Heavy Ions Physics

A new treatment planning program was developed for the heavy-ion therapy facility at GS1. In addition, a concise quality standard for treatment planning has been set up. It covers acceptance and constancy checks of all critical aspects in treatment planning. Dose verification measurements done during the commissioning phase show an overall good agreement with the treatment planning calculations.

We have measured charged nuclear fragments produced by 1 GeV/nucleon 56 Fe ions interacting with aluminium, polyethylene and lead. These materials are relevant for assessment of radiation risk for manned space flight. The data will be presented in a form suitable for comparison with models of nuclear fragmentation and transport, including linear energy transfer (LET) spectrum, fluence for iron and fragments, event-tack-and event-dose-averaged LET, total dose and iron contribution to dose. Ó 2005 Published by Elsevier Ltd on behalf of COSPAR.

We report results from high-resolution studies of D 5 + cluster ion collisions with low-energy electrons performed in a heavy ion storage ring. Absolute dissociative recombination (DR) and dissociative excitation (DE) cross sections were determined for the energy range from 0.0005 to 20 eV. The DR cross sections were exceedingly large at low energies, and DR resulted in efficient internal energy redistribution and pronounced fragmentation with two main product channels: D 2 + 3D (0.62 ± 0.03) and 2D 2 + D (0.35 ± 0.01). The DR and DE cross sections were comparable in the energy range from 0.2 to 20 eV, which suggest that the two processes follow similar dynamics and are competing outcomes of the ion-electron interaction. A simple picture of the recombination process of D 5 + which captures the essential physics is suggested.

Ataxia telangiectasia (AT) cells, with their defective double-strand break (DSB) repair processes, exhibit high sensitivity to low-LET radiation such as X-rays irradiation and gamma beams. Since heavy ion beam treatment for cancer is becoming increasingly common in Japan and elsewhere, it is important to also determine their sensitivity to high-LET radiation. For this purpose we irradiated AT and normal human cells immortalized with the human telomerase gene using high-(24-60 keV/μm carbon and 200 keV/μm iron ions) or low-LET (X-rays) radiation in non-proliferative conditions. In normal cells the RBE (relative biological effectiveness) of carbon and iron ions increased from 1.19 to 1.81 in proportion to LET. In contrast, their RBE in AT cells increased from 1.32 at 24 keV/μm to 1.59 at 40 keV/μm, and exhibited a plateau at over 40 keV/μm. In normal cells most γ-H2AX foci induced by both carbon-and iron-ion beams had disappeared at 40 h. In AT cells, however, a significant number of γ-H2AX foci were still observed at 40 h. The RBEs found in the AT cells after heavy-ion irradiation were consistent with the effects predicted from the presence of non-homologous end joining defects. The DSBs remaining after heavy-ion irradiation suggested defects in the AT cells' DSB repair ability.

The need for high]y charged heavy ions from projected particle accelerators has recently led to a re-evaluation of the complex processes of ion production in laser generated plasmas. Possible mechanisms for the production of intense beams of high charge state ions are investigated as is the experimental evidence for these mechanisms. The hypothesis that 20 keV ions are driven by "hot electrons" is not supported by experimental work to date. This work, on the other hand, suggests that 30ps pulsation is the basic mechanism for the acceleration of tantalum ions up fo charge state 8-t-whose energy increases linearly with charge state up to 24keV. For long pulses and charge states between 8-}-and 18n u, it appears that there is a secondary mechanism of electron impact ionisation by plasma electrons of approximately 200 eV in the plasma in front of the target, resulting in ions whose energy of around 24 keV is independent of charge state.

A compact 14 C AMS system manufactured by the National Electrostatics Corporation has been installed at the Institute of Heavy Ion Physics, Peking University. The system is based on a Model 1.5SDH-1 Pelletron accelerator with a maximum terminal voltage of 0.6 MV. The 14 C measurement accuracy with this system is better than 0.4% and the machine background is lower than 0.03 pMC. The performance of the new system, especially the background and the d 13 C measurements, is presented. Several important applications are also described briefly.

