• K. Kondo
  Department of Energy Sciences, Tokyo Institute of Technology, Yokohama
• R. Dabrowski, M. Okamura
  BNL, Upton, Long Island, New York
• T. Kanesue
  RIKEN Nishina Center, Wako

In a laser ion source, a high power pulsed laser shot focused on a solid state target produces laser ablation plasma. This plasma has initial velocity towards the normal direction of the target and simultaneously expands three dimensionally. Since charge state distribution, velocity distribution and plasma temperature strongly depends on laser power density, power density is one of the important parameter to the angular distribution of plasma. Angular distribution of expanding plasma was measured by changing laser power density. Details of the experiment will be shown in the paper.

• K. Kondo
  Department of Energy Sciences, Tokyo Institute of Technology, Yokohama
• R. Dabrowski, M. Okamura
  BNL, Upton, Long Island, New York
• T. Kanesue
  Kyushu University, Department of Applied Quantum Physics and Nuclear Engineering, Fukuoka

The Electron Beam Ion Source (EBIS) project at Brookhaven National Laboratory is a new heavy ion pre-injector for Relativistic Heavy Ion Collider (RHIC) and NASA Space Radiation Laboratory science programs. An important requirement for EBIS is an ion source capable of efficiently providing a variety of heavy ion species to many users within short period of time. In that respect, Laser Ion Source (LIS), which can supply many heavy ion species from solid targets, is a good candidate for RHIC-EBIS, however, LIS has an issue to be resolved. This is the requirement of limited current in low energy beam transport. LIS in the condition that laser power density is low, is expected to provide limited current with long pulse length. The discussions of the experimental results are presented.

• R. Dabrowski, M. Okamura
  BNL, Upton, Long Island, New York
• T. Kanesue
  Kyushu University, Department of Applied Quantum Physics and Nuclear Engineering, Fukuoka
• K. Kondo
  Department of Energy Sciences, Tokyo Institute of Technology, Yokohama

The Laser Ion Source is an efficient method for generating heavy ions for acceleration. The output produces high current and high charge-state beams from almost any type of elemental species. Using the Laser Ion Source apparatus, we consider improving the efficiency of this method by heating the target prior to laser irradiation. Prior deposition of any thermal energy into the target could add with the energy being delivered by the pulsed laser to produce higher current beams. These beams could be composed of higher charge-state ions and/or an increased net number of ions. We investigate by using a retrofitted heater to heat the target to a variety of high temperatures and subsequently analyze the produced beam.

• T. Kanesue
  Kyushu University, Department of Applied Quantum Physics and Nuclear Engineering, Fukuoka
• R. Dabrowski, M. Okamura
  BNL, Upton, Long Island, New York
• K. Kondo
  Department of Energy Sciences, Tokyo Institute of Technology, Yokohama

A laser ion source can provide high-current highly-charged ions with a simple structure. Previously we have demonstrated acceleration of >60 mA carbon and aluminum ion beams using a direct plasma injection scheme. However, it was not easy to control the ion pulse width. Especially to provide longer ion pulse, a plasma drift length which is the distance between laser target and extraction point, has to be extended and the plasma is diluted severely. We apply a solenoid field to prevent reduction of ion density at the extraction point. A solenoid field of a few hundred Gauss enhanced the ion density up to 40 times. We present these results, including details of the solenoidal field effects on the expanding laser plasma.