J. W. McDonald

Filter-fluorescer diagnostic system for the National Ignition Facility

An early filter-fluorescer diagnostic system is being fielded at the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) to measure the amount of hard x rays (20<hν<150u2002keV) generated in laser fusion experiments. From these measurements we hope to quantify the number of hot electrons produced in laser fusion experiments. The measurement of hot electron production is important for ignition experiments because these electrons can preheat the fuel capsule. Hot electrons can also be employed in experimentation by preheating hydrodynamic packages or by driving plasmas out of equilibrium. The experimental apparatus, data collection, analysis and calibration issues are discussed. Expected data signal levels are predicted and discussed.

Extraction of highly charged ions from the electron beam ion trap at LBNL for applications in surface analysis and materials science

We describe results from highly ion extraction experiments at the Electron Beam Ion Trap (EBIT) facility which is now operated at Lawrence Berkeley National Laboratory after transfer from Lawrence Livermore National Laboratory. Requirements on ion source performance for the application of highly charged ions (e. g. Xe{sup 44+}) in surface analysis and materials science are discussed.

Single-ion implantation for solid state quantum computer development

Several solid state quantum computer schemes are based on the manipulation of electron and nuclear spins of single donor atoms in a solid matrix. The fabrication of qubit arrays requires the placement of individual atoms with nanometer precision and high efficiency. In this article we describe first results from low dose, low energy implantations and our development of a low energy (<10 keV), single ion implantation scheme for 31Pq+ ions. When 31Pq+ ions impinge on a wafer surface, their potential energy (9.3 keV for P15+) is released, and about 20 secondary electrons are emitted. The emission of multiple secondary electrons allows detection of each ion impact with 100% efficiency. The beam spot on target is controlled by beam focusing and collimation. Exactly one ion is implanted into a selected area avoiding a Poissonian distribution of implanted ions.

Extraction of highly charged ions (up to 90+) from a high-energy electron-beam ion trap

The extraction of high-Z high-charge-state ions up to U90+ from a high-energy electron-beam ion trap, the SuperEBIT at Lawrence Livermore National Laboratory, is reported. The SuperEBIT provides a 240 mA electron beam with up to 200 keV of energy. Depending on the operating conditions (pulsed, continuous) and charge state, the number of ions extracted from the SuperEBIT varies between 102 and 105 ions per second under the tested conditions. The ions produced in SuperEBIT are extracted at potentials ranging from 0.5 to 20 keV (continuously variable) to provide highly charged low-emittance ion beams with energies between a few keV and several MeV. The performance of the SuperEBIT as an ion source is described and aspects for future developments and potential applications are discussed.

Preliminary performance measurements for a streak camera with a large-format direct-coupled charge-coupled device readout

The University of Rochester’s Laboratory for Laser Energetics (Rochester, New York) is leading an effort to develop a modern, fully automated streak camera. Characterization of a prototype camera shows spatial resolution better than 20u2002lp/mm, temporal resolution of 12u2002ps, line-spread function of 40u2002μm (full width at half maximum) contrast transfer ratio of 60% at 10u2002lp/mm, system gain of 101 charge-coupled device electrons per photoelectron, and a dynamic range of 500 for a 2u2002ns window.

Static and time-resolved 10–1000 keV x-ray imaging detector options for NIF

High energy (>10u2002keV) x-ray self-emission imaging and radiography will be essential components of many NIF high energy density physics experiments. In preparation for such experiments, we have evaluated the pros and cons of various static [x-ray film, bare charge-coupled device (CCD), and scintillator +u2002CCD] and time-resolved (streaked and gated) 10–1000u2002keV detectors.

Comparison of Streak Tube Performance

The performance of four streak tubes in six streak camera configurations is reported. Evaluations were made as part of a search for a streak tube to replace the obsolete RCA C73435 used in the ICF Programs optical streak cameras. Characteristics measured include linearity, spatial and temporal resolution, line-spread function, contrast transfer ratio (CTR), and dynamic range. Tubes evaluated are the RCA C73435, Photonis P510, Photek ST-Y, and Hamamatsu N8059. The RCA C73435 was evaluated in three camera configurations: large format CCD coupled directly to the streak tube, CCD directly coupled to an image intensifier tube (IIT), and the original configuration with a smaller CCD lens coupled to the IIT output. The Photonis and Photek tubes were characterized in configurations where they were directly coupled to large format CCDs. Optimum spatial resolution is achieved when the IIT is removed. Maximum dynamic range requires a configuration where a single photoelectron from the photocathode produces a signal that is {approx}5 times the CCD read noise. The Photonis P510 tube with the E2V CCD forms a well-optimized streak camera system.

Highly charged ion-secondary ion mass spectrometry (HCI-SIMS): toward metrology solutions for sub-100-nm technology nodes

The transition to semiconductor design nodes below 100 nm will create high demands on metrology solutions for the detection and chemical characterization of defects and particles throughout all processing steps. The compositional analysis of particles with sizes below about 20 nm is one particular challenge. We describe progress in the development of a highly charged ion based secondary ion mass spectrometry (HCI-SIMS) schemes aimed at addressing this challenge. Using ions like Xe48+ as projectiles increases secondary ion yields by several orders of magnitude and enables the application of coincidence counting techniques for the characterization of nano-environments of selected species. Additionally, an ion emission microscope was developed for defect imaging and we report examples of its application. We discuss steps of combining beam focusing, coincidence analysis and emission microscopy to enable compositional analysis of sub 20-nm size particles.