Measurement of ion beam from laser ion source for RHIC EBIS.

Laser ion source (LIS) is a candidate of the primary ion source for the RHIC EBIS. LIS will provide intense charge state 1+ ions to the EBIS for further ionization. We measured plasma properties of a variety of atomic species from C to Au using the second harmonics of Nd:YAG laser (532 nm wave length, up to 0.5 J/6 ns). Since properties of laser produced plasma is different from different species, laser power density for singly charged ion production should be verified experimentally for each atomic species. After plasma analysis experiments, Au ions was extracted from plasma and emittance of the ion beam was measured using a pepper pot type emittance monitor

Target life time of laser ion source for low charge state ion production

Laser ion source (LIS) produces ions by irradiating pulsed high power laser shots onto the solid state target. For the low charge state ion production, laser spot diameter on the target can be over several millimeters using a high power laser such as Nd:YAG laser. In this case, a damage to the target surface is small while there is a visible crater in case of the best focused laser shot for high charge state ion production (laser spot diameter can be several tens of micrometers). So the need of target displacement after each laser shot to use fresh surface to stabilize plasma is not required for low charge state ion production. We tested target lifetime using Nd:YAG laser with 5 Hz repetition rate. Also target temperature and vacuum condition were recorded during experiment. The feasibility of a long time operation was verified

Toward inertial confinement fusion energy based on heavy ion beam

Heavy ion inertial fusion (HIF) energy would be one of promising energy resources securing our future energy in order to sustain our human life for centuries and beyond. The heavy ion beam (HIB) has remarkable preferable features to release the fusion energy in inertial confinement fusion: in particle accelerators HIBs are generated with a high driver efficiency of ~ 30-40%, and the HIB ions deposit their energy inside of materials. Therefore, a requirement for the fusion target energy gain is relatively low, that would be ~50-70 to operate a HIF fusion reactor with the standard energy output of 1GW of electricity. The HIF reactor operation frequency would be ~10~15 Hz or so. Several-MJ HIBs illuminate a fusion fuel target, and the fuel target is imploded to about a thousand times of the solid density. Then the DT fuel is ignited and burned. The HIB ion deposition range would be ~0.5-1 mm or so depending on the material. Therefore, a relatively large density-scale length appears in the fuel target material. The large density-gradient-scale length helps to reduce the Rayleigh-Taylor (R-T) growth rate. The key merits in HIF physics are presented in the article toward our bright future energy resource.Comment: 17 pages. arXiv admin note: substantial text overlap with arXiv:1511.06508, arXiv:1608.0106

Status of DPIS development in BNL

Direct injection scheme was proposed in 2000 at RIKEN in Japan. The first beam test was done at Tokyo Institute of Technology using a CO{sub 2} laser and an 80 MHz 4 vane RFQ in 2001, and further development continued in RIKEN. In 2006, all the experimental equipment were moved to BNL and a new development program was started. We report on our recent activities at BNL including the use of a frozen gas target for the laser source, low charge state ion beam production and a newly developed laser irradiation system

Linear accelerator design study with direct plasma injection scheme for warm dense matter

Warm Dense Matter (WDM) is a challenging science field, which is related to heavy ion inertial fusion and planetary science. It is difficult to expect the behavior because the state with high density and low temperature is completely different from ideal condition. The well-defined WDM generation is required to understand it. Moderate energy ion beams ({approx} MeV/u) slightly above Bragg peak is an advantageous method for WDM because of the uniform energy deposition. Direct Plasma Injection Scheme (DPIS) with a Interdigital H-mode (IH) accelerator has a potential for the beam parameter. We show feasible parameters of the IH accelerator for WDM. WDM physics is a challenging science and is strongly related to Heavy Ion Fusion science. WDM formation by Direct Plasma Injection Scheme (DPIS) with IH accelerator, which is a compact system, is proposed. Feasible parameters for IH accelerator are shown for WDM state. These represents that DPIS with IH accelerator can access a different parameter region of WDM

Dipole magnet for use of RHIC EBIS HEBT line.

Construction and magnetic field measurement of dipole magnets for RHIC-EBIS HEBT line have completed. These magnets will be used to guide highly charged ion beams ranging from proton to Uranium provided by a new injector toward the Booster ring in BNL. In this paper, overview of the magnetic design of the dipoles and results of magnetic field measurement are summarized

Laser ion source for low charge heavy ion beams

For heavy ion inertial fusion application, a combination of a laser ion source and direct plasma injection scheme into an RFQ is proposed. The combination might provide more than 100 mA of singly charged heavy ion beam from a single laser shot. A planned feasibility test with moderate current is also discussed

Design study of a DPIS injector for a heavy ion FFAG

A new heavy ion injector linac is proposed for providing heavy ion beams to a fixed field alternating gradient (FFAG) accelerator in Kyushu University. A combination of the new intense laser source based injector and the FFAG will be able to accelerate high current ion beams with 100 Hz of a repetition rate. The planned average current reaches 7 {micro}A with carbon 6+ beam

Optically Pumped Polarized 3^3He++^{++} Ion Source Development for RHIC/EIC

The proposed polarized $^3$He$^{++}$ acceleration in RHIC and the future Electron-Ion Collider will require about $2\times10^{11}$ ions in the source pulse. A new technique had been proposed for production of high intensity polarized $^3$He$^{++}$ ion beams. It is based on ionization and accumulation of the $^3$He gas (polarized by metastability-exchange optical pumping and in the 5 T high magnetic field) in the existing Electron Beam Ion Source (EBIS). A novel $^3$He cryogenic purification and storage technique was developed to provide the required gas purity. An original gas refill and polarized $^3$He gas injection to the EBIS long drift tubes, (which serves as the storage cell) were developed to ensure polarization preservation. An infrared laser system for optical pumping and polarization measurements in the high 3--5 T field has been developed. The $^3$He polarization 80--85\% (and sufficiently long $\sim30$ min relaxation time) was obtained in the \lq\lq{open}\rq\rq\ cell configuration with refilling valve tube inlet and isolation valve closed. The development of the spin-rotator and $^3$He $^4$He absolute nuclear polarimeter at 6 MeV $^3$He$^{++}$ beam energy is also presented.Comment: 9 pages, 11 figure

Beam commissioning of the RFQ for the RHIC-EBIS project

Beam commissioning of a new 4 rod RFQ has started at Brookhaven National Laboratory (BNL). The RFQ will accelerate intense heavy ion beams provided by an Electron Beam ion Source (EBIS) up to 300 keV/u. The RFQ will accelerate a range of Q/M from 1 to 1/6, and the accelerated beam will be finally delivered to the Relativistic Heavy Ion Collider (RHIC) and NASA Space Radiation Laboratory (NSRL). The first beam was successfully accelerated and the bunch structures of He{sup +} and Cu{sup 10+} beams were measured. The further beam tests are in progress