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1.
Stefan K. Zeisler Vinder Jaggi 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2011,655(1):64-65
TRIUMF operates several high power industrial cyclotrons for the commercial production of isotopes for radiological diagnostics and therapy. Two of these accelerators, TR30-1 and TR30-2, are capable of delivering H− beams of 30 MeV and beam currents in excess of 1000 μA. For many years, in-house produced diamond-like carbon (DLC) foils of various compositions have been utilized to extract proton beams from these cyclotrons (Zeisler and Jaggi, 2008) [1].The TRIUMF Carbon Foil Laboratory, now incorporated as MicromatterTM, uses pulsed laser deposition to fabricate DLC films in a wide thickness range (from 10 nm to ∼10 μm). More recently, we reported the production of DLC foils containing boron (Zeisler and Jaggi, 2010) [2]. Carbon-boron multilayer foils have outstanding mechanical stability and show an extended lifetime in high intensity proton beams. In an attempt to further enhance the quality of our beam strippers, we investigated the production of carbon-silicon multilayer foils. 相似文献
2.
Connie S. Jolivet Shawn A. Miller John O. Stoner Jr. Peter Ladd 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2008,590(1-3):47
The Spallation Neutron Source (SNS) currently under construction at Oak Ridge National Laboratory, Oak Ridge, Tennessee, is planned to initially utilize carbon stripper foils having areal densities approximately 260 μg/cm2. The projected design requires that each foil be supported by only one fixed edge. For stability of the foil, additional support is to be provided by carbon fibers. The feasibility of manufacturing and shipping such mounted carbon foils produced by arc evaporation was studied using two prototypes. Production of the foils is described. Fibers were chosen for satisfactory mechanical strength consistent with minimal interference with the SNS beam. Mounting of the fibers, and packaging of the assemblies for shipping are described. Ten completed assemblies were shipped to SNS for further testing. Preliminary evaluation of the survivability of the foils in the SNS foil changer is described. 相似文献
3.
Connie S. Jolivet John O. Stoner Jr. 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2008,590(1-3):51
While research and development continue to produce forms of carbon for longer lasting stripper foils, relatively little attention has been paid to other factors that affect their survival in use. It becomes apparent that the form of carbon is only part of the issue. Specific mounting methods increase the lifetimes of carbon stripper foils. These methods are determined in part by the specific use and carbon type for a foil. With careful handling, appropriate adhesive, and slack mounting, premature breakage can be avoided. Foil lifetimes are then primarily affected by less easily controlled factors such as high-temperature expansion, shrinkage and evaporation. 相似文献
4.
A.G. Muirhead J.K. Heighway 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2011,655(1):61-63
It is easy to say “Just float and mount the carbon foils". However learning the art can be more difficult than old masters have shown it to be. In this article we will share our experience of some difficulties we have had at Australian National University (ANU). We also present results from some in beam endurance testing of foils using carbon supplied by Vacuum Technology (Germany), Micromatter (Canada) and those made at the ANU (Australia). 相似文献
5.
I. Sugai M. Oyaizu Y. Takeda H. Kawakami T. Hattori K. Kawasaki 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2008,590(1-3):37
Carbon stripper foils with a higher nitrogen content were made by ion beam sputtering with reactive nitrogen gas. Such foils seem to be very useful as strippers for high-intensity heavy ion accelerators. To know further characteristics of the lifetime of such carbon foils, we have measured the sputtering yield of the carbon source material at a sputtering voltage of 4–15 kV and the lifetime dependence of such foils on thickness. Lifetime measurement was performed with a 3.2 MeV Ne+ ion beam. The sputtering yield on average showed 0.75 atoms/ion at over 9 kV sputtering voltage. The lifetime of the foils noticeably depends on the foil thickness, and the thickness range as practical stripper foil is to be around 15 to 33 μg/cm2. Two foils made at 13 kV showed extremely long lifetimes of 6800 and 6000 mC/cm2 at maximum and the foils made above 10 kV lived longer than about 900 mC/cm2, which correspond to about 270 and 40 times longer than commercially available best foils. We measured the thickness ratio of nitrogen to carbon in each foil made at the different sputtering voltages and at the different irradiation stages (mC/cm2) by RBS method. We also inspected the structure of a nitrided carbon foil by transmission electron microscopy. 相似文献
6.
