The DCU laser ion source

Yeates, P.; Costello, J. T.; Kennedy, E. T.

doi:doi:10.1063/1.3374123

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High Voltage-Cylinder Sector Analyzer 300/15: A cylindrical sector analyzer for electron kinetic energies up to 15 keV

We have developed an energy analyzer, High Voltage-Cylinder Sector Analyzer 300/15, for electron kinetic energies up to 15 keV. It is especially suited for hard x-ray photoelectron spectroscopy, but also for ultraviolet and soft x-ray photoelectron spectroscopy (ultraviolet photoemission spectroscopy, x-ray photoemission spectroscopy), Auger electron spectroscopy, and reflection high energy electron spectroscopy. The analyzer is based on a cylinder sector with 90° deflection, 300 mm slit-to-sli...

Fast integrator based data acquisition system for the SST-1 Thomson scattering system

An operational transconductance amplifier based fast charge-integrating module (FCIM) is designed and developed for an easy acquisition of fast Thomson scattered and background signal. FCIM based data acquisition technique can be used for the measurement of charge pulses of <20 ns duration. The response of the module is tested using a standard pulsed charge-generating module. The measuring charge range of the module depends on the integrating capacitor. Comparison of the performance of FCIM ...

Laser ion sources are used to generate and deliver highly charged ions of various masses and energies. We present details on the design and basic parameters of the DCU laser ion source (LIS). The theoretical aspects of a high voltage (HV) linear LIS are presented and the main issues surrounding laser-plasma formation, ion extraction and modeling of beam transport in relation to the operation of a LIS are detailed. A range of laser power densities (I ∼ 10⁸–10¹¹ W cm⁻²) and fluences (F = 0.1–3.9 kJ cm⁻²) from a Q-switched ruby laser (full-width half-maximum pulse duration ∼ 35 ns, λ = 694 nm) were used to generate a copper plasma. In “basic operating mode,” laser generated plasma ions are electrostatically accelerated using a dc HV bias (5–18 kV). A traditional einzel electrostatic lens system is utilized to transport and collimate the extracted ion beam for detection via a Faraday cup. Peak currents of up to I ∼ 600 μA for Cu⁺ to Cu³⁺ ions were recorded. The maximum collected charge reached 94 pC (Cu²⁺). Hydrodynamic simulations and ion probe diagnostics were used to study the plasma plume within the extraction gap. The system measured performance and electrodynamic simulations indicated that the use of a short field-free (L = 48 mm) region results in rapid expansion of the injected ion beam in the drift tube. This severely limits the efficiency of the electrostatic lens system and consequently the sources performance. Simulations of ion beam dynamics in a “continuous einzel array” were performed and experimentally verified to counter the strong space-charge force present in the ion beam which results from plasma extraction close to the target surface. Ion beam acceleration and injection thus occur at “high pressure.” In “enhanced operating mode,” peak currents of 3.26 mA (Cu²⁺) were recorded. The collected currents of more highly charged ions (Cu⁴⁺–Cu⁶⁺) increased considerably in this mode of operation.

Article Outline

INTRODUCTION
LASER ION SOURCES: GENERAL OVERVIEW
LASER ION SOURCES: GENERAL PRINCIPLES
1. Plasma generation and expansion
2. Extraction dynamics
3. Ion beam transport
EXPERIMENTAL SETUP
BASIC OPERATIONAL PERFORMANCE
PLASMA SIMULATION AND BEAM TRANSPORT MODELING
1. MEDUSA simulations
2. Ion probe measurements
3. SIMION simulations
ENHANCED OPERATIONAL PERFORMANCE
DISCUSSION
CONCLUSION

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KEYWORDS and PACS

Keywords

copper, ion beams, ion sources, plasma diagnostics, plasma production by laser, plasma sources, plasma-beam interactions, Q-switching

PACS

52.50.Jm

Plasma production and heating by laser beams (laser-foil, laser-cluster, etc.)
52.50.Dg

Plasma sources
52.40.Mj

Particle beam interactions in plasmas
52.70.-m

Plasma diagnostic techniques and instrumentation

ARTICLE DATA

Digital Object Identifier

http://dx.doi.org/10.1063/1.3374123

PUBLICATION DATA

ISSN

0034-6748 (print)

1089-7623 (online)

Publisher

$abstract.society.value is a Member of CrossRef

American Institute of Physics

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