-Tae

    2015-02-01

    The 100-MeV proton linac of the Korea multi-purpose accelerator complex (KOMAC) has been operated to provide a proton beam to users. The 100-MeV linac consists of a 3-MeV radio-frequency quadrupole accelerator (RFQ), four 20-MeV drift-tube linac (DTL) tanks, two medium-energy beam-transmitter (MEBT) tanks, and seven 100-MeV DTL tanks. The requirements of the field stability are within ±1% in RF amplitude and ±1 degree in RF phase. The RF phase stability is influenced by a RF reference line, RF transmission lines, and a RF control system. The RF reference signal is chosen to be a 300-MHz local oscillator (LO) signal, and a rigid copper coaxial line with temperature control was installed for an RF reference distribution. A phase stability of ±0.1 degrees was measured under a temperature change of ±0.1 °C. A digital feedback control system with a field-programmable gate-array (FPGA) module was adopted for a high RF stability. The RF phase was maintained within ±0.1 degrees with a dummy cavity and was within ±0.3 degrees at RFQ operation. In the case of the 20-MeV DTL tanks, one klystron drives 4 tanks, and the input phases of 4 tanks were designed to be in phase. The input phases of 4 tanks were fixed within ±1 degree by adjusting a phase shifter in each waveguide.

  20. Acceleration tests of a 3 GHz proton linear accelerator (LIBO) for hadrontherapy

    NASA Astrophysics Data System (ADS)

    De Martinis, C.; Giove, D.; Amaldi, U.; Berra, P.; Crandall, K.; Mauri, M.; Weiss, M.; Zennaro, R.; Rosso, E.; Szeless, B.; Vretenar, M.; Masullo, M. R.; Vaccaro, V.; Calabretta, L.; Rovelli, A.

    2012-07-01

    This paper describes the acceleration tests performed at the Catania LNS Laboratory on a 3 GHz linac module of the side coupled type, which boosts the proton energy of a beam extracted from a cyclotron from 62 to 72 MeV. The output proton energy was measured with two devices: a NaI(Tl) crystal and a bending magnet. The experimental spectra are in good agreement with the calculated ones. From their shape it is obtained that (18±3.0)% of the transmitted protons fall in a ±2 MeV interval centered around 72 MeV. This result is in good agreement with the 20% value derived from the simulation of the acceleration process. The measured energy of the accelerated protons was used to check that the shunt impedance of the structure is equal to the computed one within 3%. This was the first time that a 3 GHz structure has been used to accelerate protons, and the results of the tests have demonstrated that a high frequency linac can be used as a cyclotron booster.

  1. First test of a partial Siberian snake for acceleration of polarized protons

    NASA Astrophysics Data System (ADS)

    Caussyn, D. D.; Baiod, R.; Blinov, B. B.; Chu, C. M.; Courant, E. D.; Crandell, D. A.; Derbenev, Ya. S.; Ellison, T. J. P.; Kaufman, W. A.; Krisch, A. D.; Lee, S. Y.; Minty, M. G.; Nurushev, T. S.; Ohmori, C.; Phelps, R. A.; Raczkowski, D. B.; Ratner, L. G.; Schwandt, P.; Stephenson, E. J.; Sperisen, F.; Przewoski, B. von; Wienands, U.; Wong, V. K.

    1995-09-01

    We recently studied the first acceleration of a spin-polarized proton beam through a depolarizing resonance using a partial Siberian snake. We accelerated polarized protons from 95 to 140 MeV with a constant 10% partial Siberian snake obtained using rampable solenoids. The 10% partial snake suppressed all observable depolarization during acceleration due to the Gγ=2 imperfection depolarizing resonance which occurred near 108 MeV. However, 20% and 30% partial Siberian snakes apparently moved an intrinsic depolarizing resonance, normally near 177 MeV, into our energy range; this caused some interesting, although not-yet-fully understood, depolarization.

  2. MeV proton flux predictions near Saturn's D ring.

    PubMed

    Kollmann, P; Roussos, E; Kotova, A; Cooper, J F; Mitchell, D G; Krupp, N; Paranicas, C

    2015-10-01

    Radiation belts of MeV protons have been observed just outward of Saturn's main rings. During the final stages of the mission, the Cassini spacecraft will pass through the gap between the main rings and the planet. Based on how the known radiation belts of Saturn are formed, it is expected that MeV protons will be present in this gap and also bounce through the tenuous D ring right outside the gap. At least one model has suggested that the intensity of MeV protons near the planet could be much larger than in the known belts. We model this inner radiation belt using a technique developed earlier to understand Saturn's known radiation belts. We find that the inner belt is very different from the outer belts in the sense that its intensity is limited by the densities of the D ring and Saturn's upper atmosphere, not by radial diffusion and satellite absorption. The atmospheric density is relatively well constrained by EUV occultations. Based on that we predict an intensity in the gap region that is well below that of the known belts. It is more difficult to do the same for the region magnetically connected to the D ring since its density is poorly constrained. We find that the intensity in this region can be comparable to the known belts. Such intensities pose no hazard to the mission since Cassini would only experience these fluxes on timescales of minutes but might affect scientific measurements by decreasing the signal-to-contamination ratio of instruments.

  3. MeV proton flux predictions near Saturn's D ring

    NASA Astrophysics Data System (ADS)

    Kollmann, P.; Roussos, E.; Kotova, A.; Cooper, J. F.; Mitchell, D. G.; Krupp, N.; Paranicas, C.

    2015-10-01

    Radiation belts of MeV protons have been observed just outward of Saturn's main rings. During the final stages of the mission, the Cassini spacecraft will pass through the gap between the main rings and the planet. Based on how the known radiation belts of Saturn are formed, it is expected that MeV protons will be present in this gap and also bounce through the tenuous D ring right outside the gap. At least one model has suggested that the intensity of MeV protons near the planet could be much larger than in the known belts. We model this inner radiation belt using a technique developed earlier to understand Saturn's known radiation belts. We find that the inner belt is very different from the outer belts in the sense that its intensity is limited by the densities of the D ring and Saturn's upper atmosphere, not by radial diffusion and satellite absorption. The atmospheric density is relatively well constrained by EUV occultations. Based on that we predict an intensity in the gap region that is well below that of the known belts. It is more difficult to do the same for the region magnetically connected to the D ring since its density is poorly constrained. We find that the intensity in this region can be comparable to the known belts. Such intensities pose no hazard to the mission since Cassini would only experience these fluxes on timescales of minutes but might affect scientific measurements by decreasing the signal-to-contamination ratio of instruments.

  4. Flare vs. Shock Acceleration of High-energy Protons in Solar Energetic Particle Events

    NASA Astrophysics Data System (ADS)

    Cliver, E. W.

    2016-12-01

    Recent studies have presented evidence for a significant to dominant role for a flare-resident acceleration process for high-energy protons in large (“gradual”) solar energetic particle (SEP) events, contrary to the more generally held view that such protons are primarily accelerated at shock waves driven by coronal mass ejections (CMEs). The new support for this flare-centric view is provided by correlations between the sizes of X-ray and/or microwave bursts and associated SEP events. For one such study that considered >100 MeV proton events, we present evidence based on CME speeds and widths, shock associations, and electron-to-proton ratios that indicates that events omitted from that investigation’s analysis should have been included. Inclusion of these outlying events reverses the study’s qualitative result and supports shock acceleration of >100 MeV protons. Examination of the ratios of 0.5 MeV electron intensities to >100 MeV proton intensities for the Grechnev et al. event sample provides additional support for shock acceleration of high-energy protons. Simply scaling up a classic “impulsive” SEP event to produce a large >100 MeV proton event implies the existence of prompt 0.5 MeV electron events that are approximately two orders of magnitude larger than are observed. While classic “impulsive” SEP events attributed to flares have high electron-to-proton ratios (≳5 × 105) due to a near absence of >100 MeV protons, large poorly connected (≥W120) gradual SEP events, attributed to widespread shock acceleration, have electron-to-proton ratios of ˜2 × 103, similar to those of comparably sized well-connected (W20-W90) SEP events.

  5. ETFE polymer bombarded with 1 MeV proton

    NASA Astrophysics Data System (ADS)

    Parada, M. A.; de Almeida, A.; Muntele, I.; Muntele, C.; Delalez, N.; Ila, D.

    2005-12-01

    The ethylenetetrafluoroethylene (ETFE) is a polymer formed by alternating ethylene and tetrafluoroethylene segments. It has high impact resistance and useful mechanical properties. ETFE can be used as components of pumps, valves, tie wraps, and electrical components. It can also be applied in the field of medical physics as intra venous catheters and as radiation dosimeter. When a material is exposed to the ionizing radiation, it suffers damage that depends on the type, energy and intensity of the radiation. In order to determine the radiation damage mechanism, ETFE films were bombarded with 1 MeV protons to the fluence between 1 × 1011 and 1 × 1016 protons/cm2 and the chemical species emitted during the bombardment were measured with residual gas analysis (RGA) and show that HF gas is the entity preferentially emitted. Optical absorption photospectrometry (OAP) and attenuated total reflectometry fourier transform infrared (ATR-FTIR) shows quantitative chemical evidence of the damage. Our results show that damage is detectable at low proton fluence, but damage that can compromise the application in dosimetry occurs only for fluence greater than 1014 protons/cm2.

  6. The LILIA experiment: Energy selection and post-acceleration of laser generated protons

    NASA Astrophysics Data System (ADS)

    Turchetti, Giorgio; Sinigardi, Stefano; Londrillo, Pasquale; Rossi, Francesco; Sumini, Marco; Giove, Dario; De Martinis, Carlo

    2012-12-01

    The LILIA experiment is planned at the SPARCLAB facility of the Frascati INFN laboratories. We have simulated the laser acceleration of protons, the transport and energy selection with collimators and a pulsed solenoid and the post-acceleration with a compact high field linac. For the highest achievable intensity corresponding to a = 30 over 108 protons at 30 MeV with a 3% spread are selected, and at least107 protons are post-accelerated up to 60 MeV. If a 10 Hz repetition rated can be achieved the delivered dose would be suitable for the treatment of small superficial tumors.

  7. First acceleration of a proton beam in a side coupled drift tube linac

    NASA Astrophysics Data System (ADS)

    Ronsivalle, C.; Picardi, L.; Ampollini, A.; Bazzano, G.; Marracino, F.; Nenzi, P.; Snels, C.; Surrenti, V.; Vadrucci, M.; Ambrosini, F.

    2015-07-01

    We report the first experiment aimed at the demonstration of low-energy protons acceleration by a high-efficiency S-band RF linear accelerator. The proton beam has been accelerated from 7 to 11.6 MeV by a 1 meter long SCDTL (Side Coupled Drift Tube Linac) module powered with 1.3 MW. The experiment has been done in the framework of the Italian TOP-IMPLART (Oncological Therapy with Protons-Intensity Modulated Proton Therapy Linear Accelerator for Radio-Therapy) project devoted to the realization of a proton therapy centre based on a proton linear accelerator for intensity modulated cancer treatments to be installed at IRE-IFO, the largest oncological hospital in Rome. It is the first proton therapy facility employing a full linear accelerator scheme based on high-frequency technology.

  8. Compact Proton Accelerator for Cancer Therapy

    SciTech Connect

    Chen, Y; Paul, A C

    2007-06-12

    An investigation is being made into the feasibility of making a compact proton dielectric wall (DWA) accelerator for medical radiation treatment based on the high gradient insulation (HGI) technology. A small plasma device is used for the proton source. Using only electric focusing fields for transporting and focusing the beam on the patient, the compact DWA proton accelerator m system can deliver wide and independent variable ranges of beam currents, energies and spot sizes.

  9. Cross sections from proton irradiation of thorium at 800 MeV

    NASA Astrophysics Data System (ADS)

    Engle, Jonathan W.; Mashnik, Stepan G.; Weidner, John W.; Wolfsberg, Laura E.; Fassbender, Michael E.; Jackman, Kevin; Couture, Aaron; Bitteker, Leo J.; Ullmann, John L.; Gulley, Mark S.; Pillai, Chandra; John, Kevin D.; Birnbaum, Eva R.; Nortier, Francois M.

    2013-07-01

    Nuclear formation cross sections are reported for 65 nuclides produced from 800-MeV proton irradiation of thorium foils. These data are useful as benchmarks for computational predictions in the ongoing process of theoretical code development and also in the design of spallation-based radioisotope production currently being considered for multiple radiotherapeutic pharmaceutical agents. Measured data are compared with the predictions of three mcnp6 event generators and used to evaluate the potential for 800-MeV productions of radioisotopes of interest for medical radiotherapy. In only a few instances code predictions are discrepant from measured values by more than a factor of 2, demonstrating satisfactory predictive power across a large mass range. Similarly, agreement between measurements presented here and those previously reported is good, lending credibility to predictions of target yields and radioimpurities for high-energy accelerator-produced radionuclides.

  10. a Survey of Giant Resonance Excitations with 200 Mev Protons

    NASA Astrophysics Data System (ADS)

    Tinsley, James Royce

    The giant resonance region in ('60)Ni, ('90)Zr, ('120)Sn, and ('208)Pb has been studied using inelastic scattering of 200 MeV protons. Angular distributions were obtained for the giant quadrupole resonance, giant octupole resonance, and for the combined giant dipole and giant monopole resonance between 4 and 20 degrees. The 2(H/2PI)(omega) component of the giant hexadecapole resonance has been directly observed for the first time in ('208)Pb. In the other nuclei, upper limits on the amount of hexadecapole strength contained within the giant quadrupole resonance have been obtained. Peaks are observed in ('60)Ni and ('90)Zr that are consistent with recently reported M1 states. Discrepancies between sum rules extracted from this data and from previous work are discussed. Possible explanations include DWBA breakdown or difficulties in estimating the magnitude of the continuum. Systematics obtained for the giant resonances are compared to earlier work.

  11. Measurement of Neutron Proton Going to Proton Proton Negative Pion at 443 Mev

    NASA Astrophysics Data System (ADS)

    Bachman, Mark Gregory

    Experiment E372 at TRIUMF measured the analyzing powers (A_{rm NO}, A_ {rm SO}, A_{rm LO}) and relative differential cross section for the reaction np to pppi ^- at 443 MeV. We directed a polarized neutron beam on to a liquid hydrogen target and measured the scattered events in a large solid angle detector capable of measuring the velocities and directions of all of the protons produced in the reaction as well as many of the pions. Kinematic analysis of the events allowed us to remove almost all background and resulted in a clean set of np to pppi^- events. These events were binned against appropriate kinematic variables to produce yields which correspond to relative differential cross sections, and asymmetries which correspond to A _{rm NO}, A_{rm SO}, and A_{rm LO }. These results are the first of their kind for this energy. Comparisons to a theoretical model of Kloet and Lomon and a preliminary study using partial waves are presented.

  12. A Study of Polarized Proton Acceleration in J-PARC

    SciTech Connect

    Luccio, A. U.; Bai, M.; Roser, T.; Molodojentsev, A.; Ohmori, C.; Sato, H.; Hatanaka, K.

    2007-06-13

    We have studied the feasibility of polarized proton acceleration in rhe J-PARC accelerator facility, consisting of a 400 MeV linac, a 3 GeV rapid cycling synchrotron (RCS) and a 50 GeV synchrotron (MR). We show how the polarization of the beam can be preserved using an rf dipole in the RCS and two superconductve partial helical Siberian snakes in the MR. The lattice of the MR will be modified with the addition of quadrupoles to compensate for the focusing properties of the snakes.

  13. A STUDY OF POLARIZED PROTON ACCELERATION IN J-PARC.

    SciTech Connect

    LUCCIO, A.U.; BAI, M.; ROSER, T.

    2006-10-02

    We have studied the feasibility of polarized proton acceleration in rhe J-PARC accelerator facility, consisting of a 400 MeV linac, a 3 GeV rapid cycling synchrotron (RCS) and a 50 GeV synchrotron (MR). We show how the polarization of the beam can be preserved using an rf dipole in the RCS and two superconductive partial helical Siberian snakes in the MR. The lattice of the MR will be modified with the addition of quadrupoles to compensate for the focusing properties of the snakes.

  14. Laser acceleration of protons with an optically shaped, near-critical hydrogen gas target

    NASA Astrophysics Data System (ADS)

    Chen, Yu-hsin; Helle, Michael; Ting, Antonio; Gordon, Daniel; Dover, Nicholas; Ettlinger, Oliver; Najmudin, Zulfikar; Polyanskiy, Mikhail; Pogorelsky, Igor; Babzien, Marcus

    2017-03-01

    We report our recent experimental results on CO2 laser acceleration of protons, with a near-critical hydrogen gas target tailored by a Nd:YAG laser-produced blast wave. Monoenergetic protons with energies up to 2.5 MeV were observed.

  15. Deep proton writing with 12 MeV protons for rapid prototyping of microstructures in polymethylmethacrylate

    NASA Astrophysics Data System (ADS)

    Ebraert, Evert; Gökçe, Berkcan; Van Vlierberghe, Sandra; Vervaeke, Michael; Meyer, Pascal; Guttmann, Markus; Dubruel, Peter; Thienpont, Hugo; Van Erps, Jürgen

    2016-10-01

    Deep proton writing (DPW) is a fabrication technology developed for the rapid prototyping of polymer microstructures. We use polymethylmethacrylate (PMMA) substrates, which act as a positive resist, for irradiation with a collimated 12-MeV energy proton beam. Using 12 MeV enables the irradiation of increasingly thick PMMA substrates with less conicity of the sidewalls compared to the lower energies used in previous work. A microhole of 47.7 μm diameter over a depth of 1 mm is achieved, leading to a maximum aspect ratio of 21∶1. The sidewalls of the irradiated structures show a slightly conical shape and their root-mean-square surface roughness is lower than 50 nm averaged over 72 measured areas of 56 μm×44 μm. This means that DPW components have optical surface quality sidewalls for wavelengths larger than 400 nm. Based on the trade-off among the sidewall roughness, conicity, and the development time, we determine that the optimal proton fluence for 12-MeV DPW in PMMA is 7.75×106 μm-2. Finally, we discuss some high aspect ratio microstructures with optical surface quality that were created with DPW to be used for a myriad of applications, such as micromirrors, microlenses, optofluidic devices, and high-precision alignment structures for single-mode optical fiber connectors.

  16. Neutron production from 200-500 MeV proton interaction with spacecraft materials.

    PubMed

    Maurer, Richard H; Kinnison, James D; Roth, David R

    2005-01-01

    We report on detailed energy spectra of neutron production > 14 MeV from collisions of 200-500 MeV protons with combinations of aluminium, graphite and polyethylene. Comparisons of normalised neutron spectra are made with respect to incident proton energy, angle of neutron production and material. In general, carbon (graphite) or polyethylene (by itself or in combination with aluminium) reduce secondary neutron production > 14 MeV relative to the production from interactions in aluminium.

  17. Shielding design for a laser-accelerated proton therapy system.

    PubMed

    Fan, J; Luo, W; Fourkal, E; Lin, T; Li, J; Veltchev, I; Ma, C-M

    2007-07-07

    In this paper, we present the shielding analysis to determine the necessary neutron and photon shielding for a laser-accelerated proton therapy system. Laser-accelerated protons coming out of a solid high-density target have broad energy and angular spectra leading to dose distributions that cannot be directly used for therapeutic applications. A special particle selection and collimation device is needed to generate desired proton beams for energy- and intensity-modulated proton therapy. A great number of unwanted protons and even more electrons as a side-product of laser acceleration have to be stopped by collimation devices and shielding walls, posing a challenge in radiation shielding. Parameters of primary particles resulting from the laser-target interaction have been investigated by particle-in-cell simulations, which predicted energy spectra with 300 MeV maximum energy for protons and 270 MeV for electrons at a laser intensity of 2 x 10(21) W cm(-2). Monte Carlo simulations using FLUKA have been performed to design the collimators and shielding walls inside the treatment gantry, which consist of stainless steel, tungsten, polyethylene and lead. A composite primary collimator was designed to effectively reduce high-energy neutron production since their highly penetrating nature makes shielding very difficult. The necessary shielding for the treatment gantry was carefully studied to meet the criteria of head leakage <0.1% of therapeutic absorbed dose. A layer of polyethylene enclosing the whole particle selection and collimation device was used to shield neutrons and an outer layer of lead was used to reduce photon dose from neutron capture and electron bremsstrahlung. It is shown that the two-layer shielding design with 10-12 cm thick polyethylene and 4 cm thick lead can effectively absorb the unwanted particles to meet the shielding requirements.

  18. Shielding design for a laser-accelerated proton therapy system

    NASA Astrophysics Data System (ADS)

    Fan, J.; Luo, W.; Fourkal, E.; Lin, T.; Li, J.; Veltchev, I.; Ma, C.-M.

    2007-07-01

    In this paper, we present the shielding analysis to determine the necessary neutron and photon shielding for a laser-accelerated proton therapy system. Laser-accelerated protons coming out of a solid high-density target have broad energy and angular spectra leading to dose distributions that cannot be directly used for therapeutic applications. A special particle selection and collimation device is needed to generate desired proton beams for energy- and intensity-modulated proton therapy. A great number of unwanted protons and even more electrons as a side-product of laser acceleration have to be stopped by collimation devices and shielding walls, posing a challenge in radiation shielding. Parameters of primary particles resulting from the laser-target interaction have been investigated by particle-in-cell simulations, which predicted energy spectra with 300 MeV maximum energy for protons and 270 MeV for electrons at a laser intensity of 2 × 1021 W cm-2. Monte Carlo simulations using FLUKA have been performed to design the collimators and shielding walls inside the treatment gantry, which consist of stainless steel, tungsten, polyethylene and lead. A composite primary collimator was designed to effectively reduce high-energy neutron production since their highly penetrating nature makes shielding very difficult. The necessary shielding for the treatment gantry was carefully studied to meet the criteria of head leakage <0.1% of therapeutic absorbed dose. A layer of polyethylene enclosing the whole particle selection and collimation device was used to shield neutrons and an outer layer of lead was used to reduce photon dose from neutron capture and electron bremsstrahlung. It is shown that the two-layer shielding design with 10-12 cm thick polyethylene and 4 cm thick lead can effectively absorb the unwanted particles to meet the shielding requirements.

  19. Response functions of Fuji imaging plates to monoenergetic protons in the energy range 0.6-3.2 MeV

    SciTech Connect

    Bonnet, T.; Denis-Petit, D.; Gobet, F.; Hannachi, F.; Tarisien, M.; Versteegen, M.; Aleonard, M. M.

    2013-01-15

    We have measured the responses of Fuji MS, SR, and TR imaging plates (IPs) to protons with energies ranging from 0.6 to 3.2 MeV. Monoenergetic protons were produced with the 3.5 MV AIFIRA (Applications Interdisciplinaires de Faisceaux d'Ions en Region Aquitaine) accelerator at the Centre d'Etudes Nucleaires de Bordeaux Gradignan (CENBG). The IPs were irradiated with protons backscattered off a tantalum target. We present the photo-stimulated luminescence response of the IPs together with the fading measurements for these IPs. A method is applied to allow correction of fading effects for variable proton irradiation duration. Using the IP fading corrections, a model of the IP response function to protons was developed. The model enables extrapolation of the IP response to protons up to proton energies of 10 MeV. Our work is finally compared to previous works conducted on Fuji TR IP response to protons.

  20. Technical assessment of the Loma Linda University proton therapy accelerator

    SciTech Connect

    Not Available

    1989-10-01

    In April 1986, officials of Loma Linda University requested that Fermilab design and construct a 250 MeV proton synchrotron for radiotherapy, to be located at the Loma Linda University Medical Center. In June 1986 the project, having received all necessary approvals, commenced. In order to meet a desirable schedule providing for operation in early 1990, it was decided to erect such parts of the accelerator as were complete at Fermilab and conduct a precommissioning activity prior to the completion of the building at Loma Linda which will house the final radiotherapy facility. It was hoped that approximately one year would be saved by the precommissioning, and that important information would be obtained about the system so that improvements could be made during installation at Loma Linda. This report contains an analysis by Fermilab staff members of the information gained in the precommissioning activity and makes recommendations about steps to be taken to enhance the performance of the proton synchrotron at Loma Linda. In the design of the accelerator, effort was made to employ commercially available components, or to industrialize the products developed so that later versions of the accelerator could be produced industrially. The magnets could only be fabricated at Fermilab if the schedule was to be met, but efforts were made to transfer that technology to industry. Originally, it was planned to use a 1.7 MeV RFQ fabricated at the Lawrence Berkeley Laboratory as injector, but LBL would have found it difficult to meet the project schedule. After consideration of other options, for example a 3.4 MeV tandem accelerator, a supplier (AccSys Inc.) qualified itself to provide a 2 MeV RFQ on a schedule well matched to the project schedule. This choice was made, but a separate supplier was selected to develop and provide the 425 MHz power amplifier for the RFQ.

  1. Commissioning of a compact laser-based proton beam line for high intensity bunches around 10Â MeV

    NASA Astrophysics Data System (ADS)

    Busold, S.; Schumacher, D.; Deppert, O.; Brabetz, C.; Kroll, F.; Blažević, A.; Bagnoud, V.; Roth, M.

    2014-03-01

    We report on the first results of experiments with a new laser-based proton beam line at the GSI accelerator facility in Darmstadt. It delivers high current bunches at proton energies around 9.6 MeV, containing more than 109 particles in less than 10 ns and with tunable energy spread down to 2.7% (ΔE/E0 at FWHM). A target normal sheath acceleration stage serves as a proton source and a pulsed solenoid provides for beam collimation and energy selection. Finally a synchronous radio frequency (rf) field is applied via a rf cavity for energy compression at a synchronous phase of -90 deg. The proton bunch is characterized at the end of the very compact beam line, only 3 m behind the laser matter interaction point, which defines the particle source.

  2. Solid hydrogen target for laser driven proton acceleration

    NASA Astrophysics Data System (ADS)

    Perin, J. P.; Garcia, S.; Chatain, D.; Margarone, D.

    2015-05-01

    The development of very high power lasers opens up new horizons in various fields, such as laser plasma acceleration in Physics and innovative approaches for proton therapy in Medicine. Laser driven proton acceleration is commonly based on the so-called Target Normal Sheath Acceleration (TNSA) mechanisms: a high power laser is focused onto a solid target (thin metallic or plastic foil) and interact with matter at very high intensity, thus generating a plasma; as a consequence "hot" electrons are produced and move into the forward direction through the target. Protons are generated at the target rear side, electrons try to escape from the target and an ultra-strong quasi-electrostatic field (~1TV/m) is generated. Such a field can accelerate protons with a wide energy spectrum (1-200 MeV) in a few tens of micrometers. The proton beam characteristics depend on the laser parameters and on the target geometry and nature. This technique has been validated experimentally in several high power laser facilities by accelerating protons coming from hydrogenated contaminant (mainly water) at the rear of metallic target, however, several research groups are investigating the possibility to perform experiments by using "pure" hydrogen targets. In this context, the low temperature laboratory at CEA-Grenoble has developed a cryostat able to continuously produce a thin hydrogen ribbon (from 40 to 100 microns thick). A new extrusion concept, without any moving part has been carried out, using only the thermodynamic properties of the fluid. First results and perspectives are presented in this paper.

  3. Acceleration of polarized protons in circular accelerators

    SciTech Connect

    Courant, E.D.; Ruth, R.D.

    1980-09-12

    The theory of depolarization in circular accelerators is presented. The spin equation is first expressed in terms of the particle orbit and then converted to the equivalent spinor equation. The spinor equation is then solved for three different situations: (1) a beam on a flat top near a resonance, (2) uniform acceleration through an isolated resonance, and (3) a model of a fast resonance jump. Finally, the depolarization coefficient, epsilon, is calculated in terms of properties of the particle orbit and the results are applied to a calculation of depolarization in the AGS.

  4. Proton-induced cross sections relevant to production of 225Ac and 223Ra in natural thorium targets below 200 MeV.

    PubMed

    Weidner, J W; Mashnik, S G; John, K D; Hemez, F; Ballard, B; Bach, H; Birnbaum, E R; Bitteker, L J; Couture, A; Dry, D; Fassbender, M E; Gulley, M S; Jackman, K R; Ullmann, J L; Wolfsberg, L E; Nortier, F M

    2012-11-01

    Cross sections for (223,)(225)Ra, (225)Ac and (227)Th production by the proton bombardment of natural thorium targets were measured at proton energies below 200 MeV. Our measurements are in good agreement with previously published data and offer a complete excitation function for (223,)(225)Ra in the energy range above 90 MeV. Comparison of theoretical predictions with the experimental data shows reasonable-to-good agreement. Results indicate that accelerator-based production of (225)Ac and (223)Ra below 200 MeV is a viable production method.

  5. Experimental study of ion-beam self-pinched transport for MeV protons

    SciTech Connect

    Neri, J.M.; Young, F.C.; Stephanakis, S.J.; Ottinger, P.F.; Rose, D.V.; Hinshelwood, D.D.; Weber, B.V.

    1999-07-01

    A 100-kA, 1.2-MeV proton beam from a pinch-reflex ion diode on the Gamble II accelerator is used to test the concept of self-pinched ion transport. Self-pinched transport (SPT) uses the self-generated magnetic field from the ion beam to radially confine the ion beam. A proton beam is injected through a 3-cm radius aperture covered with a 2-{micro}m thick polycarbonate foil into a 10-cm radius transport region. The transport region is filled with helium at pressures of 30--250 mTorr, vacuum (10{sup {minus}4} Torr), or 1-Torr air. The beam is diagnosed with witness plates, multiple-pinhole-camera imaging onto radiochromic film, time- and space-resolved proton-scattering, and with prompt-{gamma} and nuclear-activation from LiF targets. Witness-plates and the multiple-pinhole-camera are used to determine the size, location, and uniformity of the beam at different distances from the injection aperture. A beam global divergence of 200 mrad is measured at 15 cm. At 50 cm, the beam fills the transport region. At 110 cm and 100- to 200-mTorr helium, there is evidence of beam filamentation. The measured increase in protons is consistent with the physical picture for SPT, and comparisons with IPROP simulations are in qualitative agreement with the measurements.

  6. The R/D of high power proton accelerator technology in China

    NASA Astrophysics Data System (ADS)

    Xialing, Guan

    2002-12-01

    In China, a multipurpose verification system as a first phase of our ADS program consists of a low energy accelerator (150 MeV/3 mA proton LINAC) and a swimming pool light water subcritical reactor. In this paper the activities of HPPA technology related to ADS in China, which includes the intense proton ECR source, the RFQ accelerator and some other technology of HPPA, are described.

  7. Particle in cell simulation of laser-accelerated proton beams for radiation therapy.

    PubMed

    Fourkal, E; Shahine, B; Ding, M; Li, J S; Tajima, T; Ma, C M

    2002-12-01

    In this article we present the results of particle in cell (PIC) simulations of laser plasma interaction for proton acceleration for radiation therapy treatments. We show that under optimal interaction conditions protons can be accelerated up to relativistic energies of 300 MeV by a petawatt laser field. The proton acceleration is due to the dragging Coulomb force arising from charge separation induced by the ponderomotive pressure (light pressure) of high-intensity laser. The proton energy and phase space distribution functions obtained from the PIC simulations are used in the calculations of dose distributions using the GEANT Monte Carlo simulation code. Because of the broad energy and angular spectra of the protons, a compact particle selection and beam collimation system will be needed to generate small beams of polyenergetic protons for intensity modulated proton therapy.

  8. Study on strontium isotope abundance-ratio measurements by using a 13-MeV proton beam

    NASA Astrophysics Data System (ADS)

    Jeong, Cheol-Ki; Jang, Han; Lee, Goung-Jin

    2016-09-01

    The Rb-Sr dating method is used in dating Paleozoic and Precambrian rocks. This method measures the 87Rb and the 87Sr concentrations by using thermal ionization mass spectrometry (TIMS) [J. Hefne et al., Inter. J. Phys. Sci. 3(1), 28 (2008)]. In addition, it calculates the initial 87Sr/86Sr ratio to increase the reliability of Rb-Sr dating. In this study, the 87Sr/86Sr ratio was measured by using a 13-MeV proton accelerator. Proton kinetic energies are in the range of tens of megaelectronvolts, and protons have large absorption cross-sections for ( p, n) reactions with most substances. After absorbing a proton with such a high kinetic energy, an element is converted into a nuclide with its atomic number increased by one via nuclear transmutation. These nuclides usually have short half-lives and return to the original state through radioactive decay. When a strontium sample is irradiated with protons, nuclear transmutation occurs; thus, the strontium isotope present in the sample changes to a yttrium isotope, which is an activated radioisotope. Based on this, the 87Sr/86Sr ratio was calculated by analyzing the gamma-rays emitted by each yttrium isotope. The KIRAMS-13 cyclotron at the Cyclotron Center of Chosun University, where 13-MeV protons can be extracted, was utilized in our experiment. The 87Sr/86Sr isotope ratio was computed for samples irradiated with these protons, and the result was similar to the isotope ratio for the Standard Reference Material, i.e., 98.2 ± 3.4%. As part of the analysis, proton activation analyses were performed using 13-MeV protons, and the experimental results of this research suggest a possible approach for measuring the strontium-isotope abundance ratio of samples.

  9. High power solid state rf amplifier for proton accelerator.

    PubMed

    Jain, Akhilesh; Sharma, Deepak Kumar; Gupta, Alok Kumar; Hannurkar, P R

    2008-01-01

    A 1.5 kW solid state rf amplifier at 352 MHz has been developed and tested at RRCAT. This rf source for cw operation will be used as a part of rf system of 100 MeV proton linear accelerator. A rf power of 1.5 kW has been achieved by combining output power from eight 220 W rf amplifier modules. Amplifier modules, eight-way power combiner and divider, and directional coupler were designed indigenously for this development. High efficiency, ease of fabrication, and low cost are the main features of this design.

  10. 225Ac and 223Ra production via 800 MeV proton irradiation of natural thorium targets.

    PubMed

    Weidner, J W; Mashnik, S G; John, K D; Ballard, B; Birnbaum, E R; Bitteker, L J; Couture, A; Fassbender, M E; Goff, G S; Gritzo, R; Hemez, F M; Runde, W; Ullmann, J L; Wolfsberg, L E; Nortier, F M

    2012-11-01

    Cross sections for the formation of (225,227)Ac, (223,225)Ra, and (227)Th via the proton bombardment of natural thorium targets were measured at a nominal proton energy of 800 MeV. No earlier experimental cross section data for the production of (223,225)Ra, (227)Ac and (227)Th by this method were found in the literature. A comparison of theoretical predictions with the experimental data shows agreement within a factor of two. Results indicate that accelerator-based production of (225)Ac and (223)Ra is a viable production method.

  11. Interlock system for machine protection of the KOMAC 100-MeV proton linac

    NASA Astrophysics Data System (ADS)

    Song, Young-Gi

    2015-02-01

    The 100-MeV proton linear accelerator of the Korea Multi-purpose Accelerator Complex (KOMAC) has been developed. The beam service started this year after performing the beam commissioning. If the very sensitive and essential equipment is to be protected during machine operation, a machine interlock system is required, and the interlock system has been implemented. The purpose of the interlock system is to shut off the beam when the radio-frequency (RF) and ion source are unstable or a beam loss occurs. The interlock signal of the KOMAC linac includes a variety of sources, such as the beam loss, RF and high-voltage converter modulator faults, and fast closing valves of the vacuum window at the beam lines and so on. This system consists of a hardware-based interlock system using analog circuits and a software-based interlock system using an industrial programmable logic controller (PLC). The hardware-based interlock system has been fabricated, and the requirement has been satisfied with the results being within 10 µs. The software logic interlock system using the PLC has been connected to the framework of with the experimental physics and industrial control system (EPICS) to integrate a variety of interlock signals and to control the machine components when an interlock occurs. This paper will describe the design and the construction of the machine interlock system for the KOMAC 100-MeV linac.

  12. Resistively enhanced proton acceleration via high-intensity laser interactions with cold foil targets

    SciTech Connect

    Gibbon, Paul

    2005-08-01

    The acceleration of MeV protons by high-intensity laser interaction with foil targets is studied using a recently developed plasma simulation technique. Based on a hierarchical N-body tree algorithm, this method provides a natural means of treating three-dimensional, collisional transport effects hitherto neglected in conventional explicit particle-in-cell simulations. For targets with finite resistivity, hot electron transport is strongly inhibited, even at temperatures in the MeV range. This leads to suppression of ion acceleration from the rear of the target and an enhancement in energies and numbers of protons originating from the front.

  13. Microstructured snow targets for high energy quasi-monoenergetic proton acceleration

    NASA Astrophysics Data System (ADS)

    Schleifer, E.; Nahum, E.; Eisenmann, S.; Botton, M.; Baspaly, A.; Pomerantz, I.; Abricht, F.; Branzel, J.; Priebe, G.; Steinke, S.; Andreev, A.; Schnuerer, M.; Sandner, W.; Gordon, D.; Sprangle, P.; Ledingham, K. W. D.; Zigler, A.

    2013-05-01

    Compact size sources of high energy protons (50-200MeV) are expected to be key technology in a wide range of scientific applications 1-8. One promising approach is the Target Normal Sheath Acceleration (TNSA) scheme 9,10, holding record level of 67MeV protons generated by a peta-Watt laser 11. In general, laser intensity exceeding 1018 W/cm2 is required to produce MeV level protons. Another approach is the Break-Out Afterburner (BOA) scheme which is a more efficient acceleration scheme but requires an extremely clean pulse with contrast ratio of above 10-10. Increasing the energy of the accelerated protons using modest energy laser sources is a very attractive task nowadays. Recently, nano-scale targets were used to accelerate ions 12,13 but no significant enhancement of the accelerated proton energy was measured. Here we report on the generation of up to 20MeV by a modest (5TW) laser system interacting with a microstructured snow target deposited on a Sapphire substrate. This scheme relax also the requirement of high contrast ratio between the pulse and the pre-pulse, where the latter produces the highly structured plasma essential for the interaction process. The plasma near the tip of the snow target is subject to locally enhanced laser intensity with high spatial gradients, and enhanced charge separation is obtained. Electrostatic fields of extremely high intensities are produced, and protons are accelerated to MeV-level energies. PIC simulations of this targets reproduce the experimentally measured energy scaling and predict the generation of 150 MeV protons from laser power of 100TW laser system18.

  14. Proton Acceleration at Oblique Shocks

    NASA Astrophysics Data System (ADS)

    Galinsky, V. L.; Shevchenko, V. I.

    2011-06-01

    Acceleration at the shock waves propagating oblique to the magnetic field is studied using a recently developed theoretical/numerical model. The model assumes that resonant hydromagnetic wave-particle interaction is the most important physical mechanism relevant to motion and acceleration of particles as well as to excitation and damping of waves. The treatment of plasma and waves is self-consistent and time dependent. The model uses conservation laws and resonance conditions to find where waves will be generated or damped, and hence particles will be pitch-angle-scattered. The total distribution is included in the model and neither introduction of separate population of seed particles nor some ad hoc escape rate of accelerated particles is needed. Results of the study show agreement with diffusive shock acceleration models in the prediction of power spectra for accelerated particles in the upstream region. However, they also reveal the presence of spectral break in the high-energy part of the spectra. The role of the second-order Fermi-like acceleration at the initial stage of the acceleration is discussed. The test case used in the paper is based on ISEE-3 data collected for the shock of 1978 November 12.

  15. PROTON ACCELERATION AT OBLIQUE SHOCKS

    SciTech Connect

    Galinsky, V. L.; Shevchenko, V. I.

    2011-06-20

    Acceleration at the shock waves propagating oblique to the magnetic field is studied using a recently developed theoretical/numerical model. The model assumes that resonant hydromagnetic wave-particle interaction is the most important physical mechanism relevant to motion and acceleration of particles as well as to excitation and damping of waves. The treatment of plasma and waves is self-consistent and time dependent. The model uses conservation laws and resonance conditions to find where waves will be generated or damped, and hence particles will be pitch-angle-scattered. The total distribution is included in the model and neither introduction of separate population of seed particles nor some ad hoc escape rate of accelerated particles is needed. Results of the study show agreement with diffusive shock acceleration models in the prediction of power spectra for accelerated particles in the upstream region. However, they also reveal the presence of spectral break in the high-energy part of the spectra. The role of the second-order Fermi-like acceleration at the initial stage of the acceleration is discussed. The test case used in the paper is based on ISEE-3 data collected for the shock of 1978 November 12.

  16. Two-stage acceleration of protons from relativistic laser-solid interaction

    SciTech Connect

    Liu Jinlu; Sheng, Z. M.; Zheng, J.; Wang, W. M.; Yu, M. Y.; Liu, C. S.; Zhang, J.

    2012-12-21

    A two-stage proton acceleration scheme using present-day intense lasers and a unique target design is proposed. The target system consists of a hollow cylinder, inside which is a hollow cone, which is followed by the main target with a flat front and dish-like flared rear surface. At the center of the latter is a tapered proton layer, which is surrounded by outer proton layers at an angle to it. In the first acceleration stage, protons in both layers are accelerated by target normal sheath acceleration. The center-layer protons are accelerated forward along the axis and the side protons are accelerated and focused towards them. As a result, the side-layer protons radially compress as well as axially further accelerate the front part of the accelerating center-layer protons in the second stage, which are also radially confined and guided by the field of the fast electrons surrounding them. Two-dimensional particle-incell simulation shows that a 79fs 8.5 Multiplication-Sign 10{sup 20} W/cm{sup 2} laser pulse can produce a proton bunch with {approx} 267MeV maximum energy and {approx} 9.5% energy spread, which may find many applications, including cancer therapy.

  17. Applications of High Intensity Proton Accelerators

    NASA Astrophysics Data System (ADS)

    Raja, Rajendran; Mishra, Shekhar

    2010-06-01

    Superconducting radiofrequency linac development at Fermilab / S. D. Holmes -- Rare muon decay experiments / Y. Kuno -- Rare kaon decays / D. Bryman -- Muon collider / R. B. Palmer -- Neutrino factories / S. Geer -- ADS and its potential / J.-P. Revol -- ADS history in the USA / R. L. Sheffield and E. J. Pitcher -- Accelerator driven transmutation of waste: high power accelerator for the European ADS demonstrator / J. L. Biarrotte and T. Junquera -- Myrrha, technology development for the realisation of ADS in EU: current status & prospects for realisation / R. Fernandez ... [et al.] -- High intensity proton beam production with cyclotrons / J. Grillenberger and M. Seidel -- FFAG for high intensity proton accelerator / Y. Mori -- Kaon yields for 2 to 8 GeV proton beams / K. K. Gudima, N. V. Mokhov and S. I. Striganov -- Pion yield studies for proton driver beams of 2-8 GeV kinetic energy for stopped muon and low-energy muon decay experiments / S. I. Striganov -- J-Parc accelerator status and future plans / H. Kobayashi -- Simulation and verification of DPA in materials / N. V. Mokhov, I. L. Rakhno and S. I. Striganov -- Performance and operational experience of the CNGS facility / E. Gschwendtner -- Particle physics enabled with super-conducting RF technology - summary of working group 1 / D. Jaffe and R. Tschirhart -- Proton beam requirements for a neutrino factory and muon collider / M. S. Zisman -- Proton bunching options / R. B. Palmer -- CW SRF H linac as a proton driver for muon colliders and neutrino factories / M. Popovic, C. M. Ankenbrandt and R. P. Johnson -- Rapid cycling synchrotron option for Project X / W. Chou -- Linac-based proton driver for a neutrino factory / R. Garoby ... [et al.] -- Pion production for neutrino factories and muon colliders / N. V. Mokhov ... [et al.] -- Proton bunch compression strategies / V. Lebedev -- Accelerator test facility for muon collider and neutrino factory R&D / V. Shiltsev -- The superconducting RF linac for muon

  18. Improvement Plans of Fermilab's Proton Accelerator Complex

    SciTech Connect

    Shiltsev, Vladimir

    2016-01-01

    The flagship of Fermilab's long term research program is the Deep Underground Neutrino Experiment (DUNE), located Sanford Underground Research Facility (SURF) in Lead, South Dakota, which will study neutrino oscillations with a baseline of 1300 km. The neutrinos will be produced in the Long Baseline Neutrino Facility (LBNF), a proposed new beam line from Fermilab's Main Injector. The physics goals of the DUNE require a proton beam with a power of some 2.4 MW at 120 GeV, which is roughly four times the current maximum power. Here I discuss current performance of the Fermilab proton accelerator complex, our plans for construction of the SRF proton linac as key part of the Proton Improvement Plan-II (PIP-II), outline the main challenges toward multi-MW beam power operation of the Fermilab accelerator complex and the staged plan to achieve the required performance over the next 15 years.

  19. Neutrino mixing in accelerated proton decays

    NASA Astrophysics Data System (ADS)

    Ahluwalia, Dharam Vir; Labun, Lance; Torrieri, Giorgio

    2016-07-01

    We discuss the inverse β-decay of accelerated protons in the context of neutrino flavor superpositions (mixings) in mass eigenstates. The process p→ n ℓ+ ν_{ℓ} is kinematically allowed because the accelerating field provides the rest energy difference between initial and final states. The rate of p→ n conversions can be evaluated in either the laboratory frame (where the proton is accelerating) or the co-moving frame (where the proton is at rest and interacts with an effective thermal bath of ℓ and ν_{ℓ} due to the Unruh effect). By explicit calculation, we show that the rates in the two frames disagree when taking into account neutrino mixings, because the weak interaction couples to charge eigenstates whereas gravity couples to neutrino mass eigenstates (D.V. Ahluwalia et al., arXiv:1505.04082 [hep-ph]). The contradiction could be resolved experimentally, potentially yielding new information on the origins of neutrino masses.

  20. Design study for a 500 MeV proton synchrotron with CSNS linac as an injector

    NASA Astrophysics Data System (ADS)

    Huang, Liang-Sheng; Ji, Hong-Fei; Wang, Sheng

    2016-09-01

    Using the China Spallation Neutron Source (CSNS) linac as the injector, a 500 MeV proton synchrotron is proposed for multidisciplinary applications, such as biology, material science and proton therapy. The synchrotron will deliver proton beam with energy from 80 MeV to 500 MeV. A compact lattice design has been worked out, and all the important beam dynamics issues have been investigated. The 80 MeV H- beam is stripped and injected into the synchrotron by using multi-turn injection. In order to continuously extraction the proton with small beam loss, an achromatic structure is proposed and a slow extraction method with RF knock-out is adopted and optimized.

  1. Injection and diffusive transport of suprathermal through energetic solar flare protons (35 keV to 20 MeV)

    NASA Technical Reports Server (NTRS)

    Beeck, J.; Mason, G. M.; Hamilton, D. C.; Marsden, R. G.; Sanderson, T. R.

    1990-01-01

    Consideration is given to the injection and interplanetary propagation of low-energy protons caused by the solar particle event of July 20, 1981, in which flare protons in the range from 35 keV to 20 MeV were observed by instruments on ISEE 3. The observed time-intensity and time-anisotropy profiles were fitted over the entire energy range using a model based on the spherically symmetric Fokker-Plank equation, including convection, diffusion, and adiabatic deceleration. The results are used to discuss the behavior of the radial interplanetary diffusion coefficient and the scattering mean free path for protons. Also, evidence is found for diffusive coronal shock acceleration of protons during the event.

  2. Post-acceleration of laser driven protons with a compact high field linac

    NASA Astrophysics Data System (ADS)

    Sinigardi, Stefano; Londrillo, Pasquale; Rossi, Francesco; Turchetti, Giorgio; Bolton, Paul R.

    2013-05-01

    We present a start-to-end 3D numerical simulation of a hybrid scheme for the acceleration of protons. The scheme is based on a first stage laser acceleration, followed by a transport line with a solenoid or a multiplet of quadrupoles, and then a post-acceleration section in a compact linac. Our simulations show that from a laser accelerated proton bunch with energy selection at ~ 30MeV, it is possible to obtain a high quality monochromatic beam of 60MeV with intensity at the threshold of interest for medical use. In the present day experiments using solid targets, the TNSA mechanism describes accelerated bunches with an exponential energy spectrum up to a cut-off value typically below ~ 60MeV and wide angular distribution. At the cut-off energy, the number of protons to be collimated and post-accelerated in a hybrid scheme are still too low. We investigate laser-plasma acceleration to improve the quality and number of the injected protons at ~ 30MeV in order to assure efficient post-acceleration in the hybrid scheme. The results are obtained with 3D PIC simulations using a code where optical acceleration with over-dense targets, transport and post-acceleration in a linac can all be investigated in an integrated framework. The high intensity experiments at Nara are taken as a reference benchmarks for our virtual laboratory. If experimentally confirmed, a hybrid scheme could be the core of a medium sized infrastructure for medical research, capable of producing protons for therapy and x-rays for diagnosis, which complements the development of all optical systems.

  3. AWAKE, The Advanced Proton Driven Plasma Wakefield Acceleration Experiment at CERN

    NASA Astrophysics Data System (ADS)

    Gschwendtner, E.; Adli, E.; Amorim, L.; Apsimon, R.; Assmann, R.; Bachmann, A.-M.; Batsch, F.; Bauche, J.; Berglyd Olsen, V. K.; Bernardini, M.; Bingham, R.; Biskup, B.; Bohl, T.; Bracco, C.; Burrows, P. N.; Burt, G.; Buttenschön, B.; Butterworth, A.; Caldwell, A.; Cascella, M.; Chevallay, E.; Cipiccia, S.; Damerau, H.; Deacon, L.; Dirksen, P.; Doebert, S.; Dorda, U.; Farmer, J.; Fedosseev, V.; Feldbaumer, E.; Fiorito, R.; Fonseca, R.; Friebel, F.; Gorn, A. A.; Grulke, O.; Hansen, J.; Hessler, C.; Hofle, W.; Holloway, J.; Hüther, M.; Jaroszynski, D.; Jensen, L.; Jolly, S.; Joulaei, A.; Kasim, M.; Keeble, F.; Li, Y.; Liu, S.; Lopes, N.; Lotov, K. V.; Mandry, S.; Martorelli, R.; Martyanov, M.; Mazzoni, S.; Mete, O.; Minakov, V. A.; Mitchell, J.; Moody, J.; Muggli, P.; Najmudin, Z.; Norreys, P.; Öz, E.; Pardons, A.; Pepitone, K.; Petrenko, A.; Plyushchev, G.; Pukhov, A.; Rieger, K.; Ruhl, H.; Salveter, F.; Savard, N.; Schmidt, J.; Seryi, A.; Shaposhnikova, E.; Sheng, Z. M.; Sherwood, P.; Silva, L.; Soby, L.; Sosedkin, A. P.; Spitsyn, R. I.; Trines, R.; Tuev, P. V.; Turner, M.; Verzilov, V.; Vieira, J.; Vincke, H.; Wei, Y.; Welsch, C. P.; Wing, M.; Xia, G.; Zhang, H.

    2016-09-01

    The Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) aims at studying plasma wakefield generation and electron acceleration driven by proton bunches. It is a proof-of-principle R&D experiment at CERN and the world's first proton driven plasma wakefield acceleration experiment. The AWAKE experiment will be installed in the former CNGS facility and uses the 400 GeV/c proton beam bunches from the SPS. The first experiments will focus on the self-modulation instability of the long (rms 12 cm) proton bunch in the plasma. These experiments are planned for the end of 2016. Later, in 2017/2018, low energy ( 15 MeV) electrons will be externally injected into the sample wakefields and be accelerated beyond 1 GeV. The main goals of the experiment will be summarized. A summary of the AWAKE design and construction status will be presented.

  4. Polarized Proton Acceleration in AGS and RHIC

    SciTech Connect

    Roser, Thomas

    2008-02-06

    As the first hadron accelerator and collider consisting of two independent superconducting rings RHIC has operated with a wide range of beam energies and particle species including polarized proton beams. The acceleration of polarized beams in both the injector and the collider rings is complicated by numerous depolarizing spin resonances. Partial and full Siberian snakes have made it possible to overcome the depolarization and beam polarizations of up to 65% have been reached at 100 GeV in RHIC.

  5. POLARIZED PROTON ACCELERATION IN AGS AND RHIC.

    SciTech Connect

    ROSER,T.

    2007-09-10

    As the first hadron accelerator and collider consisting of two independent superconducting rings RHIC has operated with a wide range of beam energies and particle species including polarized proton beams. The acceleration of polarized beams in both the injector and the collider rings is complicated by numerous depolarizing spin resonances. Partial and full Siberian snakes have made it possible to overcome the depolarization and beam polarizations of up to 65% have been reached at 100 GeV in RHIC.

  6. Proton Injection into the Fermilab Integrable Optics Test Accelerator (IOTA)

    SciTech Connect

    Prebys, Eric; Antipov, Sergey; Piekarz, Henryk; Valishev, A.

    2015-06-01

    The Integrable Optics Test Accelerator (IOTA) is an experimental synchrotron being built at Fermilab to test the concept of non-linear "integrable optics". These optics are based on a lattice including non-linear elements that satisfies particular conditions on the Hamiltonian. The resulting particle motion is predicted to be stable but without a unique tune. The system is therefore insensitive to resonant instabilities and can in principle store very intense beams, with space charge tune shifts larger than those which are possible in conventional linear synchrotrons. The ring will initially be tested with pencil electron beams, but this poster describes the ultimate plan to install a 2.5 MeV RFQ to inject protons, which will produce tune shifts on the order of unity. Technical details will be presented, as well as simulations of protons in the ring.

  7. Ultrashort Pulse Laser Accelerated Proton Beams for First Radiobiological Applications

    SciTech Connect

    Schramm, U.; Zeil, K.; Beyreuther, E.; Bussmann, M.; Cowan, T. E.; Kluge, T.; Kraft, S.; Metzkes, J.; Sauerbrey, R.; Richter, C.; Enghardt, W.; Pawelke, J.; Karsch, L.; Laschinsky, L.; Naumburger, D.

    2010-11-04

    We report on the generation of proton pulses with maximum energies exceeding 15 MeV by means of the irradiation of few micron thick metal foils by ultrashort (30 fs) laser pulses at a power level of 100 TW. In contrast to the well known situation for longer laser pulses, here, a near linear scaling of the maximum proton energy with laser power can be found. Aiming for radiobiological applications the long and short term stability of the laser plasma accelerator as well as a compact energy selection and dosimetry system is presented. The first irradiation of in vitro tumour cells showing dose dependent biological damage is demonstrated paving the way for systematic radiobiological studies.

  8. CHALLENGES FACING HIGH POWER PROTON ACCELERATORS

    SciTech Connect

    Plum, Michael A

    2013-01-01

    This presentation will provide an overview of the challenges of high power proton accelerators such as SNS, J-PARC, etc., and what we have learned from recent experiences. Beam loss mechanisms and methods to mitigate beam loss will also be discussed.

  9. Rf cavity primer for cyclic proton accelerators

    SciTech Connect

    Griffin, J.E.

    1988-04-01

    The purpose of this note is to describe the electrical and mechanical properites of particle accelerator rf cavities in a manner which will be useful to physics and engineering graduates entering the accelerator field. The discussion will be limited to proton (or antiproton) synchrotron accelerators or storage rings operating roughly in the range of 20 to 200 MHz. The very high gradient, fixed frequency UHF or microwave devices appropriate for electron machines and the somewhat lower frequency and broader bandwidth devices required for heavy ion accelerators are discussed extensively in other papers in this series. While it is common pratice to employ field calculation programs such as SUPERFISH, URMEL, or MAFIA as design aids in the development of rf cavities, we attempt here to elucidate various of the design parameters commonly dealt with in proton machines through the use of simple standing wave coaxial resonator expressions. In so doing, we treat only standing wave structures. Although low-impedance, moderately broad pass-band travelling wave accelerating systems are used in the CERN SPS, such systems are more commonly found in linacs, and they have not been used widely in large cyclic accelerators. Two appendices providing useful supporting material regarding relativistic particle dynamics and synchrotron motion in cyclic accelerators are added to supplement the text.

  10. COMPACT PROTON INJECTOR AND FIRST ACCELERATOR SYSTEM TEST FOR COMPACT PROTON DIELECTRIC WALL CANCER THERAPY ACCELERATOR

    SciTech Connect

    Chen, Y; Guethlein, G; Caporaso, G; Sampayan, S; Blackfield, D; Cook, E; Falabella, S; Harris, J; Hawkins, S; Nelson, S; Poole, B; Richardson, R; Watson, J; Weir, J; Pearson, D

    2009-04-23

    A compact proton accelerator for cancer treatment is being developed by using the high-gradient dielectric insulator wall (DWA) technology [1-4]. We are testing all the essential DWA components, including a compact proton source, on the First Article System Test (FAST). The configuration and progress on the injector and FAST will be presented.

  11. Proton acceleration from magnetized overdense plasmas

    NASA Astrophysics Data System (ADS)

    Kuri, Deep Kumar; Das, Nilakshi; Patel, Kartik

    2017-01-01

    Proton acceleration by an ultraintense short pulse circularly polarized laser from an overdense three dimensional (3D) particle-in-cell (PIC) 3D-PIC simulations. The axial magnetic field modifies the dielectric constant of the plasma, which causes a difference in the behaviour of ponderomotive force in case of left and right circularly polarized laser pulse. When the laser is right circularly polarized, the ponderomotive force gets enhanced due to cyclotron effects generating high energetic electrons, which, on reaching the target rear side accelerates the protons via target normal sheath acceleration process. On the other hand, in case of left circular polarization, the effects get reversed causing a suppression of the ponderomotive force at a short distance and lead towards a rise in the radiation pressure, which results in the effective formation of laser piston. Thus, the axial magnetic field enhances the effect of radiation pressure in case of left circularly polarized laser resulting in the generation of high energetic protons at the target front side. The transverse motion of protons get reduced as they gyrate around the axial magnetic field which increases the beam collimation to some extent. The optimum thickness of the overdense plasma target is found to be increased in the presence of an axial magnetic field.

  12. Capture and Transport of Laser Accelerated Protons by Pulsed Magnetic Fields: Advancements Toward Laser-Based Proton Therapy

    NASA Astrophysics Data System (ADS)

    Burris-Mog, Trevor J.

    The interaction of intense laser light (I > 10 18 W/cm2) with a thin target foil leads to the Target Normal Sheath Acceleration mechanism (TNSA). TNSA is responsible for the generation of high current, ultra-low emittance proton beams, which may allow for the development of a compact and cost effective proton therapy system for the treatment of cancer. Before this application can be realized, control is needed over the large divergence and the 100% kinetic energy spread that are characteristic of TNSA proton beams. The work presented here demonstrates control over the divergence and energy spread using strong magnetic fields generated by a pulse power solenoid. The solenoidal field results in a parallel proton beam with a kinetic energy spread DeltaE/E = 10%. Assuming that next generation lasers will be able to operate at 10 Hz, the 10% spread in the kinetic energy along with the 23% capture efficiency of the solenoid yield enough protons per laser pulse to, for the first time, consider applications in Radiation Oncology. Current lasers can generate proton beams with kinetic energies up to 67.5 MeV, but for therapy applications, the proton kinetic energy must reach 250 MeV. Since the maximum kinetic energy Emax of the proton scales with laser light intensity as Emax ∝ I0.5, next generation lasers may very well accelerate 250 MeV protons. As the kinetic energy of the protons is increased, the magnetic field strength of the solenoid will need to increase. The scaling of the magnetic field B with the kinetic energy of the protons follows B ∝ E1/2. Therefor, the field strength of the solenoid presented in this work will need to be increased by a factor of 2.4 in order to accommodate 250 MeV protons. This scaling factor seems reasonable, even with present technology. This work not only demonstrates control over beam divergence and energy spread, it also allows for us to now perform feasibility studies to further research what a laser-based proton therapy system

  13. COMPACT ACCELERATOR CONCEPT FOR PROTON THERAPY

    SciTech Connect

    Caporaso, G; Sampayan, S; Chen, Y; Harris, J; Hawkins, S; Holmes, C; Krogh, M; Nelson, S; Nunnally, W; Paul, A; Poole, B; Rhodes, M; Sanders, D; Selenes, K; Sullivan, J; Wang, L; Watson, J

    2006-08-18

    A new type of compact induction accelerator is under development at the Lawrence Livermore National Laboratory that promises to increase the average accelerating gradient by at least an order of magnitude over that of existing induction machines. The machine is based on the use of high gradient vacuum insulators, advanced dielectric materials and switches and is being developed as a compact flash x-ray radiography source. Research describing an extreme variant of this technology aimed at proton therapy for cancer will be presented.

  14. Emittance growth mechanisms for laser-accelerated proton beams.

    PubMed

    Kemp, Andreas J; Fuchs, J; Sentoku, Y; Sotnikov, V; Bakeman, M; Antici, P; Cowan, T E

    2007-05-01

    In recent experiments the transverse normalized rms emittance of laser-accelerated MeV ion beams was found to be < 0.002 mm mrad, which is at least 100 times smaller than the emittance of thermal ion sources used in accelerators [T. E. Cowan, Phys. Rev. Lett. 92, 204801 (2004)]. We investigate the origin for the low emittance of laser-accelerated proton beams by studying several candidates for emittance-growth mechanisms. As our main tools, we use analytical models and one- and two-dimensional particle-in-cell simulations that have been modified to include binary collisions between particles. We find that the dominant source of emittance is filamentation of the laser-generated hot electron jets that drive the ion acceleration. Cold electron-ion collisions that occur before ions are accelerated contribute less than ten percent of the final emittance. Our results are in qualitative agreement with the experiment, for which we present a refined analysis relating emittance to temperature, a better representative of the fundamental beam physics.

  15. Polarization measurement of laser-accelerated protons

    SciTech Connect

    Raab, Natascha; Engels, Ralf; Engin, Ilhan; Greven, Patrick; Holler, Astrid; Lehrach, Andreas; Maier, Rudolf; Büscher, Markus; Cerchez, Mirela; Swantusch, Marco; Toncian, Monika; Toncian, Toma; Willi, Oswald; Gibbon, Paul; Karmakar, Anupam

    2014-02-15

    We report on the successful use of a laser-driven few-MeV proton source to measure the differential cross section of a hadronic scattering reaction as well as on the measurement and simulation study of polarization observables of the laser-accelerated charged particle beams. These investigations were carried out with thin foil targets, illuminated by 100 TW laser pulses at the Arcturus laser facility; the polarization measurement is based on the spin dependence of hadronic proton scattering off nuclei in a Silicon target. We find proton beam polarizations consistent with zero magnitude which indicates that for these particular laser-target parameters the particle spins are not aligned by the strong magnetic fields inside the laser-generated plasmas.

  16. Design of a 10 MeV normal conducting CW proton linac based on equidistant multi-gap CH cavities

    NASA Astrophysics Data System (ADS)

    Li, Zhi-Hui

    2015-09-01

    Continuous wave (CW) high current proton linacs have wide applications as the front end of high power proton machines. The low energy part of such a linac is the most difficult and there is currently no widely accepted solution. Based on the analysis of the focusing properties of the CW low energy proton linac, a 10 MeV low energy normal conducting proton linac based on equidistant seven-gap Cross-bar H-type (CH) cavities is proposed. The linac is composed of ten 7-gap CH cavities and the transverse focusing is maintained by quadrupole doublets located between the cavities. The total length of the linac is less than 6 meters and the average acceleration gradient is about 1.2 MeV/m. The electromagnetic properties of the cavities are investigated by Microwave Studio. At the nominal acceleration gradient the maximum surface electric field in the cavities is less than 1.3 times the Kilpatrick limit, and the Ohmic loss of each cavity is less than 35 kW. Multi-particle beam dynamics simulations are performed with Tracewin code, and the results show that the beam dynamics of the linac are quite stable, the linac has the capability to accelerate up to 30 mA beam with acceptable dynamics behavior. Supported by National Natural Science Foundation of China (11375122, 91126003)

  17. 25 MeV Solar Proton Events in Cycle 24 and Previous Cycles

    NASA Astrophysics Data System (ADS)

    Richardson, I. G.; Cane, H. V.; von Rosenvinge, T. T.

    2014-12-01

    We summarize observations of nearly 1000 solar energetic particle events that include 25 MeV protons made by Goddard instruments on various spacecraft (IMPs IV, V, 7, 8, ISEE-3) and by other instruments on SOHO, since 1967, encompassing solar cycles 20 to 24. We also include recent observations of such events from the STEREO spacecraft. These extended observations place studies focusing on Cycles 23 and 24 in a broader context. For example, the time distribution of 25 MeV proton events varies from cycle to cycle such that each cycle is unique. In the current cycle, ~25 MeV proton events were absent during the preceding solar minimum, whereas earlier minima showed occasional, often reasonably intense events, and there have been, so far, fewer exceptionally intense events compared to Cycles 22 and 23, though Cycle 21 also apparently lacked such events.

  18. Neutron production by a 13C thick target irradiated by 20 90 MeV protons

    NASA Astrophysics Data System (ADS)

    Lhersonneau, G.; Malkiewicz, T.; Vakhtin, D.; Plokhoi, V.; Alyakrinskiy, O.; Barbui, M.; Brandenburg, S.; Dendooven, P.; Cinausero, M.; Kandiev, Ya.; Kettunen, H.; Khlebnikov, S.; Lyapin, V.; Penttilä, H.; Prete, G.; Rizzi, V.; Samarin, S.; Tecchio, L. B.; Trzaska, W. H.; Tyurin, G.

    2008-10-01

    Neutron production using an enriched 13C carbon converter has been measured during the design study of the italian RIB facility SPES. Energy and angular distributions of neutrons emitted by bombarding a 13C target of stopping length with protons in the range of 20 to 90 MeV have been measured by time-of-flight and activation and compared with the prediction of a Monte Carlo code developed at Snezhinsk. At the proton energy of 100 MeV, firstly envisaged for SPES, the gain with respect to a natural C target is less than a factor of two, while yields still compare well with those for 40 MeV deuterons on natural carbon adopted by SPIRAL-II. At energies near 30 MeV the 13C thick target is definitely more prolific than the target of natural carbon, but both yields with protons are clearly lower than the one with deuterons. At the energy of 20 MeV envisaged for a first stage of SPES it might be more efficient to irradiate the uranium target with protons rather than using the two-stage method with converter.

  19. Advanced polymer targets for TNSA regime producing 6 MeV protons at 1016 W/cm2 laser intensity

    NASA Astrophysics Data System (ADS)

    Torrisi, L.