Radiation assessment and protection in space is the Wrst step in planning future missions to the Moon and Mars, where mission and number of space travelers will increase and the protection of the geomagnetic shielding against the cosmic radiation will be absent. In this framework, the shielding eVectiveness of two Xexible materials, Kevlar and Nextel, were tested, which are largely used in the construction of spacecrafts. Accelerator-based tests clearly demonstrated that Kevlar is an excellent shield for heavy ions, close to polyethylene, whereas Nextel shows poor shielding characteristics. Measurements on Xight performed onboard of the International Space Station and of the Foton-M3 capsule have been carried out with special attention to the neutron component; shielded and unshielded detectors (thermoluminescence dosemeters, bubble detectors) were exposed to a real radiation environment to test the shielding properties of the materials under study. The results indicate no signiWcant eVects of shielding, suggesting that thin shields in low-Earth Orbit have little eVect on absorbed dose. This manuscript is based on a contribution given at the Heavy Ions in Therapy and Space Symposium

The Heidelberg heavy ion test storage ring TSR started operation in May 1988. The lifetimes of the ion beams observed in the first experiments can be explained by interactions with the residual gas. Multiple Coulomb scattering, single Coulomb scattering, electron capture and electron stripping are the relevant processes. Electron cooling of ions as heavy as 08+ has been observed for the first time. With increasing particle number, the longitudinal Schottky noise spectrum becomes dominated by collective waves for cooled beams, allowing a determination of velocities of sound. After correcting for these coherent distortions fo the Schottky spectrum, the longitudinal beam temperature could be extracted. The observed longitudinal equilibrium beam temperatures increase strongly with the charge of the ions. For a cooled C 6+ beam, temperatures a factor of 120 higher were measured compared to a proton beam with the same particle number. The shrinking of the beam diameter due to electron cooling was observed with detectors which measured the profile of charge-changed ions behind a bending magnet. A strong laser-induced fluorescence was detected when storing metastable 7Li+ ions in the ring. Via the Doppler effect a very accurate measurement of the ion velocity profile could be performed. First attempts to observe laser cooling failed, probably due to heating effects from intrabeam scattering and a coupling between lon~tudinal and transversal motion in the beam. Several experiments under preparation are outlined.

The simulation methodology coupling radial ionization profiles issued from Geant4 and the SEE prediction tool MUSCA SEP 3 is used to investigate the MBU sensitivity of SOI SRAM cells of different technologies. The simulation approach is first validated against experimental results for a 45 nm SOI SRAM cell, showing very good agreement. The variability of the MBU probability is then studied depending on various parameters. A worst case is identified, for a particular data pattern irradiated with a high LET ion at grazing angle, showing the possibility for three-and four-bit events to occur. The cause for these high multiplicities is identified by examining the cells topology and new design by hardening strategies are proposed to improve the device hardness to MBU, for a 32 nm SOI SRAM cell. The possibilities of the SEE prediction tool for bulk devices are finally discussed. Index Terms-MBU, SRAM cell, Monte Carlo, SEU prediction tool, Geant4. M. Raine, M. Gaillardin and P. Paillet are with CEA, DAM,

Thin films of hafnium oxide (HfO 2 ) have been grown by high pressure reactive sputtering on transparent quartz substrates (UV-grade silica) and silicon wafers. Deposition conditions were adjusted to obtain polycrystalline as well as amorphous films. Optical properties of the films deposited on the silica substrates were investigated by transmittance and reflectance spectroscopy in the ultraviolet, visible and near infrared range. A numerical analysis method that takes into account the different surface roughness of the polycrystalline and amorphous films was applied to calculate the optical constants (refractive index and absorption coefficient). Amorphous films were found to have a higher refractive index and a lower transparency than polycrystalline films. This is attributed to a higher density of the amorphous samples, which was confirmed by atomic density measurements performed by heavy-ion elastic recoil detection analysis. The absorption coefficient gave an excellent fit to the Tauc law (indirect gap), which allowed a band gap value of 5.54 eV to be obtained. The structure of the films (amorphous or polycrystalline) was found to have no significant influence on the nature of the band gap. The Tauc plots also give information about the structure of the films, because the slope of the plot (the Tauc parameter) is related to the degree of order in the bond network. The amorphous samples had a larger value of the Tauc parameter, i.e. more order than the polycrystalline samples. This is indicative of a uniform bond network with percolation of the bond chains, in contrast to the randomly oriented polycrystalline grains separated by grain boundaries.

