[7]. Donor electron and nuclear spins are promising candidates for implementation of quantum bits in silicon [7]. The detection of low energy single ion impacts for device integration has been accomplished via detection of secondary electrons [2,4,9], or by collection of electron holepairs in optimized diodes [3]. It is also well known that high energy (MeV) single ion impacts can upset device currents [10], and an extension of this approach to low energy ions was recently outlined in Ref. 11. Also, random telegraph noise due to switching occupancies of single Coulomb scattering centers [12] has long been observed in sub-micron transistors, and it can thus be expected that the impact of lower energy (<100 keV) single ions, which is accompanied by the generation of multiple charged defects, can also be sensed in FETs.In this letter we report on the detection of low energy (50 to 70 keV) antimony and xenon ion impacts in FETs with channel areas of 4 μm 2 at room temperature. FETs were formed for development of single donor spin readout techniques, and spin dependent neutral donor scattering was recently observed in transport studies with similar devices used here [13]. Single ions change transistor channel mobilities through formation of defects upon impact, enabling precision placement of defined numbers of dopants into transistor channels. Upon further reduction of the beam current to ~0.1 ions/s, pulses contain mostly no ions, and current steps from single ion hits are recorded (Figure 2 c)). The probability for multiple ion hits in one pulse under these conditions of reduced beam current was less then 3%.During exposures with ions of different impact energies and charge states we found that the sensitivity to ion impacts, i. e. the magnitude of current steps, was gradually reduced with increasing implant dose. Further, variations in step heights at the given noise level did not allow us to confidently discriminate multiple hits from single ion hits based on the step heights. Due to the degrading sensitivity, it was also difficult to investigate charge state effects on the single ion induced current step height. It can be expected that the localized deposition of potential energy of multiply and highly charged ions [21] contributes significantly to the formation of defects in the gate oxide and at the Si-SiO 2 interface, and future work aims at quantifying this effect.Following a series of exposures with an accumulated dose of ~10 11 cm -2 , devices were annealed for damage repair and dopant activation. Rapid thermal annealing (RTA) was performed in an AGA Heatpulse at 900º C for 20 s in Argon, followed by another 30 min. N 2 /H 2 -forming gas anneal at 400º C. In figure 3, we show a series of I-V curves of a pristine A-FET 5 (Fig. 3 a) and NMOS-FET (Fig. 3 b), after FIB processing and forming gas anneal, and then after monitored implantation with noble gas and Sb ions and the consecutive anneals, demonstrating that devices were functional transistors after the full process sequence. The threshold voltages, V...

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A high-yield D-T neutron generator has been developed for neutron interrogation in homeland security applications such as cargo screening. The generator has been designed as a sealed tube with a performance goal of producing 5·10 11 n/s over a long lifetime. The key generator components developed are a radio-frequency (RF) driven ion source and a beam-

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All of the neutron generators developed in the Plasma and Ion Source Technology Group are utilizing powerful RF-induction discharge to generate the deuterium plasma. One of the advantages of using the RF-induction discharge is it's ability to generate high fraction of atomic ions from molecular gases, and the ability to generate high plasma densities for high extractable ion current from relatively small discharge volume. Figure 1. Schematic drawing of the co-axial neutron generator on the left, the co-axial neutron generator on the right. SHIELDING STRUCTURE NEUTRON GENERATOR

High-intensity fast white neutron pulses are needed for pulsed fast neutron transmission spectroscopy ͑PFNTS͒. A compact tritium-tritium fusion reaction neutron generator with an integrated ion beam chopping system has been designed, simulated, and tested for PFNTS. The design consists of a toroidal plasma chamber with 20 extraction slits, concentric cylindrical electrodes, chopper plates, and a central titanium-coated beam target. The total ion beam current is 1 A. The beam chopping is done at 30 keV energy with a parallel-plate deflector integrated with an Einzel lens. Beam pulses with 5 ns width can be achieved with a 15 ns rise/fall time ±1500 V sweep on the chopper plates. The neutrons are produced at 120 keV energy. A three-dimensional simulation code based on Vlasov iteration was developed for simulating the ion optics of this system. The results with this code were found to be consistent with other simulation codes. So far we have measured 50 ns ion beam pulses from the system.