    2017-02-01

    High intensity laser pulses, at an intensity of the order of 1016 W/cm2, are employed to irradiate in vacuum polyethylene terephthalate thin foils in the target normal sheath acceleration (TNSA) regime. The plasma obtained in the forward emission is investigated using ion collectors and semiconductor detectors connected in a time-of-flight configuration, Thomson parabola spectrometer, and X-ray streak camera. The results indicate that the foil thickness of 1 micron is optimal to accelerate protons of up to 6.5 MeV. The high ion acceleration can be due to different effects such as the high absorption in the advanced semicrystalline polymer containing spherulite centers, the high resonant absorption in gold nanoparticles embedded in the polymer, the optimal thickness of the used polymer to enhance the electron density in the forward plasma, and the self-focusing effect induced by preplasma created in front of the irradiated target.

  20. Inelastic scattering of 61 MeV protons by pb-207

    NASA Technical Reports Server (NTRS)

    Owais, M.

    1976-01-01

    Differential cross sections for the excitation of the first four neutron-hole states and the doublet at 2.61 MeV by 61.2 MeV protons were measured. The data are analyzed in terms of both a purely collective model description and a microscopic model supplemented by macroscopic core polarization. A realistic two-body interaction is used and knock-on amplitudes are included. Core polarization is found to be important but represents a relatively smaller contribution than in most nuclei previously studied. A parallel analysis of similar data at lower proton bombarding energies reveals a surprisingly strong energy dependence of the reaction mechanisms.

  1. Radiation shielding for 250 MeV protons

    SciTech Connect

    Awschalom, M.

    1987-04-01

    This paper is targetted at personnel who have the responsibility of designing the radiation shielding against neutron fluences created when protons interact with matter. Shielding of walls and roofs are discussed, as well as neutron dose leakage through labyrinths. Experimental data on neutron flux attenuation are considered, as well as some calculations using the intranuclear cascade calculations and parameterizations.

  2. 1000 MeV Proton beam therapy facility at Petersburg Nuclear Physics Institute Synchrocyclotron

    NASA Astrophysics Data System (ADS)

    Abrosimov, N. K.; Gavrikov, Yu A.; Ivanov, E. M.; Karlin, D. L.; Khanzadeev, A. V.; Yalynych, N. N.; Riabov, G. A.; Seliverstov, D. M.; Vinogradov, V. M.

    2006-05-01

    Since 1975 proton beam of PNPI synchrocyclotron with fixed energy of 1000 MeV is used for the stereotaxic proton therapy of different head brain diseases. 1300 patients have been treated during this time. The advantage of high energy beam (1000 MeV) is low scattering of protons in the irradiated tissue. This factor allows to form the dose field with high edge gradients (20%/mm) that is especially important for the irradiation of the intra-cranium targets placed in immediate proximity to the life critical parts of the brain. Fixation of the 6 0mm diameter proton beam at the isodose centre with accuracy of ±1.0 mm, two-dimensional rotation technique of the irradiation provide a very high ratio of the dose in the irradiation zone to the dose at the object's surface equal to 200:1. The absorbed doses are: 120-150 Gy for normal hypophysis, 100-120 Gy for pituitary adenomas and 40-70 Gy for arterio-venous malformation at the rate of absorbed dose up to 50 Gy/min. In the paper the dynamics and the efficiency of 1000 MeV proton therapy treatment of the brain deceases are given. At present time the feasibility study is in progress with the goal to create a proton therapy on Bragg peak by means of the moderation of 1000 MeV proton beam in the absorber down to 200 MeV, energy required for radiotherapy of deep seated tumors.

  3. Beam collimation and energy spectrum compression of laser-accelerated proton beams using solenoid field and RF cavity

    NASA Astrophysics Data System (ADS)

    Teng, J.; Gu, Y. Q.; Zhu, B.; Hong, W.; Zhao, Z. Q.; Zhou, W. M.; Cao, L. F.

    2013-11-01

    This paper presents a new method of laser produced proton beam collimation and spectrum compression using a combination of a solenoid field and a RF cavity. The solenoid collects laser-driven protons efficiently within an angle that is smaller than 12 degrees because it is mounted few millimeters from the target, and collimates protons with energies around 2.3 MeV. The collimated proton beam then passes through a RF cavity to allow compression of the spectrum. Particle-in-cell (PIC) simulations demonstrate the proton beam transport in the solenoid and RF electric fields. Excellent energy compression and collection efficiency of protons are presented. This method for proton beam optimization is suitable for high repetition-rate laser acceleration proton beams, which could be used as an injector for a conventional proton accelerator.

  4. Laser Acceleration of Quasi-Monoenergetic Protons via Radiation Pressure Driven Thin Foil

    SciTech Connect

    Liu, Chuan S.; Shao Xi; Liu, T. C.; Dudnikova, Galina; Sagdeev, Roald Z.; Eliasson, Bengt

    2011-01-04

    We present a theoretical and simulation study of laser acceleration of quasi-monoenergetic protons in a thin foil irradiated by high intensity laser light. The underlying physics of radiation pressure acceleration (RPA) is discussed, including the importance of optimal thickness and circularly polarized light for efficient acceleration of ions to quasi-monoenergetic beams. Preliminary two-dimensional simulation studies show that certain parameter regimes allow for stabilization of the Rayleigh-Taylor instability and possibility of acceleration of monoenergetic ions to an excess of 200 MeV, making them suitable for important applications such as medical cancer therapy and fast ignition.

  5. Neutron yield from a thick 13C target irradiated by 90 MeV protons

    NASA Astrophysics Data System (ADS)

    Alyakrinskiy, O.; Andrighetto, A.; Barbui, M.; Brandenburg, S.; Cinausero, M.; Dalena, B.; Dendooven, P.; Fioretto, E.; Lhersonneau, G.; Lyapin, W.; Prete, G.; Simonetti, G.; Stroe, L.; Tecchio, L. B.; Trzaska, W. H.

    2005-08-01

    In the context of the design of an intense source of low and intermediate energy neutrons, the angular and energy distributions of neutrons produced in the interaction of 90 MeV protons in a 13C target, in which the protons are stopped, have been measured by time-of-flight and activation techniques. As compared to 12C the yield is less than a factor two higher, while it is somewhat less than for a 9Be target.

  6. ACCELERATING POLARIZED PROTONS TO 250 GEV

    SciTech Connect

    BAI,M.; AHRENS, L.; ALEKSEEV, I.G.; ALESSI, J.; BEEBE-WANG, J.; ET AL.

    2007-06-25

    The Relativistic Heavy Ion Collider (RHIC) as the first high energy polarized proton collider was designed t o provide polarized proton collisions a t a maximum beam energy of 250 GeV. I t has been providing collisions a t a beam energy of 100 Gel' since 2001. Equipped with two full Siberian snakes in each ring, polarization is preserved during the acceleration from injection to 100 GeV with careful control of the betatron tunes and the vertical orbit distortions. However, the intrinsic spin resonances beyond 100 GeV are about a factor of two stronger than those below 100 GeV? making it important t o examine the impact of these strong intrinsic spin resonances on polarization survival and the tolerance for vertical orbit distortions. Polarized protons were accelerated t o the record energy of 250 GeV in RHIC with a polarization of 46% measured a t top energy in 2006. The polarization measurement as a function of beam energy also shows some polarization loss around 136 GeV, the first strong intrinsic resonance above 100 GeV. This paper presents the results and discusses the sensitivity of the polarization survival t o orbit distortions.

  7. Laser-accelerated proton conversion efficiency thickness scaling

    SciTech Connect

    Hey, D. S.; Foord, M. E.; Key, M. H.; LePape, S. L.; Mackinnon, A. J.; Patel, P. K.; Ping, Y.; Akli, K. U.; Stephens, R. B.; Bartal, T.; Beg, F. N.; Fedosejevs, R.; Friesen, H.; Tiedje, H. F.; Tsui, Y. Y.

    2009-12-15

    The conversion efficiency from laser energy into proton kinetic energy is measured with the 0.6 ps, 9x10{sup 19} W/cm{sup 2} Titan laser at the Jupiter Laser Facility as a function of target thickness in Au foils. For targets thicker than 20 {mu}m, the conversion efficiency scales approximately as 1/L, where L is the target thickness. This is explained by the domination of hot electron collisional losses over adiabatic cooling. In thinner targets, the two effects become comparable, causing the conversion efficiency to scale weaker than 1/L; the measured conversion efficiency is constant within the scatter in the data for targets between 5 and 15 {mu}m, with a peak conversion efficiency of 4% into protons with energy greater than 3 MeV. Depletion of the hydrocarbon contaminant layer is eliminated as an explanation for this plateau by using targets coated with 200 nm of ErH{sub 3} on the rear surface. The proton acceleration is modeled with the hybrid-particle in cell code LSP, which reproduced the conversion efficiency scaling observed in the data.

  8. Double-Relativistic-Electron-Layer Proton Acceleration with High-Contrast Circular-Polarization Laser Pulses

    NASA Astrophysics Data System (ADS)

    Huang, Yong-Sheng; Wang, Nai-Yan; Tang, Xiu-Zhang; Shi, Yi-Jin; Zhang, Shan

    2013-02-01

    A new laser-proton acceleration scheme consisting of two relativistic electron layers, a suprathermal electron layer and a thermal electron cloud is proposed for a0 ≳ 80σ0, where a0 is the normalized laser field and σ0 is the normalized plasma surface density. This is essentially different from target normal sheath acceleration and radiation pressure acceleration. The persistent opaqueness of the first relativistic electron layer for the incident circular-polarization laser pulse and electron recirculation are key points in forming the new acceleration scheme. A proton beam with a uniform energy distribution in the energy range 1-2 GeV and a monoenergetic proton beam with hundreds of MeV have been predicted for a0 = 39.5.

  9. Increased laser-accelerated proton energies via direct laser-light-pressure acceleration of electrons in microcone targets

    SciTech Connect

    Gaillard, S. A.; Kluge, T.; Bussmann, M.; Cowan, T. E.; Flippo, K. A.; Offermann, D. T.; Gall, B.; Lockard, T.; Sentoku, Y.; Geissel, M.; Schollmeier, M.

    2011-05-15

    We present experimental results showing a laser-accelerated proton beam maximum energy cutoff of 67.5 MeV, with more than 5 x 10{sup 6} protons per MeV at that energy, using flat-top hollow microcone targets. This result was obtained with a modest laser energy of {approx}80 J, on the high-contrast Trident laser at Los Alamos National Laboratory. From 2D particle-in-cell simulations, we attribute the source of these enhanced proton energies to direct laser-light-pressure acceleration of electrons along the inner cone wall surface, where the laser light wave accelerates electrons just outside the surface critical density, in a potential well created by a shift of the electrostatic field maximum with respect to that of the magnetic field maximum. Simulations show that for an increasing acceleration length, the continuous loading of electrons into the accelerating phase of the laser field yields an increase in high-energy electrons.

  10. Observations of low-energy /0.3- to 1.8-MeV/ differential spectrums of trapped protons.

    NASA Technical Reports Server (NTRS)

    Venkatesan, D.; Krimigis, S. M.

    1971-01-01

    Measurements of differential energy spectrums of trapped protons obtained from several passes during the period January to November 1969 using the polar orbiting, low-altitude Injun 5 satellite equipped with a special solid-state detector proton-electron telescope are presented. Results reveal the existence of a quasi-persistent peak in the differential energy spectrum in the McIlwain shell parameter (L) range 2 to 2.6 and in the energy range of approximately 0.32 to 0.72 MeV. The fact that the shape of the spectrum is stable for several days or can change with time scales as small as 4 hours suggests an impulsive acceleration mechanism deep in the radiation belts. Other features of the spectrum show that if the spectrum is represented by an exponential form in energy, the dependence of the spectral parameter is in general agreement with diffusion theory over the L range of approximately 2 to 4.

  11. Prompt radiation, shielding and induced radioactivity in a high-power 160 MeV proton linac

    NASA Astrophysics Data System (ADS)

    Magistris, Matteo; Silari, Marco

    2006-06-01

    CERN is designing a 160 MeV proton linear accelerator, both for a future intensity upgrade of the LHC and as a possible first stage of a 2.2 GeV superconducting proton linac. A first estimate of the required shielding was obtained by means of a simple analytical model. The source terms and the attenuation lengths used in the present study were calculated with the Monte Carlo cascade code FLUKA. Detailed FLUKA simulations were performed to investigate the contribution of neutron skyshine and backscattering to the expected dose rate in the areas around the linac tunnel. An estimate of the induced radioactivity in the magnets, vacuum chamber, the cooling system and the concrete shield was performed. A preliminary thermal study of the beam dump is also discussed.

  12. {eta}-meson production in proton-proton collisions at excess energies of 40 and 72 MeV

    SciTech Connect

    Petren, H.; Calen, H.; Fransson, K.; Faeldt, G.; Hoeistad, B.; Jacewicz, M.; Johansson, T.; Keleta, S.; Koch, I.; Kullander, S.; Kupsc, A.; Marciniewski, P.; Schoenning, K.; Wolke, M.; Zlomanczuk, J.; Bargholtz, Chr.; Geren, L.; Lindberg, K.; Tegner, P.-E.; Thoerngren Engblom, P.

    2010-11-15

    The production of {eta} mesons in proton-proton collisions has been studied using the WASA detector at the CELSIUS storage ring at excess energies of Q=40 MeV and Q=72 MeV. The {eta} was detected through its 2{gamma} decay in a near-4{pi} electromagnetic calorimeter, whereas the protons were measured by a combination of straw chambers and plastic scintillator planes in the forward hemisphere. About 6.9x10{sup 4} and 9.3x10{sup 4} events were found at Q=40 MeV and Q=72 MeV, respectively, with background contributions of less than 5%. A simple parametrization of the production cross section in terms of low partial waves was used to evaluate the acceptance corrections. Strong evidence was found for the influence of higher partial waves. The Dalitz plots show the presence of p waves in both the pp and the {eta}{l_brace}pp{r_brace} systems and the angular distributions of the {eta} in the center-of-mass frame suggest the influence of d-wave {eta} mesons.

  13. η-meson production in proton-proton collisions at excess energies of 40 and 72 MeV

    NASA Astrophysics Data System (ADS)

    Petrén, H.; Bargholtz, Chr.; Bashkanov, M.; Bogoslavsky, D.; Calén, H.; Clement, H.; Demirörs, L.; Ekström, C.; Fransson, K.; Fäldt, G.; Gerén, L.; Höistad, B.; Ivanov, G.; Jacewicz, M.; Jiganov, E.; Johansson, T.; Keleta, S.; Khakimova, O.; Koch, I.; Kren, F.; Kullander, S.; Kupść, A.; Lindberg, K.; Marciniewski, P.; Morosov, B.; Pauly, C.; Petukhov, Y.; Povtorejko, A.; Schönning, K.; Scobel, W.; Skorodko, T.; Stepaniak, J.; Tegnér, P.-E.; Thörngren Engblom, P.; Tikhomirov, V.; Wilkin, C.; Wolke, M.; Zabierowski, J.; Zartova, I.; Złomańczuk, J.

    2010-11-01

    The production of η mesons in proton-proton collisions has been studied using the WASA detector at the CELSIUS storage ring at excess energies of Q=40 MeV and Q=72 MeV. The η was detected through its 2γ decay in a near-4π electromagnetic calorimeter, whereas the protons were measured by a combination of straw chambers and plastic scintillator planes in the forward hemisphere. About 6.9×104 and 9.3×104 events were found at Q=40 MeV and Q=72 MeV, respectively, with background contributions of less than 5%. A simple parametrization of the production cross section in terms of low partial waves was used to evaluate the acceptance corrections. Strong evidence was found for the influence of higher partial waves. The Dalitz plots show the presence of p waves in both the pp and the η{pp} systems and the angular distributions of the η in the center-of-mass frame suggest the influence of d-wave η mesons.

  14. Analysis of latent tracks for MeV protons in CR-39

    NASA Astrophysics Data System (ADS)

    Kar, S.; Borghesi, M.; Romagnani, L.; Takahashi, S.; Zayats, A.; Malka, V.; Fritzler, S.; Schiavi, A.

    2007-02-01

    For protons of energy up to a few MeV, the temporal evolution of etched latent tracks in CR-39 nuclear track detector has been numerically modeled by assuming that the electronic energy loss of the protons governs the latent track formation. The technique is applied in order to obtain the energy spectrum of high intensity laser driven proton beams, with high accuracy. The precise measurement of the track length and areal track density have been achieved by scanning short etched, highly populated CR-39 employing atomic force microscope.

  15. Design study of the ESS-Bilbao 50 MeV proton beam line for radiobiological studies

    NASA Astrophysics Data System (ADS)

    Huerta-Parajon, M.; Martinez-Ballarin, R.; Abad, E.

    2015-02-01

    The ESS-Bilbao proton accelerator facility has been designed fulfilling the European Spallation Source (ESS) specifications to serve as the Spanish contribution to the ESS construction. Furthermore, several applications of the ESS-Bilbao proton beam are being considered in order to contribute to the knowledge in the field of radiobiology, materials and aerospace components. Understanding of the interaction of radiation with biological systems is of vital importance as it affects important applications such as cancer treatment with ion beam therapy among others. ESS-Bilbao plans to house a facility exclusively dedicated to radiobiological experiments with protons up to 50 MeV. Beam line design, optimisation and initial calculations of flux densities and absorbed doses were undertaken using the Monte Carlo simulation package FLUKA. A proton beam with a flux density of about 106 protons/cm2 s reaches the water sample with a flat lateral distribution of the dose. The absorbed dose at the pristine Bragg peak calculated with FLUKA is 2.4 ± 0.1 Gy in 1 min of irradiation time. This value agrees with the clinically meaningful dose rates, i.e. around 2 Gy/min, used in hadrontherapy. Optimisation and validation studies in the ESS-Bilbao line for radiobiological experiments are detailed in this article.

  16. The response of CR-39 nuclear track detector to 1-9 MeV protons

    SciTech Connect

    Sinenian, N.; Rosenberg, M. J.; Manuel, M.; McDuffee, S. C.; Casey, D. T.; Zylstra, A. B.; Rinderknecht, H. G.; Johnson, M. Gatu; Seguin, F. H.; Frenje, J. A.; Li, C. K.; Petrasso, R. D.

    2011-10-28

    The response of CR-39 nuclear track detector (TasTrak®) to protons in the energy range of 0.92-9.28 MeV has been studied. Previous studies of the CR-39 response to protons have been extended by examining the piece-to-piece variability in addition to the effects of etch time and etchant temperature; it is shown that the shape of the CR-39 response curve to protons can vary from piece-to-piece. The effects due to the age of CR-39 have also been studied using 5.5 MeV alpha particles over a 5-year period. Track diameters were found to degrade with the age of the CR-39 itself rather than the age of the tracks, consistent with previous studies utilizing different CR-39 over shorter time periods.

  17. A new proton fluence model for E greater than 10 MeV

    NASA Technical Reports Server (NTRS)

    Feynman, Joan; Armstrong, T. P.; Dao-Gibner, L.; Silverman, S.

    1988-01-01

    Researchers describe a new engineering model for the fluence of protons with energies greater than 10 MeV. The data set used is a combination of observations made primarily from the Earth's surface between 1956 and 1963 and observations made from spacecraft in the vicinity of Earth between 1963 and 1985. With this data set we find that the distinction between ordinary proton events and anomalously large proton events made in earlier work disappears. The greater than 10 MeV fluences at 1 AU calculated with the new model are about twice those expected on the basis of models now in use. In contrast to earlier models, results do not depend critically on the fluence from any one event.

  18. The response of CR-39 nuclear track detector to 1-9 MeV protons

    DOE PAGES

    Sinenian, N.; Rosenberg, M. J.; Manuel, M.; ...

    2011-10-28

    The response of CR-39 nuclear track detector (TasTrak®) to protons in the energy range of 0.92-9.28 MeV has been studied. Previous studies of the CR-39 response to protons have been extended by examining the piece-to-piece variability in addition to the effects of etch time and etchant temperature; it is shown that the shape of the CR-39 response curve to protons can vary from piece-to-piece. The effects due to the age of CR-39 have also been studied using 5.5 MeV alpha particles over a 5-year period. Track diameters were found to degrade with the age of the CR-39 itself rather thanmore » the age of the tracks, consistent with previous studies utilizing different CR-39 over shorter time periods.« less

  19. Enhancement of proton acceleration field in laser double-layer target interaction

    SciTech Connect

    Gu, Y. J.; Kong, Q.; Li, X. F.; Yu, Q.; Wang, P. X.; Kawata, S.; Izumiyama, T.; Ma, Y. Y.

    2013-07-15

    A mechanism is proposed to enhance a proton acceleration field in laser plasma interaction. A double-layer plasma with different densities is illuminated by an intense short pulse. Electrons are accelerated to a high energy in the first layer by the wakefield. The electrons accelerated by the laser wakefield induce the enhanced target normal sheath (TNSA) and breakout afterburner (BOA) accelerations through the second layer. The maximum proton energy reaches about 1 GeV, and the total charge with an energy higher than 100 MeV is about several tens of μC/μm. Both the acceleration gradient and laser energy transfer efficiency are higher than those in single-target-based TNSA or BOA. The model has been verified by 2.5D-PIC simulations.

  20. Enhancement of proton acceleration field in laser double-layer target interaction

    NASA Astrophysics Data System (ADS)

    Gu, Y. J.; Kong, Q.; Kawata, S.; Izumiyama, T.; Li, X. F.; Yu, Q.; Wang, P. X.; Ma, Y. Y.

    2013-07-01

    A mechanism is proposed to enhance a proton acceleration field in laser plasma interaction. A double-layer plasma with different densities is illuminated by an intense short pulse. Electrons are accelerated to a high energy in the first layer by the wakefield. The electrons accelerated by the laser wakefield induce the enhanced target normal sheath (TNSA) and breakout afterburner (BOA) accelerations through the second layer. The maximum proton energy reaches about 1 GeV, and the total charge with an energy higher than 100 MeV is about several tens of μC/μm. Both the acceleration gradient and laser energy transfer efficiency are higher than those in single-target-based TNSA or BOA. The model has been verified by 2.5D-PIC simulations.

  1. Proton-induced polonium production in massive lead bismuth target irradiated by 660 MeV protons

    NASA Astrophysics Data System (ADS)

    Polanski, Aleksander; Petrochenkov, Sergey; Pohorecki, Wladyslaw

    2006-06-01

    The paper presents study of polonium production in bismuth foils placed in lead target. Proton-induced production of residual nuclei 206Po, 207Po, 208Po, 209Po, 210Po in 209Bi foils placed in lead target irradiated by 660 MeV protons was calculated. A comparison with calculated spatial distribution of polonium production using an MCNPX code and experimental results has been performed. The results of calculation will be useful for design of target of Subcritical Assembly in Dubna (SAD).

  2. Particle selection and beam collimation system for laser-accelerated proton beam therapy.

    PubMed

    Luo, Wei; Fourkal, Eugene; Li, Jinsheng; Ma, Chang-Ming

    2005-03-01

    In a laser-accelerated proton therapy system, the initial protons have broad energy and angular distributions, which are not suitable for direct therapeutic applications. A compact particle selection and collimation device is needed to deliver small pencil beams of protons with desired energy spectra. In this work, we characterize a superconducting magnet system that produces a desired magnetic field configuration to spread the protons with different energies and emitting angles for particle selection. Four magnets are set side by side along the beam axis; each is made of NbTi wires which carry a current density of approximately 10(5) A/cm2 at 4.2 K, and produces a magnetic field of approximately 4.4 T in the corresponding region. Collimation is applied to both the entrance and the exit of the particle selection system to generate a desired proton pencil beam. In the middle of the magnet system, where the magnetic field is close to zero, a particle selection collimator allows only the protons with desired energies to pass through for therapy. Simulations of proton transport in the presence of the magnetic field show that the selected protons have successfully refocused on the beam axis after passing through the magnetic field with the optimal magnet system. The energy spread for any given characteristic proton energy has been obtained. It is shown that the energy spread is a function of the magnetic field strength and collimator size and reaches the full width at half maximum of 25 MeV for 230 MeV protons. Dose distributions have also been calculated with the GEANT3 Monte Carlo code to study the dosimetric properties of the laser-accelerated proton beams for radiation therapy applications.

  3. Response functions of Fuji imaging plates to monoenergetic protons in the energy range 0.6-3.2 MeV.

    PubMed

    Bonnet, T; Comet, M; Denis-Petit, D; Gobet, F; Hannachi, F; Tarisien, M; Versteegen, M; Aleonard, M M

    2013-01-01

    We have measured the responses of Fuji MS, SR, and TR imaging plates (IPs) to protons with energies ranging from 0.6 to 3.2 MeV. Monoenergetic protons were produced with the 3.5 MV AIFIRA (Applications Interdisciplinaires de Faisceaux d'Ions en Région Aquitaine) accelerator at the Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG). The IPs were irradiated with protons backscattered off a tantalum target. We present the photo-stimulated luminescence response of the IPs together with the fading measurements for these IPs. A method is applied to allow correction of fading effects for variable proton irradiation duration. Using the IP fading corrections, a model of the IP response function to protons was developed. The model enables extrapolation of the IP response to protons up to proton energies of 10 MeV. Our work is finally compared to previous works conducted on Fuji TR IP response to protons.

  4. Accelerating protons to therapeutic energies with ultraintense, ultraclean, and ultrashort laser pulses

    PubMed Central

    Bulanov, Stepan S.; Brantov, Andrei; Bychenkov, Valery Yu.; Chvykov, Vladimir; Kalinchenko, Galina; Matsuoka, Takeshi; Rousseau, Pascal; Reed, Stephen; Yanovsky, Victor; Krushelnick, Karl; Litzenberg, Dale William; Maksimchuk, Anatoly

    2008-01-01

    Proton acceleration by high-intensity laser pulses from ultrathin foils for hadron therapy is discussed. With the improvement of the laser intensity contrast ratio to 10−11 achieved on the Hercules laser at the University of Michigan, it became possible to attain laser-solid interactions at intensities up to 1022 W∕cm2 that allows an efficient regime of laser-driven ion acceleration from submicron foils. Particle-in-cell (PIC) computer simulations of proton acceleration in the directed Coulomb explosion regime from ultrathin double-layer (heavy ions∕light ions) foils of different thicknesses were performed under the anticipated experimental conditions for the Hercules laser with pulse energies from 3 to 15 J, pulse duration of 30 fs at full width half maximum (FWHM), focused to a spot size of 0.8 μm (FWHM). In this regime heavy ions expand predominantly in the direction of laser pulse propagation enhancing the longitudinal charge separation electric field that accelerates light ions. The dependence of the maximum proton energy on the foil thickness has been found and the laser pulse characteristics have been matched with the thickness of the target to ensure the most efficient acceleration. Moreover, the proton spectrum demonstrates a peaked structure at high energies, which is required for radiation therapy. Two-dimensional PIC simulations show that a 150–500 TW laser pulse is able to accelerate protons up to 100–220 MeV energies. PMID:18561651

  5. Enhancement of proton energy by polarization switch in laser acceleration of multi-ion foils

    SciTech Connect

    Liu, Tung-Chang; Shao, Xi; Liu, Chuan-Sheng; Eliasson, Bengt; Wang, Jyhpyng; Chen, Shih-Hung

    2013-10-15

    We present a scheme to significantly increase the energy of quasi-monoenergetic protons accelerated by a laser beam without increasing the input power. This improvement is accomplished by first irradiating the foil several wave periods with circular polarization and then switching the laser to linear polarization. The polarization switch increases the electron temperature and thereby moves more electrons ahead of the proton layer, resulting in a space charge electric field pushing the protons forwards. The scaling of the proton energy evolution with respect to the switching time is studied, and an optimal switching time is obtained. The proton energy for the case with optimal switching time can reach about 80 MeV with an input laser power of 70 TW, an improvement of more than 30% compared to the case without polarization switch.

  6. Acceleration of protons in plasma produced from a thin plastic or aluminum target by a femtosecond laser

    NASA Astrophysics Data System (ADS)

    Rosinski, M.; Badziak, J.; Parys, P.; Zaras-Szydlowska, A.; Ryc, L.; Torrisi, L.; Szydlowski, A.; Malinowska, A.; Kaczmarczyk, B.; Makowski, J.; Torrisi, A.

    2016-05-01

    The acceleration of protons in plasma produced from thin mylar (3.5 μ m) and aluminum (2 μm) targets by a 45-fs laser pulses with the energy of 400 mJ and the intensity of up to 1019 W/cm2 was investigated. Characteristics of forward-accelerated protons were measured by the time-of-flight method. In the measurements, special attention was paid to the dependence of proton beam parameters on the laser focus position (FP) in relation to the target surface which resulted in the intensity change within a factor of ~ 10. It was observed that in the case of using the Mylar target, the dependence of both the maximum (Epmax) and the mean (langleEprangle) proton energy on |Δx| is clearly non-symmetric with regard to the point where FP = 0 (the focal plane on the target surface) and highest proton energies are achieved when the focal plane is situated in front of the target. In particular, for the target with the thickness of 3.5 μ m Epmax reached 2.2 MeV for FP = +50 μm while for FP = 0 and FP = -100 μm the maximum proton energies reached only 1.6 MeV and 1.3 MeV, respectively. For the aluminum target of 2 μm thickness Ep changed only within ~ 40% and the highest proton energies reached 2.4 MeV.

  7. Calculation of A x for the Proton-Deuteron Breakup Reaction at 135 MeV

    NASA Astrophysics Data System (ADS)

    Eslami-Kalantari, M.; Mehmandoost-Khajeh-Dad, A. A.; Shafaei, M. A.; Amir-Ahmadi, H. R.; Biegun, A.; Gašparic, I.; Joulaeizadeh, L.; Kalantar-Nayestanaki, N.; Kistryn, St.; Kozela, A.; Mardanpour, H.; Messchendorp, J. G.; Moeini, H.; Ramazani-Moghaddam-Arani, A.; Shende, S. V.; Stephan, E.; Sworst, R.

    2013-08-01

    Observables in proton-deuteron scattering are sensitive probes of the nucleon-nucleon interaction and three-nucleon force effects (3NF). Several facilities in the world, including Kernfysisch Versneller Instituut (KVI), allow a detailed study a few-nucleon interaction below the pion-production threshold exploiting polarized proton and deuteron beams. In this contribution we explored 3NF effects in the break-up scattering process by performing a measurement of differential cross section and the analyzing power, especially the x component of the analyzing power, using a 135 MeV polarized-proton beam impinging on a liquid-deuteron target. The proton-deuteron breakup reaction leads to a final state with three free particles and a rich phase space that allows us to study observables for continuous set of kinematical configurations of the outgoing nucleons. The results are interpreted with the help of state-of-the-art Faddeev calculations.

  8. A proton medical accelerator by the SBIR route: An example of technology transfer

    SciTech Connect

    Martin, R.L.

    1988-01-01

    Medical facilities for radiation treatment of cancer with protons have been established in many laboratories throughout the world. Essentially all of these have been designed as physics facilities, however, because of the requirement for protons up to 250 MeV. Most of the experience in this branch of accelerator technology lies in the national laboratories and a few large universities. A major issue is the transfer of this technology to the commercial sector to provide hospitals with simple, reliable, and relatively inexpensive accelerators for this application. The author has chosen the SBIR route to accomplish this goal. ACCTEK Associates have received grants from the National Cancer Institute for development of the medical accelerator and beam delivery systems. Considerable encouragement and help has been received from Argonne National Laboratory and the Department of Energy. The experiences to date and the pros and cons on this approach to commercializing medical accelerators are described. 4 refs., 1 fig.

  9. Elastic scattering of polarized protons on deuterium at 800 MeV

    SciTech Connect

    Weston, G.S.

    1984-07-01

    A specific set of spin transfer coefficients has been measured for proton-deuteron elastic scattering at 800 MeV using an unpolarized liquid deuterium target. The experiment was done using the High Resolution Spectrometer (HRS) at the Los Alamos Meson Physics Facility (LAMPF) with a polarized proton beam. The scattered proton spin direction was determined using the Focal Plane Polarimeter (FPP) of the HRS, which employs a carbon analyzer. Some of the spin dependent parameters measured in this experiment are of considerable interest because they provide selective information about the nucleon-nucleon (NN) amplitude. Since the deuteron is the simplest bound nucleus, pd elastic scattering is particularly well suited for testing multiple scattering theories. These measurements will also be used to eventually determine the full pd collision matrix, which contains all possible information about the scattering process. In addition, the experimental setup is described for a polarized proton-polarized deuterium target spin transfer experiment also done at the HRS at 800 MeV incident proton energy. 71 references.

  10. Target depth dependence of damage rate in metals by 150 MeV proton irradiation

    NASA Astrophysics Data System (ADS)

    Yoshiie, T.; Ishi, Y.; Kuriyama, Y.; Mori, Y.; Sato, K.; Uesugi, T.; Xu, Q.

    2015-01-01

    A series of irradiation experiments with 150 MeV protons was performed. The relationship between target depth (or shield thickness) and displacement damage during proton irradiation was obtained by in situ electrical resistance measurements at 20 K. Positron annihilation lifetime measurements were also performed at room temperature after irradiation, as a function of the target thickness. The displacement damage was found to be high close to the beam incident surface area, and decreased with increasing target depth. The experimental results were compared with damage production calculated with an advanced Monte Carlo particle transport code system (PHITS).

  11. Microscopic description of 295 MeV polarized protons incident on Sn isotopes

    SciTech Connect

    Haider, W.; Sharma, Manjari; Gambhir, Y. K.; Kailas, S.

    2010-03-15

    We present a Brueckner theory analysis of proton-scattering data from Sn isotopes at 295 MeV. A soft-core Urbana v{sub 14} internucleon potential has been used to calculate reaction matrices that are folded with point-nucleon (both proton and neutron) densities obtained in the relativistic mean field (RMF) framework to calculate the optical potential. We get reasonably satisfactory agreement with the differential cross-section and analyzing-power data using only three scaling parameters for all isotopes. It is observed that the calculated neutron skin increases smoothly as the neutron number increases, in conformity with earlier findings.

  12. Laser beam-profile impression and target thickness impact on laser-accelerated protons

    NASA Astrophysics Data System (ADS)

    Schollmeier, M.; Harres, K.; Nürnberg, F.; Blažević, A.; Audebert, P.; Brambrink, E.; Fernández, J. C.; Flippo, K. A.; Gautier, D. C.; Geißel, M.; Hegelich, B. M.; Schreiber, J.; Roth, M.

    2008-05-01

    Experimental results on the influence of the laser focal spot shape onto the beam profile of laser-accelerated protons from gold foils are reported. The targets' microgrooved rear side, together with a stack of radiochromic films, allowed us to deduce the energy-dependent proton source-shape and size, respectively. The experiments show, that shape and size of the proton source depend only weakly on target thickness as well as shape of the laser focus, although they strongly influence the proton's intensity distribution. It was shown that the laser creates an electron beam that closely follows the laser beam topology, which is maintained during the propagation through the target. Protons are then accelerated from the rear side with an electron created electric field of a similar shape. Simulations with the Sheath-Accelerated Beam Ray-tracing for IoN Analysis code SABRINA, which calculates the proton distribution in the detector for a given laser-beam profile, show that the electron distribution during the transport through a thick target (50μm Au) is only modified due to multiple small angle scattering. Thin targets (10μm) show large source sizes of over 100μm diameter for 5MeV protons, which cannot be explained by multiple scattering only and are most likely the result of refluxing electrons.

  13. Laser beam-profile impression and target thickness impact on laser-accelerated protons

    SciTech Connect

    Schollmeier, M.; Harres, K.; Nuernberg, F.; Roth, M.; Blazevic, A.; Audebert, P.; Brambrink, E.; Fernandez, J. C.; Flippo, K. A.; Gautier, D. C.; Geissel, M.; Hegelich, B. M.; Schreiber, J.

    2008-05-15

    Experimental results on the influence of the laser focal spot shape onto the beam profile of laser-accelerated protons from gold foils are reported. The targets' microgrooved rear side, together with a stack of radiochromic films, allowed us to deduce the energy-dependent proton source-shape and size, respectively. The experiments show, that shape and size of the proton source depend only weakly on target thickness as well as shape of the laser focus, although they strongly influence the proton's intensity distribution. It was shown that the laser creates an electron beam that closely follows the laser beam topology, which is maintained during the propagation through the target. Protons are then accelerated from the rear side with an electron created electric field of a similar shape. Simulations with the Sheath-Accelerated Beam Ray-tracing for IoN Analysis code SABRINA, which calculates the proton distribution in the detector for a given laser-beam profile, show that the electron distribution during the transport through a thick target (50 {mu}m Au) is only modified due to multiple small angle scattering. Thin targets (10 {mu}m) show large source sizes of over 100 {mu}m diameter for 5 MeV protons, which cannot be explained by multiple scattering only and are most likely the result of refluxing electrons.

  14. Isotopic production cross sections in proton-nucleus collisions at 200 MeV

    SciTech Connect

    Machner, H.; Aschman, D.G.; Steyn, D.; Baruth-Ram, K.; Carter, J.; Sideras-Haddad, E.; Sellschop, J.P.F.; Cowley, A.A.; Goldenbaum, F.; Nangu, B.M.; Spoelstra, B.; Pilcher, J.V.; Smit, F.D.

    2006-04-15

    Intermediate-mass fragments from the interaction of {sup 27}Al, {sup 59}Co, and {sup 197}Au with 200-MeV protons were measured in an angular range from 20 deg. to 120 deg. in the laboratory system. The fragments, ranging from isotopes of helium up to isotopes of carbon, were isotopically resolved. Double-differential cross sections, energy-differential cross sections, and total cross sections were extracted.

  15. The radiation dosimetry of a quartz viewer irradiated with a 4.5 MeV proton beam

    NASA Astrophysics Data System (ADS)

    Ouyasathian, Kalong

    The present dissertation describes a procedure to measure the radiation dose received by an accelerator operator who uses a quartz viewer to locate an ion beam. This procedure consists of the following steps: (i) A solid-state gamma radiation detector was calibrated to determine its efficiency and its energy scale. (ii) The calibrated detector was used to measure the gamma energy spectrum obtained when bombarding the viewer with the ion beam. This measurement was normalized, that is, beam current and measurement duration were determined. (iii) Individual gamma energy lines were extracted from the gamma spectrum and the respective energies and emission rates were obtained. Energies were checked with known transitions in silicon and oxygen, to ensure correct identification. (iv) The Compton gamma energy spectrum generated by the primary gamma rays was determined using a Compton code. (v) Finally the charged-ion bremsstrahlung spectrum was obtained using the formalism of Alder et. al. In this dissertation several prospective contributors to the radiation dose have been checked and were found to be insignificant. They were: the radiation dose due to x-rays generated by Compton electrons and the radiation dose generated by electrons produced by collisions with the incident ions. With a proton energy of 4.5 MeV the eye dose equivalent was determined at 0 and 90 degrees to the proton beam. At 0 degree with a proton fluence rate of 8.9 x 1011 protons/s the dose was 8.7 x 10-3 rem/hr. At 90 degrees with a proton fluence rate of 1.1 x 1012 protons/s the dose was 8.1 x 10-3 rem/hr.

  16. ACCELERATING AND COLLIDING POLARIZED PROTONS IN RHIC WITH SIBERIAN SNAKES.

    SciTech Connect

    ROSER,T.; AHRENS,L.; ALESSI,J.; BAI,M.; BEEBE - WANG,J.; BRENNAN,J.M.; BROWN,K.A.; BUNCE,G.; CAMERON,P.; COURANT,E.D.; DREES,A.; FISCHER,W.; ET AL

    2002-06-02

    We successfully injected polarized protons in both RHIC rings and maintained polarization during acceleration up to 100 GeV per ring using two Siberian snakes in each ring. Each snake consists of four helical superconducting dipoles which rotate the polarization by 180{sup o} about a horizontal axis. This is the first time that polarized protons have been accelerated to 100 GeV. We report on our experiences during commissioning and operation of collider with polarized protons.

  17. Requirements of a proton beam accelerator for an accelerator-driven reactor

    SciTech Connect

    Takahashi, H.; Zhao, Y.; Tsoupas, N.; An, Y.; Yamazaki, Y.

    1997-12-31

    When the authors first proposed an accelerator-driven reactor, the concept was opposed by physicists who had earlier used the accelerator for their physics experiments. This opposition arose because they had nuisance experiences in that the accelerator was not reliable, and very often disrupted their work as the accelerator shut down due to electric tripping. This paper discusses the requirements for the proton beam accelerator. It addresses how to solve the tripping problem and how to shape the proton beam.

  18. Particle Simulations of a Linear Dielectric Wall Proton Accelerator

    SciTech Connect

    Poole, B R; Blackfield, D T; Nelson, S D

    2007-06-12

    The dielectric wall accelerator (DWA) is a compact induction accelerator structure that incorporates the accelerating mechanism, pulse forming structure, and switch structure into an integrated module. The DWA consists of stacked stripline Blumlein assemblies, which can provide accelerating gradients in excess of 100 MeV/meter. Blumleins are switched sequentially according to a prescribed acceleration schedule to maintain synchronism with the proton bunch as it accelerates. A finite difference time domain code (FDTD) is used to determine the applied acceleration field to the proton bunch. Particle simulations are used to model the injector as well as the accelerator stack to determine the proton bunch energy distribution, both longitudinal and transverse dynamic focusing, and emittance growth associated with various DWA configurations.

  19. Proton beam studies with a 1.25 MeV, cw radio frequency quadrupole linac

    SciTech Connect

    Bolme, G.O.; Hardek, T.W.; Hansborough, L.D.

    1998-12-31

    A high-current, cw linear accelerator has been proposed as a spallation neutron source driver for tritium production. Key features of this accelerator are high current (100 mA), low emittance-growth beam propagation, cw operation, high efficiency, and minimal maintenance downtime. A 268 MHz, cw radio frequency quadrupole (RFQ) LINAC section and klystrode based rf system were obtained from the Chalk River Laboratories and were previously installed at LANL to support systems development and advanced studies in support of cw, proton accelerators. A variation of the Low Energy Demonstration Accelerator (LEDA) proton injector, modified to operate at 50 keV, was mated to the RFQ and was operated to support advance developments for the Accelerator Production of Tritium (APT) program. High current, proton beam studies were completed which focused on the details of injector-RFQ integration, development of beam diagnostics, development of operations procedures, and personnel and equipment safety systems integration. This development led to acceleration of up to 100 mA proton beam.

  20. Measurement of natW(p,xn)177,178,179Re excitation function of natural tungsten by using a 100-MeV proton beam

    NASA Astrophysics Data System (ADS)

    Yoon, Jungran; Lee, Jieun; Lee, Samyol

    2017-01-01

    Measurements of the proton-induced excitation function for the natW(p,xn)177,178,179Re nuclear reaction has been measured in the energy region below 100 MeV by using the 100-MeV proton linear accelerator at the Korea Multi-Purpose Accelerator Complex. The stacked foil activation technique was adopted in the present study. The gamma-rays generated from the proton-irradiated samples were measured by using a gamma-ray spectroscopy system with a HPGe detector. The 27Al(p,3p+n)24Na reaction was used as a monitor reaction for proton flux monitoring. The nuclear reactions of natW(p,xn)177,178,179Re were observed in the present study. The proton-induced excitation functions of natural tungsten were derived from the delayed gamma-ray yield of the produced nucleus. The present results were compared with the previous experimental excitation function data of Yu. E. Titarenko et al. [1].

  1. Occurrence of brain tumors in rhesus monkeys exposed to 55-MeV protons

    NASA Astrophysics Data System (ADS)

    Wood, D. H.; Yochmowitz, M. G.; Hardy, K. A.; Salmon, Y. L.

    Twenty-year observation of monkeys exposed to single doses of high energy protons simulating solar particles revealed that the most prevalent fatal cancers were brain tumors in the group of animals exposed to 55-MeV protons. Of 72 animals (50 males and 22 females) receiving 0.25 to 8.0 Gy total body surface dose, nine developed fatal tumors classified as grade IV astrocytoma or glioblastoma multiforme. The latent period for tumor development ranged from 14 months to 20 years, with a median of 5 years. Doses associated with the tumors were 4.0 to 8.0 Gy. Eight males and one female were affected. Depth-dose determinations suggest that the high incidence of cerebral neoplasia is associated with the Bragg Peak energy distribution of the 55-MeV protons. Comparison of the tumor incidence with that in humans with brain exposures incidental to radiotherapy indicates a high biological effectiveness compared with gamma radiation. Studies are in progress to attempt to replicate the results in rodents and establish a dose-response curve for proton-induced brain tumors.

  2. Proton acceleration by multi-terawatt interaction with a near-critical density hydrogen jet

    NASA Astrophysics Data System (ADS)

    Goers, Andy; Feder, Linus; Hine, George; Salehi, Fatholah; Woodbury, Daniel; Su, J. J.; Papadopoulos, Dennis; Zigler, Arie; Milchberg, Howard

    2016-10-01

    We investigate the high intensity laser interaction with thin, near critical density plasmas as a means of efficient acceleration of MeV protons. A promising mechanism is magnetic vortex acceleration, where the ponderomotive force of a tightly focused laser pulse drives a relativistic electron current which generates a strong azimuthal magnetic field. The rapid expansion of this azimuthal magnetic field at the back side of the target can accelerate plasma ions to MeV scale energies. Compared to typical ion acceleration experiments utilizing a laser- thin solid foil interaction, magnetic vortex acceleration in near critical density plasma may be realized in a high density gas jet, making it attractive for applications requiring high repetition rates. We present preliminary experiments studying laser-plasma interaction and proton acceleration in a thin (< 200 μm) near-critical density hydrogen gas jet delivering electron densities 1020 -1021 cm-3 . This research was funded by the United States Department of Energy and the Defense Advanced Research Projects Agency (DARPA) under Contract Number W911-NF-15-C-0217, issued by the Army Research Office.

  3. Trends and applications for MeV electrostatic ion beam accelerators

    NASA Astrophysics Data System (ADS)

    Norton, G. A.; Stodola, S. E.

    2014-08-01

    The 1970s into the 1980s saw a major broadening of applications for electrostatic accelerators. Prior to this time, all accelerators were used primarily for nuclear structure research. In the 70s there was a significant move into production ion implantation with the necessary MeV ion beam analysis techniques such as RBS and ERD. Accelerators are still being built for these materials analysis techniques today. However, there is still a great ongoing expansion of applications for these machines. At the present time, the demand for electrostatic accelerators is near an all time high. The number of applications continues to grow. This paper will touch on some of the current applications which are as diverse as nuclear fission reactor developments and pharmacokinetics. In the field of nuclear engineering, MeV ion beams from electrostatic accelerators are being used in material damage studies and for iodine and actinide accelerator mass spectrometry (AMS). In the field of pharmacokinetics, electrostatic MeV accelerators are being used to detect extremely small amounts of above background 14C. This has significantly reduced the time required to reach first in human studies. These and other applications will be discussed.

  4. Single event upsets calculated from new ENDF/B-VI proton and neutron data up to 150 MeV

    SciTech Connect

    Chadwick, M.B.; Normand, E.

    1999-06-01

    Single-event upsets (SEU) in microelectronics are calculated from newly-developed silicon nuclear reaction recoil data that extend up to 150 MeV, for incident protons and neutrons. Calculated SEU cross sections are compared with measured data.

  5. Modification of radiobiological effects of 171 MeV protons by elements of physical protection

    NASA Astrophysics Data System (ADS)

    Bulinina, Taisia; Shurshakov, Vyacheslav; Ivanov, Alexander; Molokanov, Alexander

    2016-07-01

    Space radiation includes protons of various energies. Physical protection is effective in the case of low energy protons (50-100 MeV) and becomes insufficient for radiation with a high part of high-energy protons. In the experiment performed on outbred mice, the purpose of the study was to evaluate the radiobiological effect of 171 MeV protons and protons modified by elements of physical protection of the spacecraft, on a complex of indicators of the functional condition of the system hematopoiesis and the central nervous system in 24 hours after irradiation at 20 cGy dose. The spacecraft radiation protection elements used in the experiment were a construction of wet hygiene wipes called a «protective curtain», and a glass plate imitating an ISS window. Mass thickness of the " protective curtain" in terms of water equivalent was ̴ 6,2 g/cm2. Physical shielding along the path of 171 MeV protons increases their linear energy transfer leading to the absorbed dose elevation and strengthening of the radiobiological effect. In the experiment, the two types of shielding together raised the absorbed dose from 20 to 23.2 cGy. Chemically different materials (glass and water in the wipes) were found to exert unequal modifying effects on physical and biological parameters of the proton-irradiated mice. There was a distinct dose-dependent reduction of bone marrow cellularity within the dose range from 20 cGy to 23.2 cGy in 24 hours after exposure. No modifying effect of the radiation protection elements on spontaneous motor activity was discovered when compared with entrance protons. The group of animals protected by the glass plate exhibited normal orientative-trying reactions and weakened grip with the forelimbs. The effects observed in the experiment indicate the necessity to carry out comprehensive radiobiological researches (physical, biological and mathematical) in assessing the effects of physical protection, that are actual for ensuring radiation safety of crews in

  6. Radiation effects induced in pin photodiodes by 40- and 85-MeV protons

    NASA Technical Reports Server (NTRS)

    Becher, J.; Kernell, R. L.; Reft, C. S.

    1985-01-01

    PIN photodiodes were bombarded with 40- and 85-MeV protons to a fluence of 1.5 x 10 to the 11th power p/sq cm, and the resulting change in spectral response in the near infrared was determined. The photocurrent, dark current and pulse amplitude were measured as a function of proton fluence. Changes in these three measured properties are discussed in terms of changes in the diode's spectral response, minority carrier diffusion length and depletion width. A simple model of induced radiation effects is presented which is in good agreement with the experimental results. The model assumes that incident protons produce charged defects within the depletion region simulating donor type impurities.

  7. Response of Cellulose detectors to different doses of 62 MeV protons

    NASA Astrophysics Data System (ADS)

    Tripathy, S. P.; Mishra, R.; Dwivedi, K. K.; Ghosh, S.; Fink, D.; Khathing, D. T.

    2003-08-01

    Optical and thermal responses of two cellulose detectors, Cellulose triacetate (Triafol-TN) and Cellulose acetate butyrate (Triafol-BN), to four different doses of 62 MeV protons were studied using spectroscopic, thermal and track-etching techniques. The spectroscopic analysis revealed that though the optical band-gap in the polymers was affected by proton irradiation, the polymers showed high resistance against any major structural modification by radiation. The thermal stability of the polymers was found to be affected by proton irradiation. The activation energy of etching was found to be almost constant for both the polymers even after irradiation. It is hoped that the findings in this work would be of significant relevance to material science and applications of polymers.

  8. New Capabilties of 800 MeV Proton Radiography at LOS Alamos

    NASA Astrophysics Data System (ADS)

    Schwartz, C. L.; Hogan, G. E.; Kwiatkowski, K.; Rigg, P. A.; Rightley, P. M.; Mariam, F. G.; Marr-Lyon, M.; Merrill, F. E.; Morris, C. L.; Saunders, A.; Tupa, D.

    2007-12-01

    Three new capabilities have recently been commissioned at the proton radiography [1] facility at Los Alamos. A powder gun driver system has been installed and commissioned and a series of demonstration measurements have been completed. This powder gun is now regularly used to drive dynamic experiments. A new CMOS hybrid camera technology has been developed and fielded resulting in dramatic improvements in quantum efficiency as well as providing eight additional radiographic images per dynamic event. A proton x3 magnifier was designed, built and commissioned to provide improved radiographic resolution for 800 MeV proton radiography experiments. Details of these new capabilities will be presented along with data from recent experiments which utilized these new capabilities.

  9. Bend-fatigue properties of 590 MeV proton irradiated JPCA and 316F SS

    NASA Astrophysics Data System (ADS)

    Saito, S.; Kikuchi, K.; Usami, K.; Ishikawa, A.; Nishino, Y.; Kawai, M.; Dai, Y.

    2004-08-01

    A beam window of a spallation target will be subjected to proton/neutron irradiation, pressure wave and thermal stresses accompanied by high-energy proton beam injection. To obtain irradiation data, the SINQ target irradiation program (STIP) was initiated in 1996 at PSI. JAERI takes part in STIP and conducted the post-irradiation examination of JPCA, 316F. Irradiation conditions of JAERI specimens were as follows: proton energy was 590 MeV. Irradiation temperature ranged from 135 to 360 °C and irradiation dose from 6.3 to 12.5 dpa. The fatigue life of irradiated specimens is almost the same as that of unirradiated specimens. On the other hand, fracture surfaces varied with irradiation conditions. Specimens irradiated at low temperature fractured in a ductile manner. However, intergranular fractured surfaces were observed for 316F irradiated up to 12.5 dpa at 360 °C.

  10. Field-Guided Proton Acceleration at Reconnecting x-Points in Flares

    NASA Astrophysics Data System (ADS)

    Hamilton, B.; McCLEMENTS, K. G.; Fletcher, L.; Thyagaraja, A.

    2003-06-01

    An explicitly energy-conserving full orbit code CUEBIT, developed originally to describe energetic particle effects in laboratory fusion experiments, has been applied to the problem of proton acceleration in solar flares. The model fields are obtained from solutions of the linearised MHD equations for reconnecting modes at an X-type neutral point, with the additional ingredient of a longitudinal magnetic field component. To accelerate protons to the highest observed energies on flare timescales, it is necessary to invoke anomalous resistivity in the MHD solution. It is shown that the addition of a longitudinal field component greatly increases the efficiency of ion acceleration, essentially because it greatly reduces the magnitude of drift motions away from the vicinity of the X-point, where the accelerating component of the electric field is largest. Using plasma parameters consistent with flare observations, we obtain proton distributions extending up to γ-ray-emitting energies (>1 MeV). In some cases the energy distributions exhibit a bump-on-tail in the MeV range. In general, the shape of the distribution is sensitive to the model parameters.

  11. Chromosome aberrations in human lymphocytes induced by 250 MeV protons: effects of dose, dose rate and shielding

    NASA Technical Reports Server (NTRS)

    George, K.; Willingham, V.; Wu, H.; Gridley, D.; Nelson, G.; Cucinotta, F. A.

    2002-01-01

    Although the space radiation environment consists predominantly of energetic protons, astronauts inside a spacecraft are chronically exposed to both primary particles as well as secondary particles that are generated when the primary particles penetrate the spacecraft shielding. Secondary neutrons and secondary charged particles can have an LET value that is greater than the primary protons and, therefore, produce a higher relative biological effectiveness (RBE). Using the accelerator facility at Loma Linda University, we exposed human lymphocytes in vitro to 250 MeV protons with doses ranging from 0 to 60 cGy at three different dose rates: a low dose rate of 7.5 cGy/h, an intermediate dose rate of 30 cGy/h and a high dose rate of 70 cGy/min. The effect of 15 g/cm2 aluminum shielding on the induction of chromosome aberrations was investigated for each dose rate. After exposure, lymphocytes were incubated in growth medium containing phytohemagglutinin (PHA) and chromosome spreads were collected using a chemical-induced premature chromosome condensation (PCC) technique. Aberrations were analyzed using the fluorescence in situ hybridization (FISH) technique with three different colored chromosome-painting probes. The frequency of reciprocal and complex-type chromosome exchanges were compared in shielded and unshielded samples. c2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved.

  12. Chromosome aberrations in human lymphocytes induced by 250 MeV protons: effects of dose, dose rate and shielding.

    PubMed

    George, K; Willingham, V; Wu, H; Gridley, D; Nelson, G; Cucinotta, F A

    2002-01-01

    Although the space radiation environment consists predominantly of energetic protons, astronauts inside a spacecraft are chronically exposed to both primary particles as well as secondary particles that are generated when the primary particles penetrate the spacecraft shielding. Secondary neutrons and secondary charged particles can have an LET value that is greater than the primary protons and, therefore, produce a higher relative biological effectiveness (RBE). Using the accelerator facility at Loma Linda University, we exposed human lymphocytes in vitro to 250 MeV protons with doses ranging from 0 to 60 cGy at three different dose rates: a low dose rate of 7.5 cGy/h, an intermediate dose rate of 30 cGy/h and a high dose rate of 70 cGy/min. The effect of 15 g/cm2 aluminum shielding on the induction of chromosome aberrations was investigated for each dose rate. After exposure, lymphocytes were incubated in growth medium containing phytohemagglutinin (PHA) and chromosome spreads were collected using a chemical-induced premature chromosome condensation (PCC) technique. Aberrations were analyzed using the fluorescence in situ hybridization (FISH) technique with three different colored chromosome-painting probes. The frequency of reciprocal and complex-type chromosome exchanges were compared in shielded and unshielded samples.

  13. Experimental stand for studying the impact of laser-accelerated protons on biological objects

    NASA Astrophysics Data System (ADS)

    Burdonov, K. F.; Eremeev, A. A.; Ignatova, N. I.; Osmanov, R. R.; Sladkov, A. D.; Soloviev, A. A.; Starodubtsev, M. V.; Ginzburg, V. N.; Kuz'min, A. A.; Maslennikova, A. V.; Revet, G.; Sergeev, A. M.; Fuchs, J.; Khazanov, E. A.; Chen, S.; Shaykin, A. A.; Shaikin, I. A.; Yakovlev, I. V.

    2016-04-01

    An original experimental stand is presented, aimed at studying the impact of high-energy protons, produced by the laser-plasma interaction at a petawatt power level, on biological objects. In the course of pilot experiments with the energy of laser-accelerated protons up to 25 MeV, the possibility is demonstrated of transferring doses up to 10 Gy to the object of study in a single shot with the magnetic separation of protons from parasitic X-ray radiation and fast electrons. The technique of irradiating the cell culture HeLa Kyoto and measuring the fraction of survived cells is developed. The ways of optimising the parameters of proton beams and the suitable methods of their separation with respect to energy and transporting to the studied living objects are discussed. The construction of the stand is intended for the improvement of laser technologies for hadron therapy of malignant neoplasms.

  14. Proton acceleration in the interaction of high power laser and cryogenic hydrogen targets

    NASA Astrophysics Data System (ADS)

    Mishra, Rohini; Fiuza, Frederico; Glenzer, Siegfried

    2014-10-01

    High intensity laser driven ion acceleration has attracted great interest due to many prospective applications ranging from inertial confinement fusion, cancer therapy, particle accelerators. Particle-in-Cell (PIC) simulations are performed to model and design experiments at MEC for high power laser interaction with cryogenic hydrogen targets of tunable density and thickness. Preliminary 1D and 2D simulations, using fully relativistic particle-in-cell code PICLS, show a unique regime of proton acceleration, e.g. ~ 300 MeV peak energy protons are observed in the 1D run for interaction of ~1020 W/cm2, 110 fs intense laser with 6nc dense (nc = 1021 cm-3) and 2 micron thin target. The target is relativistically under-dense for the laser and we observe that a strong (multi-terawatt) shock electric field is produced and protons are reflected to high velocities by this field. Further, the shock field and the laser field keep propagating through the hydrogen target and meets up with target normal sheath acceleration (TNSA) electric field produced at the target rear edge and vacuum interface and this superposition amplifies the TNSA fields resulting in higher proton energy. In addition, the electrons present at the rear edge of the target continue to gain energy via strong interaction with laser that crosses the target and these accelerated electrons maintains higher electric sheath fields which further provides acceleration to protons. We will also present detailed investigation with 2D PICLS simulations to gain a better insight of such physical processes to characterize multidimensional effects and establish analytical scaling between laser and target conditions for the optimization of proton acceleration.

  15. The 500-MeV, 2 1/2% duty factor linear electron accelerator (MEA)

    SciTech Connect

    Bruinsma, P.J.T.; Kroes, F.B.; Kuijer, L.H.; Noomen, J.G.; Spelt, J.B.; Vogel, A.G.C.

    1983-08-01

    Although the intermediate energy electron accelerator in Amsterdam has not reached completely its design specifications, since early 1981 a fully grown scientific program has developed using beams with an energy ranging from 20 to 120 MeV in the 140 MeV substation (for radio-chemistry and low-energy electron scattering over 180/sup 0/) and from 70 to 400 MeV in the high energy stations for electron scattering and physics with pion and muon beams. A brief description of the MIT-type accelerator and its performance will be given with emphasis on typical features of the machine. Some examples will be given of recently obtained scientific data from which can be derived that the quality of the beam is in full accordance with the high performance level of the scientific equipment, involving a complex beam transport system and a pair of spectrometers for high resolution (1x10/sup -4/) work.

  16. Neutron Induced Reactions with the 17 Mev Facility at the Athens Tandem Accelerator NCSR 'Demokritos'

    NASA Astrophysics Data System (ADS)

    Vlastou, R.; Kalamara, A.; Serris, M.; Diakaki, M.; Kokkoris, M.; Paneta, V.; Axiotis, M.; Lagoyannis, A.

    In the 5.5 MV tandem T11/25 Accelerator Laboratory of NCSR "Demokritos" monoenergetic neutron beams have been produced in the energy range∼ 15-20 MeV using anew Ti-tritiated target of 373 GBq activity, by means of the 3H(d,n)4He reaction. The corresponding deuteron beam energies obtained from the accelerator, were in the 1.5-4.5MeV range.The maximum flux has been determined to be of the order of 106 n/cm2 s, implementing reference reactions. The 17.1MeV neutron beam has been used for the measurement of 197Au(n,2n) reaction cross section. Theoretical calculations have been performed via the statistical model code EMPIRE and compared to the experimental data of the present work and data from literature.

  17. High intensity electron cyclotron resonance proton source for low energy high intensity proton accelerator.

    PubMed

    Roychowdhury, P; Chakravarthy, D P

    2009-12-01

    Electron cyclotron resonance (ECR) proton source at 50 keV, 50 mA has been designed, developed, and commissioned for the low energy high intensity proton accelerator (LEHIPA). Plasma characterization of this source has been performed. ECR plasma was generated with 400-1100 W of microwave power at 2.45 GHz, with hydrogen as working gas. Microwave was fed in the plasma chamber through quartz window. Plasma density and temperature was studied under various operating conditions, such as microwave power and gas pressure. Langmuir probe was used for plasma characterization using current voltage variation. The typical hydrogen plasma density and electron temperature measured were 7x10(11) cm(-3) and 6 eV, respectively. The total ion beam current of 42 mA was extracted, with three-electrode extraction geometry, at 40 keV of beam energy. The extracted ion current was studied as a function of microwave power and gas pressure. Depending on source pressure and discharge power, more than 30% total gas efficiency was achieved. The optimization of the source is under progress to meet the requirement of long time operation. The source will be used as an injector for continuous wave radio frequency quadrupole, a part of 20 MeV LEHIPA. The required rms normalized emittance of this source is less than 0.2 pi mm mrad. The simulated value of normalized emittance is well within this limit and will be measured shortly. This paper presents the study of plasma parameters, first beam results, and the status of ECR proton source.

  18. High intensity electron cyclotron resonance proton source for low energy high intensity proton accelerator

    SciTech Connect

    Roychowdhury, P.; Chakravarthy, D. P.

    2009-12-15

    Electron cyclotron resonance (ECR) proton source at 50 keV, 50 mA has been designed, developed, and commissioned for the low energy high intensity proton accelerator (LEHIPA). Plasma characterization of this source has been performed. ECR plasma was generated with 400-1100 W of microwave power at 2.45 GHz, with hydrogen as working gas. Microwave was fed in the plasma chamber through quartz window. Plasma density and temperature was studied under various operating conditions, such as microwave power and gas pressure. Langmuir probe was used for plasma characterization using current voltage variation. The typical hydrogen plasma density and electron temperature measured were 7x10{sup 11} cm{sup -3} and 6 eV, respectively. The total ion beam current of 42 mA was extracted, with three-electrode extraction geometry, at 40 keV of beam energy. The extracted ion current was studied as a function of microwave power and gas pressure. Depending on source pressure and discharge power, more than 30% total gas efficiency was achieved. The optimization of the source is under progress to meet the requirement of long time operation. The source will be used as an injector for continuous wave radio frequency quadrupole, a part of 20 MeV LEHIPA. The required rms normalized emittance of this source is less than 0.2 {pi} mm mrad. The simulated value of normalized emittance is well within this limit and will be measured shortly. This paper presents the study of plasma parameters, first beam results, and the status of ECR proton source.

  19. a Technique to Calibrate Neutron-Proton Elastic Scattering Spin Observables Near 183 Mev

    NASA Astrophysics Data System (ADS)

    Bowyer, Theodore William

    Free neutron-proton scattering is one of the most fundamental reactions we can study in the field of nuclear physics, yet the n-p scattering data base is quite sparse. The data that does exist is often plagued by systematic uncertainties associated with the determination of beam and/or target polarizations. In contrast, there is an abundance of high quality, high statistics p-p elastic scattering data. We report on a technique which we have developed which exploits the high quality of the p-p data to calibrate n-p elastic scattering spin observables by simultaneous measurement of vec n-vec p and p-vec p elastic scattering by bombarding a polarized proton target with a mixed beam of polarized neutrons and protons. This technique has allowed us to calibrate the n-p elastic spin observables at 183 MeV: the beam and target analyzing powers A _{n}(theta_{p}),A _{p}(theta p), and the spin correlation coefficient, C_{NN}( theta_{p}). The mixed secondary beam was produced by bombarding a liquid deuterium target with a 200 MeV beam of polarized protons. The experiment was preformed in the Polarized Neutron Facility at the Indiana University Cyclotron Facility utilizing a left-right symmetric detection system, sensitive to both scattered protons and neutrons, and spanned the laboratory angular range of 24^circ to 62^circ. We identified free scattering events through a number of kinematic correlations. We compare our results to various phase shift calculations and potential models and examine the sensitivity of magnitude of various phase shifts results to the inclusion of our data into the n-p data base.

  20. Laser Radiation Pressure Accelerator for Quasi-Monoenergetic Proton Generation and Its Medical Implications

    NASA Astrophysics Data System (ADS)

    Liu, C. S.; Shao, X.; Liu, T. C.; Su, J. J.; He, M. Q.; Eliasson, B.; Tripathi, V. K.; Dudnikova, G.; Sagdeev, R. Z.; Wilks, S.; Chen, C. D.; Sheng, Z. M.

    Laser radiation pressure acceleration (RPA) of ultrathin foils of subwavelength thickness provides an efficient means of quasi-monoenergetic proton generation. With an optimal foil thickness, the ponderomotive force of the intense short-pulse laser beam pushes the electrons to the edge of the foil, while balancing the electric field due to charge separation. The electron and proton layers form a self-organized plasma double layer and are accelerated by the radiation pressure of the laser, the so-called light sail. However, the Rayleigh-Taylor instability can limit the acceleration and broaden the energy of the proton beam. Two-dimensional particle-in-cell (PIC) simulations have shown that the formation of finger-like structures due to the nonlinear evolution of the Rayleigh-Taylor instability limits the acceleration and leads to a leakage of radiation through the target by self-induced transparency. We here review the physics of quasi-monoenergetic proton generation by RPA and recent advances in the studies of energy scaling of RPA, and discuss the RPA of multi-ion and gas targets. The scheme for generating quasi-monoenergetic protons with RPA has the potential of leading to table-top accelerators as sources for producing monoenergetic 50-250 MeV protons. We also discuss potential medical implications, such as particle therapy for cancer treatment, using quasi-monoenergetic proton beams generated from RPA. Compact monoenergetic ion sources also have applications in many other areas such as high-energy particle physics, space electronics radiation testing, and fast ignition in laser fusion.