Single MeV ion induced currents are directly responsible for a wide range of single event phenomena leading to temporary or permanent malfunction of devices in radiation environments such as space. The active regions of a device act as a source of transient currents injected into a device subsystem by collecting the charge induced by MeV ions. As such, the charge collection process is an important step in understanding mechanisms that lead to device malfunction. In this paper, we present transient current data collected on Si epilayer devices with 15 MeV O 4þ ions focused using a MeV heavy ion micro-probe. The measured transient currents are compared to quasi-3D simulation using ISE TCAD software. Critical factors influencing the fidelity of the measurement technique and modeling of heavy ion track models are also discussed.

Allelic loss is an important mutational mechanism in human carcinogenesis. Loss of heterozygosity (LOH) at an autosomal locus is one outcome of the repair of DNA double-strand breaks (DSBs) and can occur by deletion or by mitotic recombination. We report that mitotic recombination between homologous chromosomes occurred in human lymphoid cells exposed to densely ionizing radiation. We used cells derived from the same donor that express either normal TP53 (TK6 cells) or homozygous mutant TP53 (WTK1 cells) to assess the influence of TP53 on radiation-induced mutagenesis. Expression of mutant TP53 (Met 237 Ile) was associated with a small increase in mutation frequencies at the hemizygous HPRT (hypoxanthine phosphoribosyl transferase) locus, but the mutation spectra were unaffected at this locus. In contrast, WTK1 cells (mutant TP53) were 30-fold more susceptible than TK6 cells (wild-type TP53) to radiation-induced mutagenesis at the TK1 (thymidine kinase) locus. Gene dosage analysis c...

Single event burnout was seen in power MOSFETs exposed to high energy neutrons. Devices with rated voltage 2 400 volts exhibited burnout at substantially less than the rated voltage. Tests with high energy protons gave similar results. Burnout was also seen in limited tests with lower energy protons and neutrons. Correlations with heavy-ion data are discussed. Accelerator proton data gave favorable comparisons with burnout rates .measured on the APEX spacecraft. Implications for burnout at lower altitudes are also discussed.

BARC has been exploring some of the unique features of silicon detector in a variety of nuclear structure experiment using high energy photons and heavy ions projectiles. Current experimental application makes use of large area silicon detector with depletion thickness of ~150-1000 mum. The low cost silicon detector shows excellent energy and position resolution. In this paper, we discuss the simulation result for silicon detector using SILVACO and the physical mechanism involved in detector operation and one set of mask designing for the silicon radiation detector then we will clarify how these effects set a limit to achievable timing performance.

The microdosimetric one-hit detector model has been developed and applied to calculate the dose response, energy response and relative e ciency of thermoluminescent LiF:Mg,Cu,P and CaF2: Tm detectors, and of the free-radical alanine dosimeter, after their exposure to radiation of di erent quality. The one-hit detector is described by two model parameters: the target diameter, d and the saturation parameter, . Combining these parameters with microdosimetric distributions in nanometer-size targets calculated using Monte Carlo track structure codes TRION and MOCA-14, it was possible to describe and predict a great variety of experimental data for photon, X-ray, beta-electron, proton, alpha-particles and heavy ion irradiation. Within the framework of this biophysical model of radiation action, some mechanistic insight into the physics of radiation action in solid state detectors can be obtained.

Shielding is the only countermeasure currently available for exposure to cosmic radiation during space travel. We compared aluminum (Al) and polymethylmethacrylate (PMMA, or lucite) shields of 20 g/cm 2 thickness using 1 GeV protons accelerated at the NASA Space Radiation Laboratory. The dose rate increased after the shield, and the increase was more pronounced after the Al than the PMMA shield. No significant differences in the induction of chromosomal aberrations were observed in human lymphocytes exposed to the same dose with no shield or behind the Al and PMMA blocks. However, the biological effectiveness per incident proton was increased by the shields. Simulations using the General-Purpose Particle and Heavy-Ion Transport Code System (PHITS) show that the increase in dose is caused by target fragments, and aluminum produces more secondary protons than PMMA. Nevertheless, the spectrum of particles behind the shield is confined within the low-LET region, and the biological effectiveness is consequently similar.