Hiroo Hasebe Hiromichi Ryuto Nobuhisa Fukunishi Akira Goto Masayuki Kase Yasushige Yano 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2008,590(1-3):13
The problem of handling the fragile carbon foils (mounting on the frame, placing in the stripper changer) that easily break when self-supporting has been solved by coating carbon foils with poly-monochloro-para-xylylene. It was found that the polymer-coating method could also be used to produce carbon foils thicker than 100 μg/cm2 by alternated deposition of carbon and poly-monochloro-para-xylylene layers. Carbon foil of 500 μg/cm2 thick and 10 cm in diameter was produced by this method and mounted to a foil holder. Results of lifetime measurement for singly coated foils are also presented. 相似文献
7.
8.
Shawn A. Miller Connie S. Jolivet John O. Stoner Jr. 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2008,590(1-3):57
Carbon foils are used in cyclotrons and other accelerators to strip electrons from fast ions, enabling the extraction or further acceleration of those ions. Lifetimes of stripper foils (extractor foils) need to be as long as possible to maximize the efficiency of accelerator use and minimize radiation exposure of maintenance personnel. A foil's useful lifetime is determined in part by operating temperatures, manufacturing method, and mounting method. We used two methods to test foils in a simulated accelerator environment. These methods involve the heating in vacuum to temperature ranges 500–1750 and 500–4000 K. Either kind of testing can be done in a few minutes instead of the days or weeks typically needed in a cyclotron. Such tests show clearly that foils manufactured by different methods have different responses to elevated temperatures. Because of this fact, optimum mounting techniques depend on the foil type. Results to date are summarized. 相似文献
9.
T. Spickermann M.J. Borden R.J. Macek R.W. Shaw C.S. Feigerle I. Sugai 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2008,590(1-3):25
To accumulate high-intensity proton pulses, the Los Alamos Proton Storage Ring (PSR) uses the charge-exchange injection method. H− ions merge with already circulating protons in a bending magnet, and then are stripped off their two electrons in a carbon stripper foil. The circulating protons continue to interact with the foil. Despite efforts to minimize the number of these foil hits, like “painting” of the vertical phase space, they cannot totally be eliminated. As a result, foil heating and probably also radiation damage limit the lifetime of these foils. In recent years, LANL has collaborated with KEK to improve the carbon foils in use at PSR, and these foils now last typically for about 2 months. Recently, an alternative in the form of corrugated diamond foils has been proposed for use at SNS. These foils have now been tested in PSR production for a year, and have already shown to be at least as enduring as the LANL/KEK carbon foils. Advantages of the diamond foil concept, as well as some noteworthy differences that we observed with respect to the LANL carbon foils, will be discussed here. 相似文献
10.
V.Kh. Liechtenstein T.M. Ivkova A.V. Spitsyn E.D. Olshanski 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2008,590(1-3):171
Measurements of vacuum tightness and mechanical strength of diamond-like carbon (DLC) foils in the thickness range of 1–7 μg cm−2 have been performed with a purpose to evaluate suitability of foils as a gas barrier. Hydrogen and argon at pressures from 10−2 Pa to 20 kPa were used as test gases. The permeation rate specified as conductance density was found for the best sample of self-supporting foil to be around 1.5×10−3 l and 3.3×10−4 l s−1 cm−2 for H2 and Ar, respectively. Conductance density of the same foils mounted on the frames with a mesh along the apertures as support was about twice higher than that for the self-supporting ones, likely due to the mechanical imperfections of the foil assemblies of the first ones. On the other hand, mesh-supported foils as thin as 3 μg cm−2 and of 5 mm in diameter were withstanding the pressure of up to 18 kPa, while self-supporting foils of the same thickness ruptured at around 1.2 kPa. There was no observed relation between thickness of the foil and its mechanical properties and permeation rate. This suggests that rather tears and pinholes present in foils are the limiting factors of the foil–vacuum tightness and strength. Results obtained in the studies, presented in this work, demonstrate the ability of very thin DLC to isolate a high vacuum beam line from a gas cell in a variety of applications and ability to withstand the gas pressure relevant, in particular, to some gas-filled ionization chambers. 相似文献
11.
I. Sugai M. Oyaizu Y. Takeda H. Kawakami T. Hattori K. Kawasaki 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2008,590(1-3):32
We control the amount of carbon buildup on slackened thin cluster carbon stripper foils (less than 3.5 μg/cm2) by heating with a high-power infrared lamp during beam bombardment. Foil lifetime measurements were performed using 2.0±0.5 μA beams of 3.2 MeV Ne+ ions and quantified as the total charge/area before breakage. Lifetimes were obtained up to 1286 mC/cm2 at maximum and 1139 mC/cm2 on the average; these values are, respectively, approximately 51 times at maximum and 46 times on average greater than the best commercially available foils, when used unheated and unslackened. 相似文献
12.