  1. Utilization of an intense beam of 800 MeV protons to prepare radionuclides

    SciTech Connect

    O'Brien, H.A.

    1988-01-01

    Since the early 1970's, a program has been underway at this institution to employ the excess proton beam emerging from the major experimental areas of the LAMPF accelerator to make a wide variety of radioactive nuclides. This paper presents a review of the targets irradiated, cross section data, and nuclide yield measurements. 32 refs., 1 figs., 8 tabs.

  2. High quality proton beams from hybrid integrated laser-driven ion acceleration systems

    NASA Astrophysics Data System (ADS)

    Sinigardi, Stefano; Turchetti, Giorgio; Rossi, Francesco; Londrillo, Pasquale; Giove, Dario; De Martinis, Carlo; Bolton, Paul R.

    2014-03-01

    We consider a hybrid acceleration scheme for protons where the laser generated beam is selected in energy and angle and injected into a compact linac, which raises the energy from 30 to 60 MeV. The laser acceleration regime is TNSA and the energy spectrum is determined by the cutoff energy and proton temperature. The dependence of the spectrum on the target properties and the incidence angle is investigated with 2D PIC simulations. We base our work on widely available technologies and on laser with a short pulse, having in mind a facility whose cost is approximately 15 M €. Using a recent experiment as the reference, we choose the laser pulse and target so that the energy spectrum obtained from the 3D PIC simulation is close to the one observed, whose cutoff energy was estimated to be over 50 MeV. Laser accelerated protons in the TNSA regime have wide energy spectrum and broad divergence. In this paper we compare three transport lines, designed to perform energy selection and beam collimation. They are based on a solenoid, a quadruplet of permanent magnetic quadrupoles and a chicane. To increase the maximum available energy, which is actually seen as an upper limit due to laser properties and available targets, we propose to inject protons into a small linac for post-acceleration. The number of selected and injected protons is the highest with the solenoid and lower by one and two orders of magnitude with the quadrupoles and the chicane respectively. Even though only the solenoid enables achieving to reach a final intensity at the threshold required for therapy with the highest beam quality, the other systems will be very likely used in the first experiments. Realistic start-to-end simulations, as the ones reported here, are relevant for the design of such experiments.

  3. Cross Sections and Analyzing Powers of Nitrogen -15(PROTON, NEUTRON)OXYGEN-15 at 200 Mev and 494 Mev.

    NASA Astrophysics Data System (ADS)

    Ciskowski, Douglas Edward

    Differential cross sections and analyzing powers have been measured for the ^{15} N(p,n)^{15}O(g.s.) reaction at bombarding energies of 200 MeV and 494 MeV. The 494 MeV data were obtained at the LAMPF Neutron Time-Of -Flight Facility on an 82 m flight path with a resolution of about 2.7 MeV. The 200 MeV data were obtained at IUCF on a 76 m flight path with a resolution of about 1.1 MeV. At both energies, the measured analyzing power is small, the magnitude is less than.2 for momentum transfers of less than 1 fm^{-1}. In contrast, both Relativistic and standard DWIA calculations predict a maximum of A = -.7 near q = 0.7 fm ^{-1}.

  4. An 800-MeV proton radiography facility for dynamic experiments

    NASA Astrophysics Data System (ADS)

    King, N. S. P.; Ables, E.; Adams, Ken; Alrick, K. R.; Amann, J. F.; Balzar, Stephen; Barnes, P. D., Jr.; Crow, M. L.; Cushing, S. B.; Eddleman, J. C.; Fife, T. T.; Flores, Paul; Fujino, D.; Gallegos, R. A.; Gray, N. T.; Hartouni, E. P.; Hogan, G. E.; Holmes, V. H.; Jaramillo, S. A.; Knudsson, J. N.; London, R. K.; Lopez, R. R.; McDonald, T. E.; McClelland, J. B.; Merrill, F. E.; Morley, K. B.; Morris, C. L.; Naivar, F. J.; Parker, E. L.; Park, H. S.; Pazuchanics, P. D.; Pillai, C.; Riedel, C. M.; Sarracino, J. S.; Shelley, F. E., Jr.; Stacy, H. L.; Takala, B. E.; Thompson, Richard; Tucker, H. E.; Yates, G. J.; Ziock, H.-J.; Zumbro, J. D.

    1999-11-01

    The capability has successfully been developed at the Los Alamos Nuclear Science Center (LANSCE) to utilize a spatially and temporally prepared 800 MeV proton beam to produce proton radiographs. A series of proton bursts are transmitted through a dynamic object and transported, via a unique magnetic lens system, to an image plane. The magnetic lens system permits correcting for the effects of multiple coulomb scattering which would otherwise completely blur the spatially transmitted information at the image plane. The proton radiographs are recorded either on a time integrating film plate or with a recently developed multi-frame electronic imaging camera system. The latter technique permits obtaining a time dependent series of proton radiographs with time intervals (modulo 358 ns) up to many microseconds and variable time intervals between images. One electronically shuttered, intensified, CCD camera is required per image. These cameras can detect single protons interacting with a scintillating fiber optic array in the image plane but also have a dynamic range which permits recording radiographs with better than 5% statistics for observation of detailed density variations in the object. A number of tests have been carried out to characterize the quality of the proton radiography system for absolute mass determination, resolution, and dynamic range. Initial dynamic experiments characterized the temporal and spatial behavior of shock propagation in a high explosive sample with up to six images per experiment. Based on experience with the prototype system, a number of upgrades are being implemented including the anticipated capability for enhanced mass discrimination through differential multiple coulomb scattering radiographs and more images with improved imaging techniques.

  5. Nuclear excitation functions from 40 to 200 MeV proton irradiation of terbium

    NASA Astrophysics Data System (ADS)

    Engle, Jonathan W.; Mashnik, Stepan G.; Parker, Lauren A.; Jackman, Kevin R.; Bitteker, Leo J.; Ullmann, John L.; Gulley, Mark S.; Pillai, Chandra; John, Kevin D.; Birnbaum, Eva R.; Nortier, Francois M.

    2016-01-01

    Nuclear formation cross sections are reported for 26 radionuclides, measured with 40-200 MeV proton irradiations of terbium foils. These data provide the basis for the production of medically relevant radionuclides (e.g., 152Tb, 155Tb, 155Eu, and 156Eu) and 153Gd, a potential source used in ongoing efforts to characterize stellar nucleosynthesis routes. Computational predictions from the ALICE2011, CEM03.03, Bertini, and INCL + ABLA codes are compared with newly measured data to contribute to the ongoing process of code development, and yields are calculated for selected radionuclides using measured data.

  6. Phenomenological optical potential analysis of proton-carbon elastic scattering at 200 MeV

    NASA Technical Reports Server (NTRS)

    Bidasaria, H. B.; Townsend, L. W.

    1982-01-01

    Differential cross sections for 200 MeV protons elastically scattered from C-12 were analyzed utilizing a local, complex, spin-dependent optical potential with a harmonic well radial dependence. Analyses were performed using the WKB and eikonal approximations. For the latter, first-order corrections to he phase shifts were incorporated to account for the spin-orbit contribution. Large disagreement between theory and experiment was observed when the usual Thomas form for the spin-orbit potential was utilized. Substantial improvement was obtained by allowing the parameters in the central and spin-orbit potential terms to vary independently.

  7. Neutron-proton spin-correlation parameter A sub z z at 68 MeV

    SciTech Connect

    Hammans, M.; Brogli-Gysin, C.; Burzynski, S.; Campbell, J.; Haffter, P.; Henneck, R.; Lorenzon, W.; Pickar, M.A.; Sick, I. ); Konter, J.A.; Mango, S.; van den Brandt, B. )

    1991-05-06

    We report a first measurement of the spin-correlation parameter {ital A}{sub {ital z}{ital z}} in neutron-proton scattering at 67.5 MeV. The results, obtained in the angular range 105{degree}{le}{theta}{sub c.m.}{le}170{degree} with typical accuracies of 0.008, are highly sensitive to the {sup 3}{ital S}{sub 1}-{sup 3}{ital D}{sub 1} mixing parameter {epsilon}{sub 1}. A phase-shift analysis based on the current world data yields a value of {epsilon}{sub 1} significantly higher than predicted by modern potential models.

  8. Parity nonconservation in proton-water scattering at 800 MeV

    SciTech Connect

    Nagle, D.E.; Bowman, J.D.; Carlini, R.; Mischke, R.E.; Frauenfelder, H.; Harper, R.W.; Yuan, V.; McDonald, A.B.; Talaga, R.

    1982-01-01

    A search has been made for parity nonconservation in the scattering of 800 MeV polarized protons from an unpolarized water target. The result is for the longitudinal asymmetry, A/sub L/ = +(6.6 +- 3.2) x 10/sup -7/. Control runs with Pb, using a thickness which gave equivalent beam broadening from Coulomb multiple scattering, but a factor of ten less nuclear interactions than the water target, gave A/sub L/ = -(0.5 +- 6.0) x 10/sup -7/.

  9. Charged pions from the isotopes sup 58,64 Ni by 201 MeV protons

    SciTech Connect

    Palmeri, A.; Aiello, S.; Badala, A.; Barbera, R.; Pappalardo, G.S. ); Bimbot, L. ); Reide, F. ); Willis, N.; Oeschler, H.

    1989-08-01

    Charged pion production induced by 201 MeV protons on {sup 58}Ni and {sup 64}Ni has been studied. The double differential cross sections have been measured over a wide angular range. Different behavior of the angular distribution is observed for low and high energy pions. The yield of positive pions shows a pronounced forward peaked component. The deduced total production yields are about the same for ({ital p},{pi}{sup +}) on both isotopes whereas that for {sup 64}Ni({ital p},{pi}{sup {minus}}) is twice as large as for {sup 58}Ni({ital p},{pi}{sup {minus}}).

  10. Parity Nonconservation in Proton-water Scattering at 800 MeV

    DOE R&D Accomplishments Database

    Nagle, D. E.; Bowman, J. D.; Carlini, R.; Mischke, R. E.; Frauenfelder, H.; Harper, R. W.; Yuan, V.; McDonald, A. B.; Talaga, R.

    1982-01-01

    A search has been made for parity nonconservation in the scattering of 800 MeV polarized protons from an unpolarized water target. The result is for the longitudinal asymmetry, A{sub L} = +(6.6 +- 3.2) x 10{sup -7}. Control runs with Pb, using a thickness which gave equivalent beam broadening from Coulomb multiple scattering, but a factor of ten less nuclear interactions than the water target, gave A{sub L} = -(0.5 +- 6.0) x 10{sup -7}.

  11. Beam collimation and transport of quasineutral laser-accelerated protons by a solenoid field

    NASA Astrophysics Data System (ADS)

    Harres, K.; Alber, I.; Tauschwitz, A.; Bagnoud, V.; Daido, H.; Günther, M.; Nürnberg, F.; Otten, A.; Schollmeier, M.; Schütrumpf, J.; Tampo, M.; Roth, M.

    2010-02-01

    This article reports about controlling laser-accelerated proton beams with respect to beam divergence and energy. The particles are captured by a pulsed high field solenoid with a magnetic field strength of 8.6 T directly behind a flat target foil that is irradiated by a high intensity laser pulse. Proton beams with energies around 2.3 MeV and particle numbers of 1012 could be collimated and transported over a distance of more than 300 mm. In contrast to the protons the comoving electrons are strongly deflected by the solenoid field. They propagate at a submillimeter gyroradius around the solenoid's axis which could be experimentally verified. The originated high flux electron beam produces a high space charge resulting in a stronger focusing of the proton beam than expected by tracking results. Leadoff particle-in-cell simulations show qualitatively that this effect is caused by space charge attraction due to the comoving electrons. The collimation and transport of laser-accelerated protons is the first step to provide these unique beams for further applications such as postacceleration by conventional accelerator structures.

  12. POLARIZED PROTON ACCELERATION AT THE BROOKHAVEN AGS - AN UPDATE.

    SciTech Connect

    HUANG,H.; AHRENS,L.; ALESSI,J.; BAI,M.; BEEBE-WANG,J.; BROWN,K.A.; GLENN,W.; LUCCIO,A.U.; MACKAY,W.W.; MONTAG,C.; PTITSYN,V.; ROSER,T.; TSOUPAS,N.; ZELENSKI,A.; ZENO,K.; CADMAN,B.; SPINKA,H.; UNDERWOOD,D.; RANJBAR,V.

    2002-06-02

    The RHIC spin design goal assumes 2 x 10{sup 11} proton/bunch with 70% polarization. As the injector to RHIC, polarized protons have been accelerated at the AGS for years to increase the polarization transmission efficiency. Several novel techniques have been applied in the AGS to overcome the intrinsic and imperfection resonances. The present level of accelerator performance is discussed. Progress on understanding the beam polarization behavior is presented. The outlook and future plan are also discussed.

  13. Spallation yield of neutrons produced in thick lead target bombarded with 250 MeV protons

    NASA Astrophysics Data System (ADS)

    Chen, L.; Ma, F.; Zhanga, X. Y.; Ju, Y. Q.; Zhang, H. B.; Ge, H. L.; Wang, J. G.; Zhou, B.; Li, Y. Y.; Xu, X. W.; Luo, P.; Yang, L.; Zhang, Y. B.; Li, J. Y.; Xu, J. K.; Liang, T. J.; Wang, S. L.; Yang, Y. W.; Gu, L.

    2015-01-01

    The neutron yield from thick target of Pb irradiated with 250 MeV protons has been studied experimentally. The neutron production was measured with the water-bath gold method. The thermal neutron distributions in the water were determined according to the measured activities of Au foils. Corresponding results calculated with the Monte Carlo code MCNPX were compared with the experimental data. It was found out that the Au foils with cadmium cover significantly changed the spacial distribution of the thermal neutron field. The corrected neutron yield was deduced to be 2.23 ± 0.19 n/proton by considering the influence of the Cd cover on the thermal neutron flux.

  14. Proton-Deuteron Break-Up Measurements with Bina at 135 MeV

    NASA Astrophysics Data System (ADS)

    Eslami-Kalantari, M.; Amir-Ahmadi, H. R.; Biegun, A.; Gašparić, I.; Joulaeizadeh, L.; Kalantar-Nayestanaki, N.; Kistryn, St.; Kozela, A.; Mardanpour, H.; Messchendorp, J. G.; Moeini, H.; Ramazani-Moghaddam-Arani, A.; Shende, S. V.; Stephan, E.; Sworst, R.

    High-precision measurements of the proton-deuteron elastic and break-up reaction have been performed in the past at KVI and elsewhere with the aim to study three-nucleon force (3NF) effects. In the present work, we explored 3NF effects in the break-up scattering process by performing a measurement of vector analyzing powers and differential cross sections using a 135 MeV polarized-proton beam impinging on a liquid-deuterium target. For this study, we used a new experimental setup, Big Instrument for Nuclear-polarization Analysis, BINA, which covers almost the entire kinematical phase space of the break-up reaction. The results are interpreted with the help of state-of-the-art Faddeev calculations.

  15. Effects of nanosecond-scale prepulse on generation of high-energy protons in target normal sheath acceleration

    SciTech Connect

    Wang, W. P.; Shen, B. F.; Zhang, H.; Xu, Y.; Li, Y. Y.; Lu, X. M.; Wang, C.; Liu, Y. Q.; Shi, Y.; Leng, Y. X.; Liang, X. Y.; Li, R. X.; Xu, Z. Z.; Lu, J. X.; Wang, N. Y.

    2013-06-03

    A pulse cleaner based on noncollinear optical-parametric amplification and second-harmonic generation processes is used to improve the contrast of a laser of peak intensity {approx}2 Multiplication-Sign 10{sup 19} W/cm{sup 2} to {approx}10{sup 11} at 100 ps before the peak of the main pulse. A 7 MeV proton beam is observed when a 2.5 {mu}m-thick Al foil is irradiated by this high-contrast laser. The maximum proton energy decreases to 2.9 MeV when a low-contrast ({approx}10{sup 8}) laser is used. Two-dimensional particle-in-cell simulations combined with MULTI simulations show that the maximum proton energy sensitively relies on the detecting direction. The ns-time-scale prepulse can bend a thin target before the main pulse arrives, which reduces maximum proton energy in the target normal sheath acceleration.

  16. Stochastic spatial energy deposition profiles for MeV protons and keV electrons

    NASA Astrophysics Data System (ADS)

    Udalagama, C.; Bettiol, A. A.; Watt, F.

    2009-12-01

    With the rapid advances being made in novel high-energy ion-beam techniques such as proton beam writing, single-ion-event effects, ion-beam-radiation therapy, ion-induced fluorescence imaging, proton/ion microscopy, and ion-induced electron imaging, it is becoming increasingly important to understand the spatial energy-deposition profiles of energetic ions as they penetrate matter. In this work we present the results of comprehensive yet straightforward event-by-event Monte Carlo calculations that simulate ion/electron propagation and secondary electron ( δ ray) generation to yield spatial energy-deposition data. These calculations combine SRIM/TRIM features, EEDL97 data and volume-plasmon-localization models with a modified version of one of the newer δ ray generation models, namely, the Hansen-Kocbach-Stolterfoht. The development of the computer code DEEP (deposition of energy due to electrons and protons) offers a unique means of studying the energy-deposition/redistribution problem while still retaining the important stochastic nature inherent in these processes which cannot be achieved with analytical modeling. As an example of an application of DEEP we present results that compare the energy-deposition profiles of primary MeV protons and primary keV electrons in polymethymethacrylate. Such data are important when comparing proximity effects in the direct write lithography processes of proton-beam writing and electron-beam writing. Our calculations demonstrate that protons are able to maintain highly compact spatial energy-deposition profiles compared with electrons.

  17. Radiotherapy using a laser proton accelerator

    SciTech Connect

    Murakami, Masao; Hishikawa, Yoshio; Miyajima, Satoshi; Okazaki, Yoshiko; Sutherland, Kenneth L.; Abe, Mitsuyuki; Bulanov, Sergei V.; Daido, Hiroyuki; Esirkepov, Timur Zh.; Koga, James; Yamagiwa, Mitsuru; Tajima, Toshiki

    2008-06-24

    Laser acceleration promises innovation in particle beam therapy of cancer where an ultra-compact accelerator system for cancer beam therapy can become affordable to a broad range of patients. This is not feasible without the introduction of a technology that is radically different from the conventional accelerator-based approach. Because of its compactness and other novel characteristics, the laser acceleration method provides many enhanced capabilities.

  18. Neutron production for 250 MeV protons bombarding on thick grain-made tungsten target

    NASA Astrophysics Data System (ADS)

    Zhang, Xueying; Zhang, Yanbin; Ma, Fei; Ju, Yongqin; Chen, Liang; Zhang, Hongbin; Li, Yanyan; Wan, Bo; Wang, Jianguo; Ge, Honglin

    2015-08-01

    Neutron yield for 250 MeV protons incident on a tungsten target has been measured using the water bath method. The target was made of many randomly placed tungsten grains. Through analyzing the activity of Au foils, the neutron flux distribution in water was obtained. The neutrons slowing down process shows that the neutrons from tungsten have an average energy lower than neutrons from the lead target. The neutron yield was experimentally determined to be 2.02 ± 0.15 neutron/proton. Detailed simulation was also performed with the Geant4 toolkit. Comparison has been made with the experimentally derived neutron yield. It was found that, around 250 MeV, experimental results were described satisfactorily with a combination of high-energy spallation, low-energy neutron reaction and scattering. It was shown that the grain-packed target does not affect much the main neutronic properties, which are of crucial importance for the design of the spallation target.

  19. Spill-to-spill and daily proton energy consistency with a new accelerator control system.

    PubMed

    Moyers, M F; Ghebremedhin, A

    2008-05-01

    The Loma Linda University proton accelerator has had several upgrades installed including synchrotron dipole power supplies and a system for monitoring the beam energy. The consistency of the energy from spill-to-spill has been tested by measuring the depth ionization at the distal edge as a function of time. These measurements were made with a minimally equipped beamline to reduce interference from confounding factors. The consistency of the energy over several months was measured in a treatment room beamline using an ionization chamber based daily quality assurance device. The results showed that the energy of protons delivered from the accelerator (in terms of water equivalent range) was consistent from spill-to-spill to better than +/-0.03 mm at 70, 155, and 250 MeV and that the energy check performed each day in the treatment room over a several month period was within +/-0.11 mm (+/-0.06 MeV) at 149 MeV. These results are within the tolerances required for the energy stacking technique.

  20. A Monte Carlo Model for LET Spectra of 200 MeV Protons Used for Microelectronic Testing

    NASA Technical Reports Server (NTRS)

    O'Neill, Patrick M.; Culpepper, William X.

    2003-01-01

    The direct ionization Linear Energy Transfer (LET) for 200 MeV protons in silicon is much smaller than that for higher charged particles since LET increases as the square of the ion charge. However, occasionally the proton interacts with the silicon nuclei and produces a shower of fragments and a recoiling nucleus. When this happens, the LET produced is much greater than the direct ionization LET. Testing the single event effect susceptibility of components using energetic (200 MeV) protons is often the only viable option for system level testing commercial-off-the-shelf (COTS) avionics that have not been designed for space environments. However, the question of how a system tested with protons will perform in a heavy ion environment arises. Here the concern is not only with prediction of on-orbit upset rate, but also about possibility of on-orbit failures that were not observed during proton testing.

  1. Independent isotopic yields in 25 MeV and 50 MeV proton-induced fission of natU

    NASA Astrophysics Data System (ADS)

    Penttilä, H.; Gorelov, D.; Elomaa, V.-V.; Eronen, T.; Hager, U.; Hakala, J.; Jokinen, A.; Kankainen, A.; Karvonen, P.; Moore, I. D.; Parkkonen, J.; Peräjärvi, K.; Pohjalainen, I.; Rahaman, S.; Rinta-Antila, S.; Rissanen, J.; Rubchenya, V. A.; Saastamoinen, A.; Simutkin, V.; Sonoda, T.; Weber, C.; Voss, A.; Äystö, J.

    2016-04-01

    Independent isotopic yields for elements from Zn to La in the 25 MeV proton-induced fission of {}^{nat}U were determined with the JYFLTRAP facility. In addition, isotopic yields for Zn, Ga, Rb, Sr, Zr, Pd and Xe in the 50 MeV proton-induced fission of {}^{nat}U were measured. The deduced isotopic yield distributions are compared with a Rubchenya model, the GEF model with universal parameters and the semi-empirical Wahl model. Of these, the Rubchenya model gives the best overall agreement with the obtained data. Combining the isotopic yield data with mass yield data to obtain the absolute independent yields was attempted. The result depends on the mass yield distribution.

  2. 1 MeV, 10 kW DC electron accelerator for industrial applications

    NASA Astrophysics Data System (ADS)

    Nayak, B.; Acharya, S.; Bhattacharjee, D.; Bakhtsingh, R. I.; Rajan, R.; Sharma, D. K.; Dewangan, S.; Sharma, V.; Patel, R.; Tiwari, R.; Benarjee, S.; Srivastava, S. K.

    2016-03-01

    Several modern applications of radiation processing like medical sterilization, rubber vulcanization, polymerization, cross-linking and pollution control from thermal power stations etc. require D.C. electron accelerators of energy ranging from a few hundred keVs to few MeVs and power from a few kilowatts to hundreds of kilowatts. To match these requirements, a 3 MeV, 30 kW DC electron linac has been developed at BARC, Mumbai and current operational experience of 1 MeV, 10 kW beam power will be described in this paper. The LINAC composed mainly of Electron Gun, Accelerating Tubes, Magnets, High Voltage source and provides 10 kW beam power at the Ti beam window stably after the scanning section. The control of the LINAC is fully automated. Here Beam Optics study is carried out to reach the preferential parameters of Accelerating as well as optical elements. Beam trials have been conducted to find out the suitable operation parameters of the system.

  3. Materials irradiation facilities at the high-power Swiss proton accelerator complex

    NASA Astrophysics Data System (ADS)

    Wagner, Werner; Dai, Yong; Glasbrenner, Heike; Aebersold, Hans-Ulrich

    2007-04-01

    Within the Swiss proton accelerator complex at the Paul-Scherrer-Institute (PSI), several irradiation facilities are operated for investigation of materials behavior under high-dose irradiation conditions as well as for neutron activation analysis and isotope production. In LiSoR (liquid solid reaction), a liquid metal loop connected to the 72 MeV proton accelerator Injector 1, steel samples are irradiated while being in contact with flowing lead-bismuth-eutectic (LBE) at elevated temperatures and under tensile stress. In the spallation neutron source SINQ, the STIP program (SINQ Target Irradiation Program) allows materials irradiation under realistic spallation conditions, i.e. in a mixed spectrum of 570 MeV protons and spallation neutrons. Hundreds of samples, mainly austenitic and ferritic-martensitic steels such as 316L, T91 or F82H, were irradiated to doses up to 20 dpa as part of STIP. These also included steel samples in contact with liquid Hg and liquid LBE. MEGAPIE (MEGAwatt PIlot Experiment), a liquid metal target employing LBE, operated in SINQ during the second half of 2006, can be taken as a materials irradiation facility on its own. Adjacent to the target position, SINQ houses a neutron irradiation rabbit system serving activation analysis and isotope production.

  4. Visualization experiment of 30 MeV proton beam irradiated water target

    NASA Astrophysics Data System (ADS)

    Hwan Hong, Bong; Gun Yang, Tea; Su Jung, In; Soo Park, Yeun; Hee Cho, Hyung

    2011-11-01

    The nucleate boiling phenomena in a water target irradiated by 30 MeV proton beam were visualized experimentally. The beam size was 10 mm in diameter and beam current of 10, 15 and 20 μA were used, respectively. A target cavity of 4.5 cc in volume was filled with distilled water without atmosphere. A CMOS camera is used to record the phenomena through a side window. The temperature and pressure were measured during experiments. The depth of the Bragg peak was indicated by the blue light emission of the proton beam in the water target. In the case of 10 μA beam intensity, there was no visible phase change but fluxes by convection was observed at the Bragg peak and near the foil surface region. At 15 μA beam intensity, steam bubbles were generated by homogenous nuclear boiling at the Bragg peak and corrupted by cavitation at the upper region. The steam bubble generation point can be indicated by the blue light emission, which can show us the position of the Bragg peak. At 20 μΑ beam intensity, the steam bubbles were generated at Bragg peak and near the foil surface. The homogenous nucleate boiling at the Bragg peak was dominant and the heterogeneous nucleate boiling near the foil surface took place, occasionally. The cavitation of the steam bubble was also observed in the upper region within the target. The penetration depth of the proton beam was change along with the steam bubble formation. The blue light emission of the proton beam in water shows that the penetration depth of the proton beam becomes deeper when vapor bubbles are generated.

  5. Acceleration of Solar Wind Ions to 1 Mev by Electromagnetic Moguls in the Foreshock

    NASA Astrophysics Data System (ADS)

    Stasiewicz, K.; Strumik, M.; Markidis, S.; Eliasson, B.; Yamauchi, M.

    2013-05-01

    We present measurements from the ESA/NASA Cluster mission that show in situ acceleration of ions to energies of 1 MeV outside the bow shock. The observed heating can be associated with the presence of electromagnetic structures with strong spatial gradients (divergence) of the electric field that lead to ion gyro-phase breaking and to the onset of chaos in ion trajectories. It results in rapid, stochastic acceleration of ions in the direction perpendicular to the ambient magnetic field. The electric potential of the structures can be compared to a field of moguls on a ski slope, capable of accelerating and ejecting the fast running skiers out of piste. This mechanism may represent the universal, basic mechanism for perpendicular acceleration and heating of ions in the magnetosphere, the solar corona and in astrophysical plasmas.

  6. Source terms and attenuation lengths for estimating shielding requirements or dose analyses of proton therapy accelerators.

    PubMed

    Sheu, Rong-Jiun; Lai, Bo-Lun; Lin, Uei-Tyng; Jiang, Shiang-Huei

    2013-08-01

    Proton therapy accelerators in the energy range of 100-300 MeV could potentially produce intense secondary radiation, which must be carefully evaluated and shielded for the purpose of radiation safety in a densely populated hospital. Monte Carlo simulations are generally the most accurate method for accelerator shielding design. However, simplified approaches such as the commonly used point-source line-of-sight model are usually preferable on many practical occasions, especially for scoping shielding design or quick sensitivity studies. This work provides a set of reliable shielding data with reasonable coverage of common target and shielding materials for 100-300 MeV proton accelerators. The shielding data, including source terms and attenuation lengths, were derived from a consistent curve fitting process of a number of depth-dose distributions within the shield, which were systematically calculated by using MCNPX for various beam-target shield configurations. The general characteristics and qualities of this data set are presented. Possible applications in cases of single- and double-layer shielding are considered and demonstrated.

  7. Simulation on buildup of electron cloud in a proton circular accelerator

    NASA Astrophysics Data System (ADS)

    Li, Kai-Wei; Liu, Yu-Dong

    2015-10-01

    Electron cloud interaction with high energy positive beams are believed responsible for various undesirable effects such as vacuum degradation, collective beam instability and even beam loss in high power proton circular accelerators. An important uncertainty in predicting electron cloud instability lies in the detailed processes of the generation and accumulation of the electron cloud. The simulation on the build-up of electron cloud is necessary to further studies on beam instability caused by electron clouds. The China Spallation Neutron Source (CSNS) is an intense proton accelerator facility now being built, whose accelerator complex includes two main parts: an H-linac and a rapid cycling synchrotron (RCS). The RCS accumulates the 80 MeV proton beam and accelerates it to 1.6 GeV with a repetition rate of 25 Hz. During beam injection with lower energy, the emerging electron cloud may cause serious instability and beam loss on the vacuum pipe. A simulation code has been developed to simulate the build-up, distribution and density of electron cloud in CSNS/RCS. Supported by National Natural Science Foundation of China (11275221, 11175193)

  8. Radiation effects on silicon bipolar transistors caused by 3-10 MeV protons and 20-60 MeV bromine ions

    NASA Astrophysics Data System (ADS)

    Li, Xingji; Geng, Hongbin; Lan, Mujie; Liu, Chaoming; Yang, Dezhuang; He, Shiyu

    2010-03-01

    The current gain degradation in silicon NPN bipolar junction transistors (BJTs) was examined under irradiation with 3-10 MeV protons and 20-60 MeV bromine (Br) ions with various dose levels. To characterize the radiation damage of the NPN BJTs, the ionizing dose D i and displacement dose D d as a function of chip depth in the NPN BJTs were calculated for both the protons and Br ions with different energies. Based on the irradiation testing and calculated results, it is shown that the current gain degradation of NPN BJTs is sensitive to the ratio of D d/( D d+ D i) in the sensitive region given by protons and Br ions. The irradiation particles (protons and Br ions), which give larger D d/( D d+ D i) at a given total dose, would generate more severe damage to the NPN BJTs. The reciprocal of the gain variation as a function of the displacement dose was compared, showing that the Messenger-Spratt equation becomes relevant to describe the experimental data, when the ratio of the D d/( D d+ D i) are larger and the displacement dose are higher than a certain value.

  9. Near realtime forecasting of MeV protons on the basis of sub relativistic electrons

    NASA Astrophysics Data System (ADS)

    Labrenz, Johannes; Heber, Bernd; Kuehl, Patrick; Sarlanis, Christos; Malandraki, Olga; Posner, Arik

    2016-04-01

    A major impact on human and robotic space exploration activities is the sudden and prompt occurrence of solar energetic ion events. In order to provide up to an hour warning before these particles arrive at Earth, relativistic electron and below 50 MeV proton data from the Electron Proton Helium Instrument (EPHIN) on SOHO were used to implement the 'Relativistic Electron Alert System for Exploration (REleASE)'. It has been demonstrated that the analysis of relativistic electron time profiles provides a low miss and false alarm rate. High Energy Solar Particle Events foRecastIng and Analysis (HESPERIA) is a project funded within the European Union's Horizon 2020 research and innovation programme (PROTEC-1-2014 Call: Space Weather). Within this project the REleASE forecasting scheme was rewritten in the open access programming language PYTHON and will be made public. As a next step, we have analyzed the possibility to also use, along with relativistic electrons (v > 0.9 c) provided by SOHO, near-relativistic (v <0.8 c) electron measurements from other instruments like the Electron Proton Alpha Monitor (EPAM) aboard the Advanced Composition Explorer (ACE). This would prove to be particularly useful during periods that SOHO does not provide continuous near real-time data. We show that the ACE/EPAM observations can be adapted to the REleASE forecasting scheme to provide reliable SEP forecasts. A comparison of measured and forecast proton intensities by SOHO/EPHIN and ACE/EPAM will be presented. In addition we investigated the false alarm rate and detection probability of solar ion events. This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 637324.

  10. Energetics and energy scaling of quasi-monoenergetic protons in laser radiation pressure acceleration

    SciTech Connect

    Liu Tungchang; Shao Xi; Liu Chuansheng; Su Jaojang; Dudnikova, Galina; Sagdeev, Roald Z.; Eliasson, Bengt; Tripathi, Vipin

    2011-12-15

    Theoretical and computational studies of the ion energy scaling of the radiation pressure acceleration of an ultra-thin foil by short pulse intense laser irradiation are presented. To obtain a quasi-monoenergetic ion beam with an energy spread of less than 20%, two-dimensional particle-in-cell simulations show that the maximum energy of the quasi-monoenergetic ion beam is limited by self-induced transparency at the density minima caused by the Rayleigh-Taylor instability. For foils of optimal thickness, the time over which Rayleigh-Taylor instability fully develops and transparency occurs is almost independent of the laser amplitude. With a laser power of about one petawatt, quasi-monogenetic protons with 200 MeV and carbon ions with 100 MeV per nucleon can be obtained, suitable for particle therapy applications.

  11. Fermilab's Proton Accelerator Complex : World Record Performance and Upgrade Plans

    NASA Astrophysics Data System (ADS)

    Shiltsev, Vladimir

    2017-01-01

    The flagship of Fermilab's long term research program is the Deep Underground Neutrino Experiment (DUNE), located Sanford Underground Research Facility (SURF) in Lead, South Dakota, which will study neutrino oscillations with a baseline of 1300 km. The neutrinos will be produced in the Long Baseline Neutrino Facility (LBNF), a proposed new beam line from Fermilab's Main Injector. The physics goals of the DUNE require a proton beam with a power of some 2.4 MW at 120 GeV, which is roughly four times the current maximum power. Here I discuss current performance of the Fermilab proton accelerator complex, our plans for construction of the SRF proton linac as key part of the Proton Improvement Plan-II (PIP-II), outline the main challenges toward multi-MW beam power operation of the Fermilab accelerator complex and the staged plan to achieve the required performance over the next 15 years.

  12. Mutation effect of MeV protons on bioflocculant bacteria Bacillus cereus

    NASA Astrophysics Data System (ADS)

    Yang, Y. N.; Ren, N.; Xue, J. M.; Yang, J.; Rong, B. L.

    2007-09-01

    A 3.2 MeV proton beam was used to irradiate bioflocculant bacteria (Bacillus cereus) to achieve mutation. The ion fluence ranged from 1011 to 1014/cm2. Most of the bacteria were killed when the ion fluence reached 1012 ions/cm2. The survival ratio drops in an exponential way on further increasing the ion fluence. The flocculating activity of 7 samples out of 51 showed a positive change, and a perfect mutant C7-23 with a stable high capacity of bioflocculant production was found. RAPD measurements showed that a new lane appears in this sample. The flocculating activity of the C7-23 bacteria increased by factors of 22%, 54% and 217% under pH values of 4, 7 or 10, respectively.

  13. Development of a 20 MeV Dielectric-Loaded Test Accelerator

    SciTech Connect

    Gold, S.H.; Kinkead, A.K.; Gai, W.; Power, J.G.; Konecny, R.; Jing, C.; Long, J.; Tantawi, S.G.; Nantista, C.D.; Fliflet, A.W.; Lombardi, M.; Lewis, D.; Bruce, R.W.; /Unlisted

    2007-04-13

    This paper presents a progress report on a joint project by the Naval Research Laboratory (NRL) and Argonne National Laboratory (ANL), in collaboration with the Stanford Linear Accelerator Center (SLAC), to develop a dielectric-loaded test accelerator in the magnicon facility at NRL. The accelerator will be powered by an experimental 11.424-GHz magnicon amplifier that presently produces 25 MW of output power in a {approx}250-ns pulse at up to 10 Hz. The accelerator will include a 5-MeV electron injector originally developed at the Tsinghua University in Beijing, China, and can incorporate DLA structures up to 0.5 m in length. The DLA structures are being developed by ANL, and shorter test structures fabricated from a variety of dielectric materials have undergone testing at NRL at gradients up to {approx}8 MV/m. SLAC has developed components to distribute the power from the two magnicon output arms to the injector and to the DLA accelerating structure with separate control of the power ratio and relative phase. RWBruce Associates, Inc., working with NRL, has investigated means to join short ceramic sections into a continuous accelerator tube by a brazing process using an intense 83-GHz beam. The installation and testing of the first dielectric-loaded test accelerator, including injector, DLA test structure, and spectrometer, should take place within the next year.

  14. Study of the radioactivity induced in air by a 15-MeV proton beam.

    PubMed

    Braccini, S; Ereditato, A; Nesteruk, K P; Scampoli, P; Zihlmann, K

    2015-02-01

    Radioactivity induced by a 15-MeV proton beam extracted into air was studied at the beam transport line of the 18-MeV cyclotron at the Bern University Hospital (Inselspital). The produced radioactivity was calculated and measured by means of proportional counters located at the main exhaust of the laboratory. These devices were designed for precise assessment of air contamination for radiation protection purposes. The main produced isotopes were (11)C, (13)N and (14)O. Both measurements and calculations correspond to two different irradiation conditions. In the former, protons were allowed to travel for their full range in air. In the latter, they were stopped at the distance of 1.5 m by a beam dump. Radioactivity was measured continuously in the exhausted air starting from 2 min after the end of irradiation. For this reason, the short-lived (14)O isotope gave a negligible contribution to the measured activity. Good agreement was found between the measurements and the calculations within the estimated uncertainties. Currents in the range of 120-370 nA were extracted in air for 10-30 s producing activities of 9-22 MBq of (11)C and (13)N. The total activities for (11)C and (13)N per beam current and irradiation time for the former and the latter irradiation conditions were measured to be (3.60 ± 0.48) × 10(-3) MBq (nA s)(-1) and (2.89 ± 0.37) × 10(-3) MBq (nA s)(-1), respectively.

  15. Solar Energetic Protons at >500 MeV in the Sun's Atmosphere and in Interplanetary Space: The 2012 May 17 Ground Level Event

    NASA Astrophysics Data System (ADS)

    Tylka, A. J.; Dietrich, W. F.; Murphy, R. J.; Ng, C. K.; Share, G. H.; Shea, M. A.; Smart, D. F.

    2013-12-01

    For energetic particles produced at or near the Sun, it is generally recognized that at least two distinct acceleration mechanisms are operating: (1) acceleration at coronal sites of magnetic reconnection, generally associated with flares and (2) acceleration at shocks driven by fast coronal mass ejections (CMEs). It is also generally recognized that both mechanisms can accelerate protons to multi-GeV energies, although the precise ways in which this comes about is still an area of active research. Moreover, when a very large solar energetic particle (SEP) event is observed in interplanetary space, both a large flare and the launch of a fast CME are observed nearly simultaneously (unless the flare occurs behind a limb). Numerous studies have tried to sort out how these two energetic phenomena might contribute to the particles observed in interplanetary space. Are the flare-accelerated particles confined to closed field lines? Or do some of them 'leak' to open field lines, thereby allowing them to contribute to the interplanetary SEPs? If so, how large is the flare contribution relative to particles accelerated by the CME-driven shock? To date, there is no consensus on any of these issues, particularly at the highest energies, where the release of particles from the neighborhood of the Sun generally persists for only a short period of time. Although Cycle 24 has thus far been disappointing in its rate of SEP events, the one Ground Level Event (GLE) observed so far, on 2012 May 17, provides the opportunity to address these issues in a more thorough manner than ever before. Fermi has reported sustained emission of >100 MeV gamma-rays that result from proton-induced pion-production in the solar atmosphere. At 1 AU, we have observations of the GLE from the world-wide neutron network, from which the event-integrated proton spectrum and the time-dependent anisotropy have been extracted. This event was also observed at both STEREO spacecraft, giving us the ability to model

  16. Proton linear accelerators: A theoretical and historical introduction

    SciTech Connect

    Lapostolle, P.M.

    1989-07-01

    From the beginning, the development of linear accelerators has followed a number of different directions. This report surveys the basic ideas and general principles of such machines, pointing out the problems that have led to the various improvements, with the hope that it may also aid further progress. After a brief historical survey, the principal aspects of accelerator theory are covered in some detail: phase stability, focusing, radio-frequency accelerating structures, the detailed calculation of particle dynamics, and space-charge effects at high intensities. These developments apply essentially to proton and ion accelerators, and only the last chapter deals with a few aspects relative to electrons. 134 refs.

  17. Optimization of Electron Beam Transport for a 3-MeV DC Accelerator

    NASA Astrophysics Data System (ADS)

    Baruah, S.; Bhattacharjee, D.; Tiwari, R.; Sahu, G. K.; Thakur, K. B.; Mittal, K. C.; Gantayet, L. M.

    2012-11-01

    Transport of a low-current-density electron beam is simulated for an electrostatic accelerator system. Representative charged particles are uniformly assigned for emission from a circular indirectly-heated cathode of an axial electron gun. The beam is accelerated stepwise up to energy of 1 MeV electrostatically in a length-span of ~3 m using multiple accelerating electrodes in a column of ten tubes. The simulation is done under relativistic condition and the effect of the magnetic field induced by the cathode-heating filament current is taken into account. The beam diameter is tracked at different axial locations for various settings of the electrode potentials. Attempts have been made to examine and explain data on beam transport efficiency obtained from experimental observations.

  18. Acceleration of Thermal Protons by Generic Phenomenological Mechanisms

    NASA Astrophysics Data System (ADS)

    Petrosian, Vahé; Kang, Byungwoo

    2015-11-01

    We investigate heating and acceleration of protons from a thermal gas with a generic diffusion and acceleration model, and subject to Coulomb scattering and energy loss, as was done by Petrosian & East for electrons. As protons gain energy their loss to electrons becomes important. Thus, we need to solve the coupled proton-electron kinetic equation. We numerically solve the coupled Fokker-Planck equations and compute the time evolution of the spectra of both particles. We show that this can lead to a quasi-thermal component plus a high-energy nonthermal tail. We determine the evolution of the nonthermal tail and the quasi-thermal component. The results may be used to explore the possibility of inverse bremsstrahlung radiation as a source of hard X-ray emissions from hot sources such as solar flares, accretion disk coronas, and the intracluster medium of galaxy clusters. We find that the emergence of nonthermal protons is accompanied by excessive heating of the entire plasma, unless the turbulence needed for scattering and acceleration is steeper than Kolmogorov and the acceleration parameters, the duration of the acceleration, and/or the initial distributions are significantly fine-tuned. These results severely constrain the feasibility of the nonthermal inverse bremsstrahlung process producing hard X-ray emissions. However, the nonthermal tail may be the seed particles for further re-acceleration to relativistic energies, say by a shock. In the Appendix we present some tests of the integrity of the algorithm used and present a new formula for the energy loss rate due to inelastic proton-proton interactions.

  19. On the acceleration of ions by interplanetary shock waves. 3: High time resolution observations of CIR proton events

    NASA Technical Reports Server (NTRS)

    Pesses, M. E.; Vanallen, J. A.; Tsurutani, B. T.; Smith, E. J.

    1981-01-01

    Observations within + or - 3 hours of corotating interaction region (CIR) shock waves of proton intensities, pitch angle distribution and crude differential energy spectra of the range of 0.6 E sub p 3.4 MeV are presented. The principle result is the evidence for the persistent flow of particles away from the shock. The observations are found to be in good agreement with the hypothesis of local interplanetary shock acceleration by the shock drift and compression mechanisms. The same set of observations strongly suggest that transit time damping does not play an important role in the acceleration of protons to 1 MeV in the immediate vicinity of CIR shocks.

  20. Future laser-accelerated proton beams at ELI-Beamlines as potential source of positron emitters for PET

    NASA Astrophysics Data System (ADS)

    Amato, E.; Italiano, A.; Margarone, D.; Pagano, B.; Baldari, S.; Korn, G.

    2016-04-01

    The development of novel compact PET radionuclide production systems is of great interest to promote the diffusion of PET diagnostics, especially in view of the continuous development of novel, fast and efficient, radiopharmaceutical methods of labeling. We studied the feasibility to produce clinically-relevant amounts of PET isotopes by means of laser-accelerated proton sources expected at the ELI-Beamlines facility where a PW, 30 fs, 10 Hz laser system will be available. The production yields of several positron emitters were calculated through the TALYS software, by taking into account three possible scenarios of broad proton spectra expected, with maximum energies ranging from about 8 MeV to 100 MeV. With the hypothesized proton fluencies, clinically-relevant amounts of radionuclides can be obtained, suitable to prepare single doses of radiopharmaceuticals exploiting modern fast and efficient labeling systems.

  1. Calibration of GafChromic EBT3 for absorbed dose measurements in 5 MeV proton beam and {sup 60}Co γ-rays

    SciTech Connect

    Vadrucci, M. Ronsivalle, C.; Marracino, F.; Montereali, R. M.; Picardi, L.; Piccinini, M.; Vincenti, M. A.; Esposito, G.; De Angelis, C.; Cherubini, R.; Pimpinella, M.

    2015-08-15

    Purpose: To study EBT3 GafChromic film in low-energy protons, and for comparison purposes, in a reference {sup 60}Co beam in order to use it as a calibrated dosimetry system in the proton irradiation facility under construction within the framework of the Oncological Therapy with Protons (TOP)-Intensity Modulated Proton Linear Accelerator for RadioTherapy (IMPLART) Project at ENEA-Frascati, Italy. Methods: EBT3 film samples were irradiated at the Istituto Nazionale di Fisica Nucleare—Laboratori Nazionali di Legnaro, Italy, with a 5 MeV proton beam generated by a 7 MV Van de Graaff CN accelerator. The nominal dose rates used were 2.1 Gy/min and 40 Gy/min. The delivered dose was determined by measuring the particle fluence and the energy spectrum in air with silicon surface barrier detector monitors. A preliminary study of the EBT3 film beam quality dependence in low-energy protons was conducted by passively degrading the beam energy. EBT3 films were also irradiated at ENEA-National Institute of Ionizing Radiation Metrology with gamma radiation produced by a {sup 60}Co source characterized by an absorbed dose to water rate of 0.26 Gy/min as measured by a calibrated Farmer type ionization chamber. EBT3 film calibration curves were determined by means of a set of 40 film pieces irradiated to various doses ranging from 0.5 Gy to 30 Gy absorbed dose to water. An EPSON Expression 11000XL color scanner in transmission mode was used for film analysis. Scanner response stability, intrafilm uniformity, and interfilm reproducibility were verified. Optical absorption spectra measurements were performed on unirradiated and irradiated EBT3 films to choose the most sensitive color channel to the dose range used. Results: EBT3 GafChromic films show an under response up to about 33% for low-energy protons with respect to {sup 60}Co gamma radiation, which is consistent with the linear energy transfer dependence already observed with higher energy protons, and a negligible dose

  2. Transverse Beam Emittance Measurements of a 16 MeV Linac at the Idaho Accelerator Center

    SciTech Connect

    S. Setiniyaz, T.A. Forest, K. Chouffani, Y. Kim, A. Freyberger

    2012-07-01

    A beam emittance measurement of the 16 MeV S-band High Repetition Rate Linac (HRRL) was performed at Idaho State University's Idaho Accelerator Center (IAC). The HRRL linac structure was upgraded beyond the capabilities of a typical medical linac so it can achieve a repetition rate of 1 kHz. Measurements of the HRRL transverse beam emittance are underway that will be used to optimize the production of positrons using HRRL's intense electron beam on a tungsten converter. In this paper, we describe a beam imaging system using on an OTR screen and a digital CCD camera, a MATLAB tool to extract beamsize and emittance, detailed measurement procedures, and the measured transverse emittances for an arbitrary beam energy of 15 MeV.

  3. Enhancing proton acceleration by using composite targets

    SciTech Connect

    Bulanov, S. S.; Esarey, E.; Schroeder, C. B.; Bulanov, S. V.; Esirkepov, T. Zh.; Kando, M.; Pegoraro, F.; Leemans, W. P.

    2015-07-10

    Efficient laser ion acceleration requires high laser intensities, which can only be obtained by tightly focusing laser radiation. In the radiation pressure acceleration regime, where the tightly focused laser driver leads to the appearance of the fundamental limit for the maximum attainable ion energy, this limit corresponds to the laser pulse group velocity as well as to another limit connected with the transverse expansion of the accelerated foil and consequent onset of the foil transparency. These limits can be relaxed by using composite targets, consisting of a thin foil followed by a near critical density slab. Such targets provide guiding of a laser pulse inside a self-generated channel and background electrons, being snowplowed by the pulse, compensate for the transverse expansion. The use of composite targets results in a significant increase in maximum ion energy, compared to a single foil target case.

  4. Enhanced proton acceleration in an applied longitudinal magnetic field

    NASA Astrophysics Data System (ADS)

    Arefiev, A.; Toncian, T.; Fiksel, G.

    2016-10-01

    Using two-dimensional particle-in-cell simulations, we examine how an externally applied strong magnetic field impacts proton acceleration in laser-irradiated solid-density targets. We find that a kT-level external magnetic field can sufficiently inhibit transverse transport of hot electrons in a flat laser-irradiated target. While the electron heating by the laser remains mostly unaffected, the reduced electron transport during proton acceleration leads to an enhancement of maximum proton energies and the overall number of energetic protons. The resulting proton beam is much better collimated compared to a beam generated without applying a kT-level magnetic field. A factor of three enhancement of the laser energy conversion efficiency into multi-MeV protons is another effect of the magnetic field. The required kT-level magnetic fields are becoming feasible due to a significant progress that has been made in generating magnetic fields with laser-driven coils using ns-long laser pulses. The possibility of improving characteristics of laser-driven proton beams using such fields is a strong motivation for further development of laser-driven magnetic field capabilities.

  5. Enhanced proton acceleration in an applied longitudinal magnetic field

    NASA Astrophysics Data System (ADS)

    Toncian, Toma; Arefiev, Alexey; Fiksel, Gennady

    2016-10-01

    Using two-dimensional particle-in-cell simulations, we examine how an externally applied strong magnetic impacts proton acceleration in laser-irradiated solid-density targets. We find that a kT-level external magnetic field can sufficiently inhibit transverse transport of hot electrons in a flat laser-irradiated target. While the electron heating by the laser remains mostly unaffected, the reduced electron transport during proton acceleration leads to an enhancement of maximum proton energies and the overall number of energetic protons. The resulting proton beam is much better collimated compared to a beam generated without applying a kT-level magnetic field. A factor of three enhancement of the laser energy conversion efficiency into multi-MeV protons is another effect of the magnetic field. The required kT magnetic fields are becoming feasible due to a significant progress that has been made in generating magnetic fields with laser-driven coils using ns-long laser pulses. The predicted improved characteristics of laser-driven proton beams would be critical for a number of applications. The work was supported by U.S. Department of Energy - National Nuclear Security Administration Cooperative Agreement No. DE-NA0002008. HPC resources were provided by the Texas Advanced Computing Center at The University of Texas.

  6. Proton-proton correlations at small relative momentum in neon-nucleus collisions at E/A=400 and 800 MeV

    NASA Technical Reports Server (NTRS)

    Dupieux, P.; Alard, J. P.; Augerat, J.; Babinet, R.; Bastid, N.; Brochard, F.; Charmensat, P.; De Marco, N.; Fanet, H.; Fodor, Z.; Fraysse, L.; Girard, J.; Gorodetzky, P.; Gosset, J.; Laspalles, C.; Lemaire, M. C.; L'Hote, D.; Lucas, B.; Marroncle, J.; Montarou, G.; Parizet, M. J.; Poitou, J.; Qassoud, D.; Racca, C.; Schimmerling, W.

    1988-01-01

    Proton-proton small angle correlations have been measured in neon-nucleus collisions, using the 4 pi detector Diogene, at 400 and 800 MeV per nucleon incident energies. Values of the size of the emitting region are obtained by comparison with the Koonin formula, taking into account the biases of the apparatus. The dependence of the density on target mass and incident energy is also analysed.

  7. Proton-proton correlations at small relative momentum in neon-nucleus collisions at E/A=400 and 800 MeV.

    PubMed

    Dupieux, P; Alard, J P; Augerat, J; Babinet, R; Bastid, N; Brochard, F; Charmensat, P; De Marco, N; Fanet, H; Fodor, Z; Fraysse, L; Girard, J; Gorodetzky, P; Gosset, J; Laspalles, C; Lemaire, M C; L'Hôte, D; Lucas, B; Marroncle, J; Montarou, G; Parizet, M J; Poitou, J; Qassoud, D; Racca, C; Schimmerling, W

    1988-01-07

    Proton-proton small angle correlations have been measured in neon-nucleus collisions, using the 4 pi detector Diogene, at 400 and 800 MeV per nucleon incident energies. Values of the size of the emitting region are obtained by comparison with the Koonin formula, taking into account the biases of the apparatus. The dependence of the density on target mass and incident energy is also analysed.

  8. Dynamic Pressure of Liquid Mercury Target During 800-MeV Proton Thermal Shock Tests

    SciTech Connect

    Allison, S.W.; Andriulli, J.B.; Cates, M.R.; Earl. D.D.; Haines, J.R.; Morrissey, F.X.; Tsai, C.C.; Wender, S.

    2000-02-01

    Described here are efforts to diagnose transient pressures generated by a short-pulse (about 0.5 microseconds) high intensity proton ({approximately} 2 * 10 14 per pulse) beam. Proton energy is 800-MeV. The tests were performed at the Los Alamos Neutron Science Center - Weapons Neutron Research (LANSCE-WNR). Such capability is required for understanding target interaction for the Spallation Neutron Source project as described previously at this conference.1-4 The main approach to effect the pressure measurements utilized the deflection of a diaphragm in intimate contact with the mercury. There are a wide variety of diaphragm-deflection methods used in scientific and industrial applications. Many deflection-sensing approaches are typically used, including, for instance, capacitive and optical fiber techniques. It was found, however, that conventional pressure measurement using commercial pressure gages with electrical leads was not possible due to the intense nuclear radiation enviro nment. Earlier work with a fiber optic strain gauge demonstrated the viability of using fiber optics for this environment.

  9. Production of radionuclides in artificial meteorites irradiated isotropically with 600 MeV protons

    NASA Technical Reports Server (NTRS)

    Michel, R.; Dragovitsch, P.; Englert, P.; Herpers, U.

    1986-01-01

    The understanding of the production of cosmogenic nuclides in small meteorites (R is less than 40 cm) still is not satisfactory. The existing models for the calculation of depth dependent production rates do not distinguish between the different types of nucleons reacting in a meteorite. They rather use general depth dependent particle fluxes to which cross sections have to be adjusted to fit the measured radionuclide concentrations. Some of these models can not even be extended to zero meteorite sizes without logical contradictions. Therefore, a series of three thick target irradiations was started at the 600 MeV proton beam of the CERN isochronuous cyclotron in order to study the interactions of small stony meteorites with galactic protons. The homogeneous 4 pi irradiation technique used provides a realistic meteorite model which allows a direct comparison of the measured depth profiles with those in real meteorites. Moreover, by the simultaneous measurement of thin target production cross sections one can differentiate between the contributions of primary and secondary nucleons over the entire volume of the artificial meteorite.

  10. Shielding variation effects for 250 MeV protons on tissue targets.

    PubMed

    Brandl, A; Hranitzky, C; Rollet, S

    2005-01-01

    This paper provides results of computer simulation studies with the goal to analyse issues regarding radiation protection for personnel, patients and third persons involved in hadron therapy treatment. The treatment room and the patient are modelled by simple cylindrical geometries at incident proton energies of 250 MeV. Monte Carlo simulations of the energy and angular dependence of proton, neutron and photon radiation fields and resulting ambient dose equivalent distributions outside the shielding walls are performed. In order to investigate systematic uncertainties due to the shielding materials and inherent to the computer models, various concrete compositions, densities and water contents are modelled, and the influence of simulation parameters on the results obtained is determined. Generally, good agreement is found between results provided by MCNPX and FLUKA computer codes. Variations in neutron ambient dose attenuation from -50 to +/-30% are found due to varying concrete composition. Changes in the water content of the concrete in the order of 8% may cause variations up to 20%.

  11. Estimation of thermal neutron fluences in the concrete of proton accelerator facilities from 36Cl production

    NASA Astrophysics Data System (ADS)

    Bessho, K.; Matsumura, H.; Miura, T.; Wang, Q.; Masumoto, K.; Hagura, H.; Nagashima, Y.; Seki, R.; Takahashi, T.; Sasa, K.; Sueki, K.; Matsuhiro, T.; Tosaki, Y.

    2007-06-01

    The thermal neutron fluence that poured into the shielding concrete of proton accelerator facilities was estimated from the in situ production of 36Cl. The thermal neutron fluences at concrete surfaces during 10-30 years of operation were in the range of 1012-1014 n/cm2. The maxima in thermal neutron fluences were observed at ≈5-15 cm in the depths analyzed for 36Cl/35Cl by AMS. These characteristics imply that thermalization of neutrons occurred inside the concrete. Compared to the several tens of MeV cyclotrons, secondary neutrons penetrate deeper into the concrete at the high-energy accelerators possessing acceleration energies of 400 MeV and 12 GeV. The attenuation length of neutrons reflects the energy spectra of secondary neutrons emitted by the nuclear reaction at the beam-loss points. Increasing the energy of secondary neutrons shifts the maximum in the thermal neutron fluences to deeper positions. The data obtained in this study will be useful for the radioactive waste management at accelerator facilities.

  12. Accelerating slow excited state proton transfer

    PubMed Central

    Stewart, David J.; Concepcion, Javier J.; Brennaman, M. Kyle; Binstead, Robert A.; Meyer, Thomas J.

    2013-01-01

    Visible light excitation of the ligand-bridged assembly [(bpy)2RuaII(L)RubII(bpy)(OH2)4+] (bpy is 2,2′-bipyridine; L is the bridging ligand, 4-phen-tpy) results in emission from the lowest energy, bridge-based metal-to-ligand charge transfer excited state (L−•)RubIII-OH2 with an excited-state lifetime of 13 ± 1 ns. Near–diffusion-controlled quenching of the emission occurs with added HPO42− and partial quenching by added acetate anion (OAc−) in buffered solutions with pH control. A Stern–Volmer analysis of quenching by OAc− gave a quenching rate constant of kq = 4.1 × 108 M−1⋅s−1 and an estimated pKa* value of ∼5 ± 1 for the [(bpy)2RuaII(L•−)RubIII(bpy)(OH2)4+]* excited state. Following proton loss and rapid excited-state decay to give [(bpy)2RuaII(L)RubII(bpy)(OH)3+] in a H2PO4−/HPO42− buffer, back proton transfer occurs from H2PO4− to give [(bpy)2RuaII(L)Rub(bpy)(OH2)4+] with kPT,2 = 4.4 × 108 M−1⋅s−1. From the intercept of a plot of kobs vs. [H2PO4−], k = 2.1 × 106 s−1 for reprotonation by water providing a dramatic illustration of kinetically limiting, slow proton transfer for acids and bases with pKa values intermediate between pKa(H3O+) = −1.74 and pKa(H2O) = 15.7. PMID:23277551

  13. Polarized proton acceleration program at the AGS and RHIC

    SciTech Connect

    Lee, Y.Y.

    1995-06-01

    Presented is an overview of the program for acceleration of polarized protons in the AGS and their injection into the RHIC collider. The problem of depolarizing resonances in strong focusing circulator accelerators is discussed. The intrinsic resonances are jumped over by the fast tune jump, and a partial Siberian Snake is used to compensate for over forty imperfection resonances in the AGS. Two sets of full Siberian Snake and spin rotators will be employed in RHIC.

  14. The streaming of 1.3 - 2.3 MeV cosmic-ray protons during periods between prompt solar particle events. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Marshall, F. E.

    1977-01-01

    The anisotropy of 1.3 to 2.3 MeV protons in interplanetary space was measured using the Caltech electron/isotope spectrometer aboard IMP-7 for 317 6 hour periods from 72/273 to 74/2. Periods dominated by prompt solar particle events are not included. The convective and diffusive anisotropies were determined from the observed anisotropy using concurrent solar wind speed measurements and observed energy spectra. The diffusive flow of particles was found to be typically toward the sun, indicating a positive radial gradient in the particle density. This anisotropy was inconsistent with previously proposed sources of low energy proton increases seen at 1 AU which involve continual solar acceleration. The typical properties of this new component of low-energy cosmic rays were determined for this period which is near solar minimum.

  15. Estimate of the radiation source term for 18F production via thick H218O targets bombarded with 18 MeV protons

    NASA Astrophysics Data System (ADS)

    Cruzate, Juan Ángel

    2015-12-01

    The positron-emitting radionuclide most important from the point of view of radiation protection is 18F. This isotope is usually produced by bombarding 18O-enriched water with protons. Currently there are few experimental data on the radiation source term generated during these reactions. In addition, presently there is no theoretical estimates of this source term, for use in radiation protection, validated by experimental data. Up till now this term is calculated by using nuclear interactions' simulation codes, such as ALICE91. An estimate of the energy spectra for neutrons and photons, induced by 18 MeV protons on H218O target, have been calculated by using MCNPX code with cross sections from release 0 of ENDF/B VII library for all materials except 18O, for which TENDL-2012 library was used. This estimate was validated against a recent experiment carried out at the Japan Atomic Energy Agency (JAEA). The calculated spectra have generally well reproduced experiments. The results show that the calculated radiation source term may be used to estimate the neutron activation of the accelerator components and the cyclotron building, to calculate the cyclotron shielding, and to carry out radiation protection evaluations in general, for the case of cyclotrons producing 18F by means of the 18O(p,n)18F nuclear reactions, for proton energies up to 18 MeV.

  16. Rapid acceleration of protons upstream of earthward propagating dipolarization fronts

    PubMed Central

    Ukhorskiy, AY; Sitnov, MI; Merkin, VG; Artemyev, AV

    2013-01-01

    [1] Transport and acceleration of ions in the magnetotail largely occurs in the form of discrete impulsive events associated with a steep increase of the tail magnetic field normal to the neutral plane (Bz), which are referred to as dipolarization fronts. The goal of this paper is to investigate how protons initially located upstream of earthward moving fronts are accelerated at their encounter. According to our analytical analysis and simplified two-dimensional test-particle simulations of equatorially mirroring particles, there are two regimes of proton acceleration: trapping and quasi-trapping, which are realized depending on whether the front is preceded by a negative depletion in Bz. We then use three-dimensional test-particle simulations to investigate how these acceleration processes operate in a realistic magnetotail geometry. For this purpose we construct an analytical model of the front which is superimposed onto the ambient field of the magnetotail. According to our numerical simulations, both trapping and quasi-trapping can produce rapid acceleration of protons by more than an order of magnitude. In the case of trapping, the acceleration levels depend on the amount of time particles stay in phase with the front which is controlled by the magnetic field curvature ahead of the front and the front width. Quasi-trapping does not cause particle scattering out of the equatorial plane. Energization levels in this case are limited by the number of encounters particles have with the front before they get magnetized behind it. PMID:26167430

  17. [BIOLOGICAL EFFECTIVENESS OF FISSION SPECTRUM NEUTRONS AND PROTONS WITH ENERGIES OF 60-126 MEV DURING ACUTE AND PROLONGED IRRADIATION].

    PubMed

    Shafirkin, A V

    2015-01-01

    Neutrons of the fission spectrum are characterized by relatively high values of linear energy transfer (LET). Data about their effects on biological objects are used to evaluate the risk of delayed effects of accelerated ions within the same LET range that serve as an experimental model of the nuclei component of galactic cosmic rays (GCR). Additionally, risks of delayed consequences to cosmonaut's health and average lifetime from certain GCR fluxes and secondary neutrons can be also prognosticated. The article deals with comparative analysis of the literature on reduction of average lifespan (ALS) of animals exposed to neutron reactor spectrum, 60-126 MeV protons, and X- and γ-rays in a broad range of radiation intensity and duration. It was shown that a minimal lifespan reduction by 5% occurs due to a brief exposure to neutrons with the absorbed dose of 5 cGy, whereas same lifespan reduction due to hard X- and γ-radiation occurs after absorption of a minimal dose of 100 cGy. Therefore, according to the estimated minimal ALS reduction in mice, neutron effectiveness is 20-fold higher. Biological effectiveness of protons as regards ALS reduction is virtually equal to that of standard types of radiation. Exposure to X- and γ-radiation with decreasing daily doses, and increasing number of fractions and duration gives rise to an apparent trend toward a less dramatic ALS reduction in mice; on the contrary, exposure to neutrons of varying duration had no effect on threshold doses for the specified ALS reductions. Factors of relative biological effectiveness of neutrons reached 40.

  18. Depth dose characteristics of elongated fields for electron beams from a 20-MeV accelerator.

    PubMed

    Sharma, S C; Wilson, D L

    1985-01-01

    In a Therac-20 linear accelerator, 6-20 MeV electron beams are normally produced by shaping a scanned electron beam through primary x-ray collimators and secondary electron trimmers. The collimator settings range continuously from 2 to 30 cm. Depth dose and field flatness parameters were measured for small elongated fields of the various electron energies. Depth dose of narrow fields defined either by the machine's collimator or lead cutouts agreed with data predicted from small square fields using the "square-root" method.

  19. Depth dose characteristics of elongated fields for electron beams from a 20-MeV accelerator

    SciTech Connect

    Sharma, S.C.; Wilson, D.L.

