The performance of a carbon foil (C-foil) as a charge stripper in an accelerator is directly affected by its condition and quality. C-foils are fabricated by evaporating carbon onto a substrate. ...Therefore, a suitable technique must be established for depositing and removing C-foils from substrates. The selection of appropriate releasing agents is crucial for the removal process. C-foils with thicknesses less than 0.1 mg/cm
2
were produced using the arc discharge method, wherein chloride materials were used as releasing agents. The magnetron sputtering method is suitable for manufacturing C-foils thicker than 0.1 mg/cm
2
using appropriate releasing agents, such as fluorine-based or silicon-based agents. The contact angle analysis demonstrates a negative relationship between the C-foil thickness and the wettability of the substrate treated with an appropriate releasing agent. The possibility of using ionic liquids as novel releasing agents is also investigated.
High-density highly oriented graphite sheets provided by Kaneka Corporation have been applied as stripper disks for heavy-ion acceleration at RIKEN RI Beam Factory since 2014. The graphite sheets ...withstand increasing amounts of beam intensity. We observed the graphite sheets after beam irradiation with an electron microscope and their lifetime was discussed.
Development of rotating beryllium disk stripper Hasebe, Hiroo; Okuno, Hiroki; Kuboki, Hironori ...
Journal of radioanalytical and nuclear chemistry,
09/2015, Letnik:
305, Številka:
3
Journal Article
Recenzirano
High-intensity uranium (U) ion beams are successfully provided at the RIKEN RI Beam Factory. We have attempted to extend the lifetime of the charge stripper as the U-beam intensity has increased. An ...attempt to enlarge the irradiated area using a rotating large carbon disk (C-disk) failed in 2006–2007 because no commercially available C-disk with 0.085 mm thickness met our requirements. In 2012, we tested a beryllium (Be) disk (0.1-mm-thick, diameter = 120 mm) as an alternative to the C-disk. The Be disk proved to be an adequate substitute, and has been successfully used during beam-time operation.
A carbon foil (C-foil) is commonly used as a charge stripper in the heavy-ion accelerators. Since 2005, the polymer-coated carbon foils (PCC-foils) have been fabricated at Nishina Center to prepare ...larger and thicker C-foils than those previously used as charge strippers. However, the multi-layer PCC-foils did not have sufficiently long life-time. Since August 2009, a new magnetron sputtering system is used to fabricate a thick C-foil. The foils coated with polymer are used as strippers. Life-times of the new single-layer PCC-foils under the uranium beam were measured in two configurations: at the first one a small piece of C-foil was attached to a fixed holder and in the second one a large C-foil was attached to a “rotating-cylinder stripper” device. The properties of the new single-layer PCC-foils and the results of the life-time measurements are reported in this contribution.
New carbon-nanotube–sputter-deposition-carbon (CNT–SDC) foils were developed and used in the U beam time at the RIKEN RI Beam Factory (RIBF) from October to December 2011. The lifetimes of these new ...foils were drastically extended, and stable, high-intensity U beams were successfully provided to users. The lifetime of the CNT–SDC foils was 2–5 C, which was 100 times longer than those of static C-foils previously used. The qualitative analysis of the CNT–SDC foils clearly showed that the CNT structure and bundles were broken by beam irradiation. In addition, it was found that CNT bundles in the CNT–SDC foil were grown after the carbon deposition procedure. This structure was considered to be the reason that the CNT–SDC foils maintain advantages of both CNT and SDC foils.
Recent developments in a charge-stripping system employing high-flow rate He gas circulation (~ 200 L/min) for sup.238U.sup.35+ beams injected at 10.8 MeV/u are reported. He gas is confined in a ...target section and is separated from a vacuum duct using five-stage differentially-pumped sections. To minimize the gas leakage rate via beam apertures, a high-performance differential pumping was required. To avoid huge gas consumption, a clean gas recycling with high-flow rate was simultaneously required. To realize these, we developed multi-stage mechanical booster pump array. The recycling rate of He gas was achieved as more than 99%. The system performance has been checked with the present maximum beam current up to 13 eµA(~ 1 kW beam power). Keywords Charge stripper * Uranium ion * Helium gas * Low-Z gas
Recent developments in a charge-stripping system employing high-flow rate He gas circulation (~200 L/min) for
238
U
35+
beams injected at 10.8 MeV/u are reported. He gas is confined in a target ...section and is separated from a vacuum duct using five-stage differentially-pumped sections. To minimize the gas leakage rate via beam apertures, a high-performance differential pumping was required. To avoid huge gas consumption, a clean gas recycling with high-flow rate was simultaneously required. To realize these, we developed multi-stage mechanical booster pump array. The recycling rate of He gas was achieved as more than 99 %. The system performance has been checked with the present maximum beam current up to 13 eμA (~1 kW beam power).
A negative muon induces nuclear-fusion reactions between hydrogen isotopes. In this reaction, a muon plays a role of a catalyst, i.e. muon injection causes a chain reaction of nuclear fusions in ...hydrogen system. This phenomenon is called muon catalyzed fusion or μCF for short. A fusion reaction itself is dominated by nuclear force in the energy range of mega-electron-volt, however μCF reaction is affected by much-low-energy phenomena like temperature and density in the range of milli-electron-volt. This is due to the muonic molecule formation through which a fusion reaction occurs. Therefore, μCF has been an attractive subject for atomic physics as well as nuclear physics.
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