Ionizing radiation causes many types of DNA damage, including base damage and single-and double-strand breaks. Photons, including X-rays and γ-rays, are the most widely used type of ionizing radiation in radiobiology experiments, and in radiation cancer therapy. Charged particles, including protons and carbon ions, are seeing increased use as an alternative therapeutic modality. Although the facilities needed to produce high energy charged particle beams are more costly than photon facilities, particle therapy has shown improved cancer survival rates, reflecting more highly focused dose distributions and more severe DNA damage to tumor cells. Despite early successes of charged particle radiotherapy, there is room for further improvement, and much remains to be learned about normal and cancer cell responses to charged particle radiation.

The first implementation of the AGATA spectrometer consisting of five triple germanium detector clusters has been installed at Laboratori Nazionali di Legnaro, INFN. This setup has two major goals, the first one is to validate the g-tracking concept and the second is to perform an experimental physics program using the stable beams delivered by the Tandem-PIAVE-ALPI accelerator complex. A large Keywords: AGATA PRISMA spectrometer DANTE heavy-ion detector HELENA multiplicity filter Cologne plunger TRACE Si detector variety of physics topics will be addressed during this campaign, aiming to investigate both neutron and proton-rich nuclei. The setup has been designed to be coupled with the large-acceptance magneticspectrometer PRISMA. Therefore, the in-beam prompt g rays detected with AGATA will be measured in coincidence with the products of multinucleon-transfer and deep-inelastic reactions measured by PRISMA. Moreover, the setup is versatile enough to host ancillary detectors, including the heavy-ion detector DANTE, the g-ray detector array HELENA, the Cologne plunger for lifetime measurements and the Si-pad telescope TRACE. In this paper the design, characteristics and performance figures of the setup will be described.

Arik Posner,1 Nathan A. Schwadron, Thomas H. Zurbuchen, Janet U. Kozyra, Michael W. Liemohn, and George Gloeckler2 Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, USA Received 14 May 2001; revised 15 October 2001; ...

The paper presents a summary of the recent development of the multi-purpose Monte Carlo Particle and Heavy Ion Transport code System, PHITS. In particular, we discuss in detail the development of two new models, JAM and JQMD, for high energy particle interactions, incorporated in PHITS, and show comparisons between model calculations and experiments for the validations of these models. The paper presents three applications of the code including spallation neutron source, heavy ion therapy and space radiation. The results and examples shown indicate PHITS has great ability of carrying out the radiation transport analysis of almost all particles including heavy ions within a wide energy range.

We present a compendium of optocoupler radiation test data including data on neutron, proton and heavy ion displacement damage (DD), single event transients (SET) and degradation due to total ionizing dose (TID). Proton data includes ionizing and non-ionizing damage mechanisms.

We show by example how the uncoding of Gamma-Ray Bursts (GRBs) offers unprecedented possibilities to foster new knowledge in fundamental physics and in astrophysics. After recalling some of the classic work on vacuum polarization in uniform electric fields by Klein, Sauter, Heisenberg, Euler and Schwinger, we summarize some of the efforts to observe these effects in heavy ions and high energy ion collisions. We then turn to the theory of vacuum polarization around a Kerr-Newman black hole, leading to the extraction of the blackholic energy, to the concept of dyadosphere and dyadotorus, and to the creation of an electron-positron-photon plasma. We then present a new theoretical approach encompassing the physics of neutron stars and heavy nuclei. It is shown that configurations of nuclear matter in bulk with global charge neutrality can exist on macroscopic scales and with electric fields close to the critical value near their surfaces. These configurations may represent an initial condition for the process of gravitational collapse, leading to the creation of an electron-positron-photon plasma: the basic selfaccelerating system explaining both the energetics and the high energy Lorentz factor observed in GRBs. We then turn to recall the two basic interpretational paradigms of our GRB model: 1) the Relative Space-Time Transformation (RSTT) paradigm and 2) the Interpretation of the Burst Structure (IBS) paradigm. These paradigms lead to a "canonical" GRB light curve formed from two different components: a Proper-GRB (P-GRB) and an extended afterglow comprising a raising part, a peak, and a decaying tail. When the P-GRB is energetically predominant we have a "genuine" short GRB, while when the afterglow is energetically predominant we have a so-called long GRB or a "fake" short GRB. We compare and contrast the description of the relativistic expansion of the electron-positron plasma within our approach and within the other ones in the current literature. We then turn to the special role of the baryon loading in discriminating between "genuine" short and long or "fake" short GRBs and to the special role of GRB 991216 to illustrate for the first time the "canonical" GRB bolometric light curve. We then propose a spectral analysis of GRBs, and proceed to some applications: GRB 031203, the first spectral analysis, GRB 050315, the first complete light curve fitting, GRB 060218, the first evidence for a critical value of the baryon loading, GRB 970228, the appearance of "fake" short GRBs. We finally turn to the GRB-Supernova Time Sequence (GSTS) paradigm: the concept of induced gravitational collapse. We illustrate this paradigm by the systems GRB 980425 / SN 1998bw, GRB 030329 / SN 2003dh, GRB 031203 / SN 2003lw, GRB 060218 / SN 2006aj, and we present the enigma of the URCA sources. We then present some general conclusions.