    1985-07-01

    In a Therac-20 linear accelerator, 6--20 MeV electron beams are normally produced by shaping a scanned electron beam through primary x-ray collimators and secondary electron trimmers. The collimator settings range continuously from 2 to 30 cm. Depth dose and field flatness parameters were measured for small elongated fields of the various electron energies. Depth dose of narrow fields defined either by the machine's collimator or lead cutouts agreed with data predicted from small square fields using the ''square-root'' method.

  20. Injection of electrons and protons with energies of tens of MeV into L less than 3 on 24 March 1991

    NASA Technical Reports Server (NTRS)

    Blake, J. B.; Kolasinski, W. A.; Fillius, R. W.; Mullen, E. G.

    1992-01-01

    On 24 March 1991 instrumentation aboard CRRES observed the almost instantaneous injection of electrons and protons with energies above 15 MeV into the L-region in the range 2-3. The energy spectrum of the injected electrons, a power law (E exp -6) peaked at 15 MeV and continued to at least 50 MeV.

  1. Radiograaff, a proton irradiation facility for radiobiological studies at a 4 MV Van de Graaff accelerator

    NASA Astrophysics Data System (ADS)

    Constanzo, J.; Fallavier, M.; Alphonse, G.; Bernard, C.; Battiston-Montagne, P.; Rodriguez-Lafrasse, C.; Dauvergne, D.; Beuve, M.

    2014-09-01

    A horizontal beam facility for radiobiological experiments with low-energy protons has been set up at the 4 MV Van de Graaff accelerator of the Institut de Physique Nucléaire de Lyon. A homogeneous irradiation field with a suitable proton flux is obtained by means of two collimators and two Au-scattering foils. A monitoring chamber contains a movable Faraday cup, a movable quartz beam viewer for controlling the intensity and the position of the initial incident beam and four scintillating fibers for beam monitoring during the irradiation of the cell samples. The beam line is ended by a thin aluminized Mylar window (12 μm thick) for the beam extraction in air. The set-up was simulated by the GATE v6.1 Monte-Carlo platform. The measurement of the proton energy distribution, the evaluation of the fluence-homogeneity over the sample and the calibration of the monitoring system were performed using a silicon PIPS detector, placed in air in the same position as the biological samples to be irradiated. The irradiation proton fluence was found to be homogeneous to within ±2% over a circular field of 20 mm diameter. As preliminary biological experiment, two Human Head and Neck Squamous Carcinoma Cell lines (with different radiosensitivities) were irradiated with 2.9 MeV protons. The measured survival curves are compared to those obtained after X-ray irradiation, giving a Relative Biological Efficiency between 1.3 and 1.4.

  2. COPPER-64 Production Studies with Natural Zinc Targets at Deuteron Energy up to 19 Mev and Proton Energy from 141 Down to 31 Mev

    NASA Astrophysics Data System (ADS)

    Bonardi, Mauro L.; Birattari, Claudio; Groppi, Flavia; Song Mainard, Hae; Zhuikov, Boris L.; Kokhanyuk, Vladimir M.; Lapshina, Elena V.; Mebel, Michail V.; Menapace, Enzo

    2004-07-01

    High specific activity no-carrier-added 64Cu is a β-/β+ emitting radionuclide of increasing interest for PET imaging, as well as systemic and targeted radioimmunotherapy of tumors. Its peculiarity of intense Auger emitter is still under investigation. The cross-sections for production of 64Cu from Zn target of natural isotopic composition were measured in the deuteron energy range from threshold up to 19 MeV and proton energy range from 141 down to 31 MeV. The stacked-foil technique was used at both K=38 cyclotron of JRC-Ispra of CEC, Italy and 160 MeV intersection point of INR proton-LINAC in Troitsk, Russia. Several Ga, Zn, Cu, Ni, Co, V, Fe and Mn radionuclides were detected in Zn targets at the EOB. Optimized irradiation conditions are reported as a function of deuteron energy and energy loss into the Zn target, as well as target irradiation time and cooling time after radiochemistry. The activity of n.c.a. 64Cu was measured through its only γ emission of 1346 keV (i.e. 0.473 % intensity) both by instrumental and radiochemical methods, due to the non-specificity of annihilation radiation at 511 keV. To this last purpose, it was necessary to carry out a selective radiochemical separation of GaIII radionuclides by liquid/liquid extraction from the bulk of irradiated Zn targets and other spallation products, which remained in the 7 M HCl aqueous phase. Anion exchange chromatography tests had been carried out to separate the 64Cu from all others radionuclides in n.c.a. form. Theoretical calculations of cross-sections were performed with codes EMPIRE II and PENELOPE for deuteron reactions and CEF model and HMS-ALICE hybrid model for proton reactions. The theoretical results are presented and compared with the experimental values.

  3. Short term prediction of E greater than or equal to 10 MeV proton fluxes from solar flares

    NASA Technical Reports Server (NTRS)

    Kuck, G. A.

    1972-01-01

    Both the anisotropic and isotropic diffusion theories can be used to extrapolate proton fluxes for E greater than or equal to 10 meV for over 50% of the particle events. The isotropic diffusion theory uses a diffusion coefficient: D = Mr sup beta. It was found that M and beta tended to be functions of flare position on the solar disk. A measurement of the interplanetary flux in near earth space gives a good indication of the polar cap fluxes. It was found that the 30 MHz absorption over the poles during a PCA is proportional to the square root of the integral proton flux E greater than or equal to 11 meV in interplanetary space, J = KA squared, with K = 8 plus or minus 2 and J in protons/sq cm-sec-ster.

  4. Acceleration of electrons by the wake field of proton bunches

    SciTech Connect

    Ruggiero, A.G.

    1986-01-01

    This paper discusses a novel idea to accelerate low-intensity bunches of electrons (or positrons) by the wake field of intense proton bunches travelling along the axis of a cylindrical rf structure. Accelerating gradients in excess of 100 MeV/m and large ''transformer ratios'', which allow for acceleration of electrons to energies in the TeV range, are calculated. A possible application of the method is an electron-positron linear collider with luminosity of 10/sup 33/ cm/sup -2/ s/sup -1/. The relatively low cost and power consumption of the method is emphasized.

  5. Seed population for about 1 MeV per nucleon heavy ions accelerated by interplanetary shocks

    NASA Technical Reports Server (NTRS)

    Tan, L. C.; Mason, G. M.; Klecker, B.; Hovestadt, D.

    1989-01-01

    Data obtained between 1977 and 1982 by the ISEE 1 and ISEE 3 satellites on the composition of heavy ions of about 1 MeV per nucleon, accelerated in interplanetary shock events which followed solar flare events, are examined. It was found that the average relative abundances for C, O, and Fe in the shock events were very close to those found for energetic ions in the solar flares, suggesting that, at these energies, the shock accelerated particles have the solar energetic particles as their seed population. This hypothesis is supported by the fact that the Fe/O ratio in the solar particle events is very strongly correlated with the Fe/O ratio in associated diffusive shock events.

  6. SU-E-T-47: A Monte Carlo Model of a Spot Scanning Proton Beam Based On a Synchrotron Proton Therapy Accelerator

    SciTech Connect

    Xie, C; Lin, H; Jing, J; Chen, C; Cao, R; Pei, X

    2015-06-15

    Purpose: To build the model of a spot scanning proton beam for the dose calculation of a synchrotron proton therapy accelerator, which is capable of accelerating protons from 50 up to 221 MeV. Methods: The spot scanning beam nozzle is modeled using TOPAS code, a simulation tool based on Geant4.9.6. The model contained a beam pipe vacuum window, a beam profile monitor, a drift chamber, two plane-parallel ionization chambers, and a spot-position monitor consisted of a multiwire ionization chamber. A water phantom is located with its upstream surface at the isocenter plane. The initial proton beam energy and anglar deflection are modeled using a Gaussian distribution with FWHM (Full Widths at Half Maximum) deponding on its beam energy. The phase space file (PSF) on a virtual surface located at the center between the two magnets is recorded. PSF is used to analyze the pencil beam features and offset the pencil beam position. The source model parameters are verificated by fitting the simulated Result to the measurement. Results: The simulated percentage depth dose (PDD) and lateral profiles of scanning pencil beams of various incident proton energies are verificated to the measurement. Generally the distance to agreement (DTA) of Bragg peaks is less than 0.2cm. The FWHM of Gaussian anglar distribution was adjusted to fit the lateral profile difference between the simulation and the measurement to less than 2∼3cm. Conclusion: A Monte Carlo model of a spot scanning proton beam was bullt based on a synchrotron proton therapy accelerator. This scanning pencil beam model will be as a block to build the broad proton beam as a proton TPS dose verification tool.

  7. First measurements of laser-accelerated proton induced luminescence

    SciTech Connect

    Floquet, V.; Ceccotti, T.; Dobosz Dufrenoy, S.; Bonnaud, G.; Monot, P.; Martin, Ph.; Gremillet, L.

    2012-09-15

    We present our first results about laser-accelerated proton induced luminescence in solids. In the first part, we describe the optimization of the proton source as a function of the target thickness as well as the laser pulse duration and energy. Due to the ultra high contrast ratio of our laser beam, we succeeded in using targets ranging from the micron scale down to nanometers thickness. The two optimal thicknesses we put in evidence are in good agreement with numerical simulations. Laser pulse duration shows a small influence on proton maximum energy, whereas the latter turns out to vary almost linearly as a function of laser energy. Thanks to this optimisation work, we have been able to acquire images of the proton energy deposition in a solid scintillator.

  8. Shock-Wave Acceleration of Protons on OMEGA EP

    NASA Astrophysics Data System (ADS)

    Haberberger, D.; Froula, D. H.; Pak, A.; Link, A.; Patel, P.; Fiuza, F.; Tochitsky, S.; Joshi, C.

    2016-10-01

    The creation of an electrostatic shock wave and ensuing ion acceleration is studied on the OMEGA EP Laser System at the Laboratory for Laser Energetics. Previous work using a 10- μm CO2 laser in a H2 gas jet shows promising results for obtaining narrow spectral features in the accelerated proton spectra. Scaling the shock-wave acceleration mechanism to the 1- μm-wavelength drive laser makes it possible to use petawatt-scale laser systems such as OMEGA-EP, but involves tailoring of the plasma profile. To accomplish the necessitated sharp rise to near-critical plasma density and a long exponential fall, an 1- μm-thick CH foil is illuminated on the back side by thermal x rays produced from an irradiated gold foil. The plasma density is measured using the fourth-harmonic probe system, the accelerating fields are probed using an orthogonal proton source, and the accelerated protons and ions are detected with a Thomson parabola. These results will be presented and compared with particle-in-cell simulations. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944 and LLNL's Laboratory Directed Research and Development program under project 15-LW-095.

  9. Status of the 1 MeV Accelerator Design for ITER NBI

    SciTech Connect

    Kuriyama, M.; Boilson, D.; Hemsworth, R.; Svensson, L.; Graceffa, J.; Schunke, B.; Decamps, H.; Tanaka, M.; Bonicelli, T.; Masiello, A.

    2011-09-26

    The beam source of neutral beam heating/current drive system for ITER is needed to accelerate the negative ion beam of 40A with D{sup -} at 1 MeV for 3600 sec. In order to realize the beam source, design and R and D works are being developed in many institutions under the coordination of ITER organization. The development of the key issues of the ion source including source plasma uniformity, suppression of co-extracted electron in D beam operation and also after the long beam duration time of over a few 100 sec, is progressed mainly in IPP with the facilities of BATMAN, MANITU and RADI. In the near future, ELISE, that will be tested the half size of the ITER ion source, will start the operation in 2011, and then SPIDER, which demonstrates negative ion production and extraction with the same size and same structure as the ITER ion source, will start the operation in 2014 as part of the NBTF. The development of the accelerator is progressed mainly in JAEA with the MeV test facility, and also the computer simulation of beam optics also developed in JAEA, CEA and RFX. The full ITER heating and current drive beam performance will be demonstrated in MITICA, which will start operation in 2016 as part of the NBTF.

  10. Status of the 1 MeV Accelerator Design for ITER NBI

    NASA Astrophysics Data System (ADS)

    Kuriyama, M.; Boilson, D.; Hemsworth, R.; Svensson, L.; Graceffa, J.; Schunke, B.; Decamps, H.; Tanaka, M.; Bonicelli, T.; Masiello, A.; Bigi, M.; Chitarin, G.; Luchetta, A.; Marcuzzi, D.; Pasqualotto, R.; Pomaro, N.; Serianni, G.; Sonato, P.; Toigo, V.; Zaccaria, P.; Kraus, W.; Franzen, P.; Heinemann, B.; Inoue, T.; Watanabe, K.; Kashiwagi, M.; Taniguchi, M.; Tobari, H.; De Esch, H.

    2011-09-01

    The beam source of neutral beam heating/current drive system for ITER is needed to accelerate the negative ion beam of 40A with D- at 1 MeV for 3600 sec. In order to realize the beam source, design and R&D works are being developed in many institutions under the coordination of ITER organization. The development of the key issues of the ion source including source plasma uniformity, suppression of co-extracted electron in D beam operation and also after the long beam duration time of over a few 100 sec, is progressed mainly in IPP with the facilities of BATMAN, MANITU and RADI. In the near future, ELISE, that will be tested the half size of the ITER ion source, will start the operation in 2011, and then SPIDER, which demonstrates negative ion production and extraction with the same size and same structure as the ITER ion source, will start the operation in 2014 as part of the NBTF. The development of the accelerator is progressed mainly in JAEA with the MeV test facility, and also the computer simulation of beam optics also developed in JAEA, CEA and RFX. The full ITER heating and current drive beam performance will be demonstrated in MITICA, which will start operation in 2016 as part of the NBTF.

  11. Intense tera-hertz laser driven proton acceleration in plasmas

    NASA Astrophysics Data System (ADS)

    Sharma, A.; Tibai, Z.; Hebling, J.

    2016-06-01

    We investigate the acceleration of a proton beam driven by intense tera-hertz (THz) laser field from a near critical density hydrogen plasma. Two-dimension-in-space and three-dimension-in-velocity particle-in-cell simulation results show that a relatively long wavelength and an intense THz laser can be employed for proton acceleration to high energies from near critical density plasmas. We adopt here the electromagnetic field in a long wavelength (0.33 THz) regime in contrast to the optical and/or near infrared wavelength regime, which offers distinct advantages due to their long wavelength ( λ = 350 μ m ), such as the λ 2 scaling of the electron ponderomotive energy. Simulation study delineates the evolution of THz laser field in a near critical plasma reflecting the enhancement in the electric field of laser, which can be of high relevance for staged or post ion acceleration.

  12. ACCELERATION OF THERMAL PROTONS BY GENERIC PHENOMENOLOGICAL MECHANISMS

    SciTech Connect

    Petrosian, Vahé; Kang, Byungwoo E-mail: redcrux8@stanford.edu

    2015-11-01

    We investigate heating and acceleration of protons from a thermal gas with a generic diffusion and acceleration model, and subject to Coulomb scattering and energy loss, as was done by Petrosian and East for electrons. As protons gain energy their loss to electrons becomes important. Thus, we need to solve the coupled proton–electron kinetic equation. We numerically solve the coupled Fokker–Planck equations and compute the time evolution of the spectra of both particles. We show that this can lead to a quasi-thermal component plus a high-energy nonthermal tail. We determine the evolution of the nonthermal tail and the quasi-thermal component. The results may be used to explore the possibility of inverse bremsstrahlung radiation as a source of hard X-ray emissions from hot sources such as solar flares, accretion disk coronas, and the intracluster medium of galaxy clusters. We find that the emergence of nonthermal protons is accompanied by excessive heating of the entire plasma, unless the turbulence needed for scattering and acceleration is steeper than Kolmogorov and the acceleration parameters, the duration of the acceleration, and/or the initial distributions are significantly fine-tuned. These results severely constrain the feasibility of the nonthermal inverse bremsstrahlung process producing hard X-ray emissions. However, the nonthermal tail may be the seed particles for further re-acceleration to relativistic energies, say by a shock. In the Appendix we present some tests of the integrity of the algorithm used and present a new formula for the energy loss rate due to inelastic proton–proton interactions.

  13. High intensity proton beam transportation through fringe field of 70 MeV compact cyclotron to beam line targets

    NASA Astrophysics Data System (ADS)

    Zhang, Xu; Li, Ming; Wei, Sumin; Xing, Jiansheng; Hu, Yueming; Johnson, Richard R.; Piazza, Leandro; Ryjkov, Vladimir

    2016-06-01

    From the stripping points, the high intensity proton beam of a compact cyclotron travels through the fringe field area of the machine to the combination magnet. Starting from there the beams with various energy is transferred to the switching magnet for distribution to the beam line targets. In the design of the extraction and transport system for the compact proton cyclotron facilities, such as the 70 MeV in France and the 100 MeV in China, the space charge effect as the beam crosses the fringe field has not been previously considered; neither has the impact on transverse beam envelope coupled from the longitudinal direction. Those have been concerned much more with the higher beam-power because of the beam loss problem. In this paper, based on the mapping data of 70 MeV cyclotron including the fringe field by BEST Cyclotron Inc (BEST) and combination magnet field by China Institute of Atomic Energy (CIAE), the beam extraction and transport are investigated for the 70 MeV cyclotron used on the SPES project at Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro (INFN-LNL). The study includes the space charge effect and longitudinal and transverse coupling mentioned above, as well as the matching of beam optics using the beam line for medical isotope production as an example. In addition, the designs of the ±45° switching magnets and the 60° bending magnet for the extracted beam with the energy from 35 MeV to 70 MeV have been made. Parts of the construction and field measurements of those magnets have been done as well. The current result shows that, the design considers the complexity of the compact cyclotron extraction area and fits the requirements of the extraction and transport for high intensity proton beam, especially at mA intensity levels.

  14. Measurement of the displacement cross-section of copper irradiated with 125 MeV protons at 12 K

    NASA Astrophysics Data System (ADS)

    Iwamoto, Yosuke; Yoshiie, Toshimasa; Yoshida, Makoto; Nakamoto, Tatsushi; Sakamoto, Masaaki; Kuriyama, Yasutoshi; Uesugi, Tomonori; Ishi, Yoshihiro; Xu, Qiu; Yashima, Hiroshi; Takahashi, Fumiaki; Mori, Yoshiharu; Ogitsu, Toru

    2015-03-01

    To validate Monte Carlo codes for the prediction of radiation damage in metals irradiated by >100 MeV protons, the defect-induced electrical resistivity changes related to the displacement cross-section of copper were measured with 125 MeV proton irradiation at 12 K. The cryogenic irradiation system was developed with a Gifford-McMahon cryocooler to cool the sample via an oxygen-free high-conductivity copper plate by conduction cooling. The sample was a copper wire with a 250-μm diameter and 99.999% purity sandwiched between two aluminum nitride ceramic sheets. The electrical resistivity changes of the copper wire were measured using the four-probe technique. After 125 MeV proton irradiation with 1.45 × 1018 protons/m2 at 12 K, the total resistivity increase was 4.94 × 10-13 Ω m (resistance increase: 1.53 μΩ), while the resistivity of copper before irradiation was 9.44 × 10-12 Ω m (resistance: 29.41 μΩ). The resistivity increase did not change during annealing after irradiation below 15 K. The experimental displacement cross-section for 125 MeV irradiation shows similar results to the experimental data for 1.1 and 1.94 GeV. Comparison with the calculated results indicated that the defect production efficiency in Monte Carlo codes gives a good quantitative description of the displacement cross-section in the energy region >100 MeV.

  15. Laser-Accelerated Proton Beams as Diagnostics for Cultural Heritage.

    PubMed

    Barberio, M; Veltri, S; Scisciò, M; Antici, P

    2017-03-07

    This paper introduces the first use of laser-generated proton beams as diagnostic for materials of interest in the domain of Cultural Heritage. Using laser-accelerated protons, as generated by interaction of a high-power short-pulse laser with a solid target, we can produce proton-induced X-ray emission spectroscopies (PIXE). By correctly tuning the proton flux on the sample, we are able to perform the PIXE in a single shot without provoking more damage to the sample than conventional methodologies. We verify this by experimentally irradiating materials of interest in the Cultural Heritage with laser-accelerated protons and measuring the PIXE emission. The morphological and chemical analysis of the sample before and after irradiation are compared in order to assess the damage provoked to the artifact. Montecarlo simulations confirm that the temperature in the sample stays safely below the melting point. Compared to conventional diagnostic methodologies, laser-driven PIXE has the advantage of being potentially quicker and more efficient.

  16. Laser-Accelerated Proton Beams as Diagnostics for Cultural Heritage

    NASA Astrophysics Data System (ADS)

    Barberio, M.; Veltri, S.; Scisciò, M.; Antici, P.

    2017-03-01

    This paper introduces the first use of laser-generated proton beams as diagnostic for materials of interest in the domain of Cultural Heritage. Using laser-accelerated protons, as generated by interaction of a high-power short-pulse laser with a solid target, we can produce proton-induced X-ray emission spectroscopies (PIXE). By correctly tuning the proton flux on the sample, we are able to perform the PIXE in a single shot without provoking more damage to the sample than conventional methodologies. We verify this by experimentally irradiating materials of interest in the Cultural Heritage with laser-accelerated protons and measuring the PIXE emission. The morphological and chemical analysis of the sample before and after irradiation are compared in order to assess the damage provoked to the artifact. Montecarlo simulations confirm that the temperature in the sample stays safely below the melting point. Compared to conventional diagnostic methodologies, laser-driven PIXE has the advantage of being potentially quicker and more efficient.

  17. Laser-Accelerated Proton Beams as Diagnostics for Cultural Heritage

    PubMed Central

    Barberio, M.; Veltri, S.; Scisciò, M.; Antici, P.

    2017-01-01

    This paper introduces the first use of laser-generated proton beams as diagnostic for materials of interest in the domain of Cultural Heritage. Using laser-accelerated protons, as generated by interaction of a high-power short-pulse laser with a solid target, we can produce proton-induced X-ray emission spectroscopies (PIXE). By correctly tuning the proton flux on the sample, we are able to perform the PIXE in a single shot without provoking more damage to the sample than conventional methodologies. We verify this by experimentally irradiating materials of interest in the Cultural Heritage with laser-accelerated protons and measuring the PIXE emission. The morphological and chemical analysis of the sample before and after irradiation are compared in order to assess the damage provoked to the artifact. Montecarlo simulations confirm that the temperature in the sample stays safely below the melting point. Compared to conventional diagnostic methodologies, laser-driven PIXE has the advantage of being potentially quicker and more efficient. PMID:28266496

  18. The Efficiency of the BC-720 Scintillator in a High-Energy (20--800 MeV) Accelerator Neutron Field

    SciTech Connect

    Miles, Leslie H.

    2005-12-01

    High-energy neutron doses (>20 MeV) are of little importance to most radiation workers. However, space and flight crews, and people working around medical and scientific accelerators receive over half of their radiation dose from high-energy neutrons. Unfortunately, neutrons are difficult to measure, and no suitable dosimetry has yet been developed to measure this radiation. In this paper, basic high-energy neutron interactions, characteristics of high-energy neutron environments, present neutron dosimetry, and quantities used in neutron dosimetry are discussed before looking into the potential of the BC-720 scintillator to improve dosimetry. This research utilized 800 MeV protons impinging upon the WNR Facility spallation neutron source at Los Alamos National Laboratory. Time-of-flight methods and a U-238 Fission Chamber were used to aid evaluation of the efficiency of the BC-720. Results showed that the efficiency is finite over the 20–650 MeV energy region studied, although it decreases by a factor of ten between 40 and 100 MeV. This limits the use of this dosimeter to measure doses at sitespecific locations. It also encourages modifications to use this dosimeter for any unknown neutron field. As such, this dosimeter has the potential for a small, lightweight, real-time dose measurement, which could impact neutron dosimetry in all high-energy neutron environments.

  19. Trimming algorithm of frequency modulation for CIAE-230 MeV proton superconducting synchrocyclotron model cavity

    NASA Astrophysics Data System (ADS)

    Li, Pengzhan; Zhang, Tianjue; Ji, Bin; Hou, Shigang; Guo, Juanjuan; Yin, Meng; Xing, Jiansheng; Lv, Yinlong; Guan, Fengping; Lin, Jun

    2017-01-01

    A new project, the 230 MeV proton superconducting synchrocyclotron for cancer therapy, was proposed at CIAE in 2013. A model cavity is designed to verify the frequency modulation trimming algorithm featuring a half-wave structure and eight sets of rotating blades for 1 kHz frequency modulation. Based on the electromagnetic (EM) field distribution analysis of the model cavity, the variable capacitor works as a function of time and the frequency can be written in Maclaurin series. Curve fitting is applied for theoretical frequency and original simulation frequency. The second-order fitting excels at the approximation given its minimum variance. Constant equivalent inductance is considered as an important condition in the calculation. The equivalent parameters of theoretical frequency can be achieved through this conversion. Then the trimming formula for rotor blade outer radius is found by discretization in time domain. Simulation verification has been performed and the results show that the calculation radius with minus 0.012 m yields an acceptable result. The trimming amendment in the time range of 0.328-0.4 ms helps to reduce the frequency error to 0.69% in Simulation C with an increment of 0.075 mm/0.001 ms, which is half of the error in Simulation A (constant radius in 0.328-0.4 ms). The verification confirms the feasibility of the trimming algorithm for synchrocyclotron frequency modulation.

  20. The corrosion of materials in water irradiated by 800 MeV protons

    NASA Astrophysics Data System (ADS)

    Lillard, R. S.; Pile, D. L.; Butt, D. P.

    2000-02-01

    A method for measuring the real-time corrosion rates for Alloy 718, stainless steels (SS) 304L and 316L nuclear grade (NG), aluminum alloys 5052 (Al5052) and 6061 (Al6061), copper (Cu), tantalum (Ta), and tungsten (W) in two separate water systems that were irradiated by 800 MeV protons is presented. The first water system was fabricated entirely of 304 SS, thoroughly cleaned before operation, and employed hydrogen water chemistry (HWC) to mitigate the formation of some of the radiolysis products. The samples were adequately shielded from the irradiation cavity such that only the effects of water chemistry were investigated. Over the course of that irradiation period the corrosion rates for 304L SS, 316L-NG SS, Alloy 718, and Ta were less than 0.12 μm/yr. For Al6061 and Al5052, the corrosion rates were of the order of 0.50-2.0 μm/yr. The corrosion rate of W was relatively high between 5.0 and 30 μm/yr. The second water system, fabricated from copper piping and steel components, was not cleaned prior to operation, and employed no HWC. In comparison to the other system, the corrosion rates in the copper/steel system were 1-3 orders of magnitude higher. These results are discussed in terms of water radiolysis and water impurity levels.

  1. Physics and Novel Schemes of Laser Radiation Pressure Acceleration for Quasi-monoenergetic Proton Generation

    SciTech Connect

    Liu, Chuan S.; Shao, Xi

    2016-06-14

    The main objective of our work is to provide theoretical basis and modeling support for the design and experimental setup of compact laser proton accelerator to produce high quality proton beams tunable with energy from 50 to 250 MeV using short pulse sub-petawatt laser. We performed theoretical and computational studies of energy scaling and Raleigh--Taylor instability development in laser radiation pressure acceleration (RPA) and developed novel RPA-based schemes to remedy/suppress instabilities for high-quality quasimonoenergetic proton beam generation as we proposed. During the project period, we published nine peer-reviewed journal papers and made twenty conference presentations including six invited talks on our work. The project supported one graduate student who received his PhD degree in physics in 2013 and supported two post-doctoral associates. We also mentored three high school students and one undergraduate student of physics major by inspiring their interests and having them involved in the project.

  2. Defocusing beam line design for an irradiation facility at the TAEA SANAEM Proton Accelerator Facility

    NASA Astrophysics Data System (ADS)

    Gencer, A.; Demirköz, B.; Efthymiopoulos, I.; Yiğitoğlu, M.

    2016-07-01

    Electronic components must be tested to ensure reliable performance in high radiation environments such as Hi-Limu LHC and space. We propose a defocusing beam line to perform proton irradiation tests in Turkey. The Turkish Atomic Energy Authority SANAEM Proton Accelerator Facility was inaugurated in May 2012 for radioisotope production. The facility has also an R&D room for research purposes. The accelerator produces protons with 30 MeV kinetic energy and the beam current is variable between 10 μA and 1.2 mA. The beam kinetic energy is suitable for irradiation tests, however the beam current is high and therefore the flux must be lowered. We plan to build a defocusing beam line (DBL) in order to enlarge the beam size, reduce the flux to match the required specifications for the irradiation tests. Current design includes the beam transport and the final focusing magnets to blow up the beam. Scattering foils and a collimator is placed for the reduction of the beam flux. The DBL is designed to provide fluxes between 107 p /cm2 / s and 109 p /cm2 / s for performing irradiation tests in an area of 15.4 cm × 21.5 cm. The facility will be the first irradiation facility of its kind in Turkey.

  3. Efficient and stable proton acceleration by irradiating a two-layer target with a linearly polarized laser pulse

    SciTech Connect

    Wang, H. Y.; Yan, X. Q.; Chen, J. E.; He, X. T.; Ma, W. J.; Bin, J. H.; Schreiber, J.; Tajima, T.; Habs, D.

    2013-01-15

    We report an efficient and stable scheme to generate {approx}200 MeV proton bunch by irradiating a two-layer targets (near-critical density layer+solid density layer with heavy ions and protons) with a linearly polarized Gaussian pulse at intensity of 6.0 Multiplication-Sign 10{sup 20} W/cm{sup 2}. Due to self-focusing of laser and directly accelerated electrons in the near-critical density layer, the proton energy is enhanced by a factor of 3 compared to single-layer solid targets. The energy spread of proton is also remarkably reduced. Such scheme is attractive for applications relevant to tumor therapy.

  4. Acceleration of polarized protons at Saturne: First results

    SciTech Connect

    Arvieu, J.

    1982-03-20

    The accelertor SATURNE is a synchrotron which accelerates particles up to P/Z = 3.8 GeV/c. Thus the maximum energy for protons T/sub p/ is about 3 GeV, and for deuterons T/sub d/ is about 2.3 GeV. It is equipped with a polarized ion source (HYPERION, the name of a satellite of the Saturne planet) of the ''atomic beam'' type producing either protons or deuterons with either vector or tensor polarization. A heavy-ion source (CREYBIS) for production of ions up to mass 40 is now being tested.

  5. Development and calibration of a Thomson parabola with microchannel plate for the detection of laser-accelerated MeV ions

    SciTech Connect

    Harres, K.; Schollmeier, M.; Nuernberg, F.; Roth, M.; Brambrink, E.; Audebert, P.; Blazevic, A.; Wahl, H.; Flippo, K.; Gautier, D. C.; Hegelich, B. M.; Geissel, M.; Schreiber, J.

    2008-09-15

    This article reports on the development and application of a Thomson parabola (TP) equipped with a (90x70) mm{sup 2} microchannel-plate (MCP) for the analysis of laser-accelerated ions, produced by a high-energy, high-intensity laser system. The MCP allows an online measurement of the produced ions in every single laser shot. An electromagnet instead of permanent magnets is used that allows the tuning of the magnetic field to adapt the field strength to the analyzed ion species and energy. We describe recent experiments at the 100 TW laser facility at the Laboratoire d'Utilization des Lasers Intenses (LULI) in Palaiseau, France, where we have observed multiple ion species and charge states with ions accelerated up to 5 MeV/u (O{sup +6}), emitted from the rear surface of a laser-irradiated 50 {mu}m Au foil. Within the experiment the TP was calibrated for protons and for the first time conversion efficiencies of MeV protons (2-13 MeV) to primary electrons (electrons immediately generated by an ion impact onto a surface) in the MCP are presented.

  6. Lasers As Particle Accelerators In Medicine: From Laser-Driven Protons To Imaging With Thomson Sources

    SciTech Connect

    Pogorelsky, I. V.; Babzien, M.; Polyanskiy, M. N.; Yakimenko, V.; Dover, N. P.; Palmer, C. A. J.; Najmudin, Z.; Shkolnikov, P.; Williams, O.; Rosenzweig, J.; Oliva, P.; Carpinelli, M.; Golosio, B.; Delogu, P.; Stefanini, A.; Endrizzi, M.

    2011-06-01

    We report our recent progress using a high-power, picosecond CO{sub 2} laser for Thomson scattering and ion acceleration experiments. These experiments capitalize on certain advantages of long-wavelength CO{sub 2} lasers, such as their high number of photons per energy unit and beneficial wavelength- scaling of the electrons' ponderomotive energy and critical plasma frequency. High X-ray fluxes produced in the interactions of the counter-propagating laser- and electron-beams for obtaining single-shot, high-contrast images of biological objects. The laser, focused on a hydrogen jet, generated a monoenergetic proton beam via the radiation-pressure mechanism. The energy of protons produced by this method scales linearly with the laser's intensity. We present a plan for scaling the process into the range of 100-MeV proton energy via upgrading the CO{sub 2} laser. This development will enable an advance to the laser-driven proton cancer therapy.

  7. Optimizing laser-driven proton acceleration from overdense targets

    PubMed Central

    Stockem Novo, A.; Kaluza, M. C.; Fonseca, R. A.; Silva, L. O.

    2016-01-01

    We demonstrate how to tune the main ion acceleration mechanism in laser-plasma interactions to collisionless shock acceleration, thus achieving control over the final ion beam properties (e. g. maximum energy, divergence, number of accelerated ions). We investigate this technique with three-dimensional particle-in-cell simulations and illustrate a possible experimental realisation. The setup consists of an isolated solid density target, which is preheated by a first laser pulse to initiate target expansion, and a second one to trigger acceleration. The timing between the two laser pulses allows to access all ion acceleration regimes, ranging from target normal sheath acceleration, to hole boring and collisionless shock acceleration. We further demonstrate that the most energetic ions are produced by collisionless shock acceleration, if the target density is near-critical, ne ≈ 0.5 ncr. A scaling of the laser power shows that 100 MeV protons may be achieved in the PW range. PMID:27435449

  8. Optimizing laser-driven proton acceleration from overdense targets.

    PubMed

    Stockem Novo, A; Kaluza, M C; Fonseca, R A; Silva, L O

    2016-07-20

    We demonstrate how to tune the main ion acceleration mechanism in laser-plasma interactions to collisionless shock acceleration, thus achieving control over the final ion beam properties (e. g. maximum energy, divergence, number of accelerated ions). We investigate this technique with three-dimensional particle-in-cell simulations and illustrate a possible experimental realisation. The setup consists of an isolated solid density target, which is preheated by a first laser pulse to initiate target expansion, and a second one to trigger acceleration. The timing between the two laser pulses allows to access all ion acceleration regimes, ranging from target normal sheath acceleration, to hole boring and collisionless shock acceleration. We further demonstrate that the most energetic ions are produced by collisionless shock acceleration, if the target density is near-critical, ne ≈ 0.5 ncr. A scaling of the laser power shows that 100 MeV protons may be achieved in the PW range.

  9. High order magnetic optics for high dynamic range proton radiography at a kinetic energy of 800 MeV

    NASA Astrophysics Data System (ADS)

    Sjue, S. K. L.; Mariam, F. G.; Merrill, F. E.; Morris, C. L.; Saunders, A.

    2016-01-01

    Flash radiography with 800 MeV kinetic energy protons at Los Alamos National Laboratory is an important experimental tool for investigations of dynamic material behavior driven by high explosives or pulsed power. The extraction of quantitative information about density fields in a dynamic experiment from proton generated images requires a high fidelity model of the proton imaging process. It is shown that accurate calculations of the transmission through the magnetic lens system require terms beyond second order for protons far from the tune energy. The approach used integrates the correlated multiple Coulomb scattering distribution simultaneously over the collimator and the image plane. Comparison with a series of static calibration images demonstrates the model's accurate reproduction of both the transmission and blur over a wide range of tune energies in an inverse identity lens that consists of four quadrupole electromagnets.

  10. High order magnetic optics for high dynamic range proton radiography at a kinetic energy of 800 MeV

    SciTech Connect

    Sjue, S. K. L. Mariam, F. G.; Merrill, F. E.; Morris, C. L.; Saunders, A.

    2016-01-15

    Flash radiography with 800 MeV kinetic energy protons at Los Alamos National Laboratory is an important experimental tool for investigations of dynamic material behavior driven by high explosives or pulsed power. The extraction of quantitative information about density fields in a dynamic experiment from proton generated images requires a high fidelity model of the proton imaging process. It is shown that accurate calculations of the transmission through the magnetic lens system require terms beyond second order for protons far from the tune energy. The approach used integrates the correlated multiple Coulomb scattering distribution simultaneously over the collimator and the image plane. Comparison with a series of static calibration images demonstrates the model’s accurate reproduction of both the transmission and blur over a wide range of tune energies in an inverse identity lens that consists of four quadrupole electromagnets.

  11. A high brightness proton injector for the Tandetron accelerator at Jožef Stefan Institute

    NASA Astrophysics Data System (ADS)

    Pelicon, Primož; Podaru, Nicolae C.; Vavpetič, Primož; Jeromel, Luka; Ogrinc Potocnik, Nina; Ondračka, Simon; Gottdang, Andreas; Mous, Dirk J. M.

    2014-08-01

    Jožef Stefan Institute recently commissioned a high brightness H- ion beam injection system for its existing tandem accelerator facility. Custom developed by High Voltage Engineering Europa, the multicusp ion source has been tuned to deliver at the entrance of the Tandetron™ accelerator H- ion beams with a measured brightness of 17.1 A m-2 rad-2 eV-1 at 170 μA, equivalent to an energy normalized beam emittance of 0.767 π mm mrad MeV1/2. Upgrading the accelerator facility with the new injection system provides two main advantages. First, the high brightness of the new ion source enables the reduction of object slit aperture and the reduction of acceptance angle at the nuclear microprobe, resulting in a reduced beam size at selected beam intensity, which significantly improves the probe resolution for micro-PIXE applications. Secondly, the upgrade strongly enhances the accelerator up-time since H and He beams are produced by independent ion sources, introducing a constant availability of 3He beam for fusion-related research with NRA. The ion beam particle losses and ion beam emittance growth imply that the aforementioned beam brightness is reduced by transport through the ion optical system. To obtain quantitative information on the available brightness at the high-energy side of the accelerator, the proton beam brightness is determined in the nuclear microprobe beamline. Based on the experience obtained during the first months of operation for micro-PIXE applications, further necessary steps are indicated to obtain optimal coupling of the new ion source with the accelerator to increase the normalized high-energy proton beam brightness at the JSI microprobe, currently at 14 A m-2 rad-2 eV-1, with the output current at 18% of its available maximum.

  12. Development of a gaseous proton-recoil detector for fission cross section measurements below 1 MeV neutron energy

    NASA Astrophysics Data System (ADS)

    Marini, P.; Mathieu, L.; Aïche, M.; Czajkowski, S.; Jurado, B.; Tsekhanovich, I.

    2016-03-01

    The elastic H(n,p) reaction is sometimes used to measure neutron flux, in order to produce high precision measurements. The use of this technique is not straightforward to use below incident neutron energy of 1 MeV, due to a high background in the detected proton spectrum. Experiments have been carried out at the AIFIRA facility to investigate such background and determine its origin and components. Based on these investigations, a gaseous proton-recoil detector has been designed, with a reduced low energy background.

  13. Van Allen Probes observations of prompt MeV radiation belt electron acceleration in nonlinear interactions with VLF chorus

    NASA Astrophysics Data System (ADS)

    Foster, J. C.; Erickson, P. J.; Omura, Y.; Baker, D. N.; Kletzing, C. A.; Claudepierre, S. G.

    2017-01-01

    Prompt recovery of MeV (millions of electron Volts) electron populations in the poststorm core of the outer terrestrial radiation belt involves local acceleration of a seed population of energetic electrons in interactions with VLF chorus waves. Electron interactions during the generation of VLF rising tones are strongly nonlinear, such that a fraction of the relativistic electrons at resonant energies are trapped by waves, leading to significant nonadiabatic energy exchange. Through detailed examination of VLF chorus and electron fluxes observed by Van Allen Probes, we investigate the efficiency of nonlinear processes for acceleration of electrons to MeV energies. We find through subpacket analysis of chorus waveforms that electrons with initial energy of hundreds of keV to 3 MeV can be accelerated by 50 keV-200 keV in resonant interactions with a single VLF rising tone on a time scale of 10-100 ms.

  14. Measurements of the Argonne Wakefield Accelerator's low charge, 4 MeV RF photocathode witness beam.

    SciTech Connect

    Power, J.

    1998-04-01

    The Argonne Wakefield Accelerator's (AWA) witness RF photocathode gun produced its first electron beam in April of 1996. We have characterized the charge, energy, emittance and bunch length of the witness beam over the last several months. The emittance Was measured by both a quad scan that fitted for space charge using an in house developed Mathematica routine and a pepper pot technique. The bunch length was measured by imaging Cherenkov light from a quartz plate to a Hamamatsu streak camera with 2 psec resolution. A beam energy of 3.9 Mev was measured with a 6 inch round pole spectrometer while a beam charge was measured with both an ICT and a Faraday Cup. Although the gun will normally be run at 100 pC it has produced charges from 10 pC to 4 nc. All results of the measurements to date are presented here.

  15. Radiation protection measurements around a 12 MeV mobile dedicated IORT accelerator

    SciTech Connect

    Soriani, Antonella; Felici, Giuseppe; Fantini, Mario; Paolucci, Massimiliano; Borla, Oscar; Evangelisti, Giovanna; Benassi, Marcello; Strigari, Lidia

    2010-03-15

    Purpose: The aim of this study is to investigate radioprotection issues that must be addressed when dedicated accelerators for intraoperative radiotherapy (IORT) are used in operating rooms. Recently, a new version of a mobile IORT accelerator (LIAC Sordina SpA, Italy) with 12 MeV electron beam has been implemented. This energy is necessary in some specific pathology treatments to allow a better coverage of thick lesions. At an electron energy of 10 MeV, leakage and scattered x-ray radiation (stray radiation) coming from the accelerator device and patient must be considered. If the energy is greater than 10 MeV, the x-ray component will increase; however, the most meaningful change should be the addition of neutron background. Therefore, radiation exposure of personnel during the IORT procedure needs to be carefully evaluated. Methods: In this study, stray x-ray radiation was measured and characterized in a series of spherical projections by means of an ion chamber survey meter. To simulate the patient during all measurements, a polymethylmethacrylate (PMMA) slab phantom with volume 30x30x15 cm{sup 3} and density 1.19 g/cm{sup 3} was used. The PMMA phantom was placed along the central axis of the beam in order to absorb the electron beams and the tenth value layer (TVL) and half value layer (HVL) of scattered radiation (at 0 deg., 90 deg., and 180 deg. scattering angles) were also measured at 1 m of distance from the phantom center. Neutron measurements were performed using passive bubble dosimeters and a neutron probe, specially designed to evaluate ambient dose equivalent H{sup *}(10). Results: The x-ray equivalent dose measured at 1 m along the beam axis at 12 MeV was 260 {mu}Sv/Gy. The value measured at 1 m at 90 deg. scattering angle was 25 {mu}Sv/Gy. The HVL and TVL values were 1.1 and 3.5 cm of lead at 0 deg., and 0.4 and 1 cm at 90 deg., respectively. The highest equivalent dose of fast neutrons was found to be at the surface of the phantom on the central

  16. Energy enhancement of proton acceleration in combinational radiation pressure and bubble by optimizing plasma density

    SciTech Connect

    Bake, Muhammad Ali; Xie Baisong; Shan Zhang; Hong Xueren; Wang Hongyu

    2012-08-15

    The combinational laser radiation pressure and plasma bubble fields to accelerate protons are researched through theoretical analysis and numerical simulations. The dephasing length of the accelerated protons bunch in the front of the bubble and the density gradient effect of background plasma on the accelerating phase are analyzed in detail theoretically. The radiation damping effect on the accelerated protons energy is also considered. And it is demonstrated by two-dimensional particle-in-cell simulations that the protons bunch energy can be increased by using the background plasma with negative density gradient. However, radiation damping makes the maximal energy of the accelerated protons a little reduction.

  17. Scalability of the LEU-Modified Cintichem Process: 3-MeV Van de Graaff and 35-MeV Electron Linear Accelerator Studies

    SciTech Connect

    Rotsch, David A.; Brossard, Tom; Roussin, Ethan; Quigley, Kevin; Chemerisov, Sergey; Gromov, Roman; Jonah, Charles; Hafenrichter, Lohman; Tkac, Peter; Krebs, John; Vandegrift, George F.

    2016-10-31

    Molybdenum-99, the mother of Tc-99m, can be produced from fission of U-235 in nuclear reactors and purified from fission products by the Cintichem process, later modified for low-enriched uranium (LEU) targets. The key step in this process is the precipitation of Mo with α-benzoin oxime (ABO). The stability of this complex to radiation has been examined. Molybdenum-ABO was irradiated with 3 MeV electrons produced by a Van de Graaff generator and 35 MeV electrons produced by a 50 MeV/25 kW electron linear accelerator. Dose equivalents of 1.7–31.2 kCi of Mo-99 were administered to freshly prepared Mo-ABO. Irradiated samples of Mo-ABO were processed according to the LEU Modified-Cintichem process. The Van de Graaff data indicated good radiation stability of the Mo-ABO complex up to ~15 kCi dose equivalents of Mo-99 and nearly complete destruction at doses >24 kCi Mo-99. The linear accelerator data indicate that even at 6.2 kCi of Mo-99 equivalence of dose, the sample lost ~20% of Mo-99. The 20% loss of Mo-99 at this low dose may be attributed to thermal decomposition of the product from the heat deposited in the sample during irradiation.

  18. The effect of stochastic re-acceleration on the energy spectrum of shock-accelerated protons

    SciTech Connect

    Afanasiev, Alexandr; Vainio, Rami; Kocharov, Leon

    2014-07-20

    The energy spectra of particles in gradual solar energetic particle (SEP) events do not always have a power-law form attributed to the diffusive shock acceleration mechanism. In particular, the observed spectra in major SEP events can take the form of a broken (double) power law. In this paper, we study the effect of a process that can modify the power-law spectral form produced by the diffusive shock acceleration: the stochastic re-acceleration of energetic protons by enhanced Alfvénic turbulence in the downstream region of a shock wave. There are arguments suggesting that this process can be important when the shock propagates in the corona. We consider a coronal magnetic loop traversed by a shock and perform Monte Carlo simulations of interactions of shock-accelerated protons with Alfvén waves in the loop. The wave-particle interactions are treated self-consistently, so the finiteness of the available turbulent energy is taken into account. The initial energy spectrum of particles is taken to be a power law. The simulations reveal that the stochastic re-acceleration leads either to the formation of a spectrum that is described in a wide energy range by a power law (although the resulting power-law index is different from the initial one) or to a broken power-law spectrum. The resulting spectral form is determined by the ratio of the energy density of shock-accelerated protons to the wave energy density in the shock's downstream region.

  19. Processing of radioactive waste by the use of low energy ({le} 100 MeV) charged particle accelerators. Optimization problems

    SciTech Connect

    Mushnikov, V.N.; Ozhigov, L.S.; Khizhnyak, N.A.

    1993-12-31

    The radiation processing of long-lived radiotoxic elements is based on transmutation reactions under the action of various particles and energies. Among the different particle sources the most promising is the proton accelerator. The present work studied the process of radiation deactivation in the stationary proton flux as functions of their flux density and energy. The Bateman-Robinson differential equations were solved.

  20. Preliminary Safety Analysis Report (PSAR), The NSLS 200 MeV Linear Electron Accelerator

    SciTech Connect

    Blumberg, L.N.; Ackerman, A.I.; Dickinson, T.; Heese, R.N.; Larson, R.A.; Neuls, C.W.; Pjerov, S.; Sheehan, J.F.

    1993-06-15

    The radiological, fire and electrical hazards posed by a 200 MeV electron Linear Accelerator, which the NSLS Department will install and commission within a newly assembled structure, are addressed in this Preliminary Safety Analysis Report. Although it is clear that this accelerator is intended to be the injector for a future experimental facility, we address only the Linac in the present PSAR since neither the final design nor the operating characteristics of the experimental facility are known at the present time. The fire detection and control system to be installed in the building is judged to be completely adequate in terms of the marginal hazard presented - no combustible materials other than the usual cabling associated with such a facility have been identified. Likewise, electrical hazards associated with power supplies for the beam transport magnets and accelerator components such as the accelerator klystrons and electron gun are classified as marginal in terms of potential personnel injury, cost of equipment lost, program downtime and public impact perceptions as defined in the BNL Environmental Safety and Health Manual and the probability of occurrence is deemed to be remote. No unusual features have been identified for the power supplies or electrical distribution system, and normal and customary electrical safety standards as practiced throughout the NSLS complex and the Laboratory are specified in this report. The radiation safety hazards are similarly judged to be marginal in terms of probability of occurrence and potential injury consequences since, for the low intensity operation proposed - a factor of 25 less than the maximum Linac capability specified by the vendor - the average beam power is only 0.4 watts. The shielding specifications given in this report will give adequate protection to both the general public and nonradiation workers in areas adjacent to the building as well as radiation workers within the controlled access building.

  1. Routine production of copper-64 using 11.7MeV protons

    SciTech Connect

    Jeffery, C. M.; Smith, S. V.; Asad, A. H.; Chan, S.; Price, R. I.

    2012-12-19

    Reliable production of copper-64 ({sup 64}Cu) was achieved by irradiating enriched nickel-64 ({sup 64}Ni, >94.8%) in an IBA 18/9 cyclotron. Nickel-64 (19.1 {+-} 3.0 mg) was electroplated onto an Au disc (125{mu}m Multiplication-Sign 15mm). Targets were irradiated with 11.7 MeV protons for 2 hours at 40{mu}A. Copper isotopes ({sup 60,61,62,64}Cu) were separated from target nickel and cobalt isotopes ({sup 55,57,61}Co) using a single ion exchange column, eluted with varying concentration of low HCl alcohol solutions. The {sup 64}Ni target material was recovered and reused. The {sup 64}Cu production rate was 1.46{+-}0.3MBq/{mu}A.hr/mg{sup 64}Ni(n = 10) (with a maximum of 2.6GBq of {sup 64}Cu isolated after 2hr irradiation at 40uA. Radionuclidic purity of the {sup 64}Cu was 98.7 {+-} 1.6 % at end of separation. Cu content was < 6mg/L (n = 21). The specific activity of {sup 64}Cu was determined by ICP-MS and by titration with Diamsar to be 28.9{+-}13.0GBq/{mu}mol[0.70{+-}0.35Ci/{mu}mol]/({mu}A.hr/mg{sup 64}Ni)(n = 10) and 13.1{+-}12.0GBq/{mu}mol[0.35{+-}0.32Ci/{mu}mol]/({mu}A.hr/mg{sup 64}Ni)(n 9), respectively; which are in agreement, however, further work is required.

  2. Proton shock acceleration using a high contrast high intensity laser

    NASA Astrophysics Data System (ADS)

    Gauthier, Maxence; Roedel, Christian; Kim, Jongjin; Aurand, Bastian; Curry, Chandra; Goede, Sebastian; Propp, Adrienne; Goyon, Clement; Pak, Art; Kerr, Shaun; Ramakrishna, Bhuvanesh; Ruby, John; William, Jackson; Glenzer, Siegfried

    2015-11-01

    Laser-driven proton acceleration is a field of intense research due to the interesting characteristics of this novel particle source including high brightness, high maximum energy, high laminarity, and short duration. Although the ion beam characteristics are promising for many future applications, such as in the medical field or hybrid accelerators, the ion beam generated using TNSA, the acceleration mechanism commonly achieved, still need to be significantly improved. Several new alternative mechanisms have been proposed such as collisionless shock acceleration (CSA) in order to produce a mono-energetic ion beam favorable for those applications. We report the first results of an experiment performed with the TITAN laser system (JLF, LLNL) dedicated to the study of CSA using a high intensity (5x1019W/cm2) high contrast ps laser pulse focused on 55 μm thick CH and CD targets. We show that the proton spectrum generated during the interaction exhibits high-energy mono-energetic features along the laser axis, characteristic of a shock mechanism.

  3. Shock-wave proton acceleration from a hydrogen gas jet

    NASA Astrophysics Data System (ADS)

    Cook, Nathan; Pogorelsky, Igor; Polyanskiy, Mikhail; Babzien, Marcus; Tresca, Olivier; Maharjan, Chakra; Shkolnikov, Peter; Yakimenko, Vitaly

    2013-04-01

    Typical laser acceleration experiments probe the interaction of intense linearly-polarized solid state laser pulses with dense metal targets. This interaction generates strong electric fields via Transverse Normal Sheath Acceleration and can accelerate protons to high peak energies but with a large thermal spectrum. Recently, the advancement of high pressure amplified CO2 laser technology has allowed for the creation of intense (10^16 Wcm^2) pulses at λ˜10 μm. These pulses may interact with reproducible, high rep. rate gas jet targets and still produce plasmas of critical density (nc˜10^19 cm-3), leading to the transference of laser energy via radiation pressure. This acceleration mode has the advantage of producing narrow energy spectra while scaling well with pulse intensity. We observe the interaction of an intense CO2 laser pulse with an overdense hydrogen gas jet. Using two pulse optical probing in conjunction with interferometry, we are able to obtain density profiles of the plasma. Proton energy spectra are obtained using a magnetic spectrometer and scintillating screen.

  4. Further Acceleration of MeV Electrons by a Relativistic Laser Pulse

    NASA Astrophysics Data System (ADS)

    He, Feng; Yu, Wei; Lu, Pei-Xiang; Xu, Han; Shen, Bai-Fei; Qian, Lie-Jia; Li, Ru-Xin; Xu, Zhi-Zhan

    2005-05-01

    With the development of photocathode rf electron gun, electrons with high-brightness and mono-energy can be obtained easily. By numerically solving the relativistic equations of motion of an electron generated from this facility in laser fields modelled by a circular polarized Gaussian laser pulse, we find the electron can obtain high energy gain from the laser pulse. The corresponding acceleration distance for this electron driven by the ascending part of the laser pulse is much longer than the Rayleigh length, and the light amplitude experienced on the electron is very weak when the laser pulse overtakes the electron. The electron is accelerated effectively and the deceleration can be neglected. For intensities around 1019 W.μm2/cm2, an electron's energy gain near 0.1 GeV can be realized when its initial energy is 4.5 MeV, and the final velocity of the energetic electron is parallel with the propagation axis. The energy gain can be up to 1 GeV if the intensity is about 1021 W.μm2/cm2. The final energy gain of the electron as a function of its initial conditions and the parameters of the laser beam has also been discussed.

  5. Energy loss straggling of (0.5 < Ep < 2.0) MeV protons in formvar

    NASA Astrophysics Data System (ADS)

    Djaroum, S.; Damache, S.; Moussa, D.; Ouichaoui, S.; Amari, L.

    2015-07-01

    Energy loss distributions for (0.5 < Ep < 2.0) MeV protons traversing polyvinyl formal have been measured in transmission. Then, they have been analyzed in order to determine energy loss straggling variance data. For avoiding non-stochastic broadenings and single collision events, only energy loss fractions within the range 2 % ⩽ ΔE/E ⩽ 20 % have been considered. The inferred energy loss straggling data are compared to values derived by several theories of the collisional energy straggling and by Yang et al. empirical formula with assuming the validity of the Bragg-Kleeman additivity rule for compounds in all the performed calculations. The obtained results are discussed with distinguishing two projectile velocity regimes delimited by the proton energy Ep ∼ 1.2 MeV. Over the high proton velocity regime, our data are in very consistent with the classical Bohr theory and the Yang et al. empirical formula predicting constant collisional energy loss straggling. It clearly appears that over the low proton velocity regime, our energy loss straggling data are in best overall quantitative agreement with values predicted by the Sigmund-Schinner binary collision stopping theory (the BCAS) involving both the shell and Barkas-Anderson corrections. Besides, the slight low energy-dependent behavior of experimental data shows to be consistent with the predictions of the Bethe-Livingston theory and the Yang et al. empirical formula.

  6. Deep level transient spectroscopy (DLTS) study of defects introduced in antimony doped Ge by 2 MeV proton irradiation

    NASA Astrophysics Data System (ADS)

    Nyamhere, C.; Das, A. G. M.; Auret, F. D.; Chawanda, A.; Pineda-Vargas, C. A.; Venter, A.

    2011-08-01

    Deep level transient spectroscopy (DLTS) and Laplace-DLTS have been used to investigate the defects created in Sb doped Ge after irradiation with 2 MeV protons having a fluence of 1×10 13 protons/cm 2. The results show that proton irradiation resulted in primary hole traps at E V +0.15 and E V +0.30 eV and electron traps at E C -0.38, E C -0.32, E C -0.31, E C -0.22, E C -0.20, E C -0.17, E C -0.15 and E C -0.04 eV. Defects observed in this study are compared with those introduced in similar samples after MeV electron irradiation reported earlier. E C -0.31, E C -0.17 and E C -0.04, and E V +0.15 eV were not observed previously in similar samples after high energy irradiation. Results from this study suggest that although similar defects are introduced by electron and proton irradiation, traps introduced by the latter are dose dependent.

  7. Laser acceleration of monoenergetic protons via a double layer emerging from an ultra-thin foil

    NASA Astrophysics Data System (ADS)

    Eliasson, Bengt; Liu, Chuan S.; Shao, Xi; Sagdeev, Roald; Shukla, Padma K.; Dudnikova, Galina; Liu, T. C.

    2009-11-01

    Theoretical and numerical studies are presented of the acceleration of monoenergetic protons in a double layer formed by the laser irradiation of an ultra-thin film. The ponderomotive force of the laser light pushes the electrons forward, and the induced space charge electric field pulls the ions and makes the thin foil accelerate as a whole. A stable double layer is formed, in which the ions are trapped by the combined electric field and inertial force in the accelerated frame, together with the electrons that are trapped in the well of the ponderomotive and ion electric field. The trapped ions reach monoenergetic energies up to 100 MeV and beyond, making them suitable for cancer treatment. We present an analytic theory for the laser-accelerated ion energy as a function of the laser intensity, foil thickness and the plasma number density. The underlying physics of the trapped and untrapped ions and of the stabilization of the Rayleigh-Taylor instability are discussed.

  8. Qualitative comparison of bremsstrahlung X-rays and 800 MeV protons for tomography of urania fuel pellets

    SciTech Connect

    Morris, Christopher L.; Bourke, Mark A.; Byler, Darrin D.; Chen, Ching-Fong; Hogan, Gary E.; Hunter, James F.; Kwiatkowski, Kris K.; Mariam, Fesseha G.; McClellan, Kenneth J.; Merrill, Frank E.; Morley, Deborah J.; Saunders, Alexander

    2013-02-11

    We present an assessment of x-rays and proton tomography as tools for studying the time dependence of the development of damage in fuel rods. Also, we show data taken with existing facilities at Los Alamos National Laboratory that support this assessment. Data on surrogate fuel rods has been taken using the 800 MeV proton radiography (pRad) facility at the Los Alamos Neutron Science Center (LANSCE), and with a 450 keV bremsstrahlung X-ray tomography facility. The proton radiography pRad facility at LANSCE can provide good position resolution (<70 μm has been demonstrate, 20 μm seems feasible with minor changes) for tomography on activated fuel rods. Bremsstrahlung x-rays may be able to provide better than 100 μm resolution but further development of sources, collimation and detectors is necessary for x-rays to deal with the background radiation for tomography of activated fuel rods.

  9. High order magnetic optics for high dynamic range proton radiography at a kinetic energy 800 MeV

    SciTech Connect

    Sjue, Sky K. L.; Morris, Christopher L.; Merrill, Frank Edward; Mariam, Fesseha Gebre; Saunders, Alexander

    2016-01-14

    Flash radiography with 800 MeV kinetic energy protons at Los Alamos National Laboratory is an important experimental tool for investigations of dynamic material behavior driven by high explosives or pulsed power. The extraction of quantitative information about density fields in a dynamic experiment from proton generated images requires a high fidelity model of the protonimaging process. It is shown that accurate calculations of the transmission through the magnetic lens system require terms beyond second order for protons far from the tune energy. The approach used integrates the correlated multiple Coulomb scattering distribution simultaneously over the collimator and the image plane. Furthermore, comparison with a series of static calibrationimages demonstrates the model’s accurate reproduction of both the transmission and blur over a wide range of tune energies in an inverse identity lens that consists of four quadrupole electromagnets.

  10. High order magnetic optics for high dynamic range proton radiography at a kinetic energy 800 MeV

    DOE PAGES

    Sjue, Sky K. L.; Morris, Christopher L.; Merrill, Frank Edward; ...

    2016-01-14

    Flash radiography with 800 MeV kinetic energy protons at Los Alamos National Laboratory is an important experimental tool for investigations of dynamic material behavior driven by high explosives or pulsed power. The extraction of quantitative information about density fields in a dynamic experiment from proton generated images requires a high fidelity model of the protonimaging process. It is shown that accurate calculations of the transmission through the magnetic lens system require terms beyond second order for protons far from the tune energy. The approach used integrates the correlated multiple Coulomb scattering distribution simultaneously over the collimator and the image plane.more » Furthermore, comparison with a series of static calibrationimages demonstrates the model’s accurate reproduction of both the transmission and blur over a wide range of tune energies in an inverse identity lens that consists of four quadrupole electromagnets.« less

  11. Optical spectroscopy and imaging of colour centres in lithium fluoride crystals and thin films irradiated by 3 MeV proton beams

    NASA Astrophysics Data System (ADS)

    Piccinini, M.; Ambrosini, F.; Ampollini, A.; Carpanese, M.; Picardi, L.; Ronsivalle, C.; Bonfigli, F.; Libera, S.; Vincenti, M. A.; Montereali, R. M.

    2014-05-01

    Lithium fluoride is a well-known dosimeter material and it is currently under investigation also for high-resolution radiation imaging detectors based on colour centre photoluminescence. In order to extend their applications, proton beams of 3 MeV energy, produced by a linear accelerator, were used to irradiate LiF crystals and thin films in the fluence range of 1010-1015 protons/cm2. The irradiation induces the formation of colour centres, mainly the primary F centre and the aggregate F2 and F3+ defects, which are stable at room temperature. By optical pumping in the blue spectral region, the F2 and F3+ centres emit broad photoluminescence bands in the visible spectral range. By conventional fluorescence microscopy, the integrated photoluminescence intensity was carefully measured in LiF crystals and thin films as a function of the irradiation fluence: a linear optical response was obtained in a large range of fluence, which is dependent on the used LiF samples. Colour centres concentrations were estimated in LiF crystals by optical absorption spectroscopy. It was possible to record the transversal proton beam intensity profile by acquiring the photoluminescence image of the irradiated spots on LiF films.

  12. Investigation of activation cross-sections of proton induced nuclear reactions on natMo up to 40 MeV: New data and evaluation

    NASA Astrophysics Data System (ADS)

    Tárkányi, F.; Ditrói, F.; Hermanne, A.; Takács, S.; Ignatyuk, A. V.

    2012-06-01

    Cross-sections of proton induced nuclear reactions on natural molybdenum have been studied in the frame of a systematic investigation of charged particle induced nuclear reactions on metals for different applications. The excitation functions of 93mTc, 93gTc(m+), 94mTc, 94gTc, 95mTc, 95gTc, 96gTc(m+), 99mTc, 90Mo(cum), 93mMo, 99Mo(cum), 90Nb(cum), 92mNb, 95mNb, 95gNb, 96Nb and 88Zr(cum), 89Zr(cum) were measured up to 40 MeV proton energy by a using stacked foil technique and activation method. The main goals of this work were to study the production possibility of the medically important 99mTc and its 99Mo parent nucleus, to get experimental data for accelerator technology, for monitoring of proton beam, for thin layer activation technique and for testing nuclear reaction theories. The experimental data were compared with critically analysed published data and with the results of model calculations, obtained by using the ALICE-IPPE, EMPIRE-II and TALYS codes.

  13. Traceable charge measurement of the pulses of a 27 MeV electron beam from a linear accelerator

    NASA Astrophysics Data System (ADS)

    Schüller, A.; Illemann, J.; Renner, F.; Makowski, C.; Kapsch, R.-P.

    2017-03-01

    This work presents a detailed description of measuring devices and calibration procedures which enable the nondestructive (non-intercepting) absolute measurement of the charge of individual beam pulses (macro-pulses) from an electron linear accelerator traceable to primary standards with high accuracy, i.e. with an expanded measurement uncertainty < 0.1%. In particular, we demonstrate the readout and calibration of a Bergoz integrating current transformer which is frequently applied at many different types of accelerators as a beam intensity monitor. The current transformer signal is calibrated against the absolute charge measurement by means of a custom-made compact Faraday cup with a high degree of collection efficiency for electron beams in the energy range of 6 MeV to 50 MeV (99.2% at 27 MeV), which is well known from measurements and consistently described by Monte Carlo calculations.

  14. Proton and Ion Acceleration on the Contrast Upgraded Texas Petawatt Laser

    NASA Astrophysics Data System (ADS)

    McCary, Edward; Roycroft, Rebecca; Jiao, Xuejing; Kupfer, Rotem; Tiwari, Ganesh; Wagner, Craig; Yandow, Andrew; Franke, Philip; Dyer, Gilliss; Gaul, Erhard; Toncian, Toma; Ditmire, Todd; Hegelich, Bjorn; CenterHigh Energy Density Science Team

    2016-10-01

    Recent upgrades to the Texas Petawatt (TPW) laser system have eliminated pre-pulses and reduced the laser pedestal, resulting in improved laser contrast. Previously unwanted pre-pulses and amplified spontaneous emission (ASE) would ionize targets thinner than 1 micron, leaving an under-dense plasma which was not capable of accelerating ions to high energies. After the upgrade the contrast was drastically improved allowing us to successfully shoot targets as thin as 20 nm without plasma mirrors. We have also observed evidence of relativistic transparency and Break-Out Afterburner (BOA) ion acceleration when shooting ultra-thin, nanometer scale targets. Data taken with a wide angle ion spectrometer (IWASP) showed the characteristic asymmetry of BOA in the plane orthogonal to the laser polarization on thin targets but not on micron scale targets. Thick micron scale targets saw improvement as well; shots on 2 μm thick gold targets saw ions with energies up to 100 MeV, which broke the former record proton energy on the TPW. Switching the focusing optic from an f/3 parabolic mirror to an f/40 spherical mirror showed improvement in the number of low energy protons created, and provided a source for hundreds of picosecond heating of aluminum foils for warm dense matter measurements.