K. Shima S. Ishii T. Takahashi I. Sugai 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2001,460(2-3):233-238
Optimum thickness of charge stripper foils installed at the terminal of a tandem accelerator has been investigated from the view of (1) charge stripping effect, (2) transmission of ions through accelerator, (3) lifetime of foils for the irradiation of ions. For this purpose, measurements have been done for (a) transmission of H, Li, O, Br and Au ions, passing through 12 UD Pelletron tandem accelerator for carbon stripper foils of 1.8–19.5 μg/cm2 thickness, at terminal voltages of 5 and 10 MV, and (b) lifetime of 2–15 μg/cm2 thick Tanashi foils developed by Sugai by irradiating Au ions at the terminal voltage of 10 MV. The results obtained are as follows: (a) From the view of above items (1) and (2), the optimum thickness of foils is 10 μg/cm2 for ions of Z=1, several μg/cm2 for Z=8, and less than a few μg/cm2 for heavier ions. (b) From the view of item (3), the lifetime of Tanashi foils by means of new arc-discharge method is demonstrated to be much longer than that of commercial foils for foils thicker than about 5 μg/cm2 thick. This superiority rapidly decreases with decreasing foil thickness, and at around 2 μg/cm2, the lifetime of Tanashi foils is at the most 2.4 times longer than that of commercial foils. 相似文献
13.
Yasuhiro Takeda Yoshiro Irie Akira Takagi Hirokane Kawakami Katsunori Kawasaki 《Vacuum》2010,84(12):1448-1451
Thin carbon stripper foils used in high-intensity proton accelerators and heavy-ion accelerators must have long lifetimes. Thin carbon foils were fabricated by ion-beam sputtering using reactive and inert gas ions. The lifetime of the foils was measured using a KEK 650-keV high-intensity DC H− (negative hydrogen ion) beam; changes in the foil thickness and surface deformations during irradiation were investigated. The lifetime of a typical stripper foil fabricated by heavy-ion-beam (Ar and Kr) sputtering was 60-70 times longer than that of the best commercially available foils. This paper reports a fabrication method for carbon stripper foils, along with an investigation of their lifetimes and changes in foil thickness during beam irradiation. 相似文献
14.
W. Chou M. Kostin Z. Tang 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2008,590(1-3):1
Charge-exchange injection by means of carbon foils is a widely used method in accelerators. This paper discusses two critical issues concerning the use of carbon foils: efficiency and lifetime. An energy scaling of stripping efficiency was suggested and compared with measurements. Several factors that determine the foil lifetime—energy deposition, heating, stress and buckling—were studied by using the simulation codes MARS and ANSYS. 相似文献
15.
V. KopustinskasS. Meskinis S. TamuleviciusG. Niaura A. Guobien? V. Grigaliunas 《Vacuum》2003,72(2):193-198
Carbon films and clusters have been formed by direct ion beam deposition. In all experiments crystalline n-Si 〈1 0 0〉 wafers with the 300 nm thermal SiO2 film have been used as substrates. Effects of thermally microstructured Ni and substrate temperature were studied. Chemical structure of the carbon films was investigated using Raman spectroscopy. Surface morphology was studied by atomic force microscopy (AFM). Supplemental research on sheet resistance of the films has been performed. Rough diamond-like carbon film was grown onto the catalytic layer at 400 K temperature, and surface of the diamond-like carbon film deposited directly onto the SiO2 layer at 400 K temperature was very smooth. At 750 K growth of the array of cylindrically shaped clusters was observed by AFM in the case of catalytically assisted deposition. Raman spectra of deposited films were typical for glassy carbon and/or carbon nanotubes with the carbonaceous deposits. Catalyticless deposition at 750 K temperature resulted in the formation of the conductive polymer-like carbon film with the graphite clusters in it. 相似文献
16.