We present the results from the heavy quarks and quarkonia working group. This report gives benchmark heavy quark and quarkonium cross sections for pp and pA collisions at the LHC against which the AA rates can be compared in the study of the quark-gluon plasma. We also provide an assessment of the theoretical uncertainties in these benchmarks. We then discuss some of the cold matter effects on quarkonia production, including nuclear absorption, scattering by produced hadrons, and energy loss in the medium. Hot matter effects that could reduce the observed quarkonium rates such as color screening and thermal activation are then discussed. Possible quarkonium enhancement through coalescence of uncorrelated heavy quarks and antiquarks is also described. Finally, we discuss the capabilities of the LHC detectors to measure heavy quarks and quarkonia as well as the Monte Carlo generators used in the data analysis. 2 Authors: S. Frixione, M. L. Mangano.

The International Atomic Energy Agency has sponsored a formal intercomparison exercise for the seven depth profiling ion beam analysis codes, which are: GISA, RUMP, RBX, DEPTH, DataFurnace, SIMNRA and MCERD. This intercomparison is published in Nuclear Instruments and Methods B 262, (2007) 281-303 and summarised here. The codes implement all known physical effects and they are all evaluated. We demonstrate that there is agreement between codes often better than 0.1%; and also detailed agreement with real spectra, showing in particular that the SRIM 2003 stopping powers for Si are correct to 0.6% for 1.5MeV He.

124 Sn + 64 Ni and 112 Sn + 58 Ni reactions at 35 A MeV incident energy were studied by using the 688 Si-CsI telescopes of the forward part (1 • θ lab 30 • ) of CHIMERA multi-detector. The most central part, 1% of the total measured cross section was selected by means of a multidimensional analysis of the experimental observables. The detected isotopes of light fragments (3 Z 8) provided information on breakup temperatures of the emitting sources. The space-time structure of these sources was deduced from fragment correlations. An odd-even effect in the fragment production, enhanced by the isospin of the entrance channel, was observed. Freeze-out unbound neutron-to-proton relative densities for both studied reactions have been deduced, indicating for a possible isospin distillation mechanism related to a phenomenon of the liquid-gas phase transition in asymmetric systems.

Using vibrating sample magnetometery (VSM) 50MeV Li3+ ion irradiation effects on magnetic properties of single crystals of SrGaxInyFe12−(x+ y) O19 (where x= 0, 5, 7, 9; y= 0, 0.8, 1.3, 1.0), are reported. The substitution of Ga and In in strontium hexaferrite crystals ...