  15. Proton Acceleration Driven by a Nanosecond Laser from a Cryogenic Thin Solid-Hydrogen Ribbon

    NASA Astrophysics Data System (ADS)

    Margarone, D.; Velyhan, A.; Dostal, J.; Ullschmied, J.; Perin, J. P.; Chatain, D.; Garcia, S.; Bonnay, P.; Pisarczyk, T.; Dudzak, R.; Rosinski, M.; Krasa, J.; Giuffrida, L.; Prokupek, J.; Scuderi, V.; Psikal, J.; Kucharik, M.; De Marco, M.; Cikhardt, J.; Krousky, E.; Kalinowska, Z.; Chodukowski, T.; Cirrone, G. A. P.; Korn, G.

    2016-10-01

    A high-power pulsed laser is focused onto a solid-hydrogen target to accelerate forward a collimated stream of protons in the range 0.1-1 MeV, carrying a very high energy of about 30 J (˜5 % laser-ion conversion efficiency) and extremely large charge of about ˜0.1 mC per laser pulse. This result is achieved for the first time through the combination of a sophisticated target system (H2 thin ribbon) operating at cryogenic temperature (˜10 K ) and a very hot H plasma (˜300 keV "hot electron" temperature) generated by a subnanosecond laser with an intensity of ˜3 ×1016 W /cm2 . Both the H plasma and the accelerated proton beam are fully characterized by in situ and ex situ diagnostics. Results obtained using the ELISE (experiments on laser interaction with solid hydrogen) H2 target delivery system at PALS (Prague) kJ-class laser facility are presented and discussed along with potential multidisciplinary applications.

  16. Normal-conducting scaling fixed field alternating gradient accelerator for proton therapy

    NASA Astrophysics Data System (ADS)

    Garland, J. M.; Appleby, R. B.; Owen, H.; Tygier, S.

    2015-09-01

    In this paper we present a new lattice design for a 30-350 MeV scaling fixed-field alternating gradient accelerator for proton therapy and tomography—NORMA (NOrmal-conducting Racetrack Medical Accelerator). The energy range allows the realization of proton computed tomography and utilizes normal conducting magnets in both a conventional circular ring option and a novel racetrack configuration, both designed using advanced optimization algorithms we have developed in pyzgoubi. Both configurations consist of ten focusing-defocusing-focusing triplet cells and operate in the second stability region of Hills equation. The ring configuration has a circumference of 60 m, a peak magnetic field seen by the beam of <1.6 T , a maximum horizontal orbit excursion of 44 cm and a dynamic aperture of 68 mm mrad—determined using a novel dynamic aperture (DA) calculation technique. The racetrack alternative is realized by adding magnet-free drift space in between cells at two opposing points in the ring, to facilitate injection and extraction. Our racetrack design has a total magnet-free straight lengths of 4.9 m, a circumference of 71 m, a peak magnetic field seen by the beam of <1.74 T , a maximum horizontal orbit excursion of 50 cm and a DA of 58 mm mrad. A transverse magnet misalignment model is also presented for the ring and racetrack configurations where the DA remains above 40 mm mrad for randomly misaligned error distributions with a standard deviation up to 100 μ m .

  17. Status of intense permanent magnet proton source for China-accelerator driven sub-critical system Linac

    SciTech Connect

    Wu, Q. Ma, H. Y.; Yang, Y.; Sun, L. T.; Zhang, X. Z.; Zhang, Z. M.; Zhao, H. Y.; He, Y.; Zhao, H. W.

    2016-02-15

    Two compact intense 2.45 GHz permanent magnet proton sources and their corresponding low energy beam transport (LEBT) system were developed successfully for China accelerator driven sub-critical system in 2014. Both the proton sources operate at 35 kV potential. The beams extracted from the ion source are transported by the LEBT, which is composed of two identical solenoids, to the 2.1 MeV Radio-Frequency Quadrupole (RFQ). In order to ensure the safety of the superconducting cavities during commissioning, an electrostatic-chopper has been designed and installed in the LEBT line that can chop the continuous wave beam into a pulsed one. The minimum width of the pulse is less than 10 μs and the fall/rise time of the chopper is about 20 ns. The performance of the proton source and the LEBT, such as beam current, beam profile, emittance and the impact to RFQ injection will be presented.

  18. Radiation dosimetry of 12 MV photons from a CGR Therac 20 MeV Saturne linear accelerator.

    PubMed

    Nair, R P

    1984-10-01

    Typically useful clinical radiation dosimetry characteristics of 12 MV photon beams from a CGR Therac 20 MeV Saturne linear accelerator are briefly outlined. Central axis percent depth dose data are compared with other published data. Beam profiles for small, medium and large fields are delineated to show the uniformity of beams at various depths.

  19. Prospects of target nanostructuring for laser proton acceleration

    NASA Astrophysics Data System (ADS)

    Lübcke, Andrea; Andreev, Alexander A.; Höhm, Sandra; Grunwald, Ruediger; Ehrentraut, Lutz; Schnürer, Matthias

    2017-03-01

    In laser-based proton acceleration, nanostructured targets hold the promise to allow for significantly boosted proton energies due to strong increase of laser absorption. We used laser-induced periodic surface structures generated in-situ as a very fast and economic way to produce nanostructured targets capable of high-repetition rate applications. Both in experiment and theory, we investigate the impact of nanostructuring on the proton spectrum for different laser–plasma conditions. Our experimental data show that the nanostructures lead to a significant enhancement of absorption over the entire range of laser plasma conditions investigated. At conditions that do not allow for efficient laser absorption by plane targets, i.e. too steep plasma gradients, nanostructuring is found to significantly enhance the proton cutoff energy and conversion efficiency. In contrast, if the plasma gradient is optimized for laser absorption of the plane target, the nanostructure-induced absorption increase is not reflected in higher cutoff energies. Both, simulation and experiment point towards the energy transfer from the laser to the hot electrons as bottleneck.

  20. Prospects of target nanostructuring for laser proton acceleration

    PubMed Central

    Lübcke, Andrea; Andreev, Alexander A.; Höhm, Sandra; Grunwald, Ruediger; Ehrentraut, Lutz; Schnürer, Matthias

    2017-01-01

    In laser-based proton acceleration, nanostructured targets hold the promise to allow for significantly boosted proton energies due to strong increase of laser absorption. We used laser-induced periodic surface structures generated in-situ as a very fast and economic way to produce nanostructured targets capable of high-repetition rate applications. Both in experiment and theory, we investigate the impact of nanostructuring on the proton spectrum for different laser–plasma conditions. Our experimental data show that the nanostructures lead to a significant enhancement of absorption over the entire range of laser plasma conditions investigated. At conditions that do not allow for efficient laser absorption by plane targets, i.e. too steep plasma gradients, nanostructuring is found to significantly enhance the proton cutoff energy and conversion efficiency. In contrast, if the plasma gradient is optimized for laser absorption of the plane target, the nanostructure-induced absorption increase is not reflected in higher cutoff energies. Both, simulation and experiment point towards the energy transfer from the laser to the hot electrons as bottleneck. PMID:28290479

  1. Measurement of the free neutron-proton analyzing power and spin transfer parameters in the charge exchange region at 790 MeV

    SciTech Connect

    Ransome, R.D.

    1981-07-01

    The free neutron-proton analyzing power and the spin transfer parameters (K/sub NN/, K/sub SS/, K/sub SL/, and K/sub LL/) were measured at the Los Alamos Meson Physics Facility at 790 MeV between 165/sup 0/ and 180/sup 0/ center of mass. A 40% polarized neutron beam incident on a liquid hydrogen target was used. The recoil protons were momentum analyzed with a magnetic spectrometer to isolate elastic scatters. A large solid angle carbon polarimeter was used to measure the proton polarization. The measurements are the first at this energy and are in basic agreement with pre-existing phase shift solutions. The proton-carbon analyzing power was measured between 500 and 750 MeV. An empirical fit to the proton-carbon analyzing power between 100 and 750 MeV was done.

  2. /sup 74,76,78,80,82/Se by inelastic scattering of 64. 8 MeV protons

    SciTech Connect

    Ogino, K.

    1986-01-01

    The inelastic scattering of 64.8 MeV protons has been studied on the stable even XU YSSe isotopes. The inelastically scattered protons were momentum analyzed in a magnetic spectrograph with a resulting energy resolution of approximately 20 keV. Levels up to the excitation energy of about 5 MeV were investigated. Many new levels were observed for the isotopes studied. The angular distributions obtained were compared with the predictions of distorted-wave Born approximation and coupled-channels calculations and a number of new spin assignments were proposed. Several 4 states with comparable strengths were found at about E/sub x/ = 2.0--5.0 MeV, showing large fragmentation of octupole and hexadecapole transition strengths, in contrast to the case of Zn isotopes. The distributions of the transition strengths for the 2 , 3 , and 4 states were compared with the theoretical calculations based on the random-phase-approximation model for spherical nuclei.

  3. Spin decomposition of the responses of Ca-44 and Ca-48 to 300 MeV protons

    SciTech Connect

    F. T. Baker; L. Bimbot; R. W. Fergerson; C. Glashausser; A. Green; O. Hausser; K. Hicks; K. Jones; C. A. Miller; M. Vetterli; R. Abegg; D. Beatty; B. Bonin; B. Castel; X. Y. Chen; V. Cupps; C. Djalali; R. Henderson; K. P. Jackson; R. Jeppesen; K. Nakayama; S. K. Nanda; R. Sawafta; S. Yen

    1991-07-01

    Angular distributions of the double-differential cross section d2σ/dΩ dE(σ) and the spin-flip probability Snn have been measured for inclusive proton inelastic scattering from 44Ca at 290 MeV and from 48Ca at 318 MeV. Excitation energies up to about 50 MeV for 44Ca and 40 MeV for 48Ca have been investigated over the laboratory angular ranges of 3° to 12° for 44Ca and 3° to 9° for 48Ca. Multipole decompositions of angular distributions of both the spin-flip cross section σSnn and the estimated cross section for ΔS=0 transitions have been performed. Distributions of strengths were deduced for ΔL=1, ΔS=0 (the giant dipole), ΔL=2, ΔS=0 (the giant quadrupole), ΔL=0, ΔS=1 (the magnetic dipole), ΔL=1, ΔS=1 (the spin dipole), and ΔL=2, ΔS=1 (the spin quadrupole). The ΔS=0 summed strengths for 44Ca are lower than for 40Ca and 48Ca. The spin-dipole summed strengths are found to be approximately independent of A. For 48Ca, essentially all M1 strength observed was in the 10.23 MeV 1+ state; for 44Ca, M1 strength was observed to be fragmented over a range of 7 to 18 Mev.

  4. Residual Nuclide Production by Proton-Induced Reactions on Uranium for Energies between 20 and 70 MeV

    NASA Astrophysics Data System (ADS)

    Uosif, M. A. M.; Michel, R.; Herpers, U.; Kubik, P.-W.; Duijvestijn, M.; Koning, A.

    2005-05-01

    Within the HINDAS project, proton-irradiation experiments were performed at the injector cyclotron of the Paul Scherrer Institute at Villigen/Switzerland in order to investigate the production of residual nuclides from natural uranium. The stacked-foil technique was used to cover proton energies between 20 MeV and 70 MeV. Copper targets were used for monitoring the proton beam using the reaction 65Cu (p,n)65Zn. Residual radionuclides were measured by off-line γ-spectrometry. Excitation functions were obtained for the production of 91Y, 95Zr, 95mNb, 99Mo, 103Ru, 112Pd, 115Cd, 124Sb, 126Sb, 127Sb, 132Te, 131I, 134Cs, 136Cs, 137Cs, 140Ba, 141Ce, 144Ce, 147Nd, and 238Np. The experimental data are compared to the sparse results of earlier measurements and with theoretical excitation functions calculated by the newly developed TALYS code. Good agreement between theory and experiment was obtained for product masses up to 115. For higher-mass fission products and for 238Np, there are still systematic deviations between theory and experiment. These deviations are discussed as deficits of the fission model in the heavy part of the fission product distribution.

  5. Residual Nuclide Production by Proton-Induced Reactions on Uranium for Energies between 20 and 70 MeV

    SciTech Connect

    Uosif, M.A.M.; Michel, R.; Herpers, U.; Kubik, P.-W.; Duijvestijn, M.; Koning, A.

    2005-05-24

    Within the HINDAS project, proton-irradiation experiments were performed at the injector cyclotron of the Paul Scherrer Institute at Villigen/Switzerland in order to investigate the production of residual nuclides from natural uranium. The stacked-foil technique was used to cover proton energies between 20 MeV and 70 MeV. Copper targets were used for monitoring the proton beam using the reaction 65Cu (p,n)65Zn. Residual radionuclides were measured by off-line {gamma}-spectrometry. Excitation functions were obtained for the production of 91Y, 95Zr, 95mNb, 99Mo, 103Ru, 112Pd, 115Cd, 124Sb, 126Sb, 127Sb, 132Te, 131I, 134Cs, 136Cs, 137Cs, 140Ba, 141Ce, 144Ce, 147Nd, and 238Np. The experimental data are compared to the sparse results of earlier measurements and with theoretical excitation functions calculated by the newly developed TALYS code. Good agreement between theory and experiment was obtained for product masses up to 115. For higher-mass fission products and for 238Np, there are still systematic deviations between theory and experiment. These deviations are discussed as deficits of the fission model in the heavy part of the fission product distribution.

  6. Compensations of beamlet deflections for 1 MeV accelerator of ITER NBI

    NASA Astrophysics Data System (ADS)

    Kashiwagi, Mieko; Taniguchi, Masaki; Umeda, Naotaka; Dairaku, Masayuki; Tobari, Hiroyuki; Yamanaka, Haruhiko; Watanabe, Kazuhiro; Inoue, Takashi; de Esch, H. P. L.; Grisham, Larry R.; Boilson, Deirdre; Hemsworth, Ronald S.; Tanaka, Masanobu

    2013-02-01

    Compensation methods of beamlet deflections have been studied in a three dimensional (3D) beam analysis using OPERA-3d code for 1 MeV accelerator of the ITER neutral beam injector (NBI). The beamlet deflection is caused by i) magnetic field generated by permanent magnets embedded in the extraction grid (EXG) for electron suppression and ii) space charge repulsion between the beamlets and beam groups. Moreover, the beamlet deflection is caused due to electric field distortion formed by a grid support structure. In order to compensate the beamlet deflections due to i) and ii), an aperture offset of 0.6 mm was applied in the electron suppression grid (ESG) and a metal bar with 3 mm in thickness, so-called a kerb, was attached around the aperture area at the back side of the ESG, respectively. Detailed configuration of the compensation methods was also considered so as to suppress the beam spread due to the electric field distortion and to lower electric field concentrations at the edge of the kerb. For the beamlets near the grid support structure, the beamlet deflection due to the space charge repulsion could be negated due to the electric field distortion formed by the grid support structure.

  7. Beam dynamics study of a 30 MeV electron linear accelerator to drive a neutron source

    NASA Astrophysics Data System (ADS)

    Kumar, Sandeep; Yang, Haeryong; Kang, Heung-Sik

    2014-02-01

    An experimental neutron facility based on 32 MeV/18.47 kW electron linac has been studied by means of PARMELA simulation code. Beam dynamics study for a traveling wave constant gradient electron accelerator is carried out to reach the preferential operation parameters (E = 30 MeV, P = 18 kW, dE/E < 12.47% for 99% particles). The whole linac comprises mainly E-gun, pre-buncher, buncher, and 2 accelerating columns. A disk-loaded, on-axis-coupled, 2π/3-mode type accelerating rf cavity is considered for this linac. After numerous optimizations of linac parameters, 32 MeV beam energy is obtained at the end of the linac. As high electron energy is required to produce acceptable neutron flux. The final neutron flux is estimated to be 5 × 1011 n/cm2/s/mA. Future development will be the real design of a 30 MeV electron linac based on S band traveling wave.

  8. Analysis of accelerator based neutron spectra for BNCT using proton recoil spectroscopy

    SciTech Connect

    Wielopolski, L.; Ludewig, H.; Powell, J.R.; Raparia, D.; Alessi, J.G.; Lowenstein, D.I.

    1999-03-01

    Boron Neutron Capture Therapy (BNCT) is a promising binary treatment modality for high-grade primary brain tumors (glioblastoma multiforme, GM) and other cancers. BNCT employs a boron-10 containing compound that preferentially accumulates in the cancer cells in the brain. Upon neutron capture by {sup 10}B energetic alpha particles and triton released at the absorption site kill the cancer cell. In order to gain penetration depth in the brain Fairchild proposed, for this purpose, the use of energetic epithermal neutrons at about 10 keV. Phase 1/2 clinical trials of BNCT for GM are underway at the Brookhaven Medical Research Reactor (BMRR) and at the MIT Reactor, using these nuclear reactors as the source for epithermal neutrons. In light of the limitations of new reactor installations, e.g. cost, safety and licensing, and limited capability for modulating the reactor based neutron beam energy spectra, alternative neutron sources are being contemplated for wider implementation of this modality in a hospital environment. For example, accelerator based neutron sources offer the possibility of tailoring the neutron beams, in terms of improved depth-dose distributions, to the individual and offer, with relative ease, the capability of modifying the neutron beam energy and port size. In previous work new concepts for compact accelerator/target configuration were published. In this work, using the Van de Graaff accelerator the authors have explored different materials for filtering and reflecting neutron beams produced by irradiating a thick Li target with 1.8 to 2.5 MeV proton beams. However, since the yield and the maximum neutron energy emerging from the Li-7(p,n)Be-7 reaction increase with increase in the proton beam energy, there is a need for optimization of the proton energy versus filter and shielding requirements to obtain the desired epithermal neutron beam. The MCNP-4A computer code was used for the initial design studies that were verified with benchmark

  9. Acceleration of petaelectronvolt protons in the Galactic Centre.

    PubMed

    2016-03-24

    Galactic cosmic rays reach energies of at least a few petaelectronvolts (of the order of 10(15) electronvolts). This implies that our Galaxy contains petaelectronvolt accelerators ('PeVatrons'), but all proposed models of Galactic cosmic-ray accelerators encounter difficulties at exactly these energies. Dozens of Galactic accelerators capable of accelerating particles to energies of tens of teraelectronvolts (of the order of 10(13) electronvolts) were inferred from recent γ-ray observations. However, none of the currently known accelerators--not even the handful of shell-type supernova remnants commonly believed to supply most Galactic cosmic rays--has shown the characteristic tracers of petaelectronvolt particles, namely, power-law spectra of γ-rays extending without a cut-off or a spectral break to tens of teraelectronvolts. Here we report deep γ-ray observations with arcminute angular resolution of the region surrounding the Galactic Centre, which show the expected tracer of the presence of petaelectronvolt protons within the central 10 parsecs of the Galaxy. We propose that the supermassive black hole Sagittarius A* is linked to this PeVatron. Sagittarius A* went through active phases in the past, as demonstrated by X-ray outburstsand an outflow from the Galactic Centre. Although its current rate of particle acceleration is not sufficient to provide a substantial contribution to Galactic cosmic rays, Sagittarius A* could have plausibly been more active over the last 10(6)-10(7) years, and therefore should be considered as a viable alternative to supernova remnants as a source of petaelectronvolt Galactic cosmic rays.

  10. Long pulse acceleration of MeV class high power density negative H{sup −} ion beam for ITER

    SciTech Connect

    Umeda, N. Kojima, A.; Kashiwagi, M.; Tobari, H.; Hiratsuka, J.; Watanabe, K.; Dairaku, M.; Yamanaka, H.; Hanada, M.

    2015-04-08

    R and D of high power density negative ion beam acceleration has been carried out at MeV test facility in JAEA to realize ITER neutral beam accelerator. The main target is H{sup −} ion beam acceleration up to 1 MeV with 200 A/m{sup 2} for 60 s whose pulse length is the present facility limit. For long pulse acceleration at high power density, new extraction grid (EXG) has been developed with high cooling capability, which electron suppression magnet is placed under cooling channel similar to ITER. In addition, aperture size of electron suppression grid (ESG) is enlarged from 14 mm to 16 mm to reduce direct interception on the ESG and emission of secondary electron which leads to high heat load on the upstream acceleration grid. By enlarging ESG aperture, beam current increased 10 % at high current beam and total acceleration grid heat load reduced from 13 % to 10 % of input power at long pulse beam. In addition, heat load by back stream positive ion into the EXG is measured for the first time and is estimated as 0.3 % of beam power, while heat load by back stream ion into the source chamber is estimated as 3.5 ~ 4.0 % of beam power. Beam acceleration up to 60 s which is the facility limit, has achieved at 683 keV, 100 A/m{sup 2} of negative ion beam, whose energy density increases two orders of magnitude since 2011.

  11. The microstructure of the 1.4914 MANET martensitic steel before and after irradiation with 590 MeV protons

    NASA Astrophysics Data System (ADS)

    Gavillet, D.; Marmy, P.; Victoria, M.

    1992-09-01

    Optical and transmission electron microscope observations, together with SEM (scanning electron microscope) and ASTEM (analytical scanning transmission electron microscope) microanalysis have been performed in samples of the DIN 1.4914 martensitic steel (MANET cast), both before and after irradiation with 590 MeV protons to doses up to 1 dpa at temperatures between 363 and 703 K. The chemical composition of the different carbide geometries have been obtained. No substantial modification of the carbide and precipitate structure is observed after either deformation under fatigue or after irradiation to 1 dpa at 703 K. No bubbles have been observed in a specimen irradiated to 0.7 dpa, containing 87 appm He.

  12. Measurement of the neutron fields produced by a 62 MeV proton beam on a PMMA phantom using extended range Bonner sphere spectrometers

    NASA Astrophysics Data System (ADS)

    Amgarou, K.; Bedogni, R.; Domingo, C.; Esposito, A.; Gentile, A.; Carinci, G.; Russo, S.

    2011-10-01

    The experimental characterization of the neutron fields produced as parasitic effect in medical accelerators is assuming an increased importance for either the patient protection or the facility design aspects. Medical accelerators are diverse in terms of particle type (electrons or hadrons) and energy, but the radiation fields around them have in common (provided that a given threshold energy is reached) the presence of neutrons with energy span over several orders of magnitude. Due to the large variability of neutron energy, field or dosimetry measurements in these workplaces are very complex, and in general, cannot be performed with ready-to-use commercial instruments. In spite of its poor energy resolution, the Bonner Sphere Spectrometer (BSS) is the only instrument able to simultaneously determine all spectral components in such workplaces. The energy range of this instrument is limited to E<20 MeV if only polyethylene spheres are used, but can be extended to hundreds of MeV by including metal-loaded spheres (extended range BSS, indicated with ERBSS). With the aim of providing useful data to the scientific community involved in neutron measurements at hadron therapy facilities, an ERBSS experiment was carried out at the Centro di AdroTerapia e Applicazioni Nucleari Avanzate (CATANA) of INFN—LNS (Laboratori Nazionali del Sud), where a proton beam routinely used for ophthalmic cancer treatments is available. The 62 MeV beam was directed towards a PMMA phantom, simulating the patient, and two neutron measurement points were established at 0° and 90° with respect to the beam-line. Here the ERBSS of UAB (Universidad Autónoma de Barcelona— Grup de Física de les Radiacions) and INFN (Istituto Nazionale di Fisica Nucleare—Laboratori Nazionali di Frascati) were exposed to characterize the "forward" and "sideward" proton-induced neutron fields. The use of two ERBSS characterized by different set of spheres, central detectors, and independently established and

  13. Nuclear excitation functions of proton-induced reactions (Ep = 35-90 MeV) from Fe, Cu, and Al

    NASA Astrophysics Data System (ADS)

    Graves, Stephen A.; Ellison, Paul A.; Barnhart, Todd E.; Valdovinos, Hector F.; Birnbaum, Eva R.; Nortier, Francois M.; Nickles, Robert J.; Engle, Jonathan W.

    2016-11-01

    Fe, Cu, and Al stacked foils were irradiated by 90 MeV protons at the Los Alamos Neutron Science Center's Isotope Production Facility to measure nuclear cross sections for the production of medically relevant isotopes, such as 52gMn, 54Mn, 48Cr, 55Co, 58mCo and 57Ni. The decay of radioactive isotopes produced during irradiation was monitored using high-purity germanium gamma spectroscopy over the months following irradiation. Proton fluence was determined using the natAl(p,x)22Na, natCu(p,x)62Zn natCu(p,x)65Zn, and natCu(p,x)56Co monitor reactions. Calculated cross sections were compared against literature values and theoretical TALYS predictions. Notably this work includes the first reported independent cross section measurements of natCu(p,x)58mCo and natCu(p,x)58gCo.

  14. Theoretical study of isotopic production cross-sections in proton-nucleus reactions at 200MeV

    NASA Astrophysics Data System (ADS)

    Sabra, Mohammad S.

    2016-03-01

    As NASA's future plans are likely to include extended human missions in deep space, protections from space radiation take on increased importance. When galactic cosmic rays, mainly protons, interacts with the material of spacecraft, secondary fragments are produced, which contribute substantially to the dose and dose equivalent received by the crew inside. A detailed understanding of the reaction mechanism, as well as a knowledge of cross sections are needed. We analyze energy spectra, angular distributions, and isotopic cross-sections of intermediate-mass fragments (IMFs) from the interaction of 27Al, 59Co, and 197Au with 200 MeV protons. Calculations within the modified statistical model with final state interaction were performed using SAPTON code. General agreement is obtained with the experiment which suggests that most of the IMFs are emitted after equilibrium is reached (i.e. in the evaporation stage).

  15. Modifying proton fluence spectra to generate spread-out Bragg peaks with laser accelerated proton beams.

    PubMed

    Schell, S; Wilkens, J J

    2009-10-07

    Currently, energy spectra of laser accelerated proton beams are far from being monoenergetic. For their application in radiation therapy, energy selection systems using magnetic fields have been proposed to single out particles with the desired energy. These systems allow the choice of protons between a lowest and a highest energy. In this work, we present a slight modification that allows us to influence the relative number of particles per energy bin. In fact, the transmitted spectrum can be shaped in such a way that it corresponds to a full spread out Bragg peak delivered simultaneously. This change of the spectrum can be achieved by inserting suitably formed scattering material at the central plane of the energy selection system where the particles are separated in space depending on their energy. With the help of Monte Carlo simulations we analysed both simple wedge geometries and various stacks of lead slices. We found that these configurations can provide energy spectra that naturally produce spread out Bragg peaks within one laser shot. This increases the particle efficiency of the whole system and makes laser accelerated protons more suitable for radiation therapy.

  16. Positron annihilation on defects in silicon irradiated with 15 MeV protons.

    PubMed

    Arutyunov, N Y; Elsayed, M; Krause-Rehberg, R; Emtsev, V V; Oganesyan, G A; Kozlovski, V V

    2013-01-23

    Microstructure and thermal stability of the radiation defects in n-FZ-Si ([P] ≈ 7 × 10(15) cm(-3)) single crystals have been investigated. The radiation defects have been induced by irradiation with 15 MeV protons and studied by means of both the positron lifetime spectroscopy and low-temperature measurements of the Hall effect. At each step of the isochronal annealing over the temperature range ∼60-700 °C the positron lifetime has been measured for the temperature interval ∼30-300 K, and for samples-satellites the temperature dependences of the charge carriers and mobility have been determined over the range ∼4.2-300 K. It is argued that as-grown impurity centers influence the average positron lifetime by forming shallow (E(b) ≈ 0.013 eV) positron states. The radiation-induced defects were also found to trap positrons into weakly bound (E(b) ≤ 0.01 eV) states. These positron states are observed at cryogenic temperatures during the isochronal annealing up to T(anneal.) = 340 °C. The stages of annealing in the temperature intervals ∼60-180 °C and ∼180-260 °C reflect the disappearance of E-centers and divacancies, respectively. Besides these defects the positrons were found to be localized at deep donor centers hidden in the process of annealing up to the temperature T(anneal.) ≈ 300 °C. The annealing of the deep donors occurs over the temperature range ∼300-650 °C. At these centers positrons are estimated to be bound with energies E(b) ≈ 0.096 and 0.021 eV within the temperature intervals ∼200-270 K and ∼166-66 K, respectively. The positron trapping coefficient from these defects increases from ∼1.1 × 10(16) to ∼6.5 × 10(17) s(-1) over the temperature range ∼266-66 K, thus substantiating a cascade phonon-assisted positron trapping mechanism whose efficiency is described by ≈T(-3) law. It is argued that the value of activation energy of the isochronal annealing E(a) ≈ 0.74-0.59 eV is due to dissociation of the

  17. Radiation parameters of 6 to 20 MeV scanning electron beams from the Saturne linear accelerator.

    PubMed

    Pfalzner, P M; Clarke, H C

    1982-01-01

    Depth doses of the scanning electron beams from the Saturne Therac-20 linear accelerator at nominal energies of 6,9,13,17, and 20 MeV were measured in polystyrene using a thin window parallel plate ionization chamber. Central axis depth dose curves are derived and are analyzed according to the method of Brahme and Svensson. For each of the five electron energies, values are obtained for the most probable energy at the absorber surface Ep,0, the practical range Rp, the 50% range R50, the therapeutic range R85, the electron dose gradients, total collision energy losses, and other radiation parameters, and these are compared to corresponding values for electron beams from a 22 MeV medical microtron and a 20 MeV betatron.

  18. Acceleration of petaelectronvolt protons in the Galactic Centre

    NASA Astrophysics Data System (ADS)

    HESS Collaboration; Abramowski, A.; Aharonian, F.; Benkhali, F. Ait; Akhperjanian, A. G.; Angüner, E. O.; Backes, M.; Balzer, A.; Becherini, Y.; Tjus, J. Becker; Berge, D.; Bernhard, S.; Bernlöhr, K.; Birsin, E.; Blackwell, R.; Böttcher, M.; Boisson, C.; Bolmont, J.; Bordas, P.; Bregeon, J.; Brun, F.; Brun, P.; Bryan, M.; Bulik, T.; Carr, J.; Casanova, S.; Chakraborty, N.; Chalme-Calvet, R.; Chaves, R. C. G.; Chen, A.; Chrétien, M.; Colafrancesco, S.; Cologna, G.; Conrad, J.; Couturier, C.; Cui, Y.; Davids, I. D.; Degrange, B.; Deil, C.; Dewilt, P.; Djannati-Ataï, A.; Domainko, W.; Donath, A.; Drury, L. O'C.; Dubus, G.; Dutson, K.; Dyks, J.; Dyrda, M.; Edwards, T.; Egberts, K.; Eger, P.; Ernenwein, J.-P.; Espigat, P.; Farnier, C.; Fegan, S.; Feinstein, F.; Fernandes, M. V.; Fernandez, D.; Fiasson, A.; Fontaine, G.; Förster, A.; Füßling, M.; Gabici, S.; Gajdus, M.; Gallant, Y. A.; Garrigoux, T.; Giavitto, G.; Giebels, B.; Glicenstein, J. F.; Gottschall, D.; Goyal, A.; Grondin, M.-H.; Grudzińska, M.; Hadasch, D.; Häffner, S.; Hahn, J.; Hawkes, J.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hervet, O.; Hillert, A.; Hinton, J. A.; Hofmann, W.; Hofverberg, P.; Hoischen, C.; Holler, M.; Horns, D.; Ivascenko, A.; Jacholkowska, A.; Jamrozy, M.; Janiak, M.; Jankowsky, F.; Jung-Richardt, I.; Kastendieck, M. A.; Katarzyński, K.; Katz, U.; Kerszberg, D.; Khélifi, B.; Kieffer, M.; Klepser, S.; Klochkov, D.; Kluźniak, W.; Kolitzus, D.; Komin, Nu.; Kosack, K.; Krakau, S.; Krayzel, F.; Krüger, P. P.; Laffon, H.; Lamanna, G.; Lau, J.; Lefaucheur, J.; Lefranc, V.; Lemiére, A.; Lemoine-Goumard, M.; Lenain, J.-P.; Lohse, T.; Lopatin, A.; Lu, C.-C.; Lui, R.; Marandon, V.; Marcowith, A.; Mariaud, C.; Marx, R.; Maurin, G.; Maxted, N.; Mayer, M.; Meintjes, P. J.; Menzler, U.; Meyer, M.; Mitchell, A. M. W.; Moderski, R.; Mohamed, M.; Morå, K.; Moulin, E.; Murach, T.; de Naurois, M.; Niemiec, J.; Oakes, L.; Odaka, H.; Öttl, S.; Ohm, S.; Opitz, B.; Ostrowski, M.; Oya, I.; Panter, M.; Parsons, R. D.; Arribas, M. Paz; Pekeur, N. W.; Pelletier, G.; Petrucci, P.-O.; Peyaud, B.; Pita, S.; Poon, H.; Prokoph, H.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raab, S.; Reichardt, I.; Reimer, A.; Reimer, O.; Renaud, M.; de Los Reyes, R.; Rieger, F.; Romoli, C.; Rosier-Lees, S.; Rowell, G.; Rudak, B.; Rulten, C. B.; Sahakian, V.; Salek, D.; Sanchez, D. A.; Santangelo, A.; Sasaki, M.; Schlickeiser, R.; Schüssler, F.; Schulz, A.; Schwanke, U.; Schwemmer, S.; Seyffert, A. S.; Simoni, R.; Sol, H.; Spanier, F.; Spengler, G.; Spies, F.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Stinzing, F.; Stycz, K.; Sushch, I.; Tavernet, J.-P.; Tavernier, T.; Taylor, A. M.; Terrier, R.; Tluczykont, M.; Trichard, C.; Tuffs, R.; Valerius, K.; van der Walt, J.; van Eldik, C.; van Soelen, B.; Vasileiadis, G.; Veh, J.; Venter, C.; Viana, A.; Vincent, P.; Vink, J.; Voisin, F.; Völk, H. J.; Vuillaume, T.; Wagner, S. J.; Wagner, P.; Wagner, R. M.; Weidinger, M.; Weitzel, Q.; White, R.; Wierzcholska, A.; Willmann, P.; Wörnlein, A.; Wouters, D.; Yang, R.; Zabalza, V.; Zaborov, D.; Zacharias, M.; Zdziarski, A. A.; Zech, A.; Zefi, F.; Żywucka, N.

    2016-03-01

    Galactic cosmic rays reach energies of at least a few petaelectronvolts (of the order of 1015 electronvolts). This implies that our Galaxy contains petaelectronvolt accelerators (‘PeVatrons’), but all proposed models of Galactic cosmic-ray accelerators encounter difficulties at exactly these energies. Dozens of Galactic accelerators capable of accelerating particles to energies of tens of teraelectronvolts (of the order of 1013 electronvolts) were inferred from recent γ-ray observations. However, none of the currently known accelerators—not even the handful of shell-type supernova remnants commonly believed to supply most Galactic cosmic rays—has shown the characteristic tracers of petaelectronvolt particles, namely, power-law spectra of γ-rays extending without a cut-off or a spectral break to tens of teraelectronvolts. Here we report deep γ-ray observations with arcminute angular resolution of the region surrounding the Galactic Centre, which show the expected tracer of the presence of petaelectronvolt protons within the central 10 parsecs of the Galaxy. We propose that the supermassive black hole Sagittarius A* is linked to this PeVatron. Sagittarius A* went through active phases in the past, as demonstrated by X-ray outburstsand an outflow from the Galactic Centre. Although its current rate of particle acceleration is not sufficient to provide a substantial contribution to Galactic cosmic rays, Sagittarius A* could have plausibly been more active over the last 106-107 years, and therefore should be considered as a viable alternative to supernova remnants as a source of petaelectronvolt Galactic cosmic rays.

  19. Pionic charge exchange on the proton from 40 to 250 MeV

    NASA Astrophysics Data System (ADS)

    Breitschopf, J.; Bauer, M.; Clement, H.; Cröni, M.; Denz, H.; Friedman, E.; Gibson, E. F.; Meier, R.; Wagner, G. J.

    2006-08-01

    The total cross sections for pionic charge exchange on hydrogen were measured using a transmission technique on thin CH2 and C targets. Data were taken for π- lab energies from 39 to 247 MeV with total errors of typically 2% over the Δ-resonance and up to 10% at the lowest energies. Deviations from the predictions of the SAID phase shift analysis in the 60-80 MeV region are interpreted as evidence for isospin-symmetry breaking in the s-wave amplitudes. The charge dependence of the Δ-resonance properties appears to be smaller than previously reported.

  20. Variations in the Processing of DNA Double-Strand Breaks Along 60-MeV Therapeutic Proton Beams

    PubMed Central

    Chaudhary, Pankaj; Marshall, Thomas I.; Currell, Frederick J.; Kacperek, Andrzej; Schettino, Giuseppe; Prise, Kevin M.

    2016-01-01

    Purpose To investigate the variations in induction and repair of DNA damage along the proton path, after a previous report on the increasing biological effectiveness along clinically modulated 60-MeV proton beams. Methods and Materials Human skin fibroblast (AG01522) cells were irradiated along a monoenergetic and a modulated spread-out Bragg peak (SOBP) proton beam used for treating ocular melanoma at the Douglas Cyclotron, Clatterbridge Centre for Oncology, Wirral, Liverpool, United Kingdom. The DNA damage response was studied using the 53BP1 foci formation assay. The linear energy transfer (LET) dependence was studied by irradiating the cells at depths corresponding to entrance, proximal, middle, and distal positions of SOBP and the entrance and peak position for the pristine beam. Results A significant amount of persistent foci was observed at the distal end of the SOBP, suggesting complex residual DNA double-strand break damage induction corresponding to the highest LET values achievable by modulated proton beams. Unlike the directly irradiated, medium-sharing bystander cells did not show any significant increase in residual foci. Conclusions The DNA damage response along the proton beam path was similar to the response of X rays, confirming the low-LET quality of the proton exposure. However, at the distal end of SOBP our data indicate an increased complexity of DNA lesions and slower repair kinetics. A lack of significant induction of 53BP1 foci in the bystander cells suggests a minor role of cell signaling for DNA damage under these conditions. PMID:26452569

  1. Preliminary consideration of a double, 480 GeV, fast cycling proton accelerator for production of neutrino beams at Fermilab

    SciTech Connect

    Piekarz, Henryk; Hays, Steven; /Fermilab

    2007-03-01

    We propose to build the DSF-MR (Double Super-Ferric Main Ring), 480 GeV, fast-cycling (2 second repetition rate) two-beam proton accelerator in the Main Ring tunnel of Fermilab. This accelerator design is based on the super-ferric magnet technology developed for the VLHC, and extended recently to the proposed LER injector for the LHC and fast cycling SF-SPS at CERN. The DSF-MR accelerator system will constitute the final stage of the proton source enabling production of two neutrino beams separated by 2 second time period. These beams will be sent alternately to two detectors located at {approx} 3000 km and {approx} 7500 km away from Fermilab. It is expected that combination of the results from these experiments will offer more than 3 order of magnitudes increased sensitivity for detection and measurement of neutrino oscillations with respect to expectations in any current experiment, and thus may truly enable opening the window into the physics beyond the Standard Model. We examine potential sites for the long baseline neutrino detectors accepting beams from Fermilab. The current injection system consisting of 400 MeV Linac, 8 GeV Booster and the Main Injector can be used to accelerate protons to 45 GeV before transferring them to the DSF-MR. The implementation of the DSF-MR will allow for an 8-fold increase in beam power on the neutrino production target. In this note we outline the proposed new arrangement of the Fermilab accelerator complex. We also briefly describe the DSF-MR magnet design and its power supply, and discuss necessary upgrade of the Tevatron RF system for the use with the DSF-MR accelerator. Finally, we outline the required R&D, cost estimate and possible timeline for the implementation of the DSF-MR accelerator.

  2. Design, performance, and calculated error of a Faraday cup for absolute beam current measurements of 600-MeV protons

    NASA Technical Reports Server (NTRS)

    Beck, S. M.

    1975-01-01

    A mobile self-contained Faraday cup system for beam current measurments of nominal 600 MeV protons was designed, constructed, and used at the NASA Space Radiation Effects Laboratory. The cup is of reentrant design with a length of 106.7 cm and an outside diameter of 20.32 cm. The inner diameter is 15.24 cm and the base thickness is 30.48 cm. The primary absorber is commercially available lead hermetically sealed in a 0.32-cm-thick copper jacket. Several possible systematic errors in using the cup are evaluated. The largest source of error arises from high-energy electrons which are ejected from the entrance window and enter the cup. A total systematic error of -0.83 percent is calculated to be the decrease from the true current value. From data obtained in calibrating helium-filled ion chambers with the Faraday cup, the mean energy required to produce one ion pair in helium is found to be 30.76 + or - 0.95 eV for nominal 600 MeV protons. This value agrees well, within experimental error, with reported values of 29.9 eV and 30.2 eV.

  3. Validity of the relativistic impulse approximation for elastic proton-nucleus scattering at energies lower than 200 MeV

    SciTech Connect

    Li, Z. P.; Hillhouse, G. C.; Meng, J.

    2008-07-15

    We present the first study to examine the validity of the relativistic impulse approximation (RIA) for describing elastic proton-nucleus scattering at incident laboratory kinetic energies lower than 200 MeV. For simplicity we choose a {sup 208}Pb target, which is a spin-saturated spherical nucleus for which reliable nuclear structure models exist. Microscopic scalar and vector optical potentials are generated by folding invariant scalar and vector scattering nucleon-nucleon (NN) amplitudes, based on our recently developed relativistic meson-exchange model, with Lorentz scalar and vector densities resulting from the accurately calibrated PK1 relativistic mean field model of nuclear structure. It is seen that phenomenological Pauli blocking (PB) effects and density-dependent corrections to {sigma}N and {omega}N meson-nucleon coupling constants modify the RIA microscopic scalar and vector optical potentials so as to provide a consistent and quantitative description of all elastic scattering observables, namely, total reaction cross sections, differential cross sections, analyzing powers and spin rotation functions. In particular, the effect of PB becomes more significant at energies lower than 200 MeV, whereas phenomenological density-dependent corrections to the NN interaction also play an increasingly important role at energies lower than 100 MeV.

  4. Deuteron-proton breakup reaction at Ed=7.4 MeV

    NASA Astrophysics Data System (ADS)

    Kröger, H.; Nachabe, A. M.; Slobodrian, R. J.

    1986-04-01

    The reaction d+p-->p+p+n is investigated at Elabd=7.4 MeV. Calculations of the cross section are compared with recent kinematically complete measurements. The Coulomb potential is taken fully into account in the calculations based on the strong approximation of Mo/ller wave operator approach.

  5. A Faraday Cup with high frequency response for a 200 MeV LINAC proton beam

    SciTech Connect

    Zucker, M.S.; Bittner, J.W.

    1991-01-01

    The purpose of this device, composed essentially of coaxial line elements, is monitoring, on a per micropulse basis, the beam intensity of a 200 MeV LINAC at the BNL Radiation Effects Facility. The center conductor of the coaxial line acts as a beam stop. The output pulses are suitable for fast timing. 2 refs., 5 figs.

  6. Further results in the search for the direct two-proton decay of ^94Ag^m (J^π= 21^+, 6.7 MeV)

    NASA Astrophysics Data System (ADS)

    Cerny, J.; Lee, D. W.; Perajarvi, K.; Moltz, D. M.; Barquest, B. R.; Grossman, L. E.; Jeong, W.; Jewett, C. C.

    2008-10-01

    Both direct one-proton decay and direct two-proton decay of ^94Ag^m from this 0.4 s isomeric state have been reported in experiments utilizing the GSI on-line mass separator [1]. In the latter decay, coincident events between silicon E detectors with a threshold energy of 0.4 MeV and a summed decay energy of 1.9±0.1 MeV were observed with a yield of 350±210 pb in coincidence with γ-decays in the ^92Rh daughter. We utilized our helium-jet system at the LBNL 88-inch cyclotron to repeat this experiment, again employing the ^58Ni(^40Ca,p3n) reaction at 197 MeV. Reaction products were transported via a capillary to a detection area and collected on a slowly rotating wheel in front of an assembly of 24 δEgas-δEgas-ESi detector telescopes with a threshold of 0.4 MeV for identifying protons. Five of these telescopes observe the 0.79 MeV single proton decay from ^94Ag^m at the reported yield of 1.3 nb. In the 240/276 identified proton detector combinations with low background, no proton-proton coincidences have been observed. Data from the remaining 36 detector combinations require a separate analysis, which is in progress. Monte Carlo analyses of our anticipated proton-proton coincidences for both sets of detector combinations will be presented. ^ 1Mukha et al., Nature 439, 298 (2006).

  7. Experimental studies with two novel silicon detectors for the development of time-of-flight spectrometry of laser-accelerated proton beams

    NASA Astrophysics Data System (ADS)

    Würl, M.; Reinhardt, S.; Rosenfeld, A.; Petasecca, M.; Lerch, M.; Tran, L.; Karsch, S.; Assmann, W.; Schreiber, J.; Parodi, K.

    2017-01-01

    Laser-accelerated proton beams exhibit remarkably different beam characteristics as compared to conventionally accelerated ion beams. About 105 to 107 particles per MeV and msr are accelerated quasi-instantaneously within about 1 ps. The resulting energy spectrum typically shows an exponentially decaying distribution. Our planned approach to determine the energy spectrum of the particles generated in each pulse is to exploit the time-of-flight (TOF) difference of protons with different kinetic energies at 1 m distance from the laser-target interaction. This requires fast and sensitive detectors. We therefore tested two prototype silicon detectors, developed at the Centre for Medical Radiation Physics at the University of Wollongong with a current amplifier, regarding their suitability for TOF-spectrometry in terms of sensitivity and timing properties. For the latter, we illuminated the detectors with short laser pulses, measured the signal current and compared it to the signal of a fast photodiode. The comparison revealed that the timing properties of both prototypes are not yet sufficient for our purpose. In contrast, our results regarding the detectors’ sensitivity are promising. The lowest detectable proton flux at 10 MeV was found to be 25 protons per ns on the detector. With this sensitivity and with a smaller pixelation of the detectors, the timing properties can be improved for new prototypes, making them potential candidates for TOF-spectrometry of laser-accelerated particle beams.

  8. Accelerator measurement of the energy spectra of neutrons emitted in the interaction of 3-GeV protons with several elements

    NASA Technical Reports Server (NTRS)

    Nalesnik, W. J.; Devlin, T. J.; Merker, M.; Shen, B. S. P.

    1972-01-01

    The application of time of flight techniques for determining the shapes of the energy spectra of neutrons between 20 and 400 MeV is discussed. The neutrons are emitted at 20, 34, and 90 degrees in the bombardment of targets by 3 GeV protons. The targets used are carbon, aluminum, cobalt, and platinum with cylindrical cross section. Targets being bombarded are located in the internal circulating beam of a particle accelerator.

  9. Activation calculations for trapped protons below 200 MeV: Appendix

    NASA Technical Reports Server (NTRS)

    Laird, C. E.

    1991-01-01

    Tables are given displaying of the results of the activation calculations of metal samples and other material aboard the Long Duration Exposure Facility-1 (LDEF-1) and Spacelab-2 with the computer program, PTRAP4. The computer printouts give the reaction, the reactant product, the proton reaction cross sections as a function of the energy of the incident protons, and the activation as a function of distance into the sample from the exposed surface.

  10. Latest Diagnostic Electronics Development for the PROSCAN Proton Accelerator

    SciTech Connect

    Duperrex, P.A.; Frei, U.; Gamma, G.; Mueller, U.; Rezzonico, L.

    2004-11-10

    New VME-based diagnostic electronics are being developed for PROSCAN, a proton accelerator for medical application presently under construction at PSI. One new development is a VME-based multi-channel logarithmic amplifier for converting current to voltage (LogIV). The LogIV boards are used for measuring current from the multiple wire (harp) profile monitors. The LogIV calibration method, current dependant bandwidth and temperature stability are presented. Another development is a BPM front end, based on the newest digital receiver techniques. Features of this new system are the remote control of the preamplifier stage and the continuous monitoring of each individual signal overall gain. Characteristics of the developed prototype are given.

  11. Acceleration of solar wind ions to 1 MeV by electromagnetic structures upstream of the Earth's bow shock

    NASA Astrophysics Data System (ADS)

    Stasiewicz, K.; Markidis, S.; Eliasson, B.; Strumik, M.; Yamauchi, M.

    2013-05-01

    We present measurements from the ESA/NASA Cluster mission that show in situ acceleration of ions to energies of 1 MeV outside the bow shock. The observed heating can be associated with the presence of electromagnetic structures with strong spatial gradients of the electric field that lead to ion gyro-phase breaking and to the onset of chaos in ion trajectories. It results in rapid, stochastic acceleration of ions in the direction perpendicular to the ambient magnetic field. The electric potential of the structures can be compared to a field of moguls on a ski slope, capable of accelerating and ejecting the fast running skiers out of piste. This mechanism may represent the universal mechanism for perpendicular acceleration and heating of ions in the magnetosphere, the solar corona and in astrophysical plasmas. This is also a basic mechanism that can limit steepening of nonlinear electromagnetic structures at shocks and foreshocks in collisionless plasmas.

  12. The AWAKE Proton-driven Plasma Wakefield Acceleration Experiment at CERN

    NASA Astrophysics Data System (ADS)

    Muggli, Patric

    2012-10-01

    We are planning an experiment at CERN to accelerate externally injected electrons e^- on the wake driven by a long, self-modulated proton p^+ bunch. In the plan the 12cm-long bunch from the SPS with 10^11 p^+ experiences a two-stream transverse instability that modulates the bunch radius at the plasma wake period. The bunch is focused to 200μm into a plasma with density in the 10^14-10^15cm-3 range. The modulation instability is seeded by co-propagating with the p^+ bunch a short laser pulse that ionizes a gas or vapor. The modulation resonantly drives wakefields to large amplitude. The low energy e^- ( 5-20MeV) produced by a rf-photoinjector gun are injected after the instability has saturated, 3-5m into the plasma and is accelerated to the GeV energy range. The e^- energy spectrum is measured by a large energy acceptance magnetic spectrometer. Bunch modulation diagnostics such as time resolved OTR and electro-optic measurements are also included. The general plans for the experiment as well as the latest developments will be presented.

  13. Measurement and modelling of radionuclide production in thick spherical targets irradiated isotropically with 1600 MeV protons

    SciTech Connect

    Michel, R.; Lange, H.J.; Leya, I.; Luepke, M.; Herpers, U.; Meltzow, B.; Roesel, R.; Filges, D.; Cloth, P.; Dragovitsch, P.

    1994-12-31

    Two thick spherical targets made of gabbro and of steel with radii of 25 and 10 cm, respectively, were isotropically irradiated with 1.6 GeV protons at the Saturne accelerator at Laboratoire National Saturne/Saclay in order to simulate the interactions of galactic cosmic ray (GCR) protons with stony and iron meteoroids. The artificial meteoroids contained large numbers of individual small targets of up to 27 elements, in which the depth-dependent production of residual nuclides was measured by {gamma}-, accelerator and conventional mass spectrometry. Theoretical production depth profiles were derived by folding depth-dependent spectra of primary and secondary particles calculated by the HERMES code system with experimental and theoretical production rates shortcomings of the cross section data base can be distinguished and medium-energy neutron cross sections can be improved.

  14. Measurements of production cross sections of 10Be and 26Al by 120 GeV and 392 MeV proton bombardment of 89Y, 159Tb, and natCu targets

    NASA Astrophysics Data System (ADS)

    Sekimoto, S.; Okumura, S.; Yashima, H.; Matsushi, Y.; Matsuzaki, H.; Matsumura, H.; Toyoda, A.; Oishi, K.; Matsuda, N.; Kasugai, Y.; Sakamoto, Y.; Nakashima, H.; Boehnlein, D.; Coleman, R.; Lauten, G.; Leveling, A.; Mokhov, N.; Ramberg, E.; Soha, A.; Vaziri, K.; Ninomiya, K.; Omoto, T.; Shima, T.; Takahashi, N.; Shinohara, A.; Caffee, M. W.; Welten, K. C.; Nishiizumi, K.; Shibata, S.; Ohtsuki, T.

    2015-10-01

    The production cross sections of 10Be and 26Al were measured by accelerator mass spectrometry using 89Y, 159Tb, and natCu targets bombarded by protons with energies Ep of 120 GeV and 392 MeV. The production cross sections obtained for 10Be and 26Al were compared with those previously reported using Ep = 50 MeV-24 GeV and various targets. It was found that the production cross sections of 10Be monotonically increased with increasing target mass number when the proton energy was greater than a few GeV. On the other hand, it was also found that the production cross sections of 10Be decreased as the target mass number increased from that of carbon to those near the mass numbers of nickel and zinc when the proton energy was below approximately 1 GeV. They also increased as the target mass number increased from near those of nickel and zinc to that of bismuth, in the same proton energy range. Similar results were observed in the production cross sections of 26Al, though the absolute values were quite different between 10Be and 26Al. The difference between these production cross sections may depend on the impact parameter (nuclear radius) and/or the target nucleus stiffness.

  15. Qualitative comparison of bremsstrahlung X-rays and 800 MeV protons for tomography of urania fuel pellets

    DOE PAGES

    Morris, Christopher L.; Bourke, Mark A.; Byler, Darrin D.; ...

    2013-02-11

    We present an assessment of x-rays and proton tomography as tools for studying the time dependence of the development of damage in fuel rods. Also, we show data taken with existing facilities at Los Alamos National Laboratory that support this assessment. Data on surrogate fuel rods has been taken using the 800 MeV proton radiography (pRad) facility at the Los Alamos Neutron Science Center (LANSCE), and with a 450 keV bremsstrahlung X-ray tomography facility. The proton radiography pRad facility at LANSCE can provide good position resolution (<70 μm has been demonstrate, 20 μm seems feasible with minor changes) for tomographymore » on activated fuel rods. Bremsstrahlung x-rays may be able to provide better than 100 μm resolution but further development of sources, collimation and detectors is necessary for x-rays to deal with the background radiation for tomography of activated fuel rods.« less

  16. Validation of nuclear models in Geant4 using the dose distribution of a 177 MeV proton pencil beam.

    PubMed

    Hall, David C; Makarova, Anastasia; Paganetti, Harald; Gottschalk, Bernard

    2016-01-07

    A proton pencil beam is associated with a surrounding low-dose envelope, originating from nuclear interactions. It is important for treatment planning systems to accurately model this envelope when performing dose calculations for pencil beam scanning treatments, and Monte Carlo (MC) codes are commonly used for this purpose. This work aims to validate the nuclear models employed by the Geant4 MC code, by comparing the simulated absolute dose distribution to a recent experiment of a 177 MeV proton pencil beam stopping in water. Striking agreement is observed over five orders of magnitude, with both the shape and normalisation well modelled. The normalisations of two depth dose curves are lower than experiment, though this could be explained by an experimental positioning error. The Geant4 neutron production model is also verified in the distal region. The entrance dose is poorly modelled, suggesting an unaccounted upstream source of low-energy protons. Recommendations are given for a follow-up experiment which could resolve these issues.

  17. X-Ray Diffraction Studies of 145 MeV proton-irradiated AlBeMet 162

    SciTech Connect

    Elbakhshwan, Mohamed; McDonald, Kirk T.; Ghose, Sanjit; Zhong, Zhong; Simos, Nikolaos

    2016-08-03

    AlBeMet 162 (Materion Co., formerly Brush Wellman) has been irradiated with 145 MeV protons up to 1.2x1020 cm-2 fluence, with irradiation temperatures in the range of 100-220oC. Macroscopic postirradiation evaluation on the evolution of mechanical and thermal properties was integrated with a comprehensive X-ray- diffraction study using high-energy monochromatic and polychromatic X-ray beams, which offered a microscopic view of the irradiation damage effects on AlBeMet. The study confirmed the stability of the metal-matrix composite, its resistance to proton damage, and the continuing separation of the two distinct phases, fcc aluminum and hcp beryllium, following irradiation. Furthermore, based on the absence of inter-planar distance change during proton irradiation, it was confirmed that the stacking faults and clusters on the Al (111) planes are stable, and thus can migrate from the cascade region and be absorbed at various sinks. XRD analysis of the unirradiated AlBeMet 162 showed clear change in the texture of the fcc phase with orientation especially in the Al (111) reflection which exhibits a “non-perfect” six-fold symmetry, implying lack of isotropy in the composite.

  18. X-Ray Diffraction Studies of 145 MeV proton-irradiated AlBeMet 162

    DOE PAGES

    Elbakhshwan, Mohamed; McDonald, Kirk T.; Ghose, Sanjit; ...

    2016-08-03

    AlBeMet 162 (Materion Co., formerly Brush Wellman) has been irradiated with 145 MeV protons up to 1.2x1020 cm-2 fluence, with irradiation temperatures in the range of 100-220oC. Macroscopic postirradiation evaluation on the evolution of mechanical and thermal properties was integrated with a comprehensive X-ray- diffraction study using high-energy monochromatic and polychromatic X-ray beams, which offered a microscopic view of the irradiation damage effects on AlBeMet. The study confirmed the stability of the metal-matrix composite, its resistance to proton damage, and the continuing separation of the two distinct phases, fcc aluminum and hcp beryllium, following irradiation. Furthermore, based on the absencemore » of inter-planar distance change during proton irradiation, it was confirmed that the stacking faults and clusters on the Al (111) planes are stable, and thus can migrate from the cascade region and be absorbed at various sinks. XRD analysis of the unirradiated AlBeMet 162 showed clear change in the texture of the fcc phase with orientation especially in the Al (111) reflection which exhibits a “non-perfect” six-fold symmetry, implying lack of isotropy in the composite.« less

  19. The heliopause spectrum of galactic electrons below 4 MeV and implications for their re-acceleration.

    NASA Astrophysics Data System (ADS)

    Prinsloo, Phillip; Toit Strauss, Du; Potgieter, Marius

    2016-07-01

    With the availability of observations of electrons at energies exceeding roughly 4 MeV, from e.g. the Voyager and PAMELA missions, their intensity levels and energy distribution are relatively well-known at the heliopause, where input spectra are typically specified in cosmic-ray modulation models. Numerically solving a transport equation that accounts for the re-acceleration of galactic electrons, it becomes essential to specify the heliopause spectrum at very low energies, typically below 4 MeV, because the diffusive shock acceleration process of particles at any given energy is dependent on the spectral shape at lower energies. Informed by the results of both radio data surveys and galactic propagation modelling, a number of scenarios are considered for this very low-energy heliopause spectrum. Assuming rigidity-independent diffusion at the considered energies as an initial assumption, the contribution of re-accelerated electrons to intensity levels is probed for each of the aforementioned scenarios. The magnitudes of the resultant intensity increases are concluded to be highly dependent on the spectral shape specified for the heliopause at these low energies, with the softer distributions predictably yielding greater re-acceleration effects.

  20. Mechanisms of mutagenesis in human cells exposed to 55 MeV protons

    NASA Technical Reports Server (NTRS)

    Gauny, S.; Wiese, C.; Kronenberg, A.

    2001-01-01

    Protons represent the major type of charged particle radiation in spaceflight environments. The purpose of this study was to assess mutations arising in human lymphoid cells exposed to protons. Mutations were quantitated at the thymidine kinase (TK1) locus in cell lines derived from the same donor: TK6 cells (wt TP53) and WTK1 cells (mutant TP53). WTK1 cells were much more susceptible to mutagenesis following proton exposure than TK6 cells. Intragenic deletions were observed among early-arising TK1 mutants in TK6 cells, but not in WTK1 cells where all of the mutants arose by LOH. Deletion was the predominant mode of LOH in TK6 cells, while allelic recombination was the major mode of LOH in WTK1 cells. Deletions were of variable lengths, from <1 cM to 64 cM, while mutations that arose by allelic recombination often extended to the telomere. In summary, proton exposures elicited many types of mutations at an autosomal locus in human cells. Most involved large scale loss of genetic information, either through deletion or by recombination.

  1. The radiation field measurement and analysis outside the shielding of A 10 MeV electron irradiation accelerator

    NASA Astrophysics Data System (ADS)

    Shang, Jing; Li, Juexin; Xu, Bing; Li, Yuxiong

    2011-10-01

    Electron accelerators are employed widely for diverse purposes in the irradiation-processing industry, from sterilizing medical products to treating gemstones. Because accelerators offer high efficiency, high power, and require little preventative maintenance, they are becoming more and more popular than using the 60Co isotope approach. However, the electron accelerator exposes potential radiation hazards. To protect workers and the public from exposure to radiation, the radiation field around the electronic accelerator must be assessed, especially that outside the shielding. Thus, we measured the radiation dose at different positions outside the shielding of a 10-MeV electron accelerator using a new data-acquisition unit named Mini-DDL (Mini-Digital Data Logging). The measurements accurately reflect the accelerator's radiation status. In this paper, we present our findings, results and compare them with our theoretical calculations. We conclude that the measurements taken outside the irradiation hall are consistent with the findings from our calculations, except in the maze outside the door of the accelerator room. We discuss the reason for this discrepancy.

  2. The affect of erbium hydride on the conversion efficience to accelerated protons from ultra-shsort pulse laser irradiated foils

    SciTech Connect

    Offermann, Dustin Theodore

    2008-01-01

    This thesis work explores, experimentally, the potential gains in the conversion efficiency from ultra-intense laser light to proton beams using erbium hydride coatings. For years, it has been known that contaminants at the rear surface of an ultra-intense laser irradiated thin foil will be accelerated to multi-MeV. Inertial Confinement Fusion fast ignition using proton beams as the igniter source requires of about 1016 protons with an average energy of about 3MeV. This is far more than the 1012 protons available in the contaminant layer. Target designs must include some form of a hydrogen rich coating that can be made thick enough to support the beam requirements of fast ignition. Work with computer simulations of thin foils suggest the atomic mass of the non-hydrogen atoms in the surface layer has a strong affect on the conversion efficiency to protons. For example, the 167amu erbium atoms will take less energy away from the proton beam than a coating using carbon with a mass of 12amu. A pure hydrogen coating would be ideal, but technologically is not feasible at this time. In the experiments performed for my thesis, ErH3 coatings on 5 μm gold foils are compared with typical contaminants which are approximately equivalent to CH1.7. It will be shown that there was a factor of 1.25 ± 0.19 improvement in the conversion efficiency for protons above 3MeV using erbium hydride using the Callisto laser. Callisto is a 10J per pulse, 800nm wavelength laser with a pulse duration of 200fs and can be focused to a peak intensity of about 5 x 1019W/cm2. The total number of protons from either target type was on the order of 1010. Furthermore, the same experiment was performed on the Titan laser, which has a 500fs pulse duration, 150J of energy and can be focused to about 3 x 1020 W/cm2. In this experiment 1012 protons were seen from both erbium hydride and

  3. Beam Dynamics Studies and the Design, Fabrication and Testing of Superconducting Radiofrequency Cavity for High Intensity Proton Accelerator

    SciTech Connect

    Saini, Arun

    2012-03-01

    The application horizon of particle accelerators has been widening significantly in recent decades. Where large accelerators have traditionally been the tools of the trade for high-energy nuclear and particle physics, applications in the last decade have grown to include large-scale accelerators like synchrotron light sources and spallation neutron sources. Applications like generation of rare isotopes, transmutation of nuclear reactor waste, sub-critical nuclear power, generation of neutrino beams etc. are next area of investigation for accelerator scientific community all over the world. Such applications require high beam power in the range of few mega-watts (MW). One such high intensity proton beam facility is proposed at Fermilab, Batavia, US, named as Project-X. Project-X facility is based on H- linear accelerator (linac), which will operate in continuous wave (CW) mode and accelerate H- ion beam with average current of 1 mA from kinetic energy of 2.5 MeV to 3 GeV to deliver 3MW beam power. One of the most challenging tasks of the Project-X facility is to have a robust design of the CW linac which can provide high quality beam to several experiments simultaneously. Hence a careful design of linac is important to achieve this objective.

  4. Some aspects of raceTrack microtron 6.2 MeV accelerator-injector application

    SciTech Connect

    Galaktionov, D.V.; Danilov, A.V.

    1993-12-31

    In the present report the electron continuous wave accelerator-injector is described (energy limit of acceleration is 6.2 MeV, energy homogeneity of beam 0.002, current of beam 150 {mu}kA). We point out the preference of application of continuous beam of charged practicles in some applied tasks in comparison with methods which are existing now. In this report we show the possibility of optimal application of the accelerator in several fields such as: radioisotopic analysis of different substances; investigation of the response of different materials (used in devices which are exposed to radiation) to the impact of electrons and hard photons; and prospect of creation of materials with new properties.

  5. On the retention of high-energy protons and nuclei with charges Z or equal to 2 in large solar flares after the process of their acceleration

    NASA Technical Reports Server (NTRS)

    Volodichev, N. N.; Kuzhevsky, B. M.; Nechaev, O. Y.; Savenko, I. A.

    1985-01-01

    Data which suggest that the protons with energies of up to several GeV should be retained on the Sun after the process of their acceleration are presented. The protons are on the average retained for 15 min, irrespectively of the solar flare heliolatitude and of the accelerated particle energy ranging from 100 MeV to several GeV. It is suggested that the particles are retained in a magnetic trap formed in a solar active region. No Z or = 2 nuclei of solar origin during large solar flares. The absence of the 500 MeV/nucleon nuclei with Z or = 2 may be due to their retention in the magnetic trap which also retains the high-energy protons. During the trapping time the approx. 500 MeV/nucleon nuclei with Z or = 2 may escape due to nuclear interactions and ionization loss.

  6. Activation cross-sections of proton induced reactions on vanadium in the 37-65 MeV energy range

    NASA Astrophysics Data System (ADS)

    Ditrói, F.; Tárkányi, F.; Takács, S.; Hermanne, A.

    2016-08-01

    Experimental excitation functions for proton induced reactions on natural vanadium in the 37-65 MeV energy range were measured with the activation method using a stacked foil irradiation technique. By using high resolution gamma spectrometry cross-section data for the production of 51,48Cr, 48V, 48,47,46,44m,44g,43Sc and 43,42K were determined. Comparisons with the earlier published data are presented and results predicted by different theoretical codes (EMPIRE and TALYS) are included. Thick target yields were calculated from a fit to our experimental excitation curves and compared with the earlier experimental yield data. Depth distribution curves to be used for thin layer activation (TLA) are also presented.

  7. Absolute doubly differential cross sections for ionization of adenine by 1.0-MeV protons

    SciTech Connect

    Iriki, Y.; Kikuchi, Y.; Imai, M.; Itoh, A.

    2011-09-15

    Double-differential ionization cross sections of adenine (C{sub 5}H{sub 5}N{sub 5}) by 1.0-MeV protons have been measured using a vapor-phase adenine target. Ejected electrons were analyzed by a 45 deg. parallel-plate electrostatic spectrometer in an electron energy range from 1 to 1000 eV at electron emission angles from 15 deg. to 165 deg. The effective target thickness of adenine was determined by a Rutherford forward scattering method and a vapor deposition method. Present data are in good agreement with recent calculations. Comparisons were made with other data on various hydrocarbon molecules. It was found that the ionization cross sections of these molecules can be scaled fairly well in terms of the total number of valence electrons.