Numerous investigators have reported on pulsed laser deposition of carbon nanotubes, mostly using the Nd:YAG laser for ablation. In all cases the depositions have been conducted at high-temperatures and high pressures. Here we report on the deposition of carbon nanostructures at room temperature using a 248 nm excimer laser nm to ablate mixed graphite-nickel/cobalt targets. We find that the formation of the carbon nanomaterials is dependent on the particular ambient gas employed. In O2 gas, carbon nanotubes and nano-onions are produced. The nanotubes have notably large channel diameters of 100-200 nm and the nano-onion structures are 100-200 nm in diameter, also much larger than previously observed. High-resolution, in-situ, time-resolved emission spectroscopy has been used to follow the production of molecular carbon species such as C2 and C3, as well as metals such as Ni or Co in the different ambients employed. Spectral modeling reveals significant differences in the vibrational-rotational temperatures of C2 spectra in O2 versus Ar. Mechanistic details of the formation of carbon nanotubes and nano-onions, and in-situ optical emission spectroscopy are described. 相似文献
17.
Yasuhiro Takeda Michikazu Kinsho Jyunichiro Kamiya Isao Sugai Yoshiro Irie Osamu Takeda Hiroki Takahashi 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2008,590(1-3):213
The Japan Proton Accelerator Research Complex (J-PARC) has been under construction in Tokai-mura, Ibaraki, Japan. Three independent charge stripper devices are set up at the injection line of the 3 GeV Rapid Cycling Synchrotron (RCS). The H− beam accelerated by a 181 MeV Linac is charge-exchanged to a H+ beam by the first stripper foil, and then injected into the RCS. The H0 and H− fractions of the beam, which are not stripped by the first stripper foil, are converted into a H+ beam by the second and the third stripper foils.We have designed the charge exchange devices by adopting the transfer-rod system for moving the foils in a vacuum. We have fabricated a new type of transfer-rod, which can move over a distance of 1500 mm.We have also developed a new telescope system to observe possible wrinkles and pinholes of the foil. The system withstands more than 1 MGy of radiation dose and has a resolution of 250 μm at a distance of 10 m from an object. 相似文献
18.
Donglin Ma Yanfeng Zhang Mengxi Liu Qingqing Ji Teng Gao Yu Zhang Zhongfan Liu 《Nano Research》2013,6(9):671-678
Noble metals such as Pt are a perfect substrate for the catalytic growth of monolayer graphene. However, the requirements of the subsequent transfer process are not compatible with the traditional etching method. In this work, we find that the interaction of graphene with Pt foil can be weakened through the intercalation of carbon monoxide (CO) under ambient pressure. This intercalation process occurs on both hexagonal-shape graphene islands and irregular graphene patches on changing the CO partial pressure from 0 to 0.6 MPa, as observed by scanning electron microscopy (SEM), Raman spectroscopy and X-ray photoemission spectroscopy. We demonstrate that, on a practical timescale, the intercalation ratio is proportional to the partial pressure of CO. Furthermore, we develop a clean transfer method of CO-intercalated graphene with water as a peeling agent. We show that this method enables the transfer of tens of micrometer-scale graphene patches onto SiO2/Si, which are free from metal or oxide particle contamination. This transfer method should be a significant step towards the dean transfer of graphene, as well as the recydable use of noble metal substrates. 相似文献
19.
Takeshi Tachibana Chikara Ichihara Nobuyuki Kawakami Yoshihiro Yokota 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2008,590(1-3):22
Carbon ion beam stripper foils were fabricated from diamond films synthesized on silicon via chemical vapor deposition. Fine-grained polycrystal diamond foils with decent surface flatness were obtained using a nucleation enhancement pretreatment process. Freestanding diamond foils were formed by etching a portion of the silicon substrate on which the diamond films well-adhered. In preliminary lifetime evaluations, the 1–3 μm-thick diamond foils lasted between 20 and 420 min for 3.2 MeV Ne+ion-beam charge stripping. 相似文献
20.
Carbon thin foils are commonly used as a charge stripping material in particle accelerators. Depending on the original foil thickness, changes in thickness during beam irradiation vary: thin foils (∼10 μg/cm2) thicken by build-up, medium thickness foils (∼15 μg/cm2) remain unchanged, and thick foils (∼20 μg/cm2) become thinner. The thickness reduction differs even under identical manufacturing processes and conditions.The factor causing foil thinning is unknown. On the basis of the low sputtering rate of carbon, it can be said that impurities contained in the foil cause foil thinning.Carbon foils contain impurities such as water. These impurities dissociate and combine with carbon and then evaporate. Taking this into consideration, we examined the gas composition during beam irradiation, to determine which impurity causes foil thinning. As a result, we found that oxygen contained in the foil plays a role in foil thinning. 相似文献