Laser Ion Source

A spark discharge is coupled to a laser multicharged ion source to enhance ion generation. The
laser plasma triggers a spark discharge with electrodes located in front of the ablated target. For
an aluminum target, the spark discharge results in significant enhancement in the generation of
multicharged ions along with higher charge states than observed with the laser source alone. When
a Nd:YAG laser pulse (wavelength 1064 nm, pulse width 7.4 ns, pulse energy 72 mJ, laser spot area
on target 0.0024 cm2) is used, the total multicharged ions detected by a Faraday cup is 1.0 nC with
charge state up to Al3+. When the spark amplification stage is used (0.1 μF capacitor charged to
5.0 kV), the total charge measured increases by a factor of ∼9 with up to Al6+ charge observed.
Using laser pulse energy of 45 mJ, charge amplification by a factor of ∼13 was observed for a
capacitor voltage of 4.5 kV. The spark discharge increases the multicharged ion generation without
increasing target ablation, which solely results from the laser pulse. This allows for increased
multicharged ion generation with relatively low laser energy pulses and less damage to the surface of
the target.

5-Hydroxymethylfurfural (5-HMF) is a compound with the elemental composition C(6)H(6)O(3) that is present in powdered milk. Protonated 5-HMF (calculated m/z 127.0395) has the same nominal m/z as protonated melamine (calculated m/z 127.0732) and can interfere with direct analysis of melamine in powdered milk. Tandem mass spectrometry and high-resolution mass spectrometry have been previously used to distinguish melamine from 5-HMF. An alternative approach is presented here that uses the direct analysis in real time (DART) ion source operated with argon gas in combination with acetylacetone and pyridine reagent gases to selectively ionize melamine and eliminate the interference from 5-HMF. High-resolution/accurate mass data were used to verify the elimination of the 5-HMF interference and confirm the melamine elemental composition. With further refinement, this technique could lead to a rapid analysis method for screening large numbers of samples.

Coherent low energy electrons of 60-200 eV kinetic energy and sub-nanometer wavelength provide a tool to record holograms of individual bio-molecules, such as DNA or viruses. From the recorded holograms, the three-dimensional shape of the molecules can numerically be reconstructed. The experimental setup as well as the numerical reconstruction of low energy electron holograms from individual bio-molecules shall be discussed. Since most biological objects are transparent for electrons they introduce only a phase shift to the incident electron wave. We present a method to not only retrieve the absorbing (as most known methods do) but also the phase properties of the object wave. Finally, we present a general solution of the long-standing twin image problem in holography. It is applicable to any type of holography independent of the wavelength used and the nature of the wave, be it light, electrons, x-rays or any other coherent radiation.

Resonance ionization laser ion source (RILIS) technique has been used in the β-decay studies of 59Mn and 58Zn. The importance of the RILIS for production of these elements is discussed. The properties of the low-lying levels of the studied nuclei are discussed.

High-power pulsed lasers emitting IR and visible radiation with intensities ranging between 10^8 and 10^16 W/cm2, pulse duration from 0.4 to 9 ns and energy from 100 mJ up to 600 J, operating in single mode or in repetition rate, can be employed to produce non-equilibrium plasma in vacuum by irradiating solid targets. Such a laser-produced plasma generates highly charged and high-energy ions of various elements, as well as soft and hard X-ray radiations. Heavy ions with charge state up to 58+ and kinetic energy up to 10 MeV are detected. The plasma emits ion current densities of the order of tens of mA/cm^2. Interesting application possibilities of the generated plasmas concerning the ion implantation technique, the laser ion sources, the high intensity and resolution X-ray sources, the laser propulsion technique and the nuclear reaction of light elements are presented and discussed.

At Brookhaven National Laboratory, a high current Electron Beam Ion Source (EBIS) has been developed as part of a new preinjector that is under construction to replace the Tandem Van de Graaffs as the heavy ion preinjector for the RHIC and NASA experimental programs. This preinjector will produce milliampere-level currents of essentially any ion species, with q/A 1/6, in short

The experiment concerning the ECLISSE method (ECR ion source coupled to a laser ion source for charge state enhancement) has been carried out by coupling a laser ion source (LIS) to the superconducting electron cyclotron resonance source (SERSE) electron cyclotron resonance (ECR) ion source with the goal to obtain intense beams of highly charged ions (cw or pulsed mode) from

Laser-plasma interactions in the novel regime of relativistically induced transparency (RIT) have been harnessed to generate intense ion beams efficiently with average energies exceeding 10 MeV/nucleon (>100 MeV for protons) at "table-top" scales in experiments at the LANL Trident Laser. By further optimization of the laser and target, the RIT regime has been extended into a self-organized plasma mode. This mode yields an ion beam with much narrower energy spread while maintaining high ion energy and conversion efficiency. This mode involves self-generation of persistent high magnetic fields (∼10(4) T, according to particle-in-cell simulations of the experiments) at the rear-side of the plasma. These magnetic fields trap the laser-heated multi-MeV electrons, which generate a high localized electrostatic field (∼0.1 T V/m). After the laser exits the plasma, this electric field acts on a highly structured ion-beam distribution in phase space to reduce the energy spread, t...