  8. Experimental cross-sections for proton induced nuclear reactions on mercury up to 65 MeV

    NASA Astrophysics Data System (ADS)

    Hermanne, A.; Tárkányi, F.; Takács, S.; Ditrói, F.; Szücs, Z.; Brezovcsik, K.

    2016-07-01

    Cross-sections for formation of activation products induced by protons on natural mercury targets were measured. Results for 196m,196g,197g(cum), 198m,198g,199g(cum), 200g(cum), 201,202Tl, 194g(cum), 195g(cum), 196g(cum), 198m,199g(cum) Au and 195m,197m,203Hg are presented up to 65 MeV incident particle energy, many of these for the first time. The experimental data are compared with literature values and with the predictions of the TALYS 1.6 code (results taken from TENDL-2015 on-line library), thick target yields were derived and possible applications in biomedical sciences are discussed.

  9. MECHANICAL PROPERTIES AND MICROSTRUCTURE IN LOW ACTIVATION MARTENSITIC STEELS F82H AND OPTIMAX AFTER 800 MEV PROTON IRRADIATION

    SciTech Connect

    Y. DAI; ET AL

    1999-10-01

    Low-activation martensitic steels, F82H (mod.) and Optimax-A, have been irradiated with 800-MeV protons up to 5.9 dpa. The tensile properties and microstructure have been studied. The results show that radiation hardening increases continuously with irradiation dose. F82H has lesser irradiation hardening as compared to Optimax-A in the present work and DIN1.4926 from a previous study. The irradiation embrittlement effects are evident in the materials since the uniform elongation is reduced sharply to less than 2%. However, all the irradiated samples ruptured in a ductile-fracture mode. Defect clusters have been observed. The size and the density of defect clusters increase with the irradiation dose. Precipitates are amorphous after irradiation.

  10. The tensile and fatigue properties of DIN 1.4914 martensitic stainless steel after 590 MeV proton irradiation

    NASA Astrophysics Data System (ADS)

    Marmy, P.; Victoria, M.

    1992-09-01

    Tensile and low cycle fatigue subsize specimens of DIN 1.4914 martensitic steel (MANET) have been irradiated with 590 MeV protons to doses up to 1 dpa and at temperatures between 363 and 703 K. The helium produced by spallation reactions was measured as 130 appm/dpa. A strong radiation hardening is found, which decreases as the irradiation temperature increases. The tensile elongation is reduced after irradiation, but the fracture mode is always ductile and transgranular. The radition hardening produced at low irradiation temperatures is recovered after annealing at higher temperatures. Continous softening is observed during low cycle fatigue testing. The rate of softening of the irradiated material is stonger than that of the unirradiated material and tends to reach the saturation level of the latter. The irradiation badly affects the fatigue life, particularly in the temperature domain of dynamic strain ageing between 553 and 653 K.

  11. Numerical simulation and optimization of the variable energy 60-1000 MeV proton beams at PNPI synchrocyclotron for testing the radiation resistance of electronics

    NASA Astrophysics Data System (ADS)

    Artamonov, S. A.; Ivanov, E. M.; Ivanov, N. A.; Lebedeva, J. S.; Riabov, G. A.

    2017-01-01

    A universal center for testing electronic components (ECs) for the needs of aviation and space is created in the SC-1000 Petersburg Nuclear Physics Institute, National Research Centre "Kurchatov Institute" (PNPI NRC KI). One of the main instruments of these tests is variable energy protons beams. This paper presents Monte Carlo simulation results for a proton beam with energy of 1000 MeV passing through copper and tungsten degraders, and defines the length of these degraders to obtain energies of 60, 100, 200, 300, 400, 500, 600, 700, 800, 900, and 1000 MeV. Detailed studies of further transmission of the proton beams along the beam line using the copper degrader are accomplished. Basic theoretical parameters for each proton beam, such as the intensity, the energy heterogeneity, beam size, and uniformity of its spatial distribution are obtained.

  12. Polarized-target asymmetry in pion-proton bremsstrahlung at 298 MeV

    SciTech Connect

    Bosshard, A.; Amsler, C.; Bistirlich, J.A.; van den Brandt, B.; Crowe, K.M.; Doebeli, M.; Doser, M.; Haddock, R.P.; Konter, J.A.; Ljungfelt, S.; Loude, J.F.; Mango, S.; Meyer, C.A.; Perroud, J.P.; Riedlberger, J.; Renker, D.; Schaad, M.; Sober, D.I.; Truoel, P.; Weymuth, P. Lawrence Berkeley Laboratory, University of California at Berkeley, Berkeley California 94720 Paul Scherrer Institut, 5232 Villigen, Paul Scherrer Institut, Department of Physics, University of California at Los Angeles, Los Angeles, California 90024 Institut de Physique Nucleaire, Universite de Lausanne, 1015 Lausanne, Department of Physics, Catholic University of America, Washington, D.C. 10024 )

    1990-05-28

    First data are presented for the polarized-target asymmetry in the reaction {pi}{sup +}{ital p}{r arrow}{pi}{sup +}{ital p}{gamma} at an incident pion energy of 298 MeV. The geometry was chosen to maximize the sensitivity to the radiation of the magnetic dipole moment {mu}{sub {Delta}} of the {Delta}{sup ++}(1232 MeV). A fit of the asymmetry in the cross section {ital d}{sup 5}{sigma}/{ital d}{Omega}{sub {pi}} {ital d}{Omega}{sub {gamma}} {ital dk} as a function of the photon energy {ital k} to predictions from a recent isobar-model calculation with {mu}{sub {Delta}} as the only free parameter yields {mu}{sub {Delta}}=1.64({plus minus}0.19exp{Delta},{plus minus}0.14 theor){mu}{sub {ital p}}. Though this value agrees with bag-model corrections to the SU(6) prediction {mu}{sub {Delta}}=2{mu}{sub {ital p}}, further clarifications on the model dependence of the result are needed, in particular since the isobar model fails to describe both the cross section and the asymmetry at the highest photon energies.

  13. Calculating Variations in Biological Effectiveness for a 62 MeV Proton Beam

    PubMed Central

    Carante, Mario Pietro; Ballarini, Francesca

    2016-01-01

    A biophysical model of radiation-induced cell death and chromosome aberrations [called BIophysical ANalysis of Cell death and chromosome Aberrations (BIANCA)] was further developed and applied to therapeutic protons. The model assumes a pivotal role of DNA cluster damage, which can lead to clonogenic cell death following three main steps: (i) a DNA “cluster lesion” (CL) produces two independent chromosome fragments; (ii) fragment mis-rejoining within a threshold distance d gives rise to chromosome aberrations; (iii) certain aberration types (dicentrics, rings, and large deletions) lead to clonogenic inactivation. The yield of CLs and the probability, f, that a chromosome fragment remains un-rejoined even if other fragment(s) are present within d, were adjustable parameters. The model, implemented as a MC code providing simulated dose–responses directly comparable with experimental data, was applied to pristine and modulated Bragg peaks of the proton beam used to treat eye melanoma at INFN-LNS in Catania, Italy. Experimental survival curves for AG01522 cells exposed to the Catania beam were reproduced, supporting the model assumptions. Furthermore, cell death and chromosome aberrations at different depths along a spread-out Bragg peak (SOBP) dose profile were predicted. Both endpoints showed an increase along the plateau, and high levels of damage were found also beyond the distal dose fall-off, due to low-energy protons. Cell death and chromosome aberrations were also predicted for V79 cells, in the same irradiation scenario as that used for AG01522 cells. In line with other studies, this work indicated that assuming a constant relative biological effectiveness (RBE) along a proton SOBP may be sub-optimal. Furthermore, it provided qualitative and quantitative evaluations of the dependence of the beam effectiveness on the considered endpoint and dose. More generally, this work represents an example of therapeutic beam characterization avoiding the use of

  14. Shielding analysis of proton therapy accelerators: a demonstration using Monte Carlo-generated source terms and attenuation lengths.

    PubMed

    Lai, Bo-Lun; Sheu, Rong-Jiun; Lin, Uei-Tyng

    2015-05-01

    Monte Carlo simulations are generally considered the most accurate method for complex accelerator shielding analysis. Simplified models based on point-source line-of-sight approximation are often preferable in practice because they are intuitive and easy to use. A set of shielding data, including source terms and attenuation lengths for several common targets (iron, graphite, tissue, and copper) and shielding materials (concrete, iron, and lead) were generated by performing Monte Carlo simulations for 100-300 MeV protons. Possible applications and a proper use of the data set were demonstrated through a practical case study, in which shielding analysis on a typical proton treatment room was conducted. A thorough and consistent comparison between the predictions of our point-source line-of-sight model and those obtained by Monte Carlo simulations for a 360° dose distribution around the room perimeter showed that the data set can yield fairly accurate or conservative estimates for the transmitted doses, except for those near the maze exit. In addition, this study demonstrated that appropriate coupling between the generated source term and empirical formulae for radiation streaming can be used to predict a reasonable dose distribution along the maze. This case study proved the effectiveness and advantage of applying the data set to a quick shielding design and dose evaluation for proton therapy accelerators.

  15. X-ray photoelectron and Raman spectroscopic studies of MeV proton irradiated graphite

    NASA Astrophysics Data System (ADS)

    Mathew, S.; Joseph, B.; Sekhar, B. R.; Dev, B. N.

    2008-07-01

    Poly-crystalline graphite samples were irradiated using 2.25 MeV H + ions with a fluence of 2 × 10 17 ions/cm 2. Magnetic ordering in highly oriented pyrolytic graphite samples have been reported earlier under the similar irradiation conditions [Esquinazi et al., Phys. Rev. Lett. 91 (2003) 227201]. In that study, the authors attribute the observed irradiation induced magnetic ordering to the formation of a mixed sp 2-sp 3 hybridized carbon atoms. In the present study, we report the X-ray photoelectron and Raman spectroscopic studies on pristine and irradiated samples. Irradiated samples are found to show an increased number of sp 3 hybridized carbon atoms. However, the Raman spectrum, specially the second order data, do indicate that the nature of the graphene lattice structure has been preserved in the irradiated samples. The mechanisms for the irradiation induced enhancement in sp 3 hybridization are discussed.

  16. Simultaneous quiet time observations of energetic radiation belt protons and helium ions - The equatorial alpha/p ratio near 1 MeV

    NASA Technical Reports Server (NTRS)

    Fritz, T. A.; Spjeldvik, W. N.

    1979-01-01

    Simultaneous monitoring of energetic helium ions and protons in the earth's radiation belts has been conducted with Explorer 45 in the immediate vicinity of the equatorial plane. Protons were measured from less than 1 keV to 1.6 MeV and also above 3.3 MeV in a channel responsive up to 22 MeV; helium ions were monitored in three passbands: 910 keV to 3.15 MeV, 590 to 910 keV, and 2.0 to 3.99 MeV. Alpha/proton flux ratios were found to vary significantly with energy and location in the radiation belts. At equal energy per nucleon a range of variability for alpha/p from 0.0001 to well above 0.001 was found, and at equal energy per ion the corresponding variability was from 0.001 to above 10. The latter findings emphasize the relative importance of the very energetic helium ions in the overall radiation belt ion populations.

  17. Optimization of the combined proton acceleration regime with a target composition scheme

    SciTech Connect

    Yao, W. P.; Li, B. W.; Zheng, C. Y.; Liu, Z. J.; Yan, X. Q.; Qiao, B.

    2016-01-15

    A target composition scheme to optimize the combined proton acceleration regime is presented and verified by two-dimensional particle-in-cell simulations by using an ultra-intense circularly polarized (CP) laser pulse irradiating an overdense hydrocarbon (CH) target, instead of a pure hydrogen (H) one. The combined acceleration regime is a two-stage proton acceleration scheme combining the radiation pressure dominated acceleration (RPDA) stage and the laser wakefield acceleration (LWFA) stage sequentially together. Protons get pre-accelerated in the first stage when an ultra-intense CP laser pulse irradiating an overdense CH target. The wakefield is driven by the laser pulse after penetrating through the overdense CH target and propagating in the underdense tritium plasma gas. With the pre-accelerate stage, protons can now get trapped in the wakefield and accelerated to much higher energy by LWFA. Finally, protons with higher energies (from about 20 GeV up to about 30 GeV) and lower energy spreads (from about 18% down to about 5% in full-width at half-maximum, or FWHM) are generated, as compared to the use of a pure H target. It is because protons can be more stably pre-accelerated in the first RPDA stage when using CH targets. With the increase of the carbon-to-hydrogen density ratio, the energy spread is lower and the maximum proton energy is higher. It also shows that for the same laser intensity around 10{sup 22} W cm{sup −2}, using the CH target will lead to a higher proton energy, as compared to the use of a pure H target. Additionally, proton energy can be further increased by employing a longitudinally negative gradient of a background plasma density.

  18. Measurement of a 200 MeV proton beam using a polyurethane dosimeter

    NASA Astrophysics Data System (ADS)

    Heard, Malcolm; Adamovics, John; Ibbott, Geoffrey

    2006-12-01

    PRESAGETM (Heuris Pharma LLC, Skillman, NJ) is a three-dimensional polyurethane dosimeter containing a leuco dye that generates a color change when irradiated. The dosimeter is solid and does not require a container to maintain its shape. The dosimeter is transparent before irradiation and the maximum absorbance of the leuco dye occurs at 633 nm which is compatible with the OCT-OPUSTM laser CT scanner (MGS Research, Inc., Madison, CT). The purpose of this study was to investigate the response of PRESAGETM to proton beam radiotherapy.

  19. Noise performance of 0.35-(mu)m SOI CMOS devices and micropower preamplifier following 63-MeV, 1-Mrad (Si) proton irradiation

    NASA Technical Reports Server (NTRS)

    Binkley, D. M.; Hopper, C. E.; Cressler, J. D.; Mojarradi, M. M.; Blalock, B. J.

    2004-01-01

    This paper presents measured noise for 0.35(mu)m, silicon-on-insulator devices and a micropower preamplifier following 63-MeV, 1-Mrad (Si) proton irradiation. Flicker noise voltage, important for gyros having low frequency output, increases less than 32% after irradiation.

  20. Performance of solenoids versus quadrupoles in focusing and energy selection of laser accelerated protons

    NASA Astrophysics Data System (ADS)

    Hofmann, Ingo

    2013-04-01

    Using laser accelerated protons or ions for various applications—for example in particle therapy or short-pulse radiographic diagnostics—requires an effective method of focusing and energy selection. We derive an analytical scaling for the performance of a solenoid compared with a doublet/triplet as function of the energy, which is confirmed by TRACEWIN simulations. Generally speaking, the two approaches are equivalent in focusing capability, if parameters are such that the solenoid length approximately equals its diameter. The scaling also shows that this is usually not the case above a few MeV; consequently, a solenoid needs to be pulsed or superconducting, whereas the quadrupoles can remain conventional. It is also important that the transmission of the triplet is found only 25% lower than that of the equivalent solenoid. Both systems are equally suitable for energy selection based on their chromatic effect as is shown using an initial distribution following the RPA simulation model by Yan et al. [Phys. Rev. Lett. 103, 135001 (2009PRLTAO0031-900710.1103/PhysRevLett.103.135001].

  1. RBE and genetic susceptibility of mouse and rat spermatogonial stem cells to protons, heavy charged particles and 1.5 MeV neutrons

    NASA Astrophysics Data System (ADS)

    Vaglenov, A.; Fedorenko, B.; Kaltenboeck, B.

    The main purpose of the present study is to provide data on RBE and genetic susceptibility in the mouse and the rat when exposed to protons, HZE particles and neutrons. Genetic damage from exposure to 50 MeV and 9 GeV protons, 4 GeV/nucleon helium ions, 4 GeV/nucleon carbon ions and 1.5 MeV neutrons was studied in adult (CBA × C57Bl/6J) F1 mice. Damage from 9 GeV protons and 4 GeV helium ions was studied in adult Wistar rats. The incidence of reciprocal translocations (RT) induced in the spermatogonial stem cells of each species was recorded. RBE values were derived by comparing linear regression coefficients from dose-responses within the same dose-range for each of the radiation types tested and 60Co γ-rays or by means of a direct nonparametric method. RT yields measured after mouse and rat spermatogonial irradiation with protons, heavy charged particles and neutrons fit the linear model of the dose-response relationship. Relative to 60Co γ-rays, RBE values are as follows for mouse spermatogonia: 0.9 for 50 MeV protons; 1.3 for 9 GeV protons; 0.7 for 4 GeV helium ions; and 1.3 for 4 GeV carbon ions. For rat spermatogonia, values were: 1.7 for 9 GeV protons and 1.3 for helium ions. Compared to mice irradiated using the same experimental design, rats were more susceptible to high-LET radiations, with susceptibility assessed by genetic damage to their spermatogonial stem cells. The RBE of 1.5 MeV neutron is about 6.6.

  2. Dynamics of laser-driven proton acceleration exhibited by measured laser absorptivity and reflectivity

    PubMed Central

    Bin, J. H.; Allinger, K.; Khrennikov, K.; Karsch, S.; Bolton, P. R.; Schreiber, J.

    2017-01-01

    Proton acceleration from nanometer thin foils with intense laser pulses is investigated experimentally. We analyzed the laser absorptivity by parallel monitoring of laser transmissivity and reflectivity with different laser intensities when moving the targets along the laser axis. A direct correlation between laser absorptivity and maximum proton energy is observed. Experimental results are interpreted in analytical estimation, exhibiting a coexistence of plasma expansion and light-sail form of radiation pressure acceleration (RPA-LS) mechanisms during the entire proton acceleration process based on the measured laser absorptivity and reflectivity. PMID:28272471

  3. Dynamics of laser-driven proton acceleration exhibited by measured laser absorptivity and reflectivity

    NASA Astrophysics Data System (ADS)

    Bin, J. H.; Allinger, K.; Khrennikov, K.; Karsch, S.; Bolton, P. R.; Schreiber, J.

    2017-03-01

    Proton acceleration from nanometer thin foils with intense laser pulses is investigated experimentally. We analyzed the laser absorptivity by parallel monitoring of laser transmissivity and reflectivity with different laser intensities when moving the targets along the laser axis. A direct correlation between laser absorptivity and maximum proton energy is observed. Experimental results are interpreted in analytical estimation, exhibiting a coexistence of plasma expansion and light-sail form of radiation pressure acceleration (RPA-LS) mechanisms during the entire proton acceleration process based on the measured laser absorptivity and reflectivity.

  4. DoPET: an in-treatment monitoring system for proton therapy at 62 MeV

    NASA Astrophysics Data System (ADS)

    Rosso, V.; Belcari, N.; Bisogni, M. G.; Camarlinghi, N.; Cirrone, G. A. P.; Collini, F.; Cuttone, G.; Del Guerra, A.; Milluzzo, G.; Morrocchi, M.; Raffaele, L.; Romano, F.; Sportelli, G.; Zaccaro, E.

    2016-12-01

    Proton beam radiotherapy is highly effective in treating cancer thanks to its conformal dose deposition. This superior capability in dose deposition has led to a massive growth of the treated patients around the world, raising the need of treatment monitoring systems. An in-treatment PET system, DoPET, was constructed and tested at CATANA beam-line, LNS-INFN in Catania, where 62 MeV protons are used to treat ocular melanoma. The PET technique profits from the beta+ emitters generated by the proton beam in the irradiated body, mainly 15-O and 11-C. The current DoPET prototype consists of two planar 15 cm × 15 cm LYSO-based detector heads. With respect to the previous versions, the system was enlarged and the DAQ up-graded during the years so now also anthropomorphic phantoms, can be fitted within the field of view of the system. To demonstrate the capability of DoPET to detect changes in the delivered treatment plan with respect to the planned one, various treatment plans were used delivering a standard 15 Gy fraction to an anthropomorphic phantom. Data were acquired during and after the treatment delivery up to 10 minutes. When the in-treatment phase was long enough (more than 1 minute), the corresponding activated volume was visible just after the treatment delivery, even if in presence of a noisy background. The after-treatment data, acquired for about 9 minutes, were segmented finding that few minutes are enough to be able to detect changes. These experiments will be presented together with the studies performed with PMMA phantoms where the DoPET response was characterized in terms of different dose rates and in presence of range shifters: the system response is linear up to 16.9 Gy/min and has the ability to see a 1 millimeter range shifter.

  5. Elastic scattering of polarized protons on helium three at 800 MeV

    SciTech Connect

    Azizi, A.

    1985-07-01

    A set of spin dependent parameters and cross sections has been measured for polarized p-/sup 3/He elastic scattering over the range of q .7 to 4.2 fm/sup -1/. The experiment was done at the Los Alamos Meson Physics Facility (LAMPF) using the High Resolution Spectrometer (HRS) with a polarized proton beam at .8 GeV. The focal plane polarimeter of the HRS was used to determine the spin direction of the scattered proton. Since /sup 3/He is one of the simplest nuclei, polarized p-/sup 3/He scattering provides a very sensitive test of multiple scattering theories. The theoretical analysis was done by using two different wave functions for /sup 3/He as input to the multiple scattering theory. The theoretical calculations and experimental data together will give us useful information about nucleon-nucleon amplitudes and also help us to obtain a better understanding of the scattering process. 68 refs., 55 figs., 9 tabs.

  6. (International Panel on 14 MeV Intense Neutron Source Based on Accelerators for Fusion Materials Study)

    SciTech Connect

    Thoms, K.R.; Wiffen, F.W.

    1991-02-14

    Both travelers were members of a nine-person US delegation that participated in an international workshop on accelerator-based 14 MeV neutron sources for fusion materials research hosted by the University of Tokyo. Presentations made at the workshop reviewed the technology developed by the FMIT Project, advances in accelerator technology, and proposed concepts for neutron sources. One traveler then participated in the initial meeting of the IEA Working Group on High Energy, High Flux Neutron Sources in which efforts were begun to evaluate and compare proposed neutron sources; the Fourth FFTF/MOTA Experimenters' Workshop which covered planning and coordination of the US-Japan collaboration using the FFTF reactor to irradiate fusion reactor materials; and held discussions with several JAERI personnel on the US-Japan collaboration on fusion reactor materials.

  7. Evaluation of various operational and dosimetric parameters of an industrial electron beam accelerator of 2 MeV energy

    NASA Astrophysics Data System (ADS)

    Benny, P. G.; Khader, S. A.; Sarma, K. S. S.

    2014-07-01

    An industrial type 2 MeV/20 kW ILU-6 electron beam accelerator is operational in India for development of applications and technology demonstration to the Indian Industry in the field of polymer modifications (cross-linking and degradation). In order to adjust the treatment conditions and to control the good operation of the accelerator, it is necessary to study dose response as a function of various operational parameters. An experimental procedure for calibrating Cellulose Triacetate (CTA) film strip dosimeters in electron beam using total absorption graphite calorimeters is discussed and compared it with the results obtained from gamma calibration. Dosimetry data for process application, where the irradiation target is plane polymer sheet, have been obtained under various operational parameters.

  8. Gamma Strength Functions and Level Densities from 300 MeV Proton Scatttering at 0°

    NASA Astrophysics Data System (ADS)

    von Neumann-Cosel, Peter; Bassauer, Sergej; Martin, Dirk

    The gamma strength function (GSF) as well as total level densities (LDs) in 208Pb and 96Mo were extracted from high-resolution forward angle inelastic proton scattering data taken at RCNP, Osaka, Japan, and compared to experimental results obtained with the Oslo method in order to test the validity of the Brink-Axel (BA) hypothesis in the energy region of the pygmy dipole resonance. The case of 208Pb is inconclusive because of strong fluctuations of the GSF due to the small level density in a doubly closed-shell nucleus. In 96Mo the data are consistent with the BA hypothesis. The good agreement of LDs provides an independent confirmation of the approach underlying the decomposition of GSF and LDs in Oslo-type experiments.

  9. Hugoniot Measurements at Low Pressures in Tin Using 800 MeV proton Radiography

    SciTech Connect

    Schwartz, Cynthia; Hogan, Gary E; King, Nicholas S. P.; Kwiathowski, Kris K.; Mariam, Fesseha G.; Marr-Lyon, Mark; McNeil, Wendy Vogan; Merrill, Frank E.; Morris, Christopher; Rightley, Paul; Saunders, Alexander

    2009-08-05

    A 2cm long 8 mm diameter cylindrical tin target has been shocked to a pressure in the region of the {beta} {yields} {gamma} phase change using a small, low density PETN charge mounted on the opposite side of a stainless steel diaphragm. The density jump and shock velocity were measured radiographically as the shock wave moved through the sample and the pressure dropped, using the proton radiography facility at LANL. This provided a quasi-continuous record of the equations of state along the Hugoniot for the P1 wave from a shock velocity of 3.25 km/sec down to near the sound speed. Edge release effects were removed from the data using tomographic techniques. The data show evidence for a phase transition that extends over a broad pressure range. The data and analysis will be presented.

  10. Energy loss of MeV protons specularly reflected from metal surfaces

    SciTech Connect

    Juaristi, J.I.

    1996-05-01

    A parameter-free model is presented to study the energy loss of fast protons specularly reflected from metal surfaces. The contributions to the energy loss from excitation of valence-band electrons and ionization of localized target-atom electronic states are calculated separately. The former is calculated from the induced surface wake potential using linear response theory and the specular-reflection model, while the latter is calculated in the first Born approximation. The results obtained are in good agreement with available experimental data. However, the experimental qualitative trend of the energy loss as a function of the angle of incidence is obtained when the valence-band electron model is replaced by localized target atom electron states, though with a worse quantitative agreement. {copyright} {ital 1996 The American Physical Society.}

  11. Accelerated prompt gamma estimation for clinical proton therapy simulations

    NASA Astrophysics Data System (ADS)

    Huisman, Brent F. B.; Létang, J. M.; Testa, É.; Sarrut, D.

    2016-11-01

    There is interest in the particle therapy community in using prompt gammas (PGs), a natural byproduct of particle treatment, for range verification and eventually dose control. However, PG production is a rare process and therefore estimation of PGs exiting a patient during a proton treatment plan executed by a Monte Carlo (MC) simulation converges slowly. Recently, different approaches to accelerating the estimation of PG yield have been presented. Sterpin et al (2015 Phys. Med. Biol. 60 4915-46) described a fast analytic method, which is still sensitive to heterogeneities. El Kanawati et al (2015 Phys. Med. Biol. 60 8067-86) described a variance reduction method (pgTLE) that accelerates the PG estimation by precomputing PG production probabilities as a function of energy and target materials, but has as a drawback that the proposed method is limited to analytical phantoms. We present a two-stage variance reduction method, named voxelized pgTLE (vpgTLE), that extends pgTLE to voxelized volumes. As a preliminary step, PG production probabilities are precomputed once and stored in a database. In stage 1, we simulate the interactions between the treatment plan and the patient CT with low statistic MC to obtain the spatial and spectral distribution of the PGs. As primary particles are propagated throughout the patient CT, the PG yields are computed in each voxel from the initial database, as a function of the current energy of the primary, the material in the voxel and the step length. The result is a voxelized image of PG yield, normalized to a single primary. The second stage uses this intermediate PG image as a source to generate and propagate the number of PGs throughout the rest of the scene geometry, e.g. into a detection device, corresponding to the number of primaries desired. We achieved a gain of around 103 for both a geometrical heterogeneous phantom and a complete patient CT treatment plan with respect to analog MC, at a convergence level of 2% relative

  12. MeV electron acceleration at 1kHz with <10 mJ laser pulses

    NASA Astrophysics Data System (ADS)

    Salehi, Fatholah; Goers, Andy; Hine, George; Feder, Linus; Kuk, Donghoon; Kim, Ki-Yong; Milchberg, Howard

    2016-10-01

    We demonstrate laser driven acceleration of electrons at 1 kHz repetition rate with pC charge above 1MeV per shot using < 10 mJ pulse energies focused on a near-critical density He or H2 gas jet. Using the H2 gas jet, electron acceleration to 0.5 MeV in 10 fC bunches was observed with laser pulse energy as low as 1.3mJ . Using a near-critical density gas jet sets the critical power required for relativistic self-focusing low enough for mJ scale laser pulses to self- focus and drive strong wakefields. Experiments and particle-in-cell simulations show that optimal drive pulse duration and chirp for maximum electron bunch charge and energy depends on the target gas species. High repetition rate, high charge, and short duration electron bunches driven by very modest pulse energies constitutes an ideal portable electron source for applications such as ultrafast electron diffraction experiments and high rep. rate γ-ray production. This work is supported by the US Department of Energy, the National Science Foundation, and the Air Force Office of Scientific Research.

  13. MeV electron acceleration at 1 kHz with <10 mJ laser pulses

    NASA Astrophysics Data System (ADS)

    Salehi, Fatholah; Goers, Andy; Hine, George; Feder, Linus; Kuk, Donghoon; Miao, Bo; Woodbury, Daniel; Kim, Ki-Yong; Milchberg, Howard

    2017-01-01

    We demonstrate laser driven acceleration of electrons to MeV-scale energies at 1 kHz repetition rate using <10 mJ pulses focused on near-critical density He and H2 gas jets. Using the H2 gas jet, electron acceleration to 0.5 MeV in 10 fC bunches was observed with laser pulse energy as low as 1.3 mJ. Increasing the pulse energy to 10 mJ, we measure 1pC charge bunches with >1 MeV energy for both He and H gas jets. Such a high repetition rate, high flux ultrafast source has immediate application to time resolved probing of matter for scientific, medical, or security applications, either using the electrons directly or using a high-Z foil converter to generate ultrafast γ-rays. This work is supported by the US Department of Energy, the National Science Foundation, and the Air Force Office of Scientific Research.

  14. Simulations of proton beam characteristics for ELIMED Beamline

    NASA Astrophysics Data System (ADS)

    Psikal, Jan; Limpouch, Jiri; Klimo, Ondrej; Vyskocil, Jiri; Margarone, Daniele; Korn, Georg

    2016-03-01

    ELIMED Beamline should demonstrate the capability of laser-based particle accelerators for medical applications, mainly for proton radiotherapy of tumours which requires a sufficient number of accelerated protons with energy about 60 MeV at least. In this contribution, we study the acceleration of protons by laser pulse with parameters accessible for ELIMED Beamline (intensity ∼ 1022 W/cm2, pulse length ∼ 30 fs). In our two-dimensional particle-incell simulations, we observed higher energies of protons for linear than for circular polarization. Oblique incidence of the laser pulse on target does not seem to be favourable for proton acceleration at such high intensities as the accelerated protons are deflected from target normal axis and their energy and numbers are slightly decreased. The expected numbers of accelerated protons in the energy interval 60 MeV ± 5% are calculated between 109 and 1010 per laser shot with estimated proton beam divergence about 20° (FWHM).

  15. Laser-seeded modulation instability in a proton driver plasma wakefield accelerator

    SciTech Connect

    Siemon, Carl; Khudik, Vladimir; Austin Yi, S.; Shvets, Gennady; Pukhov, Alexander

    2013-10-15

    A new method for initiating the modulation instability (MI) of a proton beam in a proton driver plasma wakefield accelerator using a short laser pulse preceding the beam is presented. A diffracting laser pulse is used to produce a plasma wave that provides a seeding modulation of the proton bunch with the period equal to that of the plasma wave. Using the envelope description of the proton beam, this method of seeding the MI is analytically compared with the earlier suggested seeding technique that involves an abrupt truncation of the proton bunch. The full kinetic simulation of a realistic proton bunch is used to validate the analytic results. It is further used to demonstrate that a plasma density ramp placed in the early stages of the laser-seeded MI leads to its stabilization, resulting in sustained accelerating electric fields (of order several hundred MV/m) over long propagation distances (∼100–1000 m)

  16. The Elemental Analysis of Biological and Environmental Materials Using a 2MEV Proton Beam

    NASA Astrophysics Data System (ADS)

    Arshed, Waheed

    Available from UMI in association with The British Library. A programme has been developed to simulate the proton induced x-ray emission (PIXE) spectra and its uses have been described. The PIXE technique has been applied to the analysis of new biological reference materials which consist of IAEA human diet samples and NIST leaf samples. Homogeneity of these and two existing reference materials, IAEA soil -7 and Bowen's kale, has also been determined at the mug scale. A subsample representative of a material is ascertained by determination of sampling factors for the elements detected in the material. Proton induced gamma-ray emission (PIGE) analysis in conjunction with PIXE has been employed to investigate F and other elemental concentrations found in human teeth samples. The mean F concentration in enamel and dentine parts of teeth followed an age dependent model. Concentrations of Ca and P were found to be higher in the enamel than in the dentine. Analysis of blood and its components in the study of elemental models in sickle cell disease in Nigerians has been carried out. Comparisons revealed that Cl, Ca and Cu were at higher levels whereas K, Fe, Zn and Rb were at lower levels in the whole blood of the sicklers compared to controls. Similar results were obtained for the erythrocytes except that Br was found at higher concentration in erythrocytes of the sicklers. Higher concentrations of Cl, K, Fe and Cu were also observed in plasma of the sicklers compared to controls. PIXE and scanning electron microscopy (SEM) were used in the characterization of the Harmattan dust particulates collected at Kano and Ife. Most of the elements were found to be at higher concentrations as compared to those found in Recife (Brazil) and Toronto (Canada). The value of total suspended particulate was above the relevant national air quality standards. PIXE in conjunction with Rutherford backscattering spectrometry and instrumental neutron activation analysis was employed in the

  17. Surfatron acceleration of protons by an electromagnetic wave at the heliosphere periphery

    SciTech Connect

    Loznikov, V. M. Erokhin, N. S.; Zol’nikova, N. N.; Mikhailovskaya, L. A.

    2013-10-15

    The trapping and subsequent efficient surfatron acceleration of weakly relativistic protons by an electromagnetic wave propagating across an external magnetic field in plasma at the heliosphere periphery is considered. The problem is reduced to analysis of a second-order time-dependent nonlinear equation for the wave phase on the particle trajectory. The conditions of proton trapping by the wave, the dynamics of the components of the particle momentum and velocity, the structure of the phase plane, the particle trajectories, and the dependence of the acceleration rate on initial parameters of the problem are analyzed. The asymptotic behavior of the characteristics of accelerated particles for the heliosphere parameters is investigated. The optimum conditions for surfatron acceleration of protons by an electromagnetic wave are discussed. It is demonstrated that the experimentally observed deviation of the spectra of cosmic-ray protons from standard power-law dependences can be caused by the surfatron mechanism. It is shown that protons with initial energies of several GeV can be additionally accelerated in the heliosphere (the region located between the shock front of the solar wind and the heliopause at distances of about 100 astronomical units (a.u.) from the Sun) up to energies on the order of several thousands of GeV. In order to explain the proton spectra in the energy range of ∼20–500 GeV, a two-component phenomenological model is proposed. The first component corresponds to the constant (in this energy range) galactic contribution, while the second (variable) component corresponds to the heliospheric contribution, which appears due to the additional acceleration of soft cosmic-ray protons at the heliosphere periphery. Variations in the proton spectra measured on different time scales between 1992 and 2008 in the energy range from several tens to several hundred GeV, as well as the dependence of these spectra on the heliospheric weather, can be explained

  18. Certain dosimetric features of electrons from a CGR Therac-20 MeV Saturne linear accelerator.

    PubMed

    Nair, R P

    1985-03-01

    Some of the useful clinical radiation characteristics required for treatment planning using the 6,9,13,17, and 20 Me V scanning electron beams obtainable in a CGR Therac-20 Me V Saturne linear accelerator are outlined.

  19. Spot size dependence of laser accelerated protons in thin multi-ion foils

    SciTech Connect

    Liu, Tung-Chang Shao, Xi; Liu, Chuan-Sheng; Eliasson, Bengt; Wang, Jyhpyng; Chen, Shih-Hung

    2014-06-15

    We present a numerical study of the effect of the laser spot size of a circularly polarized laser beam on the energy of quasi-monoenergetic protons in laser proton acceleration using a thin carbon-hydrogen foil. The used proton acceleration scheme is a combination of laser radiation pressure and shielded Coulomb repulsion due to the carbon ions. We observe that the spot size plays a crucial role in determining the net charge of the electron-shielded carbon ion foil and consequently the efficiency of proton acceleration. Using a laser pulse with fixed input energy and pulse length impinging on a carbon-hydrogen foil, a laser beam with smaller spot sizes can generate higher energy but fewer quasi-monoenergetic protons. We studied the scaling of the proton energy with respect to the laser spot size and obtained an optimal spot size for maximum proton energy flux. Using the optimal spot size, we can generate an 80 MeV quasi-monoenergetic proton beam containing more than 10{sup 8} protons using a laser beam with power 250 TW and energy 10 J and a target of thickness 0.15 wavelength and 49 critical density made of 90% carbon and 10% hydrogen.

  20. Measurement of Dynamic Strain on a Mercury Target Vessel During 800-MeV Proton Thermal Shock Tests

    SciTech Connect

    Cates, M.R.

    2001-01-11

    A mercury target vessel, designed to simulate some aspects of the eventual target design for the proposed Spallation Neutron Source (SNS) to be built in Oak Ridge by the Department of Energy, was used in a test at the Los Alamos Neutron Science Center (LANSCE) to study the strain induced from thermal shock of bombarding protons. In the SNS, intense thermal shock loads are expected to cause an enormous rate of temperature rise ({approximately}10{sup 7} K/s), with resulting pressure waves in the mercury that may lead to large stresses on the thin walls of the mercury target. To guide the mercury target design and to benchmark the computer design codes, transient strain was measured using fiber optic Fabry-Perot sensors. Twenty strain sensors were attached in various axial and transverse orientations to a cylindrical stainless steel target vessel containing mercury. The vessel was 10 cm in diameter, about 15 cm long, and with a 5-cm radius hemispherical shell welded to the forward end. The test was done at the LANSCE Weapons Neutron Research (WNR) beam facility on 30-31 January 1999. The sensors were attached with gauge lengths of about two centimeters, and were located in pairs in most areas, for redundancy and facilitation of data analysis. The 800-MeV proton deposition of 0.5--2.3 x 10{sup 13} over a full-width at half maximum beam size of {approximately}25 mm, produced axial strains peaking at a few microstrains, with transverse (hoop) strains more than an order of magnitude higher. We describe the experiments, including the sensors and measurement configuration, and discuss the strain data analysis.

  1. Stable long range proton acceleration driven by intense laser pulse with underdense plasmas

    SciTech Connect

    Gu, Y. J.; Zhu, Z.; Li, X. F.; Yu, Q.; Huang, S.; Zhang, F.; Kong, Q.; Kawata, S.

    2014-06-15

    Proton acceleration is investigated by 2.5-dimensional particle-in-cell simulations in an interaction of an ultra intense laser with a near-critical-density plasma. It was found that multi acceleration mechanisms contribute together to a 1.67 GeV collimated proton beam generation. The W-BOA (breakout afterburner based on electrons accelerated by a wakefield) acceleration mechanism plays an important role for the proton energy enhancement in the area far from the target. The stable and continuous acceleration maintains for a long distance and period at least several pico-seconds. Furthermore, the energy scalings are also discussed about the target density and the laser intensity.

  2. Stable long range proton acceleration driven by intense laser pulse with underdense plasmas

    NASA Astrophysics Data System (ADS)

    Gu, Y. J.; Zhu, Z.; Li, X. F.; Yu, Q.; Huang, S.; Zhang, F.; Kong, Q.; Kawata, S.

    2014-06-01

    Proton acceleration is investigated by 2.5-dimensional particle-in-cell simulations in an interaction of an ultra intense laser with a near-critical-density plasma. It was found that multi acceleration mechanisms contribute together to a 1.67 GeV collimated proton beam generation. The W-BOA (breakout afterburner based on electrons accelerated by a wakefield) acceleration mechanism plays an important role for the proton energy enhancement in the area far from the target. The stable and continuous acceleration maintains for a long distance and period at least several pico-seconds. Furthermore, the energy scalings are also discussed about the target density and the laser intensity.

  3. Thick target spallation product yields from 800 MeV protons on tungsten

    SciTech Connect

    Ullmann, J.L.; Staples, P.; Butler, G.

    1994-07-01

    A number of newly-conceived accelerator based technologies will employ medium-energy particles stopping in thick targets to produce large numbers of neutrons. It is important to quantify the residual radionuclides in the target because one must understand what nuclei and decay gammas are produced in order to design adequate shielding, to estimate ultimate waste disposal problems, and to predict possible effects of accidental dispersion during operation. Because stopping-length targets are considered, radionuclide production must be known as a function of energy. Moreover, secondary particle production, mostly neutrons, implies a need to be able to calculate particle transport. To test the overall ability to calculate radionuclide yields, a thick-target measurement was carried out and the results compared to detailed calculations. Although numerous measurements of thin-target spallation yields have been made, there have been only a few measurements on thick systems. The most complete study showed results for Pb and U systems. In this contribution, the authors report on measurements made for a stopping-length W target. Special efforts were made to measure short-lived isotopes, and reliable data on isotopes with two or three minute half-lives were obtained.

  4. Measurement of double differential charged-particle emission cross sections for reactions induced by 26 MeV protons and FKK model analysis

    SciTech Connect

    Watanabe, Y.; Aoto, A.; Kashimoto, H.

    1994-06-01

    Double differential charged-particle emission cross sections of proton-induced reactions have been measured for {sup nat}C, {sup 27}Al, {sup nat}Si, {sup 98}Mo, {sup 106}Pd, {sup 159}Tb and {sup 181}Ta at energies around 26 MeV. Several (p,p{prime}) and (p,n) data for {sup 98}Mo and {sup 106}Pd in the incident energy range from 12 to 26 MeV are analysed in terms of the Feshbach-Kerman-Koonin model, in order to study preequilibrium nucleon emission from nucleon-induced reactions.

  5. Radiochemical study of the combined (p,π0) and (p,γ) reactions on bismuth with protons from 62 to 480 MeV

    NASA Astrophysics Data System (ADS)

    Ward, T. E.; Singh, P. P.; Friesel, D. L.; Yavin, A.; Doron, A.; D'Auria, J. M.; Sheffer, G.; Dillig, M.

    1981-08-01

    The excitation function for the combined 209Bi(p,γ)210Po and 209Bi(p,π0)210Po reactions was measured for proton energies from 62 to 480 MeV. The measurements were made using standard radiochemical and residual α-counting techniques. Below pion-production threshold the radiative proton-capture cross section was observed to decrease with increasing proton energy. Above threshold the combined cross section increases to about 10 μb at 170 MeV. From a smooth extrapolation of the (p,γ) cross section to energies above pion-production threshold, an estimate of a cross section for the (p,π0) process is obtained. A theoretical fit of the summed total cross section into all particle bound states was made using a density of states factor, a two nucleon t matrix, and by taking into account the initial state (proton) and final state (pion) distortions using optical potentials. [NUCLEAR REACTIONS 209Bi(p,γ)210Po+209Bi(p,π0)210Po, 209Bi(p,2n)208Po, 209Bi(p,4n)206Po, Ep=62-480 MeV, measured polonium-production cross section, thin targets, radiochemical method, α counting, theoretical fit to the (p,π0) data using two-nucleon model.

  6. Neutron spectra produced by 30, 35 and 40 MeV proton beams at KIRAMS MC-50 cyclotron with a thick beryllium target

    NASA Astrophysics Data System (ADS)

    Shin, Jae Won; Bak, Sang-In; Ham, Cheolmin; In, Eun Jin; Kim, Do Yoon; Min, Kyung Joo; Zhou, Yujie; Park, Tae-Sun; Hong, Seung-Woo; Bhoraskar, V. N.

    2015-10-01

    Neutrons over a wide range of energies are produced by bombarding a 1.05 cm thick beryllium target with protons of different energies delivered by the MC-50 Cyclotron of the Korea Institute of Radiological Medical Sciences (KIRAMS). The neutron flux Φ(En) versus neutron energy En, produced by protons of 30, 35, and 40 MeV energies, was obtained by using the GEANT4 code with a data-based hadronic model. For the experimental validation of the simulated neutron spectra, a number of pure aluminum and iron oxide samples were irradiated with the neutrons produced by 30, 35, and 40 MeV protons at 20 μA beam current. The gamma-ray activities of 24Na and 56Mn produced, respectively, through 27Al(n,α)24Na and 56Fe(n,p)56Mn reactions were measured by a HPGe detector. The neutron flux Φ(En) at each neutron energy from the simulation was multiplied with the evaluated cross-sections σ(En) of the respective nuclear reaction, and the summation ∑ Φ(En) σ(En) was calculated over the neutron spectrum for each proton energy of 30, 35, and 40 MeV. The measured gamma-ray activities of 24Na and 56Mn were found in good agreement with the activities estimated by using the summed values of ∑ Φ(En) σ(En) along with other parameters in a neutron activation method.

  7. A comparison of 4 MeV Proton and Co-60 gamma irradiation induced degradation in the electrical characteristics of N-channel MOSFETs

    NASA Astrophysics Data System (ADS)

    Anjum, Arshiya; Vinayakprasanna, N. H.; Pradeep, T. M.; Pushpa, N.; Krishna, J. B. M.; Gnana Prakash, A. P.

    2016-07-01

    N-channel depletion MOSFETs were irradiated with 4 MeV Proton and Co-60 gamma radiation in the dose range of 100 krad(Si) to 100 Mrad(Si). The electrical characteristics of MOSFET such as threshold voltage (Vth), density of interface trapped charges (ΔNit), density of oxide trapped charges (ΔNot), transconductance (gm), mobility (μ), leakage current (IL) and drain saturation current (ID Sat) were studied as a function of dose. A considerable increase in ΔNit and ΔNot and decrease in Vth,gm, μ, and ID Sat was observed after irradiation. The results of 4 MeV Proton irradiation were compared with that of Co-60 gamma radiation and it is found that the degradation is more for the devices irradiated with 4 MeV Protons when compared with the Co-60 gamma radiation. This indicates that Protons induce more trapped charges in the field oxide region when compared to the gamma radiation.

  8. Study of neutron spectra in a water bath from a Pb target irradiated by 250 MeV protons

    NASA Astrophysics Data System (ADS)

    Li, Yan-Yan; Zhang, Xue-Ying; Ju, Yong-Qin; Ma, Fei; Zhang, Hong-Bin; Chen, Liang; Ge, Hong-Lin; Wan, Bo; Luo, Peng; Zhou, Bin; Zhang, Yan-Bin; Li, Jian-Yang; Xu, Jun-Kui; Wang, Song-Lin; Yang, Yong-Wei; Yang, Lei

    2015-04-01

    Spallation neutrons were produced by the irradiation of Pb with 250 MeV protons. The Pb target was surrounded by water which was used to slow down the emitted neutrons. The moderated neutrons in the water bath were measured by using the resonance detectors of Au, Mn and In with a cadmium (Cd) cover. According to the measured activities of the foils, the neutron flux at different resonance energies were deduced and the epithermal neutron spectra were proposed. Corresponding results calculated with the Monte Carlo code MCNPX were compared with the experimental data to check the validity of the code. The comparison showed that the simulation could give a good prediction for the neutron spectra above 50 eV, while the finite thickness of the foils greatly effected the experimental data in low energy. It was also found that the resonance detectors themselves had great impact on the simulated energy spectra. Supported by National Natural Science Foundation and Strategic Priority Research Program of the Chinese Academy of Sciences (11305229, 11105186, 91226107, 91026009, XDA03030300)

  9. New excitation functions for proton induced reactions on natural titanium, nickel and copper up to 70 MeV

    NASA Astrophysics Data System (ADS)

    Garrido, E.; Duchemin, C.; Guertin, A.; Haddad, F.; Michel, N.; Métivier, V.

    2016-09-01

    New excitation functions for proton induced nuclear reactions on natural titanium, nickel and copper were measured, using the stacked-foil technique and gamma spectrometry, up to 70 MeV. The experimental cross sections were measured using the Ti-nat(p,x) V-48, Ni-nat(p,x) Ni-57 and Cu-nat(p,x) Zn-62,Co-56 monitor reactions recommended by the International Atomic Energy Agency (IAEA), depending on the investigated energy range. Data have been extracted for the Ti-nat(p,x) Sc-43,44m,46,47,48, V-48, K-42,43, Ni-nat(p,x) Ni-56,57, Co-55,56,57,58, Mn-52,54, Cu-nat(p,x) Cu-61,64, Ni-57, Co-56,57,58,60, Zn-62,65, Mn-54 reactions. Our results are discussed and compared to the existing ones as well as with the TALYS code version 1.6 calculations using default models. Our experimental data are in overall good agreement with the literature. TALYS is able to reproduce, in most cases, the experimental trend. Our new experimental results allow to expand our knowledge on these excitation functions, to confirm the existing trends and to give additional values on a large energy range. This work is in line with the new Coordinated Research Project (CRP) launched by the IAEA to expand the database of monitor reactions.

  10. Measurement of SEU cross sections in the CDF SVX3 ASIC using 63 MeV protons

    NASA Astrophysics Data System (ADS)

    Grim, G. P.; Bishai, M.; Gay, C.; Hill, C.; Nahn, S.; Pellett, D. E.; Pope, G.; Shepard, P. F.; Slaughter, A. J.; Webster, W. C., III

    2000-06-01

    The single event upset (SEU) cross section has been measured for 63 MeV protons incident on static memory cells in the CDF SVX3 pipelined silicon strip readout ASIC. The device was fabricated in the Honeywell 0.8 μm RICMOS IV bulk process, and contains a number of cells with minimum gate length transistors to control the mode of operation of the chip. Cross sections per cell of (4.4±1.8)×10 -16 cm2, (2.1±0.7)×10 -15 cm2, and (3.9±0.9)×10 -15 cm2 were measured for angles of incidence of 0°, 45°, and 80°, respectively, for cells with 0.8 μm gate length. The SVX3 SEU rate in Run II at the Fermilab Tevatron was estimated to be sufficiently low that it would not affect the performance of the CDF Silicon Tracker.

  11. Annealing characteristics of amorphous silicon alloy solar cells irradiated with 1.00 MeV protons

    NASA Technical Reports Server (NTRS)

    Abdulaziz, Salman S.; Woodyard, James R.

    1991-01-01

    Amorphous Si:H and amorphous Si sub x, Ge sub (1-x):H solar cells were irradiated with 1.00 MeV proton fluences in the range of 1.00E14 to 1.25E15 cm (exp -2). Annealing of the short circuit current density was studied at 0, 22, 50, 100, and 150 C. Annealing times ranged from an hour to several days. The measurements confirmed that annealing occurs at 0 C and the initial characteristics of the cells are restored by annealing at 200 C. The rate of annealing does not appear to follow a simple nth order reaction rate model. Calculations of the short-circuit current density using quantum efficiency measurements and the standard AM1.5 global spectrum compare favorably with measured values. It is proposed that the degradation in J sub sc with irradiation is due to carrier recombination through the fraction of D (o) states bounded by the quasi-Fermi energies. The time dependence of the rate of annealing of J sub sc does appear to be consistent with the interpretation that there is a thermally activated dispersive transport mechanism which leads to the passivation of the irradiation induced defects.

  12. Radiation performance of GaAs concentrator cells for 0.4 to 12 MeV electrons and 0.1 to 37 MeV protons

    NASA Technical Reports Server (NTRS)

    Curtis, Henry B.; Anspaugh, Bruce

    1991-01-01

    Gallium arsenide concentrator cells have been irradiated with both electrons and protons with a wide variety of energies. The cells are made using OM-VPE growth process with a junction depth of a half micron. All data are taken with bare cells without coverglasses or shielding. Performance data are given at the designed concentration level of 100X AMO. Results are presented in a number of ways, including performance of electrical parameters (Pmax, Isc, and Voc) as a function of fluence for different electron and proton energies. Critical fluences (defined at a degradation of 25 percent in Pmax) are calculated for each energy level and presented for both electron and proton irradiations.

  13. Neutron scattering cross sections for /sup 232/Th and /sup 238/U inferred from proton scattering and charge exchange measurements. [7 MeV, 26 and 27 MeV

    SciTech Connect

    Hansen, L.F.; Grimes, S.M.; Pohl, B.A.; Poppe, C.H.; Wong, C.

    1980-01-01

    Differential cross sections for the (p,n) reactions to the isobaric analog states (IAS) of /sup 232/Th and /sup 238/U targets were measured at 26 and 27 MeV. The analysis of the data was done in conjunction with the proton elastic and inelastic (2/sup +/, 4/sup +/, 6/sup +/) differential cross sections measured at 26 MeV. Because collective effects are important in this mass region, deformed coupled-channels calculations were carried out for the simultaneous analysis of the proton and neutron outgoing channels. The sensitivity of the calculations was studied with respect to the optical model parameters used in the calculations, the shape of the nuclear charge distribution, the type of coupling scheme assumed among the levels, the magnitude of the deformation parameters, and the magnitude of the isovector potentials, V/sub 1/ and W/sub 1/. A Lane model-consistent analysis of the data was used to infer optical potential parameters for 6- to 7-MeV neutrons. The neutron elastic differential cross sections obtained from these calculations are compared with measurements available in the literature, and with results obtained using neutron parameters from global sets reported at these energies. 7 figures, 3 tables.

  14. Measurements of production cross sections of 10Be and 26Al by 120 GeV and 392 MeV proton bombardment of 89Y, 159Tb, and natCu targets

    DOE PAGES

    Sekimoto, S.; Okumura, S.; Yashima, H.; ...

    2015-08-12

    The production cross sections of 10Be and 26Al were measured by accelerator mass spectrometry using 89Y, 159Tb, and natCu targets bombarded by protons with energies Ep of 120 GeV and 392 MeV. The production cross sections obtained for 10Be and 26Al were compared with those previously reported using Ep = 50 MeV–24 GeV and various targets. It was found that the production cross sections of 10Be monotonically increased with increasing target mass number when the proton energy was greater than a few GeV. On the other hand, it was also found that the production cross sections of 10Be decreased asmore » the target mass number increased from that of carbon to those near the mass numbers of nickel and zinc when the proton energy was below approximately 1 GeV. They also increased as the target mass number increased from near those of nickel and zinc to that of bismuth, in the same proton energy range. Similar results were observed in the production cross sections of 26Al, though the absolute values were quite different between 10Be and 26Al. As a result, the difference between these production cross sections may depend on the impact parameter (nuclear radius) and/or the target nucleus stiffness.« less

  15. Plasma Density Tapering for Laser Wakefield Acceleration of Electrons and Protons

    NASA Astrophysics Data System (ADS)

    Ting, A.; Gordon, D.; Helle, M.; Kaganovich, D.; Sprangle, P.; Hafizi, B.

    2010-11-01

    Extended acceleration in a Laser Wakefield Accelerator can be achieved by tailoring the phase velocity of the accelerating plasma wave, either through profiling of the density of the plasma or direct manipulation of the phase velocity. Laser wakefield acceleration has also reached a maturity that proton acceleration by wakefield could be entertained provided we begin with protons that are substantially relativistic, ˜1 GeV. Several plasma density tapering schemes are discussed. The first scheme is called "bucket jumping" where the plasma density is abruptly returned to the original density after a conventional tapering to move the accelerating particles to a neighboring wakefield period (bucket). The second scheme is designed to specifically accelerate low energy protons by generating a nonlinear wakefield in a plasma region with close to critical density. The third scheme creates a periodic variation in the phase velocity by beating two intense laser beams with laser frequency difference equal to the plasma frequency. Discussions and case examples with simulations are presented where substantial acceleration of electrons or protons could be obtained.

  16. Secondary neutron spectrum from 250-MeV passively scattered proton therapy: Measurement with an extended-range Bonner sphere system

    PubMed Central

    Howell, Rebecca M.; Burgett, E. A.

    2014-01-01

    Purpose: Secondary neutrons are an unavoidable consequence of proton therapy. While the neutron dose is low compared to the primary proton dose, its presence and contribution to the patient dose is nonetheless important. The most detailed information on neutrons includes an evaluation of the neutron spectrum. However, the vast majority of the literature that has reported secondary neutron spectra in proton therapy is based on computational methods rather than measurements. This is largely due to the inherent limitations in the majority of neutron detectors, which are either not suitable for spectral measurements or have limited response at energies greater than 20 MeV. Therefore, the primary objective of the present study was to measure a secondary neutron spectrum from a proton therapy beam using a spectrometer that is sensitive to neutron energies over the entire neutron energy spectrum. Methods: The authors measured the secondary neutron spectrum from a 250-MeV passively scattered proton beam in air at a distance of 100 cm laterally from isocenter using an extended-range Bonner sphere (ERBS) measurement system. Ambient dose equivalent H*(10) was calculated using measured fluence and fluence-to-ambient dose equivalent conversion coefficients. Results: The neutron fluence spectrum had a high-energy direct neutron peak, an evaporation peak, a thermal peak, and an intermediate energy continuum between the thermal and evaporation peaks. The H*(10) was dominated by the neutrons in the evaporation peak because of both their high abundance and the large quality conversion coefficients in that energy interval. The H*(10) 100 cm laterally from isocenter was 1.6 mSv per proton Gy (to isocenter). Approximately 35% of the dose equivalent was from neutrons with energies ≥20 MeV. Conclusions: The authors measured a neutron spectrum for external neutrons generated by a 250-MeV proton beam using an ERBS measurement system that was sensitive to neutrons over the entire

  17. Simultaneous acceleration of protons and electrons at nonrelativistic quasiparallel collisionless shocks.

    PubMed

    Park, Jaehong; Caprioli, Damiano; Spitkovsky, Anatoly

    2015-02-27

    We study diffusive shock acceleration (DSA) of protons and electrons at nonrelativistic, high Mach number, quasiparallel, collisionless shocks by means of self-consistent 1D particle-in-cell simulations. For the first time, both species are found to develop power-law distributions with the universal spectral index -4 in momentum space, in agreement with the prediction of DSA. We find that scattering of both protons and electrons is mediated by right-handed circularly polarized waves excited by the current of energetic protons via nonresonant hybrid (Bell) instability. Protons are injected into DSA after a few gyrocycles of shock drift acceleration (SDA), while electrons are first preheated via SDA, then energized via a hybrid acceleration process that involves both SDA and Fermi-like acceleration mediated by Bell waves, before eventual injection into DSA. Using the simulations we can measure the electron-proton ratio in accelerated particles, which is of paramount importance for explaining the cosmic ray fluxes measured on Earth and the multiwavelength emission of astrophysical objects such as supernova remnants, radio supernovae, and galaxy clusters. We find the normalization of the electron power law is ≲10^{-2} of the protons for strong nonrelativistic shocks.

  18. Investigation of the Isospin Response of the (4) Helium Continuum Using the HELIUM-4(PROTON, Proton'x) Reaction at T(p) = 100 Mev

    NASA Astrophysics Data System (ADS)

    Raue, Brian A.

    1993-01-01

    The principle of charge symmetry (CS) implies invariance of the strong interaction under 180 ^circ rotations in isospin space. The study of charge symmetric, proton and neutron decays from the giant dipole resonance (GDR) of ^4He (25<= E_{x}<= 35 MeV) is one way to probe the validity of CS. If CS is valid, then one would expect nearly equal charge -symmetric decay rates with small deviations due to the Coulomb interaction. An evaluation of photoabsorption measurements concluded that R_gamma= sigma(gamma,p)/sigma(gamma,n) was large indicating sizable isospin mixing in the ^4He GDR and suggested the possibility of a large CS violating component in the strong interaction. However, data used in that evaluation are in disagreement and recent experiments continue to give inconsistent values for R _gamma. Other experiments intended to provided complementary information are generally consistent with minimal isospin mixing in the ^4He GDR but questions have arisen regarding their ability to address the problem. This experiment addresses the issue of CS by measuring charge symmetric ^3H and ^3He decays of the ^4He continuum excited by proton inelastic scattering. The experiment was designed to reduce most of the systematic errors associated with Rgamma by detecting the ^4He^ star charge symmetric decay particles with the same apparatus. Angular correlation functions (ACF) have been measured concurrent with (p,p^ ') cross sections for proton scattering angles of theta_sp{p}{lab } = 24, 30 and 35^circ in order to identify the multipolarities excited by the reaction. A unique target/detector apparatus was developed to detect low-energy ions from ^4 He^star decay over a broad angle range. Analysis of the ^4He(p,p ^' t) ACF provides evidence that predominately Delta L = 1 transitions have been excited in the GDR region. This analysis cannot uniquely identify the J^pi of ^4He^star resonances. A fit to the ^4He( p,p^' t) integrated cross section using resonance lineshapes from a

  19. Control of target-normal-sheath-accelerated protons from a guiding cone

    SciTech Connect

    Zou, D. B.; Zhuo, H. B.; Yang, X. H.; Yu, T. P.; Shao, F. Q.; Pukhov, A.

    2015-06-15

    It is demonstrated through particle-in-cell simulations that target-normal-sheath-accelerated protons can be well controlled by using a guiding cone. Compared to a conventional planar target, both the collimation and number density of proton beams are substantially improved, giving a high-quality proton beam which maintained for a longer distance without degradation. The effect is attributed to the radial electric field resulting from the charge due to the hot target electrons propagating along the cone surface. This electric field can effectively suppress the spatial spread of the protons after the expansion of the hot electrons.

  20. Optimizing proton therapy at the LBL medical accelerator. Final report

    SciTech Connect

    Alonso, J.

    1992-03-01

    This Grant has marked the beginning of a multi-year study process expected to lead to design and construction of at least one, possibly several hospital-based proton therapy facilities in the United States.

  1. Optimizing proton therapy at the LBL medical accelerator

    SciTech Connect

    Alonso, J.

    1992-03-01

    This Grant has marked the beginning of a multi-year study process expected to lead to design and construction of at least one, possibly several hospital-based proton therapy facilities in the United States.

  2. Compton MeV Gamma-ray Source on Texas Petawatt Laser-Driven GeV Electron Accelerator

    NASA Astrophysics Data System (ADS)

    Shaw, Joseph M.; Tsai, Hai-En; Zgadzaj, Rafal; Wang, Xiaoming; Chang, Vincent; Fazel, Neil; Henderson, Watson; Downer, M. C.; Texas Petawatt Laser Team

    2015-11-01

    Compton Backscatter (CBS) from laser wakefield accelerated (LWFA) electron bunches is a promising compact, femtosecond (fs) source of tunable high-energy photons. CBS x-rays have been produced from LWFAs using two methods: (1) retro-reflection of the LWFA drive pulse via an in-line plasma mirror (PM); (2) scattering of a counter-propagating secondary pulse split from the drive pulse. Previously MeV photons were only demonstrated by the latter method, but the former method is self-aligning. Here, using the Texas Petawatt (TPW) laser and a self-aligned near-retro-reflecting PM, we generate bright CBS γ-rays with central energies higher than 10 MeV. The 100 μm focus of TPW delivers 100 J in 100 fs pulses, with intensity 6x1018 W/cm2 (a0 =1.5), to the entrance of a 6-cm long Helium gas cell. A thin, plastic PM immediately following the gas cell exit retro-reflects the LWFA driving pulse into the oncoming 0.5 - 2 GeV electron beam to produce a directional beam of γ-rays without significant bremsstrahlung background. A Pb-filter pack on a thick, pixelated, CsI(Tl) scintillator is used to estimate the spectrum via differential transmission and to observe the beam profile. Recorded beam profiles indicate a low divergence. Department of Physics, The University of Texas at Austin

  3. Pulsars as cosmic ray particle accelerators: Proton orbits

    NASA Technical Reports Server (NTRS)

    Thielheim, K. O.

    1985-01-01

    Proton orbits are calculated in the electromagnetic vacuum field of a magnetic point dipole rotating with its angular velocity omega perpendicular to its dipole moment mu by numerical integration of the Lorentz-Dirac equation. Trajectories are shown and discussed for various initial conditions. A critical surface is shown separating initial positions of protons which finally hit the pulsar in the polar region from those which finally recede to infinity.

  4. Investigation of the Stability and 1.0 MeV Proton Radiation Resistance of Commercially Produced Hydrogenated Amorphous Silicon Alloy Solar Cells

    NASA Technical Reports Server (NTRS)

    Lord, Kenneth R., II; Walters, Michael R.; Woodyard, James R.

    1994-01-01

    The radiation resistance of commercial solar cells fabricated from hydrogenated amorphous silicon alloys is reported. A number of different device structures were irradiated with 1.0 MeV protons. The cells were insensitive to proton fluences below 1E12 sq cm. The parameters of the irradiated cells were restored with annealing at 200 C. The annealing time was dependent on proton fluence. Annealing devices for one hour restores cell parameters for fluences below 1E14 sq cm fluences above 1E14 sq cm require longer annealing times. A parametric fitting model was used to characterize current mechanisms observed In dark I-V measurements. The current mechanism were explored with irradiation fluence, and voltage and light soaking times. The thermal generation current density and quality factor increased with proton fluence. Device simulation shows the degradation in cell characteristics may be explained by the reduction of the electric field in the intrinsic layer.

  5. Capture and Control of Laser-Accelerated Proton Beams: Experiment and Simulation

    SciTech Connect

    Nurnberg, F; Alber, I; Harres, K; Schollmeier, M; Roth, M; Barth, W; Eickhoff, H; Hofmann, I; Friedman, A; Grote, D; Logan, B G

    2009-05-13

    This paper summarizes the ongoing studies on the possibilities for transport and RF capture of laser-accelerated proton beams in conventional accelerator structures. First results on the capture of laser-accelerated proton beams are presented, supported by Trace3D, CST particle studio and Warp simulations. Based on these results, the development of the pulsed high-field solenoid is guided by our desire to optimize the output particle number for this highly divergent beam with an exponential energy spectrum. A future experimental test stand is proposed to do studies concerning the application as a new particle source.

  6. Instrumentation for diagnostics and control of laser-accelerated proton (ion) beams.

    PubMed

    Bolton, P R; Borghesi, M; Brenner, C; Carroll, D C; De Martinis, C; Fiorini, Francesca; Flacco, A; Floquet, V; Fuchs, J; Gallegos, P; Giove, D; Green, J S; Green, S; Jones, B; Kirby, D; McKenna, P; Neely, D; Nuesslin, F; Prasad, R; Reinhardt, S; Roth, M; Schramm, U; Scott, G G; Ter-Avetisyan, S; Tolley, M; Turchetti, G; Wilkens, J J

    2014-05-01

    Suitable instrumentation for laser-accelerated proton (ion) beams is critical for development of integrated, laser-driven ion accelerator systems. Instrumentation aimed at beam diagnostics and control must be applied to the driving laser pulse, the laser-plasma that forms at the target and the emergent proton (ion) bunch in a correlated way to develop these novel accelerators. This report is a brief overview of established diagnostic techniques and new developments based on material presented at the first workshop on 'Instrumentation for Diagnostics and Control of Laser-accelerated Proton (Ion) Beams' in Abingdon, UK. It includes radiochromic film (RCF), image plates (IP), micro-channel plates (MCP), Thomson spectrometers, prompt inline scintillators, time and space-resolved interferometry (TASRI) and nuclear activation schemes. Repetition-rated instrumentation requirements for target metrology are also addressed.