A detailed study has been made on the use of MeV heavy ions (Z, = 6-8) for microbeam Rutherford backscattering (RBS) analysis, to improve the depth resolution of this technique. The algorithm for determination of the depth resolution was created and applied to the Zagreb microbeam facility. Theoretical estimates of depth resolution for C and 0 ion RBS analysis of thin oxide films and semiconductors, using annular silicon surface barrier detector (SSBD). are compared to those for proton backscattering analysis. Depth resolution in certain cases may be improved by increasing the heavy-ion energy. Therefore, by the proper choice of the heavy ion and the heavy-ion energy, the depth resolution may be improved, maintaining the efficiency of the RBS method. 0168-583X/97/$17.00 0 1997 Elsevier Science B.V. All rights reserved. PII SO168-583X(97)00170-5 V. MICROPROBE ANALYTICAL TECHNIQUES

Energy loss and energy loss straggling in a thin silicon nitride foil was measured for Li, B, C, O, S and Fe ions with energies between 0.4 and 4.0 MeV. The energy distribution of ions after passage of a 34 nm thick foil was measured by an electrostatic deflector with 0.2% energy resolution. Energy loss values are in good agreement with SRIM calculations. Measured energy loss straggling however, is considerably lower than velocity-independent Bohr straggling and also lower than the values predicted by SRIM. This behavior is relatively well explained by a modified Bohr model recently developed by Sigmund.

This work aimed at measuring cell-killing effectiveness of monoenergetic and Spread-Out Bragg Peak (SOBP) carbon-ion beams in normal and tumour cells with different radiation sensitivity. Clonogenic survival was assayed in normal and tumour human cell lines exhibiting different radiosensitivity to X-or γ-rays following exposure to monoenergetic carbon-ion beams (incident LET 13-303 keV/μm) and at various positions along the ionization curve of a therapeutic carbon-ion beam, corresponding to three doseaveraged LET (LETd) values (40, 50 and 75 keV/μm). Chinese hamster V79 cells were also used. Carbon-ion effectiveness for cell inactivation generally increased with LET for monoenergetic beams, with the largest gain in cell-killing obtained in the cells most radioresistant to X-or γ-rays. Such an increased effectiveness in cells less responsive to low LET radiation was found also for SOBP irradiation, but the latter was less effective compared with monoenergetic ion beams of the same LET. Our data show the superior effectiveness for cell-killing exhibited by carbon-ion beams compared to lower LET radiation, particularly in tumour cells radioresistant to X-or γ-rays, hence the advantage of using such beams in radiotherapy. The observed lower effectiveness of SOBP irradiation compared to monoenergetic carbon beam irradiation argues against the radiobiological equivalence between dose-averaged LET in a point in the SOBP and the corresponding monoenergetic beams.

Several very large scale integrated (VLSI) devices which are not available in radiation hardened version are still required to be used in spacecraft systems. Thus these components need to be tested for highenergy heavy ion irradiation to find out their tolerance and suitability in specific space applications. This paper describes the high-energy heavy ion radiation testing of VLSI devices for single event upset (SEU) and single event latch up (SEL). The experimental set up employed to produce low flux of heavy ions viz. silicon (Si), and silver (Ag), for studying single event effects (SEE) is briefly described. The heavy ion testing of a few VLSI devices is performed in the general purpose scattering chamber of the Pelletron facility, available at Nuclear Science Centre, New Delhi. The test results with respect to SEU and SEL are discussed.

■ Abstract Moving highly-charged ions carry strong electromagnetic fields that act as a beam of photons. In collisions at large impact parameters, hadronic interactions are not possible, and the ions interact through photon-ion and photon-photon collisions known as ultra-peripheral collisions (UPCs). Hadron colliders like the Relativistic Heavy Ion Collider (RHIC), the Tevatron, and the Large Hadron Collider (LHC) produce photonuclear and two-photon interactions at luminosities and energies beyond that accessible elsewhere; the LHC will reach a γ p energy ten times that of the Hadron-Electron Ring Accelerator (HERA). Reactions as diverse as the production of anti-hydrogen, photoproduction of the ρ 0 , transmutation of lead into bismuth, and excitation of collective nuclear resonances have already been studied. At the LHC, UPCs can study many types of new physics processes.

The strain field generated by 200 MeV Ag14+ ions in Si (001) crystals has been investigated using X-ray topography. By choosing suitable diffraction vectors it has been possible to explore the lattice distortion in the inelastic and elastic loss regions separately. Stationary reflection topographs gave two spatially separated images—one originating from the surface and the other from the region affected by elastic nuclear collisions close to the end of the ion range. The spatial separation of these two images is geometrically related to the depth of this elastic loss region. These topographic findings are compared with TRIM calculations.