  7. Characterization of Hundreds of MeV 7Li(p,n) Quasi-Monoenergetic Neutron Source at RCNP Using a Proton Recoil Telescope and TOF Technique

    NASA Astrophysics Data System (ADS)

    Hagiwara, Masayuki; Iwamoto, Yosuke; Iwase, Hiroshi; Yashima, Hiroshi; Satoh, Daiki; Matsumoto, Tetsuro; Masuda, Akihiko; Nakane, Yoshihiro; Tamii, Atsushi; Shima, Tatsushi; Hatanaka, Kichiji; Nakamura, Takashi

    The peak neutron fluence of a quasi-monoenergetic 7Li(p,n) neutron source at RCNP of Osaka University have been measured for four incident proton energies between 100 and 300 MeV, using a proton recoil telescope (PRT) with event selection by a time-of-flight technique. We deduced the cross section of the peak neutron production reaction, 7Li(p,n0,1)7Be, at 0° and compared with that previously obtained with a time-of-flight (TOF) method employing an organic liquid scintillator. The results obtained with different methods are in agreement within their uncertainties and generally consistent with the other experimental data in several hundreds of MeV region.

  8. The Relationship Between CME Properties in the CDAW, CACTUS and SEEDS Catalogs and ?25 MeV Solar Proton Event Intensities

    NASA Astrophysics Data System (ADS)

    Richardson, I. G.; von Rosenvinge, T. T.; Cane, H. V.

    2013-12-01

    The existence of a correlation between the intensity of solar energetic proton (SEP) events and the speed of the associated coronal mass ejection near the Sun is well known, and is often interpreted as evidence for particle acceleration at CME-driven shocks. However, this correlation is far from perfect and might be improved by taking other parameters into consideration (e.g., CME width). In studies of cycle 23 SEP events, values of CME speed, width and other parameters were typically taken from the CDAWWeb LASCO CME catalog. This is compiled 'by hand' from examination of LASCO images by experienced observers. Other automated LASCO CME catalogs have now been developed, e.g., CACTUS (Royal Observatory of Belgium) and SEEDS (George Mason University), but the basic CME parameters do not always agree with those from the CDAWweb catalog since they are not determined in the same way. For example the 'CME speed' might be measured at a specific position angle against the plane of the sky in one catalog, or be the average of speeds taken along the CME front in another. Speeds may also be based on linear or higher order fits to the coronagraph images. There will also be projection effects in these plane of the sky speeds. Similarly, CME widths can vary between catalogs and are dependent on how they are defined. For example, the CDAW catalog lists any CME that surrounds the occulting disk as a 'halo' (360 deg. width) CME even though the CME may be highly-asymmetric and originate from a solar event far from central meridian. Another catalog may give a smaller width for the same CME. The problem of obtaining the 'true' CME width is especially acute for assessing the relationship between CME width and SEP properties when using the CDAW catalog since a significant fraction, if not the majority, of the CMEs associated with major SEP events are reported to be halo CMEs. In principle, observations of CMEs from the STEREO A and B spacecraft, launched in late 2006, might be used to

  9. Design of a proton microbeam of the PEFP

    SciTech Connect

    Kim, Kye Ryung; Kim, Yong Hwan; Chang, Ji Ho; Kim, Kui Young

    2008-02-15

    The PEFP has been developing a 100 MeV proton linear accelerator and user facilities for 20 and 100 MeV proton beams. At one end of the five 20 MeV proton beam lines, a proton microbeam construction was considered for an application in the fields of material, biological, and medical sciences. To develop the proton microbeam, realization of a few MeV proton beam with a few tens of microamperes in diameter of a beam spot was essentially required. In this report, the basic descriptions of the proton microbeam which is composed of an energy degrader, slits, magnetic lens, a target chamber, and detectors are presented including a consideration of unfavorable aspects concerning some specific characteristics of a linear accelerator, such as pulse mode operation and fixed energy. Some calculation results from a Monte Carlo simulation by using the SRIM2006 and the TURTLE codes are also included.

  10. Design of a proton microbeam of the PEFPa)

    NASA Astrophysics Data System (ADS)

    Kim, Kye Ryung; Kim, Yong Hwan; Chang, Ji Ho; Kim, Kui Young

    2008-02-01

    The PEFP has been developing a 100MeV proton linear accelerator and user facilities for 20 and 100MeV proton beams. At one end of the five 20MeV proton beam lines, a proton microbeam construction was considered for an application in the fields of material, biological, and medical sciences. To develop the proton microbeam, realization of a few MeV proton beam with a few tens of microamperes in diameter of a beam spot was essentially required. In this report, the basic descriptions of the proton microbeam which is composed of an energy degrader, slits, magnetic lens, a target chamber, and detectors are presented including a consideration of unfavorable aspects concerning some specific characteristics of a linear accelerator, such as pulse mode operation and fixed energy. Some calculation results from a Monte Carlo simulation by using the SRIM2006 and the TURTLE codes are also included.

  11. Inelastic scattering of 65 MeV protons from /sup 12/C, /sup 24/Mg, /sup 28/Si, and /sup 32/S

    SciTech Connect

    Kato, S.; Okada, K.; Kondo, M.; Hosono, K.; Saito, T.; Matsuoka, N.; Hatanaka, K.; Noro, T.; Nagamachi, S.; Shimizu, H.; Ogino, K.; Kadota, Y.; Matsuki, S.; Wakai, M.

    1985-05-01

    Measurements of angular distributions of the cross sections and analyzing powers for the elastic and inelastic scatterings of 65 MeV polarized protons from /sup 12/C, /sup 24/Mg, /sup 28/Si, and /sup 32/S are reported. Coupled channels analyses of the scattering data are presented assuming the 0/sub 1//sup +/, 2/sub 1//sup +/, and 4/sub 1//sup +/ states to be members of the ground band, the 0/sub 2//sup +/ state to begin the

  12. Radiation Tolerance Characterization of Dual Band InAs/GaSb Type-II Strain-Layer Superlattice pBp Detectors Using 63 MeV Protons

    DTIC Science & Technology

    2012-01-01

    films J. Appl. Phys. 112, 073718 (2012) Additional information on Appl. Phys. Lett. Journal Homepage: http://apl.aip.org/ Journal Information...considered for space applications due to their relative advantage in manu- facturability, compared with conventional mercury -cadmium- telluride (MCT) IR...preliminary 1–2 MeV proton irradiation studies of Sb -based T2SLS photodiodes where the detectors were unbiased and at 300 K during irradiation, which

  13. Experimental investigation of picosecond dynamics following interactions between laser accelerated protons and water

    NASA Astrophysics Data System (ADS)

    Senje, L.; Coughlan, M.; Jung, D.; Taylor, M.; Nersisyan, G.; Riley, D.; Lewis, C. L. S.; Lundh, O.; Wahlström, C.-G.; Zepf, M.; Dromey, B.

    2017-03-01

    We report direct experimental measurements with picosecond time resolution of how high energy protons interact with water at extreme dose levels (kGy), delivered in a single pulse with the duration of less than 80 ps. The unique synchronisation possibilities of laser accelerated protons with an optical probe pulse were utilized to investigate the energy deposition of fast protons in water on a time scale down to only a few picoseconds. This was measured using absorbance changes in the water, induced by a population of solvated electrons created in the tracks of the high energy protons. Our results indicate that for sufficiently high doses delivered in short pulses, intertrack effects will affect the yield of solvated electrons. The experimental scheme allows for investigation of the ultrafast mechanisms occurring in proton water radiolysis, an area of physics especially important due to its relevance in biology and for proton therapy.

  14. Characteristics of electron beams from a new 25-MeV linear accelerator.

    PubMed

    O'Brien, P; Michaels, H B; Aldrich, J E; Andrew, J W

    1985-01-01

    Clinically useful electron fields are produced on the Atomic Energy of Canada, Limited Therac 25 linear accelerator by computer-controlled scanning of the electron beam. Measurements were made to determine the properties of these electron fields. Central axis percentage depth dose and bremsstrahlung background were compared for these fields and for the fields from selected machines that use scattering foils. Dose calibrations were made in both water and polystyrene using the American Association of Physicists in Medicine Task Group 21 protocol. Measurements were made to determine the relative output factors, virtual source position, and the attenuation of the electron fields by lead.

  15. Characteristics of electron beams from a new 25-MeV linear accelerator

    SciTech Connect

    O'Brien, P.; Michaels, H.B.; Aldrich, J.E.; Andrew, J.W.

    1985-11-01

    Clinically useful electron fields are produced on the Atomic Energy of Canada, Limited Therac 25 linear accelerator by computer-controlled scanning of the electron beam. Measurements were made to determine the properties of these electron fields. Central axis percentage depth dose and bremsstrahlung background were compared for these fields and for the fields from selected machines that use scattering foils. Dose calibrations were made in both water and polystyrene using the American Association of Physicists in Medicine Task Group 21 protocol. Measurements were made to determine the relative output factors, virtual source position, and the attenuation of the electron fields by lead.

  16. Transforming in-situ observations of CME-driven shock accelerated protons into the shock's reference frame.

    NASA Astrophysics Data System (ADS)

    Robinson, I. M.; Simnett, G. M.

    2005-07-01

    We examine the solar energetic particle event following solar activity from 14, 15 April 2001 which includes a "bump-on-the-tail" in the proton energy spectra at 0.99 AU from the Sun. We find this population was generated by a CME-driven shock which arrived at 0.99 AU around midnight 18 April. As such this population represents an excellent opportunity to study in isolation, the effects of proton acceleration by the shock. The peak energy of the bump-on-the-tail evolves to progressively lower energies as the shock approaches the observing spacecraft at the inner Lagrange point. Focusing on the evolution of this peak energy we demonstrate a technique which transforms these in-situ spectral observations into a frame of reference co-moving with the shock whilst making allowance for the effects of pitch angle scattering and focusing. The results of this transform suggest the bump-on-the-tail population was not driven by the 15 April activity but was generated or at least modulated by a CME-driven shock which left the Sun on 14 April. The existence of a bump-on-the-tail population is predicted by models in Rice et al. (2003) and Li et al. (2003) which we compare with observations and the results of our analysis in the context of both the 14 April and 15 April CMEs. We find an origin of the bump-on-the-tail at the 14 April CME-driven shock provides better agreement with these modelled predictions although some discrepancy exists as to the shock's ability to accelerate 100 MeV protons. Keywords. Solar physics, astrophysics and astronomy (Energetic particles; Flares and mass ejections) Space plasma physics (Transport processes)

  17. Proton and heavy ion acceleration facilities for space radiation research

    NASA Technical Reports Server (NTRS)

    Miller, Jack

    2003-01-01

    The particles and energies commonly used for medium energy nuclear physics and heavy charged particle radiobiology and radiotherapy at particle accelerators are in the charge and energy range of greatest interest for space radiation health. In this article we survey some of the particle accelerator facilities in the United States and around the world that are being used for space radiation health and related research, and illustrate some of their capabilities with discussions of selected accelerator experiments applicable to the human exploration of space.

  18. Search for narrow structure in proton-antiproton annihilation cross sections from 1900 to 1960 MeV

    SciTech Connect

    Lowenstein, D.I.; Pealsee, D.C.; Miller, R.J.; Lewis, R.A.; Oh, B.Y.; Smith, G.A.; Whitmore, J.; Brando, T.; Daftari, I.; deGuzman, A.

    1985-01-01

    The anti pp annihilation cross section has been measured with good resolution (approx.2 MeV rms) in the mass range 1900-1960 MeV. No narrow structures are seen, the 90% confidence level upper limit being 8-12 mb-MeV for the integrated area of a resonance in this mass range. However, we do not rule out a very narrow bump-dip structure seen in an earlier experiment in the 1935-1941 MeV mass interval. The data also do not support the existence of a broad structure previously reported at 1937 MeV.

  19. Electron Acceleration beyond 200 MeV in Underdense Plasmas using Table Top Laser Systems

    NASA Astrophysics Data System (ADS)

    Fritzler, S.; Malka, V.; Lefebvre, E.; Aleonard, M.-M.; Burgy, F.; Chambaret, J.-P.; Chemin, J.-F.; Krushelnick, K.; Malka, G.; Mangles, S. P. D.; Najmudin, Z.; Rousseau, J.-P.; Scheurer, J.-N.; Walton, B.; Dangor, A. E.

    2002-12-01

    In this article we present electron acceleration by the interaction of a multi-TW, high repetition rate, table top laser at moderate intensity with an underdense plasma. We optimized this unique electron source in terms of the energy as well as the quality of the generated electron beam. The plasma period was chosen to be of the order of the laser pulse duration by adapting the plasma electron density. The waist of the laser focal spot was chosen to be larger than typical for comparable experiments. As a result, a very energetic, well-collimated, and bright electron beam was generated, which has the highest energy ever produced by laser-plasma interactions.

  20. Measurements of proton induced γ-ray emission cross-sections on Mg from 1.0 to 3.0 MeV

    NASA Astrophysics Data System (ADS)

    Sharifzadeh, N.; Kakuee, O.; Mohammadi, S.

    2016-04-01

    Differential cross-section of proton induced γ-ray emission from the reactions 24Mg(p,p‧γ)24Mg (Eγ = 1369 keV), 25Mg(p,p‧γ)25Mg (Eγ = 390, 585, 975 keV) and 26Mg(p,γ)27Al (Eγ = 1014 keV) were measured for proton energies from 1 to 3 MeV using a 60 μg/cm2 Mg target evaporated on a 40 μg/cm2 Ag thin film. The γ-rays were collected by a 50% relative efficiency HPGe detector placed at an angle of 90° with respect to the beam direction, while the backscattered protons were collected by an ion implanted Si detector placed at a scattering angle of 165°. Simultaneous collection of γ-ray and RBS spectra is a great advantage of this approach which makes differential cross-section measurements independent on the collected beam charge. Measured cross-section values were compared with the previously reported data in the literature. Absolute γ-ray differential cross-sections were obtained with an overall systematic uncertainty of about ±6% and statistical uncertainty of less than ±5% for proton energies higher than 2.24 MeV.

  1. Efficient laser-proton acceleration from an insulating foil with an attached small metal disk

    SciTech Connect

    Otani, Kazuto; Tokita, Shigeki; Nishoji, Toshihiko; Inoue, Shunsuke; Hashida, Masaki; Sakabe, Shuji

    2011-10-17

    Efficient proton acceleration by the interaction of an intense femtosecond laser pulse with a solid foil has been demonstrated. An aluminum coating (thickness: 0.2 {mu}m) on a polyethylene (PE) foil was irradiated at 2 x 10{sup 18} W/cm{sup 2} intensity. The protons from the aluminum-disk (diameter: 150 {mu}m to 15 mm) foil were accelerated to much higher energy in comparison with conventional targets such as PE and aluminum-coated PE foils. The fast electron signal along the foil surface was significantly higher from the aluminum-coated PE foil. The laser-proton acceleration appeared to be affected to the size of surrounding conductive material.

  2. Mass Limited Target Effects on Proton Acceleration with Femtosecond Laser Plasma Interactions

    NASA Astrophysics Data System (ADS)

    Zulick, Calvin; Raymond, A.; McKelvey, A.; Willingale, L.; Chvykov, V.; Maksimchuk, A.; Thomas, A. G. R.; Yanovsky, V.; Krushelnick, K.

    2014-10-01

    Experiments at the HERCULES laser facility have been performed to measure the effect of reduced mass targets on proton acceleration through the use of foil, grid, and wire targets in femtosecond laser plasma interactions. The target thickness was held approximately constant at 12 . 5 μm, while the lateral extent of the target was varied. The electron current density was measured with an imaging Cu Kα crystal. Higher current densities were observed as the target mass was reduced which corresponded to an increase in the temperature of the accelerated proton beam. Additionally, a line focusing feature was observed in the spatial distribution of protons accelerated to from the wire target, believed to be a result of azimuthal magnetic fields generated by electron currents in the wire. Particle-in-cell and Vlasov-Fokker-Plank simulations were performed in order to investigate the focusing magnetic field as well as the complex sheath formation dynamics on the mesh target.

  3. Investigation of the stability and 1.0 MeV proton radiation resistance of commercially produced hydrogenated amorphous silicon alloy solar cells

    NASA Technical Reports Server (NTRS)

    Lord, Kenneth R., II; Walters, Michael R.; Woodyard, James R.

    1994-01-01

    The radiation resistance of commercial solar cells fabricated from hydrogenated amorphous silicon alloys is reported. A number of different device structures were irradiated with 1.0 MeV protons. The cells were annealing at 200 C. The annealing time was dependent on proton fluence. Annealing devices for one hour restores cell parameters or fluences below 1(exp 14) cm(exp -2); fluences above 1(exp 14) cm(exp -2) require longer annealing times. A parametric fitting model was used to characterize current mechanisms observed in dark I-V measurements. The current mechanisms were explored with irradiation fluence, and voltage and light soaking times. The thermal generation current density and quality factor increased with proton fluence. Device simulation shows the degradation in cell characteristics may be explained by the reduction of the electric field in the intrinsic layer.

  4. Determination of electron beam output factors for a 20-MeV linear accelerator

    SciTech Connect

    Mills, M.D.; Hogstrom, K.R.; Fields, R.S.

    1985-07-01

    The demands of a busy clinic require that basic machine calculations be performed as accurately, rapidly, and simply as possible. For the electron beam of the Therac 20 Saturne linear accelerator, a method suitable for a programmable calculator is described to predict the dose output from the measurement of selected fields. One-dimensional output factors were measured; these are defined as output factors of rectangular fields where one side is always equal to the side of the square reference field. The output of an arbitrary rectangular field X, Y is given by the product of the output factors OF(X,Y) = OF(X,10) x OF(10,Y), where 10 is the side of the square reference field. The measured data indicate that the output of very large rectangular and square fields is underestimated using this method for the lower energies. A correction factor of the form CF = C x ((X-10)(Y-10)/Vertical Bar(X-10)(Y-10)Vertical Bar/sup 1//sup ///sup 2/) results in agreement with measured data to within 1.5% for all energies.

  5. Determination of electron beam output factors for a 20-MeV linear accelerator.

    PubMed

    Mills, M D; Hogstrom, K R; Fields, R S

    1985-01-01

    The demands of a busy clinic require that basic machine calculations be performed as accurately, rapidly, and simply as possible. For the electron beam of the Therac 20 Saturne linear accelerator, a method suitable for a programmable calculator is described to predict the dose output from the measurement of selected fields. One-dimensional output factors were measured; these are defined as output factors of rectangular fields where one side is always equal to the side of the square reference field. The output of an arbitrary rectangular field X, Y is given by the product of the output factors OF(X,Y) = OF(X,10) X OF(10,Y), where 10 is the side of the square reference field. The measured data indicate that the output of very large rectangular and square fields is underestimated using this method for the lower energies. A correction factor of the form CF = C X [(X - 10)(Y - 10)/(X - 10)(Y - 10) 1/2] results in agreement with measured data to within 1.5% for all energies.

  6. Di-proton decay of the 6.15 MeV 1- state in 18Ne

    NASA Astrophysics Data System (ADS)

    Brown, B. A.; Barker, F. C.; Millener, D. J.

    2002-05-01

    The widths for one- and two-proton decay of the 1-2 state in 18Ne are calculated. Shell-model wave functions are used to obtain the spectroscopic factors. The R-matrix theory of Barker which incorporates the final-state interaction between the two protons is used for the di-proton decay model. The calculated widths for both one- and two-proton decay are in qualitative agreement with experiment. We find that the decay width for sequential two-proton decay through the ghost of the 1/2+ bound state in 17F is comparable to the width of the direct di-proton decay.

  7. Cross Sections for the Production of Cosmogenic Nuclides with Protons up to 400 MeV for the Interpretation of Cosmic-Ray-produced Nuclides

    NASA Astrophysics Data System (ADS)

    Schiekel, Th.; Rosel, R.; Herpers, U.; Bodemann, R.; Leya, I.; Gloris, M.; Michel, R.; Dittrich, B.; Kubik, P.; Suter, M.

    1993-07-01

    Integral excitation functions of the cosmogenic nuclides are the basic requirement for the interpretation of interactions between cosmic ray particles and extraterrestrial and terrestrial matter. Together with the knowledge of primary and secondary particle fields inside an irradiated body, model calculations can be developed to interpret abundances of cosmogenic nuclides in dependencies of the irradiation history of the irradiated body and of the cosmic particle ray itself. The quality of those model calculations depends on the quality of the available cross-section database, which is neither comprehensive nor reliable for the most important nuclides like the long-lived radionuclides (i.e., 10Be, 26Al, 36Cl, 41Ca) and the stable rare gas isotopes. For a systematic investigation in this field of science we carried out several irradiation experiments with protons in the energy region between 45 MeV and 400 MeV at the Paul Scherrer Institut (Villigen, Switzerland) and the Laboratoire Nationale Saturne (Saclay, France) using the stacked foil technique. We included 21 different target elements with Z between 6 and 79 (C, N as Si3N4, O as SiO2, Mg, Al, Si, Ca as CaC2H2O4, Ti, V, Mn as Mn/Ni alloy, Fe, Co, Ni, Cu, Sr as SrF2, Y, Zr, Nb, Rh, Ba as Ba containing glass and Au) in our experiments. The proton fluxes were monitored via the reaction 27Al(p,3p3n)22Na using the evaluated data of [1]. Residual nuclides were measured by X-, gamma-, and after a chemical separation by accelerator mass spectrometry. In order to check the quality of our experimental procedures we included some target elements in our new experiments for which consistent excitation functions have already been determined [2,3,4]. Our new data show excellent agreement with the earlier measurements. We measured cross sections for more than 120 different reactions. Here we report on the results for target elements with Z up to 28. The exsisting database of experimental excitation functions for the production

  8. Response of human lymphocytes to proton radiation of 60 MeV compared to 250 kV X-rays by the cytokinesis-block micronucleus assay.

    PubMed

    Miszczyk, Justyna; Rawojć, Kamila; Panek, Agnieszka; Swakoń, Jan; Prasanna, Pataje G; Rydygier, Marzena

    2015-04-01

    Particle radiotherapy such as protons provides a new promising treatment modality to cancer. However, studies on its efficacy and risks are relatively sparse. Using the cytokinesis-blocked micronucleus assay, we characterized response of human peripheral blood lymphocytes, obtained from health donors irradiated in vitro in the dose range: 0-4. 0 Gy, to therapeutic proton radiation of 60 MeV from AIC-144 isochronous cyclotron, by studying nuclear division index and DNA damage and compared them with X-rays. Peripheral blood lymphocytes show decreased ability to proliferate with increasing radiation doses for both radiation types, however, in contrast to X-rays, irradiation with protons resulted in a higher proliferation index at lower doses of 0.75 and 1.0 Gy. Protons are more effective in producing MN at doses above 1.75 Gy compared to X-rays. Dose-response curves for micronucleus incidence can be best described by a cubic model for protons, while for X-rays the response was linear. The differences in the energy spectrum and intracellular distribution of energy between radiation types are also apparent at the intracellular distribution of cytogenetic damage as seen by the distribution of various numbers of micronuclei in binucleated cells. Our studies, although preliminary, further contribute to the understanding of the mechanistic differences in the response of HPBL in terms of cellular proliferation and cytogenetic damage induced by protons and X-rays as well as intra-cellular distribution of energy and thus radiobiological effectiveness.

  9. Laser accelerated protons captured and transported by a pulse power solenoid

    NASA Astrophysics Data System (ADS)

    Burris-Mog, T.; Harres, K.; Nürnberg, F.; Busold, S.; Bussmann, M.; Deppert, O.; Hoffmeister, G.; Joost, M.; Sobiella, M.; Tauschwitz, A.; Zielbauer, B.; Bagnoud, V.; Herrmannsdoerfer, T.; Roth, M.; Cowan, T. E.

    2011-12-01

    Using a pulse power solenoid, we demonstrate efficient capture of laser accelerated proton beams and the ability to control their large divergence angles and broad energy range. Simulations using measured data for the input parameters give inference into the phase-space and transport efficiencies of the captured proton beams. We conclude with results from a feasibility study of a pulse power compact achromatic gantry concept. Using a scaled target normal sheath acceleration spectrum, we present simulation results of the available spectrum after transport through the gantry.

  10. SOLAR INTERACTING PROTONS VERSUS INTERPLANETARY PROTONS IN THE CORE PLUS HALO MODEL OF DIFFUSIVE SHOCK ACCELERATION AND STOCHASTIC RE-ACCELERATION

    SciTech Connect

    Kocharov, L.; Laitinen, T.; Vainio, R.; Afanasiev, A.; Mursula, K.; Ryan, J. M.

    2015-06-10

    With the first observations of solar γ-rays from the decay of pions, the relationship of protons producing ground level enhancements (GLEs) on the Earth to those of similar energies producing the γ-rays on the Sun has been debated. These two populations may be either independent and simply coincident in large flares, or they may be, in fact, the same population stemming from a single accelerating agent and jointly distributed at the Sun and also in space. Assuming the latter, we model a scenario in which particles are accelerated near the Sun in a shock wave with a fraction transported back to the solar surface to radiate, while the remainder is detected at Earth in the form of a GLE. Interplanetary ions versus ions interacting at the Sun are studied for a spherical shock wave propagating in a radial magnetic field through a highly turbulent radial ray (the acceleration core) and surrounding weakly turbulent sector in which the accelerated particles can propagate toward or away from the Sun. The model presented here accounts for both the first-order Fermi acceleration at the shock front and the second-order, stochastic re-acceleration by the turbulence enhanced behind the shock. We find that the re-acceleration is important in generating the γ-radiation and we also find that up to 10% of the particle population can find its way to the Sun as compared to particles escaping to the interplanetary space.

  11. The effects of 800 MeV proton irradiation on the corrosion of tungsten, tantalum, stainless steel, and gold

    SciTech Connect

    Lillard, R.S.; Butt, D.P.; Kanner, G.; Daemen, L.

    1997-12-01

    Real time electrochemical data were acquired for tungsten, tantalum, stainless steel 304L, and gold targets during proton irradiation at the LANSCE Weapons Neutron Research Facility. The goal of this research was to establish a better understanding of the corrosion properties of materials as a function of proton irradiation and gain insight into the mechanism of the observed phenomena. The following electrochemical observations were made during proton irradiation of W, Ta, SS304, and Au: (1) the open circuit potential of all materials increased with increasing proton fluence; (2) the corrosion rate (at the OCP) of W and SS304 increased with increasing proton fluence; (3) the passive dissolution rate for SS304 and Ta decreased with increasing proton fluence; (4) the anodic dissolution rate for W increased with increasing proton fluence; (5) the pitting potential for SS304 increased with proton fluence, which is an indication that the material is less susceptible to pitting attack during irradiation.

  12. Cross sections for proton induced high energy γ -ray emission (PIGE) in reaction 19 F(p, αγ)16 O at incident proton energies between 1.5 and 4 MeV

    NASA Astrophysics Data System (ADS)

    Cabanelas, P.; Cruz, J.; Fonseca, M.; Henriques, A.; Lourenço, F.; Luís, H.; Machado, J.; Pires Ribeiro, J.; Sánchez-Benítez, A. M.; Teubig, P.; Velho, P.; Zarza-Moreno, M.; Galaviz, D.; Jesus, A. P.

    2016-08-01

    We have studied the high energy gamma-rays produced in the reaction 19 F(p, αγ)16 O for incident proton energies from 1.5 to 4.0 MeV over NaF/Ag and CaF2/Ag thin targets in two different sets of data. Gamma-rays were detected with a High Purity Ge detector with an angle of 130° with respect to the beam axis. The cross-sections for the high energy gamma-rays of 6.129, 6.915 and 7.115 MeV have been measured for the whole group between 5 and 7.2 MeV with accuracy better than 10%. A new energy range was covered and more points are included in the cross-sections data base expanding the existing set of data. Results are in agreement with previous measurements in similar conditions.

  13. Ultra-short laser-accelerated proton pulses have similar DNA-damaging effectiveness but produce less immediate nitroxidative stress than conventional proton beams

    NASA Astrophysics Data System (ADS)

    Raschke, S.; Spickermann, S.; Toncian, T.; Swantusch, M.; Boeker, J.; Giesen, U.; Iliakis, G.; Willi, O.; Boege, F.

    2016-08-01

    Ultra-short proton pulses originating from laser-plasma accelerators can provide instantaneous dose rates at least 107-fold in excess of conventional, continuous proton beams. The impact of such extremely high proton dose rates on A549 human lung cancer cells was compared with conventionally accelerated protons and 90 keV X-rays. Between 0.2 and 2 Gy, the yield of DNA double strand breaks (foci of phosphorylated histone H2AX) was not significantly different between the two proton sources or proton irradiation and X-rays. Protein nitroxidation after 1 h judged by 3-nitrotyrosine generation was 2.5 and 5-fold higher in response to conventionally accelerated protons compared to laser-driven protons and X-rays, respectively. This difference was significant (p < 0.01) between 0.25 and 1 Gy. In conclusion, ultra-short proton pulses originating from laser-plasma accelerators have a similar DNA damaging potential as conventional proton beams, while inducing less immediate nitroxidative stress, which probably entails a distinct therapeutic potential.

  14. Ultra-short laser-accelerated proton pulses have similar DNA-damaging effectiveness but produce less immediate nitroxidative stress than conventional proton beams

    PubMed Central

    Raschke, S.; Spickermann, S.; Toncian, T.; Swantusch, M.; Boeker, J.; Giesen, U.; Iliakis, G.; Willi, O.; Boege, F.

    2016-01-01

    Ultra-short proton pulses originating from laser-plasma accelerators can provide instantaneous dose rates at least 107-fold in excess of conventional, continuous proton beams. The impact of such extremely high proton dose rates on A549 human lung cancer cells was compared with conventionally accelerated protons and 90 keV X-rays. Between 0.2 and 2 Gy, the yield of DNA double strand breaks (foci of phosphorylated histone H2AX) was not significantly different between the two proton sources or proton irradiation and X-rays. Protein nitroxidation after 1 h judged by 3-nitrotyrosine generation was 2.5 and 5-fold higher in response to conventionally accelerated protons compared to laser-driven protons and X-rays, respectively. This difference was significant (p < 0.01) between 0.25 and 1 Gy. In conclusion, ultra-short proton pulses originating from laser-plasma accelerators have a similar DNA damaging potential as conventional proton beams, while inducing less immediate nitroxidative stress, which probably entails a distinct therapeutic potential. PMID:27578260

  15. γ strength function and level density of 208Pb from forward-angle proton scattering at 295 MeV

    NASA Astrophysics Data System (ADS)

    Bassauer, S.; von Neumann-Cosel, P.; Tamii, A.

    2016-11-01

    Background: γ strength functions (GSFs) and level densities (LDs) are essential ingredients of statistical nuclear reaction theory with many applications in astrophysics, reactor design, and waste transmutation. Purpose: The aim of the present work is a test of systematic parametrizations of the GSF recommended by the RIPL-3 database for the case of 208Pb. The upward GSF and LD in 208Pb are compared to γ decay data from an Oslo-type experiment to examine the validity of the Brink-Axel (BA) hypothesis. Methods: The E 1 and M1 parts of the total GSF are determined from high-resolution forward angle inelastic proton scattering data taken at 295 MeV at the Research Center for Nuclear Physics (RCNP), Osaka, Japan. The total LD in 208Pb is derived from the 1- LD extracted with a fluctuation analysis in the energy region of the isovector giant dipole resonance. Results: The E 1 GSF is compared to parametrizations recommended by the RIPL-3 database showing systematic deficiencies of all models in the energy region around neutron threshold. The new data for the poorly known spin-flip M 1 resonance call for a substantial revision of the model suggested in RIPL-3. The total GSF derived from the present data is larger in the PDR energy region than the Oslo data but the strong fluctuations due to the low LD resulting from the double shell closure of 208Pb prevent a conclusion on a possible violation of the BA hypothesis. Using the parameters suggested by RIPL-3 for a description of the LD in 208Pb with the back-shifted Fermi gas model, remarkable agreement between the two experiments spanning a wide excitation energy range is obtained. Conclusions: Systematic parametrizations of the E 1 and M 1 GSF parts need to be reconsidered at low excitation energies. The good agreement of the LD provides an independent confirmation of the approach underlying the decomposition of GSF and LD in Oslo-type experiments.

  16. High-energy gamma-ray emission from solar flares: Constraining the accelerated proton spectrum

    NASA Technical Reports Server (NTRS)

    Alexander, David; Dunphy, Philip P.; Mackinnon, Alexander L.

    1994-01-01

    Using a multi-component model to describe the gamma-ray emission, we investigate the flares of December 16, 1988 and March 6, 1989 which exhibited unambiguous evidence of neutral pion decay. The observations are then combined with theoretical calculations of pion production to constrain the accelerated proton spectra. The detection of pi(sup 0) emission alone can indicate much about the energy distribution and spectral variation of the protons accelerated to pion producing energies. Here both the intensity and detailed spectral shape of the Doppler-broadened pi(sup 0) decay feature are used to determine the spectral form of the accelerated proton energy distribution. The Doppler width of this gamma-ray emission provides a unique diagnostic of the spectral shape at high energies, independent of any normalisation. To our knowledge, this is the first time that this diagnostic has been used to constrain the proton spectra. The form of the energetic proton distribution is found to be severely limited by the observed intensity and Doppler width of the pi(sup 0) decay emission, demonstrating effectively the diagnostic capabilities of the pi(sup 0) decay gamma-rays. The spectral index derived from the gamma-ray intensity is found to be much harder than that derived from the Doppler width. To reconcile this apparent discrepancy we investigate the effects of introducing a high-energy cut-off in the accelerated proton distribution. With cut-off energies of around 0.5-0.8 GeV and relatively hard spectra, the observed intensities and broadening can be reproduced with a single energetic proton distribution above the pion production threshold.

  17. Compact Dielectric Wall Accelerator Development For Intensity Modulated Proton Therapy And Homeland Security Applications

    SciTech Connect

    Chen, Y -; Caporaso, G J; Guethlein, G; Sampayan, S; Akana, G; Anaya, R; Blackfield, D; Cook, E; Falabella, S; Gower, E; Harris, J; Hawkins, S; Hickman, B; Holmes, C; Horner, A; Nelson, S; Paul, A; Pearson, D; Poole, B; Richardson, R; Sanders, D; Stanley, J; Sullivan, J; Wang, L; Watson, J; Weir, J

    2009-06-17

    Compact dielectric wall (DWA) accelerator technology is being developed at the Lawrence Livermore National Laboratory. The DWA accelerator uses fast switched high voltage transmission lines to generate pulsed electric fields on the inside of a high gradient insulating (HGI) acceleration tube. Its high electric field gradients are achieved by the use of alternating insulators and conductors and short pulse times. The DWA concept can be applied to accelerate charge particle beams with any charge to mass ratio and energy. Based on the DWA system, a novel compact proton therapy accelerator is being developed. This proton therapy system will produce individual pulses that can be varied in intensity, energy and spot width. The system will be capable of being sited in a conventional linac vault and provide intensity modulated rotational therapy. The status of the developmental new technologies that make the compact system possible will be reviewed. These include, high gradient vacuum insulators, solid dielectric materials, SiC photoconductive switches and compact proton sources. Applications of the DWA accelerator to problems in homeland security will also be discussed.

  18. Physics of Double Pulse Irradiation of Targets For Proton Acceleration

    NASA Astrophysics Data System (ADS)

    Kerr, S.; Mo, M.; Masud, R.; Manzoor, L.; Tiedje, H.; Tsui, Y.; Fedosejevs, R.; Link, A.; Patel, P.; McLean, H.; Hazi, A.; Chen, H.; Ceurvorst, L.; Norreys, P.

    2016-10-01

    Experiments have been carried out on double-pulse irradiation of um-scale foil targets with varying preplasma conditions. Our experiment at the Titan Laser facility utilized two 700 fs, 1054 nm pulses, separated by 1 to 5 ps with a total energy of 100 J, and with 5-20% of the total energy contained within the first pulse. The proton spectra were measured with radiochromic film stacks and magnetic spectrometers. The prepulse energy was on the order of 10 mJ, which appears to have a moderating effect on the double pulse enhancement of proton beam. We have performed LSP PIC simulations to understand the double pulse enhancement mechanism, as well as the role of preplasma in modifying the interaction. A 1D parameter study was done to isolate various aspects of the interaction, while 2D simulations provide more detailed physical insight and a better comparison with experimental data. Work by the Univ. of Alberta was supported by the Natural Sciences and Engineering Research Council of Canada. Work by LLNL was performed under the auspices of U.S. DOE under contract DE-AC52-07NA27344.

  19. Simulation of Electron Beam Dynamics in the 22 MeV Accelerator for a Coherent Electron Cooling Proof of Principle Experiment

    SciTech Connect

    Owen, Justin

    2013-12-01

    Coherent electron cooling (CeC) offers a potential new method of cooling hadron beams in colliders such as the Relativistic Heavy Ion Collider (RHIC) or the future electron ion collider eRHIC. A 22 MeV linear accelerator is currently being built as part of a proof of principle experiment for CeC at Brookhaven National Laboratory (BNL). In this thesis we present a simulation of electron beam dynamics including space charge in the 22 MeV CeC proof of principle experiment using the program ASTRA (A Space charge TRacking Algorithm).

  20. Physics with a high-intensity proton accelerator below 30 GeV

    SciTech Connect

    Hoffman, C.M.

    1982-01-01

    The types of physics that would be pursued at a high-intensity, moderate-energy proton accelerator are discussed. The discussion is drawn from the deliberations of the 30-GeV subgroup of the Fixed-Target Group at this workshop.

  1. History of the ZGS 500 MeV booster.

    SciTech Connect

    Simpson, J.; Martin; R.; Kustom, R.

    2006-05-09

    The history of the design and construction of the Argonne 500 MeV booster proton synchrotron from 1969 to 1982 is described. This accelerator has since been in steady use for the past 25 years to power the Argonne Intense Pulsed Neutron Source (IPNS).

  2. Polarized Proton Acceleration in the AGS with Two Helical Partial Snakes

    NASA Astrophysics Data System (ADS)

    Huang, H.; Ahrens, L. A.; Bai, M.; Bravar, A.; Brown, K.; Courant, E. D.; Gardner, C.; Glenn, J. W.; Lin, F.; Luccio, A. U.; MacKay, W. W.; Okamura, M.; Ptitsyn, V.; Roser, T.; Takano, J.; Tepikian, S.; Tsoupas, N.; Wood, J.; Yip, K.; Zelenski, A.; Zeno, K.

    2007-06-01

    Acceleration of polarized protons in the energy range of 5 to 25 GeV is particularly difficult: the depolarizing resonances are strong enough to cause significant depolarization but full Siberian snakes cause intolerably large orbit excursions and are not feasible in the AGS since straight sections are too short. Recently, two helical partial snakes have been built and installed in the AGS. With careful setup of optics at injection and along the ramp, this combination can eliminate the intrinsic and imperfection depolarizing resonances encountered during acceleration. This paper presents the accelerator setup and preliminary results.

  3. Polarized Proton Acceleration in the AGS with Two Helical Partial Snakes

    SciTech Connect

    Huang, H.; Ahrens, L. A.; Bai, M.; Bravar, A.; Brown, K.; Courant, E. D.; Gardner, C.; Glenn, J. W.; Luccio, A. U.; MacKay, W. W.; Ptitsyn, V.; Roser, T.; Tepikian, S.; Tsoupas, N.; Wood, J.; Yip, K.; Zelenski, A.; Zeno, K.; Lin, F.; Okamura, M.

    2007-06-13

    Acceleration of polarized protons in the energy range of 5 to 25 GeV is particularly difficult: the depolarizing resonances are strong enough to cause significant depolarization but full Siberian snakes cause intolerably large orbit excursions and are not feasible in the AGS since straight sections are too short. Recently, two helical partial snakes have been built and installed in the AGS. With careful setup of optics at injection and along the ramp, this combination can eliminate the intrinsic and imperfection depolarizing resonances encountered during acceleration. This paper presents the accelerator setup and preliminary results.

  4. ACCELERATION OF POLARIZED PROTONS IN THE AGS WITH TWO HELICAL PARTIAL SNAKES.

    SciTech Connect

    HUANG, H.; AHRENS, L.A.; BAI, M.; BRAVAR, A.; BROWN, K.; COURANT, E.D.; GARDNER, C.; GLENN, J.W.; LUCCIO, A.U.; MACKAY, W.W.; PTITSYN, V.; ROSER, T.; TEPIKIAN, S.; TSOUPAS, N.; WOOD, J.; YIP, K.; ZELENSKI, A.; ZENO, K.

    2006-06-26

    Acceleration of polarized protons in the energy range of 5 to 25 GeV is particularly difficult: the depolarizing resonances are strong enough to cause significant depolarization but full Siberian snakes cause intolerably large orbit excursions and are not feasible in the AGS since straight sections are too short. Recently, two helical partial snakes with double pitch design have been built and installed in the AGS. With careful setup of optics at injection and along the ramp, this combination can eliminate the intrinsic and imperfection depolarizing resonances encountered during acceleration. This paper presents the accelerator setup and preliminary results.

  5. Beam Transport in a Compact Dielectric Wall Accelerator for Proton Therapy

    SciTech Connect

    Chen, Y; Caporaso, G; Blackfield, D; Nelson, S D; Poole, B

    2011-03-16

    To attain the highest accelerating gradient in the compact dielectric wall (DWA) accelerator, the DWA will be operated in the 'virtual' traveling mode with potentially non-uniform and time-dependent axial accelerating field profiles, especially near the DWA entrance and exit, which makes beam transport challenging. We have established a baseline transport case without using any external lenses. Results of simulations using the 3-D, EM PIC code, LSP indicate that the DWA transport performance meets the medical specifications for proton treatment. Sensitivity of the transport performance to Blumlein block failure will be presented.

  6. Micro-sphere layered targets efficiency in laser driven proton acceleration

    SciTech Connect

    Floquet, V.; Martin, Ph.; Ceccotti, T.; Klimo, O.; Psikal, J.; Limpouch, J.; Proska, J.; Novotny, F.; Stolcova, L.; Velyhan, A.; Macchi, A.; Sgattoni, A.; Vassura, L.; Labate, L.; Baffigi, F.; Gizzi, L. A.

    2013-08-28

    Proton acceleration from the interaction of high contrast, 25 fs laser pulses at >10{sup 19} W/cm{sup 2} intensity with plastic foils covered with a single layer of regularly packed micro-spheres has been investigated experimentally. The proton cut-off energy has been measured as a function of the micro-sphere size and laser incidence angle for different substrate thickness, and for both P and S polarization. The presence of micro-spheres with a size comparable to the laser wavelength allows to increase the proton cut-off energy for both polarizations at small angles of incidence (10∘). For large angles of incidence, however, proton energy enhancement with respect to flat targets is absent. Analysis of electron trajectories in particle-in-cell simulations highlights the role of the surface geometry in the heating of electrons.

  7. Collimated proton acceleration in light sail regime with a tailored pinhole target

    NASA Astrophysics Data System (ADS)

    Wang, H. Y.; Yan, X. Q.; Zepf, M.

    2014-06-01

    A scheme for producing collimated protons from laser interactions with a diamond-like-carbon + pinhole target is proposed. The process is based on radiation pressure acceleration in the multi-species light-sail regime [B. Qiao et al., Phys. Rev. Lett. 105, 155002 (2010); T. P. Yu et al., Phys. Rev. Lett. 105, 065002 (2010)]. Particle-in-cell simulations demonstrate that transverse quasistatic electric field at TV/m level can be generated in the pinhole. The transverse electric field suppresses the transverse expansion of protons effectively, resulting in a higher density and more collimated proton beam compared with a single foil target. The dependence of the proton beam divergence on the parameters of the pinhole is also investigated.

  8. Collimated proton acceleration in light sail regime with a tailored pinhole target

    SciTech Connect

    Wang, H. Y.; Zepf, M.; Yan, X. Q.

    2014-06-15

    A scheme for producing collimated protons from laser interactions with a diamond-like-carbon + pinhole target is proposed. The process is based on radiation pressure acceleration in the multi-species light-sail regime [B. Qiao et al., Phys. Rev. Lett. 105, 155002 (2010); T. P. Yu et al., Phys. Rev. Lett. 105, 065002 (2010)]. Particle-in-cell simulations demonstrate that transverse quasistatic electric field at TV/m level can be generated in the pinhole. The transverse electric field suppresses the transverse expansion of protons effectively, resulting in a higher density and more collimated proton beam compared with a single foil target. The dependence of the proton beam divergence on the parameters of the pinhole is also investigated.

  9. Holmium-161 produced using 11.6 MeV protons: A practical source of narrow-band X-rays.

    PubMed

    Stephens, Bryan J; Mendenhall, Marcus H

    2010-10-01

    We present a novel technique to produce narrow-band X-rays by preparing (161)Ho from the bombardment of dysprosium foil by 11.6 MeV protons. The activated foil produces predominantly 45-55 keV X-rays, which are suitable for activating iodinated radio-sensitizing agents (e.g. IUdR) for oncological therapy. We demonstrate that clinically useful quantities of the nuclide are easily produced with a medical cyclotron which is far from the current state of the art.

  10. Comparison of the (p,xn) cross sections from /sup 238/U, /sup 235/U, and /sup 232/Th targets irradiated with 200-MeV protons

    SciTech Connect

    Chu, Y.Y.; Zhou, M.L.

    1982-01-01

    We have measured absolute cross sections for (p,xn) reactions (x ranges from 0 to 8) from /sup 238/U, /sup 235/U, and /sup 232/Th targets irradiated with 200-MeV protons at the Brookhaven AGS Linac injector. Chemical yields were determined by using /sup 239/Np and /sup 233/Pa as tracers. Yield patterns obtained in this work can be compared to the experimental results and theoretical calculations from earlier work, and they are consistent within the framework of intranuclear cascade followed by neutron evaporation and fission competition.

  11. RBE for late somatic effects in mice irradiated with 60 MeV protons relative to X-rays.

    NASA Technical Reports Server (NTRS)

    Darden, E. B., Jr.; Clapp, N. K.; Bender, R. S.; Jernigan, M. C.; Upton, A. C.

    1971-01-01

    Investigation of the relative biological effectiveness of energetic protons for the induction of somatic effects in a mammal (mice) following whole body irradiation. The proton energy used approximates the mean energy for proton spectra accompanying solar events. The effects on longevity and the incidence of major neoplastic diseases are summarized. The results obtained suggest that medium energy proton irradiation is no more effective, and on the whole, probably less effective, than conventional X radiation for the induction of late radiation effects in the mouse.

  12. External-Beam Accelerated Partial Breast Irradiation Using Multiple Proton Beam Configurations

    SciTech Connect

    Wang Xiaochun; Amos, Richard A.; Zhang Xiaodong; Taddei, Phillip J.; Woodward, Wendy A.; Hoffman, Karen E.; Yu, Tse Kuan; Tereffe, Welela; Oh, Julia; Perkins, George H.; Salehpour, Mohammad; Zhang, Sean X.; Sun, Tzou Liang; Gillin, Michael; Buchholz, Thomas A.; Strom, Eric A.

    2011-08-01

    Purpose: To explore multiple proton beam configurations for optimizing dosimetry and minimizing uncertainties for accelerated partial breast irradiation (APBI) and to compare the dosimetry of proton with that of photon radiotherapy for treatment of the same clinical volumes. Methods and Materials: Proton treatment plans were created for 11 sequential patients treated with three-dimensional radiotherapy (3DCRT) photon APBI using passive scattering proton beams (PSPB) and were compared with clinically treated 3DCRT photon plans. Monte Carlo calculations were used to verify the accuracy of the proton dose calculation from the treatment planning system. The impact of range, motion, and setup uncertainty was evaluated with tangential vs. en face beams. Results: Compared with 3DCRT photons, the absolute reduction of the mean of V100 (the volume receiving 100% of prescription dose), V90, V75, V50, and V20 for normal breast using protons are 3.4%, 8.6%, 11.8%, 17.9%, and 23.6%, respectively. For breast skin, with the similar V90 as 3DCRT photons, the proton plan significantly reduced V75, V50, V30, and V10. The proton plan also significantly reduced the dose to the lung and heart. Dose distributions from Monte Carlo simulations demonstrated minimal deviation from the treatment planning system. The tangential beam configuration showed significantly less dose fluctuation in the chest wall region but was more vulnerable to respiratory motion than that for the en face beams. Worst-case analysis demonstrated the robustness of designed proton beams with range and patient setup uncertainties. Conclusions: APBI using multiple proton beams spares significantly more normal tissue, including nontarget breast and breast skin, than 3DCRT using photons. It is robust, considering the range and patient setup uncertainties.

  13. Final Report for "Modeling Electron Cloud Diagnostics for High-Intensity Proton Accelerators"

    SciTech Connect

    Seth A Veitzer

    2009-09-25

    Electron clouds in accelerators such as the ILC degrade beam quality and limit operating efficiency. The need to mitigate electron clouds has a direct impact on the design and operation of these accelerators, translating into increased cost and reduced performance. Diagnostic techniques for measuring electron clouds in accelerating cavities are needed to provide an assessment of electron cloud evolution and mitigation. Accurate numerical modeling of these diagnostics is needed to validate the experimental techniques. In this Phase I, we developed detailed numerical models of microwave propagation through electron clouds in accelerating cavities with geometries relevant to existing and future high-intensity proton accelerators such as Project X and the ILC. Our numerical techniques and simulation results from the Phase I showed that there was a high probability of success in measuring both the evolution of electron clouds and the effects of non-uniform electron density distributions in Phase II.

  14. Investigation of the radiation resistance of triple-junction a-Si:H alloy solar cells irradiated with 1.00 MeV protons

    NASA Technical Reports Server (NTRS)

    Lord, Kenneth R., II; Walters, Michael R.; Woodyard, James R.

    1993-01-01

    The effect of 1.00 MeV proton irradiation on hydrogenated amorphous silicon alloy triple-junction solar cells is reported for the first time. The cells were designed for radiation resistance studies and included 0.35 cm(sup 2) active areas on 1.0 by 2.0 cm(sup 2) glass superstrates. Three cells were irradiated through the bottom contact at each of six fluences between 5.10E12 and 1.46E15 cm(sup -2). The effect of the irradiations was determined with light current-voltage measurements. Proton irradiation degraded the cell power densities from 8.0 to 98 percent for the fluences investigated. Annealing irradiated cells at 200 C for two hours restored the power densities to better than 90 percent. The cells exhibited radiation resistances which are superior to cells reported in the literature for fluences less than 1E14 cm(sup -2).

  15. Secondary particle yields from 400 MeV/u carbon ion and 250 MeV proton beams incident on thick targets

    NASA Astrophysics Data System (ADS)

    Ferrari, A.; Ferrarini, M.; Pelliccioni, M.

    2011-07-01

    The double differential particle yield produced by hadron beams striking thick targets of copper, tungsten and ICRU tissue, have been determined by means of the Monte Carlo transport code FLUKA (version FLUKA 2008.3b.1). 400 MeV/u carbon ion and 250 MeV proton pencil beams have been considered. Secondary neutrons, photons, and protons have been scored. In order to validate the obtained data, a few simulations have been also repeated with MCNPX 2.6.0. The calculated results are presented and compared with the experimental data reported in literature. They should be very useful to solve a number of problems related to technological aspects of hadrontherapy.

  16. Absolute Differential Cross-Sections for Elastic PION(+/-)/PROTON Scattering at 30 Less than or Equal to T(pion) Less than or Equal to 140 Mev

    NASA Astrophysics Data System (ADS)

    Brack, Jeffrey Thomas

    Differential cross sections for elastic pi^{+/-}p scattering have been measured at TRIUMF for 10 incident pion energies in three separate experiments at 66.8 <= T_{pi} <= 138.8 MeV, Tpi = 66.8 MeV (pi^+p only), and 30 <= T_{pi} <= 66.8 MeV, using three independent techniques. Typical statistical accuracies are 1-3% and normalization uncertainties are 1.2-3.0%. Extensive experimental checks were employed to minimize systematic errors. Incident pion beam rates were varied by a factor of 5, target thickness was varied by a factor of 10, different target compositions were used (CH_2 and CH_{1.1 }), and derangements of the detector geometry tested the reproducibility of the cross sections under widely varying conditions. Three separate Monte Carlo routines were used. All measurements used solid targets. Thin scintillators and time-of-flight (TOF) techniques were used to count and identify particles incident on the targets and to detect the scattered pions. Recoil protons were detected in coincidence with the scattered pions in two of the three experiments. At the upper range of incident pion energies (66.8 to 138 MeV), a two-arm coincidence technique was used in which proton detection was similar to pion detection (TOF). At the three lowest incident pion energies, an active target technique was used in which the recoil particles were detected by means of the light generated within the CH_ {1.1} scintillator-target. These are the only elastic pip coincidence measurements by any experimental group below 140 MeV incident pion energy. At 66.8 MeV, a third technique was used in which no recoil particles were detected. At incident pion energies of 100 MeV and above, all pi^{+/-}p results from these three measurements are in good agreement with previous measurements, as are the pi ^-p results at all energies. However, while the pi^{+/-}p results of these three experiments are consistent within experimental error at the overlapping energy of 66.8 MeV, they are 10-25% lower than

  17. Exclusive studies of 130-270 MeV {sup 3}He- and 200-MeV proton-induced reactions on {sup 27}Al, {sup nat}Ag, and {sup 197}Au

    SciTech Connect

    Ginger, D. S.; Kwiatkowski, K.; Wang, G.; Hsi, W.-C.; Hudan, S.; Cornell, E.; Souza, R. T. de; Viola, V. E.; Korteling, R. G.

    2008-09-15

    Exclusive light-charged-particle and IMF spectra have been measured with the ISiS detector array for bombardments of {sup 27}Al, {sup nat}Ag, and {sup 197}Au nuclei with 130-270-MeV {sup 3}He and 200-MeV protons. The results are consistent with previous interpretations based on inclusive data that describe the global yield of complex fragments in terms of a time-dependent process. The emission mechanism for energetic nonequilibrium fragments observed at forward angles with momenta up to twice the beam momentum is also investigated. This poorly understood mechanism, for which the angular distributions indicate formation on a time scale comparable to the nuclear transit time, are accompanied primarily by thermal-like emissions. The data are most consistent with a schematic picture in which nonequilibrium fragments are formed in a localized region of the target nucleus at an early stage in the energy-dissipation process, where the combined effects of high energy density and Fermi motion produce the observed suprathermal spectra.

  18. From Particle Physics to Astroparticle Physics: Proton Decay and the Rise of Non-accelerator Physics

    NASA Astrophysics Data System (ADS)

    Meyer, Hinrich

    The search for proton decay was motivated by simple questions about the content of the observable universe. Why is matter so stable and why do we not see antimatter of primordial origin? The symmetry of the standard model of particle physics would have required that matter and antimatter annihilated in the early universe. In 1968, Sacharov showed that the matter-antimatter asymmetry could have formed in a state of thermal non-equilibrium of the universe, as given in big bang cosmology, together with the well-confirmed C and CP violations, and proton decay. The latter phenomenon could be only investigated in large none-accelerator experiments. The SU(5) extension of the standard model implied a proton lifetime of about 1029 years. With detectors consisting of 1 000 tons of matter and located deep under the Earth surface, such as the French-German Fréjus iron-calorimeter, in the mid 1980s one expected to detect several proton decays per year. Here, we report on the way leading from accelerator laboratories to underground physics, which paradoxically enough turned out to studying cosmic rays. There has not been any evidence for the instability of protons, and lifetime limits of more than 1034 years have been obtained. However, great progress in particle physics and in the physics of cosmic rays could be achieved with neutrinos.

  19. Warp simulations for capture and control of laser-accelerated proton beams

    SciTech Connect

    Nurnberg, F; Friedman, A; Grote, D P; Harres, K; Logan, B G; Schollmeier, M; Roth, M

    2009-10-22

    The capture of laser-accelerated proton beams accompanied by co-moving electrons via a solenoid field has been studied with particle-in-cell simulations. The main advantages of the Warp simulation suite that was used, relative to envelope or tracking codes, are the possibility of including all source parameters energy resolved, adding electrons as second species and considering the non-negligible space-charge forces and electrostatic self-fields. It was observed that the influence of the electrons is of vital importance. The magnetic effect on the electrons out balances the space-charge force. Hence, the electrons are forced onto the beam axis and attract protons. Besides the energy dependent proton density increase on axis, the change in the particle spectrum is also important for future applications. Protons are accelerated/decelerated slightly, electrons highly. 2/3 of all electrons get lost directly at the source and 27% of all protons hit the inner wall of the solenoid.

  20. Analysis of gamma-ray spectra from foils activated in a range-thick lead target by 800-MeV protons. Final technical report

    SciTech Connect

    Laird, C.E.; Mullins, D.H.

    1995-06-12

    Approximately 400 gamma-ray spectra have been analyzed to obtain the types and quantities of radioisotopes produced when 800-MeV protons interact with a range-thick lead target. These spectra were obtained from the radioactive decay of product isotopes in lead disks placed at various depths and radial positions within the target. These spectra were analyzed with the computer code HYPERMET and the photopeak areas were reduced to nuclei produced per incident proton per cubic centimeter of material. Product nuclei ranged from atomic mass 160 to mass 206 and over a range of half lives from a few minutes to several weeks. The results of this analysis have been outlined in this report and transmitted on computer disk to Los Alamos National Laboratory. The consistency of these analyses have been confirmed by a comparison of photopeak areas obtained at LANL with the computer code GAMANAL with those from HYPERMET for two gamma-ray spectra. Also, the nuclear production per proton per cm{sub 3} obtained from these two spectra analyzed both at LANL and at EKU have been found to agree to within the statistical accuracy of the peak-fitting programs. This analysis of these 400 gamma-ray spectra has determined the nuclear production per incident proton per cm{sub 3} at five regularly-spaced radial positions and depths up to 40 cm into a range-thick lead target.

  1. Stochastic Re-Acceleration of Protons in the Downstream Region of a Coronal Shock

    NASA Astrophysics Data System (ADS)

    Afanasiev, A. N.; Kocharov, L. G.; Vainio, R. O.

    2011-12-01

    Recent SDO/AIA observations of CME in the low corona have finally confirmed the formation of coronal shock waves in the low corona. This supports the viability of shock acceleration as the mechanism for the genesis of large gradual SEP events. However, a careful analysis of observational data of the early phases of large SEP events indicates that it might be hard to understand some of the spectral characteristics at deca-MeV energies in detail relying on a model of diffusive shock acceleration alone. We have recently presented a test-particle model where coronal shock acceleration and stochastic re-acceleration in the shock downstream region can account for the hard spectral features in the deca-MeV range. The problem of a test-particle calculation in the case of stochastic acceleration is, however, that a time-stationary wave field acts as an infinite energy reservoir for the particles being accelerated by turbulence. To account for this problem, we employ our self-consistent wave-particle interaction simulation code to compute the evolution of the wave frequency and proton energy spectra in the downstream region of a coronal shock. Parameter space allowed by different types of turbulence generation models is explored and regions favorable to explaining the proton energy spectra in large gradual events are identified.

  2. Acceleration of protons at 32 Jovian radii in the outer magnetosphere of jupiter

    NASA Technical Reports Server (NTRS)

    Schardt, A. W.; Mcdonald, F. B.; Trainor, J. H.

    1977-01-01

    During the inbound pass of Pioneer 10, a rapid ten-fold increase of the 0.2 to MeV proton flux was observed at 32 Jovian radii (R sub J). The total event lasted for 30 minutes and was made up of a number of superimposed individual events. At the time, the spacecraft was in the outer magnetosphere about 7 R sub J below the magnetic equator. Before and after the event, the proton flux was characteristic of the low flux level normally encountered between crossings of the magnetic equator. Flux changes at different energies were coherent within 1 minute; a time comparable to the time resolution of the data. The angular distributions were highly anisotropic with protons streaming towards Jupiter. A field-aligned dumbbell distribution was observed initially, and a pancake distribution just before the flux decayed to its pre-event value. The alpha particle flux changed as rapidly as the proton flux but peaked at different times. The energetic electron flux behaved differently; it increased gradually throughout the period.

  3. Nonlinear surface plasma wave induced target normal sheath acceleration of protons

    SciTech Connect

    Liu, C. S.; Tripathi, V. K. Shao, Xi; Liu, T. C.

    2015-02-15

    The mode structure of a large amplitude surface plasma wave (SPW) over a vacuum–plasma interface, including relativistic and ponderomotive nonlinearities, is deduced. It is shown that the SPW excited by a p-polarized laser on a rippled thin foil target can have larger amplitude than the transmitted laser amplitude and cause stronger target normal sheath acceleration of protons as reported in a recent experiment. Substantial enhancement in proton number also occurs due to the larger surface area covered by the SPW.

  4. Effect of irradiation with MeV protons and electrons on the conductivity compensation and photoluminescence of moderately doped p-4H-SiC (CVD)

    SciTech Connect

    Kozlovski, V. V.; Lebedev, A. A. Bogdanova, E. V.; Seredova, N. V.

    2015-09-15

    The compensation of moderately doped p-4H-SiC samples grown by the chemical vapor deposition (CVD) method under irradiation with 0.9-MeV electrons and 15-MeV protons is studied. The experimentally measured carrier removal rates are 1.2–1.6 cm{sup –1} for electrons and 240–260 cm{sup –1} for protons. The dependence of the concentration of uncompensated acceptors and donors, measured in the study, demonstrates a linear decrease with increasing irradiation dose to the point of complete compensation. This run of the dependence shows that compensation of the samples is due to the transition of carriers to deep centers formed by primary radiation-induced defects. It is demonstrated that, in contrast to n-SiC (CVD), primary defects in the carbon sublattice of moderately doped p-SiC (CVD) only cannot account for the compensation process. In p-SiC, either primary defects in the silicon sublattice, or defects in both sublattices are responsible for conductivity compensation. Also, photoluminescence spectra are examined in relation to the irradiation dose.

  5. Global magnetohydrodynamic simulation of the 15 March 2013 coronal mass ejection event—Interpretation of the 30-80 MeV proton flux

    NASA Astrophysics Data System (ADS)

    Wu, Chin-Chun; Liou, Kan; Vourlidas, Angelos; Plunkett, Simon; Dryer, Murray; Wu, S. T.; Mewaldt, Richard A.

    2016-01-01

    The coronal mass ejection (CME) event on 15 March 2013 is one of the few solar events in Cycle 24 that produced a large solar energetic particle (SEP) event and severe geomagnetic activity. Observations of SEP from the ACE spacecraft show a complex time-intensity SEP profile that is not easily understood with current empirical SEP models. In this study, we employ a global three-dimensional (3-D) magnetohydrodynamic (MHD) simulation to help interpret the observations. The simulation is based on the H3DMHD code and incorporates extrapolations of photospheric magnetic field as the inner boundary condition at a solar radial distance (r) of 2.5 solar radii. A Gaussian-shaped velocity pulse is imposed at the inner boundary as a proxy for the complex physical conditions that initiated the CME. It is found that the time-intensity profile of the high-energy (>10 MeV) SEPs can be explained by the evolution of the CME-driven shock and its interaction with the heliospheric current sheet and the nonuniform solar wind. We also demonstrate in more detail that the simulated fast-mode shock Mach number at the magnetically connected shock location is well correlated (rcc ≥ 0.7) with the concurrent 30-80 MeV proton flux. A better correlation occurs when the 30-80 MeV proton flux is scaled by r-1.4(rcc = 0.87). When scaled by r-2.8, the correlation for 10-30 MeV proton flux improves significantly from rcc = 0.12 to rcc = 0.73, with 1 h delay. The present study suggests that (1) sector boundary can act as an obstacle to the propagation of SEPs; (2) the background solar wind is an important factor in the variation of IP shock strength and thus plays an important role in manipulation of SEP flux; (3) at least 50% of the variance in SEP flux can be explained by the fast-mode shock Mach number. This study demonstrates that global MHD simulation, despite the limitation implied by its physics-based ideal fluid continuum assumption, can be a viable tool for SEP data analysis.

  6. Dosimetric advantages of IMPT over IMRT for laser-accelerated proton beams

    NASA Astrophysics Data System (ADS)

    Luo, W.; Li, J.; Fourkal, E.; Fan, J.; Xu, X.; Chen, Z.; Jin, L.; Price, R.; Ma, C.-M.

    2008-12-01

    As a clinical application of an exciting scientific breakthrough, a compact and cost-efficient proton therapy unit using high-power laser acceleration is being developed at Fox Chase Cancer Center. The significance of this application depends on whether or not it can yield dosimetric superiority over intensity-modulated radiation therapy (IMRT). The goal of this study is to show how laser-accelerated proton beams with broad energy spreads can be optimally used for proton therapy including intensity-modulated proton therapy (IMPT) and achieve dosimetric superiority over IMRT for prostate cancer. Desired energies and spreads with a varying δE/E were selected with the particle selection device and used to generate spread-out Bragg peaks (SOBPs). Proton plans were generated on an in-house Monte Carlo-based inverse-planning system. Fifteen prostate IMRT plans previously used for patient treatment have been included for comparison. Identical dose prescriptions, beam arrangement and consistent dose constrains were used for IMRT and IMPT plans to show the dosimetric differences that were caused only by the different physical characteristics of proton and photon beams. Different optimization constrains and beam arrangements were also used to find optimal IMPT. The results show that conventional proton therapy (CPT) plans without intensity modulation were not superior to IMRT, but IMPT can generate better proton plans if appropriate beam setup and optimization are used. Compared to IMRT, IMPT can reduce the target dose heterogeneity ((D5-D95)/D95) by up to 56%. The volume receiving 65 Gy and higher (V65) for the bladder and the rectum can be reduced by up to 45% and 88%, respectively, while the volume receiving 40 Gy and higher (V40) for the bladder and the rectum can be reduced by up to 49% and 68%, respectively. IMPT can also reduce the whole body non-target tissue dose by up to 61% or a factor 2.5. This study has shown that the laser accelerator under development has a

  7. Dosimetric advantages of IMPT over IMRT for laser-accelerated proton beams.

    PubMed

    Luo, W; Li, J; Fourkal, E; Fan, J; Xu, X; Chen, Z; Jin, L; Price, R; Ma, C-M

    2008-12-21

    As a clinical application of an exciting scientific breakthrough, a compact and cost-efficient proton therapy unit using high-power laser acceleration is being developed at Fox Chase Cancer Center. The significance of this application depends on whether or not it can yield dosimetric superiority over intensity-modulated radiation therapy (IMRT). The goal of this study is to show how laser-accelerated proton beams with broad energy spreads can be optimally used for proton therapy including intensity-modulated proton therapy (IMPT) and achieve dosimetric superiority over IMRT for prostate cancer. Desired energies and spreads with a varying deltaE/E were selected with the particle selection device and used to generate spread-out Bragg peaks (SOBPs). Proton plans were generated on an in-house Monte Carlo-based inverse-planning system. Fifteen prostate IMRT plans previously used for patient treatment have been included for comparison. Identical dose prescriptions, beam arrangement and consistent dose constrains were used for IMRT and IMPT plans to show the dosimetric differences that were caused only by the different physical characteristics of proton and photon beams. Different optimization constrains and beam arrangements were also used to find optimal IMPT. The results show that conventional proton therapy (CPT) plans without intensity modulation were not superior to IMRT, but IMPT can generate better proton plans if appropriate beam setup and optimization are used. Compared to IMRT, IMPT can reduce the target dose heterogeneity ((D5-D95)/D95) by up to 56%. The volume receiving 65 Gy and higher (V65) for the bladder and the rectum can be reduced by up to 45% and 88%, respectively, while the volume receiving 40 Gy and higher (V40) for the bladder and the rectum can be reduced by up to 49% and 68%, respectively. IMPT can also reduce the whole body non-target tissue dose by up to 61% or a factor 2.5. This study has shown that the laser accelerator under development has

  8. Reinvestigation of the direct two-proton decay of the long-lived isomer 94Ag(m) [0.4 s, 6.7 MeV, (21+)].

    PubMed

    Cerny, J; Moltz, D M; Lee, D W; Peräjärvi, K; Barquest, B R; Grossman, L E; Jeong, W; Jewett, C C

    2009-10-09

    An attempt to confirm the reported direct one-proton and two-proton decays of the (21+) isomer at 6.7(5) MeV in 94Ag has been made. The 0.39(4) s half-life of the isomer permitted use of a helium-jet system to transport reaction products from the 40Ca + (nat)Ni reaction at 197 MeV to a low-background area; 24 gas DeltaE-(Si)E detector telescopes were used to identify emitted protons down to 0.4 MeV. No evidence was obtained for two-proton radioactivity with a summed energy of 1.9(1) MeV and a branching ratio of 0.5(3)%. Two groups of one-proton radioactivity from this isomer had also been reported; our data confirm the lower energy group at 0.79(3) MeV with its branching ratio of 1.9(5)%.

  9. Output beam energy measurement of a 100-MeV KOMAC drift tube linac by using a stripline beam position monitor

    NASA Astrophysics Data System (ADS)

    Kim, Han-Sung

    2015-10-01

    The 100-MeV proton linac at the KOMAC (Korea Multi-purpose Accelerator Complex) is composed of a 50-keV proton injector, a 3-MeV RFQ (radio-frequency quadrupole) and a 100-MeV DTL (drift tube linac). The proton beam is accelerated from 3 MeV to 100 MeV through 11 DTL tanks. The precise measurement of the proton-beam's energy at the output of each DTL tank is important for the longitudinal beam dynamics and can be performed by using a time-of-flight method with a BPM (beam position monitor), which is installed between each DTL tank. The details of the output beam energy measurement of the KOMAC DTL with stripline-type BPM and BPM signal processing, along with a comparison with the simulation results, will be presented in this paper.

  10. Advanced low-beta cavity development for proton and ion accelerators

    NASA Astrophysics Data System (ADS)

    Conway, Z. A.; Kelly, M. P.; Ostroumov, P. N.

    2015-05-01

    Recent developments in designing and processing low-beta superconducting cavities at Argonne National Laboratory are very encouraging for future applications requiring compact proton and ion accelerators. One of the major benefits of these accelerating structures is achieving real-estate accelerating gradients greater than 3 MV/m very efficiently either continuously or for long-duty cycle operation (>1%). The technology has been implemented in low-beta accelerator cryomodules for the Argonne ATLAS heavy-ion linac where the cryomodules are required to have real-estate gradients of more than 3 MV/m. In offline testing low-beta cavities with even higher gradients have already been achieved. This paper will review this work where we have achieved surface fields greater than 166 mT magnetic and 117 MV/m electric in a 72 MHz quarter-wave resonator optimized for β = 0.077 ions.

  11. Proton acceleration using doped Argon plasma density gradient interacting with relativistic CO2 -laser pulse

    NASA Astrophysics Data System (ADS)

    Sahai, Aakash; Ettlinger, Oliver; Hicks, George; Ditter, Emma-Jane; Najmudin, Zulfikar

    2016-10-01

    We investigate proton and light-ion acceleration driven by the interaction of relativistic CO2 laser pulses with overdense Argon or other heavy-ion gas targets doped with lighter-ion species. Optically shaping the gas targets allows tuning of the pre-plasma scale-length from a few to several laser wavelengths, allowing the laser to efficiently drive a propagating snowplow through the bunching in the electron density. Preliminary PIC-based modeling shows that the lighter-ion species is accelerated even without any significant motion of the heavier ions which is a signature of the Relativistically Induced Transparency Acceleration mechanism. Some outlines of possible experiments at the TW CO2 laser at the Accelerator Test Facility at Brookhaven National Laboratory are presented.

  12. Proton Induced X-ray Emission Spectroscopy of Red Wine Samples Using the Union College Pelletron Accelerator

    NASA Astrophysics Data System (ADS)

    Schuff, Katie; Labrake, Scott

    2010-11-01

    A 1-megavolt tandem electrostatic Pelletron particle accelerator housed at Union College was used to measure the elemental composition and concentration of homemade Cabernet and Merlot red wine samples. A beam of 1.8-MeV protons directed at an approximately 12-μm thin Mylar substrate onto which 8-μL of concentrated red wine was dried caused inner shell electrons to be ejected from the target nuclei and these vacancies are filled through electronic transitions of higher orbital electrons accompanied by the production of an x-ray photon characteristic of the elemental composition of the target. This is the PIXE Method. Data on the intensity versus energy of the x-rays were collected using an Amptek silicon drift detector and were analyzed to determine the elemental composition and the samples were found to contain P, S, K, Cl, Ca, Sc, Mn, Al, Fe, & Co. Elemental concentrations were determined using the analysis package GUPIX. It is hypothesized that the cobalt seen is a direct result of the uptake by the grapes and as a product of the fermentation process a complex of vitamin B12 is produced.

  13. Electron versus proton accelerator driven sub-critical system performance using TRIGA reactors at power

    SciTech Connect

    Carta, M.; Burgio, N.; D'Angelo, A.; Santagata, A.; Petrovich, C.; Schikorr, M.; Beller, D.; Felice, L. S.; Imel, G.; Salvatores, M.

    2006-07-01

    This paper provides a comparison of the performance of an electron accelerator-driven experiment, under discussion within the Reactor Accelerator Coupling Experiments (RACE) Project, being conducted within the U.S. Dept. of Energy's Advanced Fuel Cycle Initiative (AFCI), and of the proton-driven experiment TRADE (TRIGA Accelerator Driven Experiment) originally planned at ENEA-Casaccia in Italy. Both experiments foresee the coupling to sub-critical TRIGA core configurations, and are aimed to investigate the relevant kinetic and dynamic accelerator-driven systems (ADS) core behavior characteristics in the presence of thermal reactivity feedback effects. TRADE was based on the coupling of an upgraded proton cyclotron, producing neutrons via spallation reactions on a tantalum (Ta) target, with the core driven at a maximum power around 200 kW. RACE is based on the coupling of an Electron Linac accelerator, producing neutrons via photoneutron reactions on a tungsten-copper (W-Cu) or uranium (U) target, with the core driven at a maximum power around 50 kW. The paper is focused on analysis of expected dynamic power response of the RACE core following reactivity and/or source transients. TRADE and RACE target-core power coupling coefficients are compared and discussed. (authors)

  14. Phase Velocity and Particle Injection in a Self-Modulated Proton-Driven Plasma Wakefield Accelerator

    SciTech Connect

    Pukhov, A.; Kumar, N.; Tueckmantel, T.; Upadhyay, A.; Lotov, K.; Muggli, P.; Khudik, V.; Siemon, C.; Shvets, G.

    2011-09-30

    It is demonstrated that the performance of the self-modulated proton driver plasma wakefield accelerator is strongly affected by the reduced phase velocity of the plasma wave. Using analytical theory and particle-in-cell simulations, we show that the reduction is largest during the linear stage of self-modulation. As the instability nonlinearly saturates, the phase velocity approaches that of the driver. The deleterious effects of the wake's dynamics on the maximum energy gain of accelerated electrons can be avoided using side-injections of electrons, or by controlling the wake's phase velocity by smooth plasma density gradients.

  15. Protons acceleration in thin CH foils by ultra-intense femtosecond laser pulses

    SciTech Connect

    Kosarev, I. N.

    2015-03-15

    Interaction of femtosecond laser pulses with the intensities 10{sup 21}, 10{sup 22 }W/cm{sup 2} with CH plastic foils is studied in the framework of kinetic theory of laser plasma based on the construction of propagators (in classical limit) for electron and ion distribution functions in plasmas. The calculations have been performed for real densities and charges of plasma ions. Protons are accelerated both in the direction of laser pulse (up to 1 GeV) and in the opposite direction (more than 5 GeV). The mechanisms of forward acceleration are different for various intensities.

  16. Phase velocity and particle injection in a self-modulated proton-driven plasma wakefield accelerator.

    PubMed

    Pukhov, A; Kumar, N; Tückmantel, T; Upadhyay, A; Lotov, K; Muggli, P; Khudik, V; Siemon, C; Shvets, G

    2011-09-30

    It is demonstrated that the performance of the self-modulated proton driver plasma wakefield accelerator is strongly affected by the reduced phase velocity of the plasma wave. Using analytical theory and particle-in-cell simulations, we show that the reduction is largest during the linear stage of self-modulation. As the instability nonlinearly saturates, the phase velocity approaches that of the driver. The deleterious effects of the wake's dynamics on the maximum energy gain of accelerated electrons can be avoided using side-injections of electrons, or by controlling the wake's phase velocity by smooth plasma density gradients.

  17. Shock wave acceleration of protons in inhomogeneous plasma interacting with ultrashort intense laser pulses

    SciTech Connect

    Lecz, Zs.; Andreev, A.

    2015-04-15

    The acceleration of protons, triggered by solitary waves in expanded solid targets is investigated using particle-in-cell simulations. The near-critical density plasma is irradiated by ultrashort high power laser pulses, which generate the solitary wave. The transformation of this soliton into a shock wave during propagation in plasma with exponentially decreasing density profile is described analytically, which allows to obtain a scaling law for the proton energy. The high quality proton bunch with small energy spread is produced by reflection from the shock-front. According to the 2D simulations, the mechanism is stable only if the laser pulse duration is shorter than the characteristic development time of the parasitic Weibel instability.

  18. Relative Biological Effectiveness Variation Along Monoenergetic and Modulated Bragg Peaks of a 62-MeV Therapeutic Proton Beam: A Preclinical Assessment

    SciTech Connect

    Chaudhary, Pankaj; Marshall, Thomas I.; Perozziello, Francesca M.; Manti, Lorenzo; Currell, Frederick J.; Hanton, Fiona; McMahon, Stephen J.; Kavanagh, Joy N.; Cirrone, Giuseppe Antonio Pablo; Romano, Francesco; Prise, Kevin M.; Schettino, Giuseppe

    2014-09-01

    Purpose: The biological optimization of proton therapy can be achieved only through a detailed evaluation of relative biological effectiveness (RBE) variations along the full range of the Bragg curve. The clinically used RBE value of 1.1 represents a broad average, which disregards the steep rise of linear energy transfer (LET) at the distal end of the spread-out Bragg peak (SOBP). With particular attention to the key endpoint of cell survival, our work presents a comparative investigation of cell killing RBE variations along monoenergetic (pristine) and modulated (SOBP) beams using human normal and radioresistant cells with the aim to investigate the RBE dependence on LET and intrinsic radiosensitvity. Methods and Materials: Human fibroblasts (AG01522) and glioma (U87) cells were irradiated at 6 depth positions along pristine and modulated 62-MeV proton beams at the INFN-LNS (Catania, Italy). Cell killing RBE variations were measured using standard clonogenic assays and were further validated using Monte Carlo simulations and the local effect model (LEM). Results: We observed significant cell killing RBE variations along the proton beam path, particularly in the distal region showing strong dose dependence. Experimental RBE values were in excellent agreement with the LEM predicted values, indicating dose-averaged LET as a suitable predictor of proton biological effectiveness. Data were also used to validate a parameterized RBE model. Conclusions: The predicted biological dose delivered to a tumor region, based on the variable RBE inferred from the data, varies significantly with respect to the clinically used constant RBE of 1.1. The significant RBE increase at the distal end suggests also a potential to enhance optimization of treatment modalities such as LET painting of hypoxic tumors. The study highlights the limitation of adoption of a constant RBE for proton therapy and suggests approaches for fast implementation of RBE models in treatment planning.

  19. Neutron scattering measurements in {sup 197}Au from 850 keV to 2.0 MeV

    SciTech Connect

    O`Connor, M.; Chen, J.; Egan, J.J.

    1995-10-01

    Differential elastic and inelastic neutron scattering cross-sections for low lying levels in {sup 197}Au have been measured for incident neutron energies of 1.0 MeV, 1.5 MeV and 2.0 MeV. In addition, the total neutron cross sections in {sup 197}Au was measured from 850 keV to 1.5 MeV. For both experiments the UML 5.5 MV Van-de-Graaff accelerator with a Mobley post acceleration compression system, produced subnanosecond proton pulses which generated neutrons via the {sup 7}Li(p,n) {sup 7}Be reaction.

  20. Towards optical polarization control of laser-driven proton acceleration in foils undergoing relativistic transparency

    PubMed Central

    Gonzalez-Izquierdo, Bruno; King, Martin; Gray, Ross J.; Wilson, Robbie; Dance, Rachel J.; Powell, Haydn; Maclellan, David A.; McCreadie, John; Butler, Nicholas M. H.; Hawkes, Steve; Green, James S.; Murphy, Chris D.; Stockhausen, Luca C.; Carroll, David C.; Booth, Nicola; Scott, Graeme G.; Borghesi, Marco; Neely, David; McKenna, Paul

    2016-01-01

    Control of the collective response of plasma particles to intense laser light is intrinsic to relativistic optics, the development of compact laser-driven particle and radiation sources, as well as investigations of some laboratory astrophysics phenomena. We recently demonstrated that a relativistic plasma aperture produced in an ultra-thin foil at the focus of intense laser radiation can induce diffraction, enabling polarization-based control of the collective motion of plasma electrons. Here we show that under these conditions the electron dynamics are mapped into the beam of protons accelerated via strong charge-separation-induced electrostatic fields. It is demonstrated experimentally and numerically via 3D particle-in-cell simulations that the degree of ellipticity of the laser polarization strongly influences the spatial-intensity distribution of the beam of multi-MeV protons. The influence on both sheath-accelerated and radiation pressure-accelerated protons is investigated. This approach opens up a potential new route to control laser-driven ion sources. PMID:27624920

  1. Towards optical polarization control of laser-driven proton acceleration in foils undergoing relativistic transparency

    NASA Astrophysics Data System (ADS)

    Gonzalez-Izquierdo, Bruno; King, Martin; Gray, Ross J.; Wilson, Robbie; Dance, Rachel J.; Powell, Haydn; MacLellan, David A.; McCreadie, John; Butler, Nicholas M. H.; Hawkes, Steve; Green, James S.; Murphy, Chris D.; Stockhausen, Luca C.; Carroll, David C.; Booth, Nicola; Scott, Graeme G.; Borghesi, Marco; Neely, David; McKenna, Paul

    2016-09-01

    Control of the collective response of plasma particles to intense laser light is intrinsic to relativistic optics, the development of compact laser-driven particle and radiation sources, as well as investigations of some laboratory astrophysics phenomena. We recently demonstrated that a relativistic plasma aperture produced in an ultra-thin foil at the focus of intense laser radiation can induce diffraction, enabling polarization-based control of the collective motion of plasma electrons. Here we show that under these conditions the electron dynamics are mapped into the beam of protons accelerated via strong charge-separation-induced electrostatic fields. It is demonstrated experimentally and numerically via 3D particle-in-cell simulations that the degree of ellipticity of the laser polarization strongly influences the spatial-intensity distribution of the beam of multi-MeV protons. The influence on both sheath-accelerated and radiation pressure-accelerated protons is investigated. This approach opens up a potential new route to control laser-driven ion sources.

  2. Laser Driven Ion accelerators - current status and perspective

    SciTech Connect

    Zepf, M.; Robinson, A. P. L.

    2009-01-22

    The interaction of ultra-intense lasers with thin foil targets has recently emerged as a route to achieving extreme acceleration gradients and hence ultra-compact proton and ion accelerators. There are a number of distinct physical processes by which the protons/ions can be accelerated to energies in excess of 10 MeV. The recent development is discussed and a new mechanism--Radiation Pressure Acceleration is highlighted as a route to achieving efficient production of relativistic ions beams.

  3. Correlated analysis of 2 MeV proton-induced radiation damage in CdZnTe crystals using photoluminescence and thermally stimulated current techniques

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

    Radiation damage induced by 2 MeV protons in CdZnTe crystals has been studied by means of photoluminescence (PL) and thermally stimulated current (TSC) techniques. A notable quenching of PL intensity is observed in the regions irradiated with a fluence of 6 × 1013 p/cm2, suggesting the increase of non-radiative recombination centers. Moreover, the intensity of emission peak Dcomplex centered at 1.48 eV dominates in the PL spectrum obtained from irradiated regions, ascribed to the increase of interstitial dislocation loops and A centers. The intensity of TSC spectra in irradiated regions decreases compared to the virgin regions, resulting from the charge collection inefficiency caused by proton-induced recombination centers. By comparing the intensity of identified traps obtained from numerical fitting using simultaneous multiple peak analysis (SIMPA) method, it suggests that proton irradiation under such dose can introduce high density of dislocation and A-centers in CdZnTe crystals, consistent with PL results.

  4. Critical current density of Nb3Sn wires after irradiation with 65MeV and 24GeV protons

    NASA Astrophysics Data System (ADS)

    Spina, T.; Scheuerlein, C.; Richter, D.; Bottura, L.; Ballarino, A.; Flükiger, R.

    2014-05-01

    Industrial Nb3Sn wires with Ti and Ta additives (RRP process) and with Ta additives (PIT process) with a diameter of 1 mm have been irradiated at room temperature with protons of 65 MeV and of 24 GeV at various fluences up to 1×1021 p/m2. A steady increase of Jc vs. fluence was observed for all the wires up to the highest fluence. The observed increase of Jc at 4.2K in all wires was quite similar in spite of the very different proton energies. With increasing fluence. the radiation induced pinning force was found to increase. the enhancement Jc/Jco after 5.04×1020 p/m2 reaching 1.4 for Ta and 1.8 for Ti alloyed wires at 10T. The present results were quantitatively analysed by assuming a radiation induced point pinning mechanism in addition to grain boundary pinning. The results are compared with those of an ongoing neutron irradiation study undertaken on the same Nb3Sn wires in collaboration with the Atominstitut Vienna. Proton irradiation was found to produce considerably higher damage than neutron irradiation.

  5. Fast fingerprinting of arson accelerants by proton transfer reaction time-of-flight mass spectrometry

    NASA Astrophysics Data System (ADS)

    Whyte, Christopher; Wyche, Kevin P.; Kholia, Mitesh; Ellis, Andrew M.; Monks, Paul S.

    2007-06-01

    Current techniques for the forensic analysis of fire debris as a means to detect the presence of arson accelerants normally use off-line sampling with the collection of accelerant vapours on activated charcoal strips and further pre-chemistry prior to analysis. An alternative method for the direct detection of arson accelerants that requires no sample pre-treatment is described here. The analysis uses proton transfer reaction mass spectrometry (PTR-MS), incorporating a time-of-flight mass spectrometer for rapid multichannel compound detection. It is demonstrated that using PTR-MS volatile organic compound (VOC) fingerprints of a given fire accelerant can be collected by simple head space analysis of accelerant burned materials. Using a set of the four most common arson accelerants and four common household building materials, characteristic VOC fingerprints are shown to provide successful identification of the accelerant used to burn each material. There is the potential to develop this methodology for the rapid screening of large numbers of samples.

  6. Analyzing powers and proton spin transfer coefficients in the elastic scattering of 800 MeV polarized protons from an L-type polarized deuteron target at small momentum transfers

    SciTech Connect

    Adams, D.L.

    1986-10-01

    Analyzing powers and spin transfer coefficients which describe the elastic scattering of polarized protons from a polarized deuteron target have been measured. The energy of the proton beam was 800 MeV and data were taken at laboratory scattering angles of 7, 11, 14, and 16.5 degrees. One analyzing power was also measured at 180 degrees. Three linearly independent orientations of the beam polarization were used and the target was polarized parallel and antiparallel to the direction of the beam momentum. The data were taken with the high resolution spectrometer at the Los Alamos Meson Physics Facility (experiment 685). The results are compared with multiple scattering predictions based on Dirac representations of the nucleon-nucleon scattering matrices. 27 refs., 28 figs., 4 tabs.

  7. How to produce a reactor neutron spectrum using a proton accelerator

    SciTech Connect

    Burns, Kimberly A.; Wootan, David W.; Gates, Robert O.; Schmitt, Bruce E.; Asner, David M.

    2015-01-01

    A method for reproducing the neutron energy spectrum present in the core of an operating nuclear reactor using an engineered target in an accelerator proton beam is proposed. The protons interact with a target to create neutrons through various (p,n) type reactions. Spectral tailoring of the emitted neutrons can be used to modify the energy of the generated neutron spectrum to represent various reactor spectra. Through the use of moderators and reflectors, the neutron spectrum can be modified to reproduce many different spectra of interest including spectra in small thermal test reactors, large pressurized water reactors, and fast reactors. The particular application of this methodology is the design of an experimental approach for using an accelerator to measure the betas produced during fission to be used to reduce uncertainties in the interpretation of reactor antineutrino measurements. This approach involves using a proton accelerator to produce a neutron field representative of a power reactor, and using this neutron field to irradiate fission foils of the primary isotopes contributing to fission in the reactor, creating unstable, neutron rich fission products that subsequently beta decay and emit electron antineutrinos. A major advantage of an accelerator neutron source over a neutron beam from a thermal reactor is that the fast neutrons can be slowed down or tailored to approximate various power reactor spectra. An accelerator based neutron source that can be tailored to match various reactor neutron spectra provides an advantage for control in studying how changes in the neutron spectra affect parameters such as the resulting fission product beta spectrum.

  8. Conceptual design of a nonscaling fixed field alternating gradient accelerator for protons and carbon ions for charged particle therapy

    NASA Astrophysics Data System (ADS)

    Peach, K. J.; Aslaninejad, M.; Barlow, R. J.; Beard, C. D.; Bliss, N.; Cobb, J. H.; Easton, M. J.; Edgecock, T. R.; Fenning, R.; Gardner, I. S. K.; Hill, M. A.; Owen, H. L.; Johnstone, C. J.; Jones, B.; Jones, T.; Kelliher, D. J.; Khan, A.; Machida, S.; McIntosh, P. A.; Pattalwar, S.; Pasternak, J.; Pozimski, J.; Prior, C. R.; Rochford, J.; Rogers, C. T.; Seviour, R.; Sheehy, S. L.; Smith, S. L.; Strachan, J.; Tygier, S.; Vojnovic, B.; Wilson, P.; Witte, H.; Yokoi, T.

    2013-03-01

    The conceptual design for a nonscaling fixed field alternating gradient accelerator suitable for charged particle therapy (the use of protons and other light ions to treat some forms of cancer) is described.

  9. Efficient proton acceleration and focusing by an ultraintense laser interacting with a parabolic double concave target with an extended rear

    SciTech Connect

    Bake, Muhammad Ali; Xie, Bai-Song; Aimidula, Aimierding; Wang, Hong-Yu

    2013-07-15

    A new scheme for acceleration and focusing of protons via an improved parabolic double concave target irradiated by an ultraintense laser pulse is proposed. When an intense laser pulse illuminates a concave target, the hot electrons are concentrated on the focal region of the rear cavity and they form a strong space-charge-separation field, which accelerates the protons. For a simple concave target, the proton energy spectrum becomes very broad outside the rear cavity because of transverse divergence of the electromagnetic fields. However, particle-in-cell simulations show that, when the concave target has an extended rear, the hot electrons along the wall surface induce a transverse focusing sheath field, resulting in a clear enhancement of proton focusing, which makes the lower proton energy spread, while, leads to a little reduction of the proton bunch peak energy.

  10. Sub-micrometer 20MeV protons or 45MeV lithium spot irradiation enhances yields of dicentric chromosomes due to clustering of DNA double-strand breaks.

    PubMed

    Schmid, T E; Friedland, W; Greubel, C; Girst, S; Reindl, J; Siebenwirth, C; Ilicic, K; Schmid, E; Multhoff, G; Schmitt, E; Kundrát, P; Dollinger, G

    2015-11-01

    In conventional experiments on biological effects of radiation types of diverse quality, micrometer-scale double-strand break (DSB) clustering is inherently interlinked with clustering of energy deposition events on nanometer scale relevant for DSB induction. Due to this limitation, the role of the micrometer and nanometer scales in diverse biological endpoints cannot be fully separated. To address this issue, hybrid human-hamster AL cells have been irradiated with 45MeV (60keV/μm) lithium ions or 20MeV (2.6keV/μm) protons quasi-homogeneously distributed or focused to 0.5×1μm(2) spots on regular matrix patterns (point distances up to 10.6×10.6μm), with pre-defined particle numbers per spot to provide the same mean dose of 1.7Gy. The yields of dicentrics and their distribution among cells have been scored. In parallel, track-structure based simulations of DSB induction and chromosome aberration formation with PARTRAC have been performed. The results show that the sub-micrometer beam focusing does not enhance DSB yields, but significantly affects the DSB distribution within the nucleus and increases the chance to form DSB pairs in close proximity, which may lead to increased yields of chromosome aberrations. Indeed, the experiments show that focusing 20 lithium ions or 451 protons per spot on a 10.6μm grid induces two or three times more dicentrics, respectively, than a quasi-homogenous irradiation. The simulations reproduce the data in part, but in part suggest more complex behavior such as saturation or overkill not seen in the experiments. The direct experimental demonstration that sub-micrometer clustering of DSB plays a critical role in the induction of dicentrics improves the knowledge on the mechanisms by which these lethal lesions arise, and indicates how the assumptions of the biophysical model could be improved. It also provides a better understanding of the increased biological effectiveness of high-LET radiation.

  11. Fabrication of nanostructured targets for improved laser-driven proton acceleration

    NASA Astrophysics Data System (ADS)

    Barberio, M.; Scisciò, M.; Veltri, S.; Antici, P.

    2016-07-01

    In this work, we present a novel realization of nanostructured targets suitable for improving laser-driven proton acceleration experiments, in particular with regard to the Target-Normal-Sheath Acceleration (TNSA) acceleration mechanism. The nanostructured targets, produced as films, are realized by a simpler and cheaper method than using conventional lithographic techniques. The growth process includes a two step approach for the production of the gold nanoparticle layers: 1) Laser Ablation in Solution and 2) spray-dry technique using a colloidal solution on target surfaces (Aluminum, Mylar and Multi Walled Carbon Nanotube). The obtained nanostructured films appear, at morphological and chemical analysis, uniformly nanostructured and the nanostructure distributed on the target surfaces without presence of oxides or external contaminants. The obtained targets show a broad optical absorption in all the visible region and a surface roughness that is two times greater than non-nanostructured targets, enabling a greater laser energy absorption during the laser-matter interaction experiments producing the laser-driven proton acceleration.

  12. Proton and Helium Injection Into First Order Fermi Acceleration at Shocks: Hybrid Simulation and Analysis

    NASA Astrophysics Data System (ADS)

    Dudnikova, Galina; Malkov, Mikhail; Sagdeev, Roald; Liseykina, Tatjana; Hanusch, Adrian

    2016-10-01

    Elemental composition of galactic cosmic rays (CR) probably holds the key to their origin. Most likely, they are accelerated at collisionless shocks in supernova remnants, but the acceleration mechanism is not entirely understood. One complicated problem is ``injection'', a process whereby the shock selects a tiny fraction of particles to keep on crossing its front and gain more energy. Comparing the injection rates of particles with different mass to charge ratio is a powerful tool for studying this process. Recent advances in measurements of CR He/p ratio have provided particularly important new clues. We performed a series of hybrid simulations and analyzed a joint injection of protons and Helium, in conjunction with upstream waves they generate. The emphasis of this work is on the bootstrap aspects of injection manifested in particle confinement to the shock and, therefore, their continuing acceleration by the self-driven waves. The waves are initially generated by He and protons in separate spectral regions, and their interaction plays a crucial role in particle acceleration. The work is ongoing and new results will be reported along with their analysis and comparison with the latest data from the AMS-02 space-based spectrometer. Work supported Grant RFBR 16-01-00209, NASA ATP-program under Award NNX14AH36G, and by the US Department of Energy under Award No. DE-FG02-04ER54738.

  13. Effective generation of the spread-out-Bragg peak from the laser accelerated proton beams using a carbon-proton mixed target.

    PubMed

    Yoo, Seung Hoon; Cho, Ilsung; Cho, Sungho; Song, Yongkeun; Jung, Won-Gyun; Kim, Dae-Hyun; Shin, Dongho; Lee, Se Byeong; Pae, Ki-Hong; Park, Sung Yong

    2014-12-01

    Conventional laser accelerated proton beam has broad energy spectra. It is not suitable for clinical use directly, so it is necessary for employing energy selection system. However, in the conventional laser accelerated proton system, the intensity of the proton beams in the low energy regime is higher than that in the high energy regime. Thus, to generate spread-out-Bragg peak (SOBP), stronger weighting value to the higher energy proton beams is needed and weaker weighting value to the lower energy proton beams is needed, which results in the wide range of weighting values. The purpose of this research is to investigate a method for efficient generating of the SOBP with varying magnetic field in the energy selection system using a carbon-proton mixture target. Energy spectrum of the laser accelerated proton beams was acquired using Particle-In-Cell simulations. The Geant4 Monte Carlo simulation toolkit was implemented for energy selection, particle transportation, and dosimetric property measurement. The energy selection collimator hole size of the energy selection system was changed from 1 to 5 mm in order to investigate the effect of hole size on the dosimetric properties for Bragg peak and SOBP. To generate SOBP, magnetic field in the energy selection system was changed during beam irradiation with each beam weighting factor. In this study, our results suggest that carbon-proton mixture target based laser accelerated proton beams can generate quasi-monoenergetic energy distribution and result in the efficient generation of SOBP. A further research is needed to optimize SOBP according to each range and modulated width using an optimized weighting algorithm.

  14. ELECTROMAGNETIC AND THERMAL SIMULATIONS FOR THE SWITCH REGION OF A COMPACT PROTON ACCELERATOR

    SciTech Connect

    Wang, L; Caporaso, G J; Sullivan, J S

    2007-06-15

    A compact proton accelerator for medical applications is being developed at Lawrence Livermore National Laboratory. The accelerator architecture is based on the dielectric wall accelerator (DWA) concept. One critical area to consider is the switch region. Electric field simulations and thermal calculations of the switch area were performed to help determine the operating limits of rmed SiC switches. Different geometries were considered for the field simulation including the shape of the thin Indium solder meniscus between the electrodes and SiC. Electric field simulations were also utilized to demonstrate how the field stress could be reduced. Both transient and steady steady-state thermal simulations were analyzed to find the average power capability of the switches.

  15. Generation of 500 MeV-1 GeV energy electrons from laser wakefield acceleration via ionization induced injection using CO{sub 2} mixed in He

    SciTech Connect

    Mo, M. Z.; Ali, A.; Fedosejevs, R.; Fourmaux, S.; Lassonde, P.; Kieffer, J. C.

    2013-04-01

    Laser wakefield acceleration of 500 MeV to 1 GeV electron bunches has been demonstrated using ionization injection in mixtures of 4% to 10% of CO{sub 2} in He. 80 TW laser pulses were propagated through 5 mm gas jet targets at electron densities of 0.4-1.5 Multiplication-Sign 10{sup 19}cm{sup -3}. Ionization injection led to lower density thresholds, a higher total electron charge, and an increased probability of producing electrons above 500 MeV in energy compared to self-injection in He gas alone. Electrons with GeV energies were also observed on a few shots and indicative of an additional energy enhancement mechanism.

  16. Neutron beams from protons on beryllium.

    PubMed

    Bewley, D K; Meulders, J P; Octave-Prignot, M; Page, B C

    1980-09-01

    Measurements of dose rate and penetration in water have been made for neutron beams produced by 30--75 MeV protons on beryllium. The effects of Polythene filters added on the target side of the collimator have also been studied. A neutron beam comparable with a photon beam from a 4--8 MeV linear accelerator can be produced with p/Be neutrons plus 5 cm Polythene filtrations, with protons in the range 50--75 MeV. This is a more economical method than use of the d/Be reaction.

  17. SU-E-T-554: Monte Carlo Calculation of Source Terms and Attenuation Lengths for Neutrons Produced by 50–200 MeV Protons On Brass

    SciTech Connect

    Ramos-Mendez, J; Faddegon, B; Paganetti, H

    2015-06-15

    Purpose: We used TOPAS (TOPAS wraps and extends Geant4 for medical physicists) to compare Geant4 physics models with published data for neutron shielding calculations. Subsequently, we calculated the source terms and attenuation lengths (shielding data) of the total ambient dose equivalent (TADE) in concrete for neutrons produced by protons in brass. Methods: Stage1: The Bertini and Binary nuclear models available in Geant4 were compared with published attenuation at depth of the TADE in concrete and iron. Stage2: Shielding data of the TADE in concrete was calculated for 50– 200 MeV proton beams on brass. Stage3: Shielding data from Stage2 was extrapolated for 235 MeV proton beams. This data was used in a point-line-source analytical model to calculate the ambient dose per unit therapeutic dose at two locations inside one treatment room at the Francis H Burr Proton Therapy Center. Finally, we compared these results with experimental data and full TOPAS simulations. Results: At larger angles (∼130o) the TADE in concrete calculated with the Bertini model was about 9 times larger than that calculated with the Binary model. The attenuation length in concrete calculated with the Binary model agreed with published data within 7%±0.4% (statistical uncertainty) for the deepest regions and 5%±0.1% for shallower regions. For iron the agreement was within 3%±0.1%. The ambient dose per therapeutic dose calculated with the Binary model, relative to the experimental data, was a ratio of 0.93±0.16 and 1.23±0.24 for two locations. The analytical model overestimated the dose by four orders of magnitude. These differences are attributed to the complexity of the geometry. Conclusion: The Binary and Bertini models gave comparable results, with the Binary model giving the best agreement with published data at large angle. Shielding data we calculated using the Binary model is useful for fast shielding calculations with other analytical models. This work was supported by

  18. Evaluation of irradiation effects of 16 MeV proton-irradiated 12Cr-1MoV steel by small punch (SP) tests

    SciTech Connect

    Chi, S.H.; Hong, J.H. ); Kim, I.S. . Dept. of Nuclear Engineering)

    1994-06-15

    Recently, interest in small-scale specimens for testing irradiated materials has arisen in conjunction with the need to develop materials for fusion reactor materials and to study irradiation effects using an ion irradiation facility. Several attempts have been made to evaluate material property changes due to irradiation using a small specimen technique. The SP (small punch) test is an example of small-scale specimen test techniques, originally developed by Baik et al. to estimate DBTT (ductile-to-brittle transition temperature) using broken standard CVN (Charpy 5-notch) specimens. The objective of the present study is to evaluate 16 MeV proton irradiation effects on a fusion reactor candidate material in terms of changes in energy up to failure and J[sub IC] fracture toughness (SP J[sub IC]) by using a SP test technique and a J[sub IC] - [bar [epsilon

  19. Vacancy-related defects in n-type Si implanted with a rarefied microbeam of accelerated heavy ions in the MeV range

    NASA Astrophysics Data System (ADS)

    Capan, I.; Pastuović, Ž.; Siegele, R.; Jaćimović, R.

    2016-04-01

    Deep level transient spectroscopy (DLTS) has been used to study vacancy-related defects formed in bulk n-type Czochralski-grown silicon after implantation of accelerated heavy ions: 6.5 MeV O, 10.5 MeV Si, 10.5 MeV Ge, and 11 MeV Er in the single ion regime with fluences from 109 cm-2 to 1010 cm-2 and a direct comparison made with defects formed in the same material irradiated with 0.7 MeV fast neutron fluences up to 1012 cm-2. A scanning ion microprobe was used as the ion implantation tool of n-Cz:Si samples prepared as Schottky diodes, while the ion beam induced current (IBIC) technique was utilized for direct ion counting. The single acceptor state of the divacancy V2(-/0) is the most prominent defect state observed in DLTS spectra of n-CZ:Si samples implanted by selected ions and the sample irradiated by neutrons. The complete suppression of the DLTS signal related to the double acceptor state of divacancy, V2(=/-) has been observed in all samples irradiated by ions and neutrons. Moreover, the DLTS peak associated with formation of the vacancy-oxygen complex VO in the neutron irradiated sample was also completely suppressed in DLTS spectra of samples implanted with the raster scanned ion microbeam. The reason for such behaviour is twofold, (i) the local depletion of the carrier concentration in the highly disordered regions, and (ii) the effect of the microprobe-assisted single ion implantation. The activation energy for electron emission for states assigned to the V2(-/0) defect formed in samples implanted by single ions follows the Meyer-Neldel rule. An increase of the activation energy is strongly correlated with increasing ion mass.

  20. ELECTRON AND PROTON ACCELERATION DURING THE FIRST GROUND LEVEL ENHANCEMENT EVENT OF SOLAR CYCLE 24

    SciTech Connect

    Li, C.; Sun, L. P.; Firoz, Kazi A.; Miroshnichenko, L. I.

    2013-06-10

    High-energy particles were recorded by near-Earth spacecraft and ground-based neutron monitors (NMs) on 2012 May 17. This event was the first ground level enhancement (GLE) of solar cycle 24. In this study, we try to identify the acceleration source(s) of solar energetic particles by combining in situ particle measurements from the WIND/3DP, GOES 13, and solar cosmic rays registered by several NMs, as well as remote-sensing solar observations from SDO/AIA, SOHO/LASCO, and RHESSI. We derive the interplanetary magnetic field (IMF) path length (1.25 {+-} 0.05 AU) and solar particle release time (01:29 {+-} 00:01 UT) of the first arriving electrons by using their velocity dispersion and taking into account contamination effects. We found that the electron impulsive injection phase, indicated by the dramatic change in the spectral index, is consistent with flare non-thermal emission and type III radio bursts. Based on the potential field source surface concept, modeling of the open-field lines rooted in the active region has been performed to provide escape channels for flare-accelerated electrons. Meanwhile, relativistic protons are found to be released {approx}10 minutes later than the electrons, assuming their scatter-free travel along the same IMF path length. Combining multi-wavelength imaging data of the prominence eruption and coronal mass ejection (CME), we obtain evidence that GLE protons, with an estimated kinetic energy of {approx}1.12 GeV, are probably accelerated by the CME-driven shock when it travels to {approx}3.07 solar radii. The time-of-maximum spectrum of protons is typical for shock wave acceleration.

  1. Relative biological effectiveness of the 60-MeV therapeutic proton beam at the Institute of Nuclear Physics (IFJ PAN) in Kraków, Poland.

    PubMed

    Słonina, Dorota; Biesaga, Beata; Swakoń, Jan; Kabat, Damian; Grzanka, Leszek; Ptaszkiewicz, Marta; Sowa, Urszula

    2014-11-01

    The aim of the study was to determine the relative biological effectiveness (RBE) of a 60-MeV proton radiotherapy beam at the Institute of Nuclear Physics, Polish Academy of Sciences (IFJ PAN) in Kraków, the first one to operate in Poland. RBE was assessed at the surviving fractions (SFs) of 0.01, 0.1, and 0.37, for normal human fibroblasts from three cancer patients. The cells were irradiated near the Bragg peak of the pristine beam and at three depths within a 28.4-mm spread-out Bragg peak (SOBP). Reference radiation was provided by 6-MV X-rays. The mean RBE value at SF = 0.01 for fibroblasts irradiated near the Bragg peak of pristine beam ranged between 1.06 and 1.15. The mean RBE values at SF = 0.01 for these cells exposed at depths of 2, 15, and 27 mm of the SOBP ranged between 0.95-1.00, 0.97-1.02, and 1.05-1.11, respectively. A trend was observed for RBE values to increase with survival level and with depth in the SOBP: at SF = 0.37 and at the depth of 27 mm, RBE values attained their maximum (1.19-1.24). The RBE values estimated at SF = 0.01 using normal human fibroblasts for the 60-MeV proton radiotherapy beam at the IFJ PAN in Kraków are close to values of 1.0 and 1.1, used in clinical practice.

  2. Initial experimental evidence of self-collimation of target-normal-sheath-accelerated proton beam in a stack of conducting foils

    SciTech Connect

    Ni, P. A.; Bieniosek, F. M.; Logan, B. G.; Lund, S. M.; Barnard, J. J.; Bellei, C.; Cohen, R. H.; McGuffey, C.; Beg, F. N.; Kim, J.; Alexander, N.; Aurand, B.; Brabetz, C.; Neumayer, P.; Roth, M.

    2013-08-15

    Phenomena consistent with self-collimation (or weak self-focusing) of laser target-normal-sheath-accelerated protons was experimentally observed for the first time, in a specially engineered structure (“lens”) consisting of a stack of 300 thin aluminum foils separated by 50 μm vacuum gaps. The experiments were carried out in a “passive environment,” i.e., no external fields applied, neutralization plasma or injection of secondary charged particles was imposed. Experiments were performed at the petawatt “PHELIX” laser user facility (E = 100 J, Δt = 400 fs, λ = 1062 nm) at the “Helmholtzzentrum für Schwerionenforschung–GSI” in Darmstadt, Germany. The observed rms beam spot reduction depends inversely on energy, with a focusing degree decreasing monotonically from 2 at 5.4 MeV to 1.5 at 18.7 MeV. The physics inside the lens is complex, resulting in a number of different mechanisms that can potentially affect the particle dynamics within the structure. We present a plausible simple interpretation of the experiment in which the combination of magnetic self-pinch forces generated by the beam current together with the simultaneous reduction of the repulsive electrostatic forces due to the foils are the dominant mechanisms responsible for the observed focusing/collimation. This focusing technique could be applied to a wide variety of space-charge dominated proton and heavy ion beams and impact fields and applications, such as HEDP science, inertial confinement fusion in both fast ignition and heavy ion fusion approaches, compact laser-driven injectors for a Linear Accelerator (LINAC) or synchrotron, medical therapy, materials processing, etc.

  3. Initial experimental evidence of self-collimation of target-normal-sheath-accelerated proton beam in a stack of conducting foils

    NASA Astrophysics Data System (ADS)

    Ni, P. A.; Lund, S. M.; McGuffey, C.; Alexander, N.; Aurand, B.; Barnard, J. J.; Beg, F. N.; Bellei, C.; Bieniosek, F. M.; Brabetz, C.; Cohen, R. H.; Kim, J.; Neumayer, P.; Roth, M.; Logan, B. G.

    2013-08-01

    Phenomena consistent with self-collimation (or weak self-focusing) of laser target-normal-sheath-accelerated protons was experimentally observed for the first time, in a specially engineered structure ("lens") consisting of a stack of 300 thin aluminum foils separated by 50 μm vacuum gaps. The experiments were carried out in a "passive environment," i.e., no external fields applied, neutralization plasma or injection of secondary charged particles was imposed. Experiments were performed at the petawatt "PHELIX" laser user facility (E = 100 J, Δt = 400 fs, λ = 1062 nm) at the "Helmholtzzentrum für Schwerionenforschung-GSI" in Darmstadt, Germany. The observed rms beam spot reduction depends inversely on energy, with a focusing degree decreasing monotonically from 2 at 5.4 MeV to 1.5 at 18.7 MeV. The physics inside the lens is complex, resulting in a number of different mechanisms that can potentially affect the particle dynamics within the structure. We present a plausible simple interpretation of the experiment in which the combination of magnetic self-pinch forces generated by the beam current together with the simultaneous reduction of the repulsive electrostatic forces due to the foils are the dominant mechanisms responsible for the observed focusing/collimation. This focusing technique could be applied to a wide variety of space-charge dominated proton and heavy ion beams and impact fields and applications, such as HEDP science, inertial confinement fusion in both fast ignition and heavy ion fusion approaches, compact laser-driven injectors for a Linear Accelerator (LINAC) or synchrotron, medical therapy, materials processing, etc.

  4. INJECTION ACCELERATION AND EXTRACTION OF HIGH INTENSITY PROTON BEAM FOR THE NEUTRINO FACILITY PROJECT AT BNL.

    SciTech Connect

    Tsoupas, N; Barton, D; Ganetis, G; Jain, A; Lee, Y; Marneris, I; Meng, W; Raparia, D; Roser, T; Ruggiero, A; Tuozzolo, J; Wanderer, P; Weng, W

    2003-05-12

    The proposed ''neutrino-production'' project [1.2] to be built at the Brookhaven National Laboratory (BNL) requires that the neutrino-production target be bombarded by a high intensity proton beam-pulse of {approx} 90 x 10{sup 12} protons of 28 GeV in energy and at a rate of 2.5 Hz, resulting in a 1 MW power of proton beam deposited on the target for the production of the neutrinos. In this paper we investigate the possibility of producing this high intensity proton beam, using as the main accelerator the Alternating Gradient Synchrotron (AGS) at the Brookhaven National Laboratory (BNL). The following aspects of the project are reported in this paper: (a) The beam injection into the AGS synchrotron of 1.2 GeV H{sup -} beam produced by a super-conducting LINAC[3]; (b) The effect of the eddy currents induced on the vacuum chamber of the circulating beam during the ''ramping'' of the main magnets of the AGS; (c) The method of the beam extraction from the AGS and the optics of the 28 GeV beam extracted from the AGS.

  5. Improved spectral data unfolding for radiochromic film imaging spectroscopy of laser-accelerated proton beams.

    PubMed

    Schollmeier, M; Geissel, M; Sefkow, A B; Flippo, K A

    2014-04-01

    An improved method to unfold the space-resolved proton energy distribution function of laser-accelerated proton beams using a layered, radiochromic film (RCF) detector stack has been developed. The method takes into account the reduced RCF response near the Bragg peak due to a high linear energy transfer (LET). This LET dependence of the active RCF layer has been measured, and published data have been re-interpreted to find a nonlinear saturation scaling of the RCF response with stopping power. Accounting for the LET effect increased the integrated particle yield by 25% after data unfolding. An iterative, analytical, space-resolved deconvolution of the RCF response functions from the measured dose was developed that does not rely on fitting. After the particle number unfold, three-dimensional interpolation is performed to determine the spatial proton beam distribution for proton energies in-between the RCF data points. Here, image morphing has been implemented as a novel interpolation method that takes into account the energy-dependent, changing beam topology.

  6. Robust energy enhancement of ultrashort pulse laser accelerated protons from reduced mass targets

    NASA Astrophysics Data System (ADS)

    Zeil, K.; Metzkes, J.; Kluge, T.; Bussmann, M.; Cowan, T. E.; Kraft, S. D.; Sauerbrey, R.; Schmidt, B.; Zier, M.; Schramm, U.

    2014-08-01

    This paper reports on a systematic investigation of the ultrashort pulse laser driven acceleration of protons from thin targets of finite size, so-called reduced mass targets (RMTs). Reproducible series of targets, manufactured with lithographic techniques, and varying in size, thickness, and mounting geometry, were irradiated with ultrashort (30 fs) laser pulses of intensities of about 8 × 1020 W cm-2. A robust maximum energy enhancement of almost a factor of two was found when comparing gold RMTs to reference irradiations of plain gold foils of the same thickness. Furthermore, a change of the thickness of these targets has less influence on the measured maximum proton energy when compared to standard foils, which, based on detailed particle-in-cell simulations, can be explained by the influence of the RMT geometry on the electron sheath. The performance gain was, however, restricted to lateral target sizes of greater than 50 µm, which can be attributed to edge and mounting structure influences.

  7. Proton-impact ionization cross sections of adenine measured at 0.5 and 2.0 MeV by electron spectroscopy

    SciTech Connect

    Iriki, Y.; Kikuchi, Y.; Imai, M.; Itoh, A.

    2011-11-15

    Double-differential ionization cross sections (DDCSs) of vapor-phase adenine molecules (C{sub 5}H{sub 5}N{sub 5}) by 0.5- and 2.0-MeV proton impact have been measured by the electron spectroscopy method. Electrons ejected from adenine were analyzed by a 45 Degree-Sign parallel-plate electrostatic spectrometer over an energy range of 1.0-1000 eV at emission angles from 15 Degree-Sign to 165 Degree-Sign . Single-differential cross sections (SDCSs) and total ionization cross sections (TICSs) were also deduced. It was found from the Platzman plot, defined as SDCSs divided by the classical Rutherford knock-on cross sections per target electron, that the SDCSs at higher electron energies are proportional to the total number of valence electrons (50) of adenine, while those at low-energy electrons are highly enhanced due to dipole and higher-order interactions. The present results of TICS are in fairly good agreement with recent classical trajectory Monte Carlo calculations, and moreover, a simple analytical formula gives nearly equivalent cross sections in magnitude at the incident proton energies investigated.

  8. A SHORTCUT FORMULA FOR THE 230-MeV PROTON-INDUCED NEUTRON DOSE EQUIVALENT IN CONCRETE AFTER A METAL SHIELD, DERIVED FROM MONTE CARLO SIMULATIONS WITH MCNPX.

    PubMed

    Taal, A; van der Kooij, A; Okx, W J C

    2016-11-01

    Monte Carlo simulations were performed with MCNPX to determine the neutron dose equivalent in thick concrete after a metal shield, a double-layered shielding configuration. In the simulations, a 230-MeV proton beam impinging on a copper target was used to produce the neutrons. For forward angles up to 30° with respect to the proton beam, it is found that the neutron dose equivalent in thick concrete after a metal layer can be expressed in a single formula. This single formula being the neutron dose equivalent formula for a single thick concrete shield enhanced with an additional exponential term. The exponent of this additional exponential term is related to the relative macroscopic neutron removal cross section of the metal with respect to the concrete. The single formula found fits MCNPX data for the neutron dose equivalent in thick concrete after layers of metal ranging from beryllium to lead. First attempts were made to make this shortcut formula applicable to alloys and compounds of metals.

  9. Proton-impact ionization cross sections of adenine measured at 0.5 and 2.0 MeV by electron spectroscopy

    NASA Astrophysics Data System (ADS)

    Iriki, Y.; Kikuchi, Y.; Imai, M.; Itoh, A.

    2011-11-01

    Double-differential ionization cross sections (DDCSs) of vapor-phase adenine molecules (C5H5N5) by 0.5- and 2.0-MeV proton impact have been measured by the electron spectroscopy method. Electrons ejected from adenine were analyzed by a 45∘ parallel-plate electrostatic spectrometer over an energy range of 1.0-1000 eV at emission angles from 15∘ to 165∘. Single-differential cross sections (SDCSs) and total ionization cross sections (TICSs) were also deduced. It was found from the Platzman plot, defined as SDCSs divided by the classical Rutherford knock-on cross sections per target electron, that the SDCSs at higher electron energies are proportional to the total number of valence electrons (50) of adenine, while those at low-energy electrons are highly enhanced due to dipole and higher-order interactions. The present results of TICS are in fairly good agreement with recent classical trajectory Monte Carlo calculations, and moreover, a simple analytical formula gives nearly equivalent cross sections in magnitude at the incident proton energies investigated.

  10. Measurement of proton induced thick target γ-ray yields on B, N, Na, Al and Si from 2.5 to 4.1 MeV

    NASA Astrophysics Data System (ADS)

    Chiari, M.; Ferraccioli, G.; Melon, B.; Nannini, A.; Perego, A.; Salvestrini, L.; Lagoyannis, A.; Preketes-Sigalas, K.

    2016-01-01

    Thick target yields for proton induced γ-ray emission (PIGE) on low-Z nuclei, namely B, N, Na, Al and Si, were measured for proton energies from 2.5 to 4.1 MeV and emission angles of 0°, 45° and 90°, at the 3 MV Tandetron laboratory of INFN-LABEC in Florence. The studied reactions were: 10B(p,α‧γ)7Be (Eγ = 429 keV), 10B(p,p‧γ)10B (Eγ = 718 keV) and 11B(p,p‧γ)11B (Eγ = 2125 keV) for boron; 14N(p,p‧γ)14N (Eγ = 2313 keV) for nitrogen; 23Na(p,p‧γ)23Na (Eγ = 441 and 1636 keV) and 23Na(p,α‧γ)20Ne (Eγ = 1634 keV) for sodium; 27Al(p,p‧γ)27Al (Eγ = 844 and 1014 keV) and 27Al(p,α‧γ)24Mg (Eγ = 1369 keV) for aluminum; 28Si(p,p‧γ)28Si (Eγ = 1779 keV) and 29Si(p,p‧γ)29Si (Eγ = 1273 keV) for silicon. The PIGE thick target yields have been measured with an overall uncertainty typically better than 10%. The use of the measured thick target yield to benchmark and validate experimental cross sections available in the literature is demonstrated.

  11. Measurements of proton induced γ-ray emission cross sections on MgF2 target in the energy range 1.95-3.05 MeV

    NASA Astrophysics Data System (ADS)

    Zamboni, I.; Siketić, Z.; Jakšić, M.; Bogdanović Radović, I.

    2015-01-01

    In this work we present differential cross sections for γ-ray emission from the reactions 19F(p,p‧γ)19F (Eγ = 110, 197, 1236 and 1349 + 1357 keV), 24Mg(p,p‧γ)24Mg (Eγ = 1369 keV) and 25Mg(p,p‧γ)25Mg (Eγ = 390, 585 and 975 keV). Differential cross sections were measured for proton energies from 1.95 to 3.05 MeV with a 15 keV step and beam energy resolution of 0.06%. Thin reference standard, 54.1 μg/cm2 of MgF2 deposited on thin Mylar foil with additionally evaporated 4 nm Au layer, was used as a target. The γ-rays were detected by a 20% relative efficiency HPGe detector placed at an angle of 135° with respect to the beam direction, while the backscattered protons were collected using silicon surface barrier detector placed at the scattering angle of 165°. Obtained cross sections were compared with the previously measured data available from the literature.

  12. Cross sections for production of the 15.10 MeV and other astrophysically significant gamma-ray lines through excitation and spallation of sup 12 C and sup 16 O with protons

    NASA Technical Reports Server (NTRS)

    Lang, F. L.; Werntz, C. W.; Crannell, C. J.; Trombka, J. I.; Chang, C. C.

    1986-01-01

    The ratio of the flux of 15.10-MeV gamma rays to the flux of 4.438-MeV gamma rays resulting from excitation of the corresponding states in C-12 as a sensitive measure of the spectrum of the exciting particles produced in solar flares and other cosmic sources. These gamma rays are produced predominantly by interactions with C-12 and O-16, both of which are relatively abundant in the solar photosphere. Gamma ray production cross sections for proton interactions have been reported previously for all important channels except for the production of 15.10-MeV gamma rays from O-16. The first reported measurement of the 15.10-MeV gamma ray production cross section from p + O-16 is presented here. The University of Maryland cyclotron was employed to produce 40-, 65-, and 86-MeV protons which interacted with CH2 and BeO targets. The resultant gamma ray spectra were measured with a high-purity germanium semiconductor detector at 70, 90, 110, 125, and 140 degrees relative to the direction of the incident beam for each proton energy. Other gamma ray lines resulting from direct excitation and spallation reactions with C-12 and 0-16 were observed as well, and their gamma ray production cross sections described.

  13. Capsule Areal-Density Asymmetries and Time Evolution Inferred from 14.7-MeV Proton Line Structure in OMEGA D^3He Implosions

    NASA Astrophysics Data System (ADS)

    Li, C. K.

    2002-11-01

    The fusion of D^3He in spherical capsule implosions results in copious production of 14.7-MeV protons. As these protons pass through the plasma, they lose energy. Importantly, this energy loss reflects the areal density (ρL) of the plasma transited. Up to 11 proton spectrometers simultaneously view D^3He implosions from different directions. While the burn-averaged and spatially averaged ρL for each implosion is typically between 50 to 75 mg/cm^2 within a group of similar implosions, there are often significant differences between the individual spectra of a given shot, in both their average implied ρL ( ˜50% about the mean) and in the low-energy tail. Some of these low-mode (ℓ ˜ 1) individual-shot asymmetries are attributable to laser drive asymmetry. However, for small amounts of energy imbalance (<=5% rms), the measured asymmetries are found to be uncorrelated with UV-measured laser imbalance. This indicates that other sources of asymmetry, such as capsule asymmetries, may play a role. In addition to nonuniformities, time evolution is the other important component to line broadening and spectral shape. To most clearly elucidate this effect, implosions of 24-μm-thick CH capsules were conducted. In a 400-ps period between first shock coalescence and compression, the spatially averaged ρL changes from ˜ 8 to ˜ 70 mg/cm^2. An important issue is whether the shell asymmetries could have already been established at the time of first shock coalescence. Supported in part by the U.S. D.O.E. Office of Inertial Confinement Fusion (Grant DE-FG03-99DP00300; Cooperative Agreement DE-FC03-92SF19460), LLE (subcontract P0410025G), LLNL (subcontract B313975). (Petrasso: Visiting Senior Scientist at LLE.)

  14. Measurement of transmission efficiency for 400 MeV proton beam through collimator at Fermilab MuCool Test Area using Chromox-6 scintillation screen

    NASA Astrophysics Data System (ADS)

    Jana, M. R.; Chung, M.; Freemire, B.; Hanlet, P.; Leonova, M.; Moretti, A.; Palmer, M.; Schwarz, T.; Tollestrup, A.; Torun, Y.; Yonehara, K.

    2013-06-01

    The MuCool Test Area (MTA) at Fermilab is a facility to develop the technology required for ionization cooling for a future Muon Collider and/or Neutrino Factory. As part of this research program, feasibility studies of various types of RF cavities in a high magnetic field environment are in progress. As a unique approach, we have tested a RF cavity filled with a high pressure hydrogen gas with a 400 MeV proton beam in an external magnetic field (B = 3 T). Quantitative information about the number of protons passing through this cavity is an essential requirement of the beam test. The MTA is a flammable gas (hydrogen) hazard zone. Due to safety reasons, no active (energized) beam diagnostic instrument can be used. Moreover, when the magnetic field is on, current transformers (toroids) used for beam intensity measurements do not work due to the saturation of the ferrite material of the transformer. Based on these requirements, we have developed a passive beam diagnostic instrumentation using a combination of a Chromox-6 scintillation screen and CCD camera. This paper describes details of the beam profile and position obtained from the CCD image with B = 0 T and B = 3 T, and for high and low intensity proton beams. A comparison is made with beam size obtained from multi-wires detector. Beam transmission efficiency through a collimator with a 4 mm diameter hole is measured by the toroids and CCD image of the scintillation screen. Results show that the transmission efficiency estimated from the CCD image is consistent with the toroid measurement, which enables us to monitor the beam transmission efficiency even in a high magnetic field environment.

  15. ACCELERATION OF POLARIZED PROTONS IN THE AGS WITH TWO HELICAL PARTIAL SNAKES.

    SciTech Connect

    HUANG,H.; AHRENS,L.; BAI,M.; ET AL.

    2005-05-16

    The RHIC spin program requires 2 x 10{sup 11} proton/bunch with 70% polarization. As the injector to RHIC, AGS is the bottleneck for preserving polarization: there is no space for a full snake to overcome numerous depolarizing resonances. An ac dipole and a partial snake have been used to preserve beam polarization in the past few years. Two helical snakes have been built and installed in the AGS. With careful setup of optics at injection and along the ramp, this combination can eliminate all depolarizing resonances encountered during acceleration. This paper presents the setup and preliminary results.

  16. On the non-thermal electron-to-proton ratio at cosmic ray acceleration sites

    NASA Astrophysics Data System (ADS)

    Merten, Lukas; Becker Tjus, Julia; Eichmann, Björn; Dettmar, Ralf-Jürgen

    2017-04-01

    The luminosity ratio of electrons to protons as it is produced in stochastic acceleration processes in cosmic ray sources is an important quantity relevant for several aspects of the modeling of the sources themselves. It is usually assumed to be around 1: 100 in the case of Galactic sources, while a value of 1: 10 is typically assumed when describing extragalactic sources. It is supported by observations that the average ratios should be close to these values. At this point, however, there is no possibility to investigate how each individual source behaves. When looking at the physics aspects, a 1: 100 ratio is well supported in theory when making the following assumptions: (1) the total number of electrons and protons that is accelerated are the same; (2) the spectral index of both populations after acceleration is αe =αp ≈ 2.2 . In this paper, we reinvestigate these assumptions. In particular, assumption (2) is not supported by observational data of the sources and PIC simulation yield different spectral indices as well. We present the detailed calculation of the electron-to-proton ratio, dropping the assumption of equal spectral indices. We distinguish between the ratio of luminosities and the ratio of the differential spectral behavior, which becomes necessary for cases where the spectral indices of the two particle populations are not the same. We discuss the possible range of values when allowing for different spectral indices concerning the spectral behavior of electrons and protons. Additionally, it is shown that the minimum energy of the accelerated population can have a large influence on the results. We find, in the case of the classical minimum energy of T0 , e =T0 , p = 10 keV, that when allowing for a difference in the spectral indices of up to 0.1 with absolute spectral indices varying between 2.0 < α < 2.3, the luminosity ratio varies between 0.008 < Kep < 0.12. The differential particle number ratio is in the range 0.008

  17. LATTICES FOR HIGH-POWER PROTON BEAM ACCELERATION AND SECONDARY BEAM COLLECTION AND COOLING.

    SciTech Connect

    WANG, S.; WEI, J.; BROWN, K.; GARDNER, C.; LEE, Y.Y.; LOWENSTEIN, D.; PEGGS, S.; SIMOS, N.

    2006-06-23

    Rapid cycling synchrotrons are used to accelerate high-intensity proton beams to energies of tens of GeV for secondary beam production. After primary beam collision with a target, the secondary beam can be collected, cooled, accelerated or decelerated by ancillary synchrotrons for various applications. In this paper, we first present a lattice for the main synchrotron. This lattice has: (a) flexible momentum compaction to avoid transition and to facilitate RF gymnastics (b) long straight sections for low-loss injection, extraction, and high-efficiency collimation (c) dispersion-free straights to avoid longitudinal-transverse coupling, and (d) momentum cleaning at locations of large dispersion with missing dipoles. Then, we present a lattice for a cooler ring for the secondary beam. The momentum compaction across half of this ring is near zero, while for the other half it is normal. Thus, bad mixing is minimized while good mixing is maintained for stochastic beam cooling.

  18. Electron self-injection in the proton-driven-plasma-wakefield acceleration

    SciTech Connect

    Hu, Zhang-Hu; Wang, You-Nian

    2013-12-15

    The self-injection process of plasma electrons in the proton-driven-plasma-wakefield acceleration scheme is investigated using a two-dimensional, electromagnetic particle-in-cell method. Plasma electrons are self-injected into the back of the first acceleration bucket during the initial bubble formation period, where the wake phase velocity is low enough to trap sufficient electrons. Most of the self-injected electrons are initially located within a distance of the skin depth c/ω{sub pe} to the beam axis. A decrease (or increase) in the beam radius (or length) leads to a significant reduction in the total charges of self-injected electron bunch. Compared to the uniform plasma, the energy spread, emittance and total charges of the self-injected bunch are reduced in the plasma channel case, due to a reduced injection of plasma electrons that initially located further away from the beam axis.

  19. Multiphysics Analysis of Frequency Detuning in Superconducting RF Cavities for Proton Particle Accelerators

    SciTech Connect

    Awida, M. H.; Gonin, I.; Passarelli, D.; Sukanov, A.; Khabiboulline, T.; Yakovlev, V.

    2016-01-22

    Multiphysics analyses for superconducting cavities are essential in the course of cavity design to meet stringent requirements on cavity frequency detuning. Superconducting RF cavities are the core accelerating elements in modern particle accelerators whether it is proton or electron machine, as they offer extremely high quality factors thus reducing the RF losses per cavity. However, the superior quality factor comes with the challenge of controlling the resonance frequency of the cavity within few tens of hertz bandwidth. In this paper, we investigate how the multiphysics analysis plays a major role in proactively minimizing sources of frequency detuning, specifically; microphonics and Lorentz Force Detuning (LFD) in the stage of RF design of the cavity and mechanical design of the niobium shell and the helium vessel.

  20. Determination of cross sections of 60Ni(n,2n)59Ni induced by 14 MeV neutrons with accelerator mass spectrometry

    NASA Astrophysics Data System (ADS)

    He, Ming; Xu, Yongning; Guan, Yongjing; Shen, Hongtao; Du, Liang; Hongtao, Chen; Dong, Kejun; Jiang, Shan; Yang, Xuran; Wang, Xiaoming; Ruan, Xiang dong; Liu, Jiancheng; Wu, Shaoyong; Zhao, Qingzhang; Cai, Li; Pang, Fangfang

    2015-10-01

    The cross section of the 60Ni(n,2n)59Ni induced by neutron with energy around 14 MeV is important for a fusion environment. However, the published values are strongly discordant. By taking advantage of the high sensitivity of 59Ni measurement at China Institute of Atomic Energy (CIAE), determination of the cross section has been carried out. A natural Nickel foil was irradiated by neutrons produce by a T(D,n)α neutron generator. 57Co and 58Co which produced in the Nickel foil were chosen for the neutron fluence determination. Then the ratio of 59Ni/60Ni for the irradiated sample was determined via accelerator mass spectrometry (AMS) utilizing a 13MV tandem accelerator and a Q3D magnet spectrometry at CIAE. As a result, the cross section of 60Ni(n,2n)59Ni for the incident neutron energy of (14.60 ± 0.40) MeV was determined to be (426 ± 53) mb.