Implementation of a prototype slow positron beam at the NC State University PULSTAR reactor

Hathaway, A.G.; Skalsey, M.; Frieze, W. E.; Vallery, Richard S.; Gidley, David W.; Hawari, Ayman I.; Xu, Jun

doi:10.1016/j.nima.2007.03.036

Cited by 21 publications

(20 citation statements)

References 4 publications

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“…Typical laboratory sources of positrons use the radioisotope 22 Na followed by a solid neon moderator to slow the positrons to electron volt energies. However, to achieve the full potential of the MCT, the initial source of positrons will need to be a strong one, such as those now operating at the Munich and North Carolina State reactors [15,16]. …”

Section: Tools For the Research The Penning-malmberg Trapmentioning

confidence: 99%

“…A potentially important use of the MCT is to multiplex the output of the ultrahigh flux positron sources, either in place now, such as NEPOMUC, or others in stages of development [32][33][34][35]. This will be useful in cases where a particular experiment does not require the entire positron flux from the source, but can use a lower flux of positrons cooled and/or delivered in a particular manner.…”

Section: Multiplexing the Output Of Intense Positron Sourcesmentioning

confidence: 99%

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Progress towards a practical multicell positron trap

Danielson

Hurst

Surko

2013

AIP Conference Proceedings

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Described here is progress in an experimental program to develop a 21 cell multicell trap for the accumulation and storage of ~ 10 12 positrons. The basic architecture is an arrangement of multiple Penning-Malmberg (PM) trapped plasmas (i.e., cells) arranged in parallel in a common vacuum system and magnetic field. Experiments are described that are intended to address several key issues, including the effects of large space charge potentials and high plasma densities on: plasma heating, deterioration of confinement, and decreased efficiency of rotating electric fields in producing plasma compression. The confinement of PM plasmas displaced both radially and toward the ends of the uniform magnetic field region will also be investigated.

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Section: Tools For the Research The Penning-malmberg Trapmentioning

confidence: 99%

Section: Multiplexing the Output Of Intense Positron Sourcesmentioning

confidence: 99%

Progress towards a practical multicell positron trap

Danielson

Hurst

Surko

2013

AIP Conference Proceedings

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“…Furthermore, the intensity of the c-radiation can be increased with the reaction 113 Cd (n, c) 114 Cd, and it was previously used in the NEP-OMUC facility at the FRM II at the Technische Universität München, which is the facility that delivers the world's highest positron beam intensity, and in the positron beam facility at the North Carolina State University [14].…”

Section: Introductionmentioning

confidence: 99%

Development of a mono-energetic positron beam line at the Kyoto University Research Reactor

Sato¹,

Xu²,

Yoshiie³

et al. 2015

Nuclear Instruments and Methods in Physics Research Section B:

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“…At this conference we have heard of many exciting developments in high intensity positron beam facilities aimed at 10 8 -10 10 slow positrons/second. We are collaborating on one such intense positron beam that is under construction at the North Carolina State University PULSTAR Nuclear Reactor in Raleigh, NC [21]. This positron beam (inspired by the intense positron facility at Delft University) is based on pair-production in the intense gamma flux near the reactor core.…”

mentioning

confidence: 99%

“…It is designed to include the latest generation of PALS spectrometers for depth-profiled dielectric film characterization and for nanophase characterization in general. A prototype beam has already achieved a reactor-power scaled rate of 3 x 10 7 positrons/s [21]. The full scale beam should be a factor of 10-50 higher rate, insuring more than sufficient beam to explore the maximum data rate in PALS fast-coincidence timing (limited by timing system deadtime) while focusing and limiting the beam to ~ 1 mm diameter.…”

mentioning

confidence: 99%

Future directions of positron annihilation spectroscopy in low‐k dielectric films

Gidley

Vallery

Liu

et al. 2007

Phys. Status Solidi (c)

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. 55.+f, 78.55.Mb, 78.70.Bj Positronium Annihilation Lifetime Spectroscopy (PALS) has become recognized in the microelectronics industry as one of only several methods capable of quantitatively characterizing engineered nanopores in next-generation (k < 2.2) interlayer dielectric (ILD) thin films. Successes and shortcomings of PALS to date will be assessed and compared with other methods of porosimetry such as ellipsometric and X-ray porosimetries (EP and XRP). A major theme in future low-k research focuses on the ability to integrate porous ILD's into chip fabrication; the vulnerability of porous dielectrics to etching, ashing, and chemical-mechanical polishing in process integration is delaying the introduction of ultra-low-k films. As device size approaches 45 nm the need to probe very small (sub-nanometer), semi-isolated pores beneath thin diffusion barriers is even more challenging. Depth-profiled PALS with its ability to determine a quantitative pore interconnection length and easily resolve 0.3 nm pores beneath diffusion barriers or in trench-patterned dielectrics should have a bright future in porous ILD research. The ability of PALS (and PAS in general) to deduce evolution and growth of pores with porosity should find broad applicability in the emerging field of high performance materials with strategically engineered nanopores.

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Implementation of a prototype slow positron beam at the NC State University PULSTAR reactor

Cited by 21 publications

References 4 publications

Progress towards a practical multicell positron trap

Progress towards a practical multicell positron trap

Development of a mono-energetic positron beam line at the Kyoto University Research Reactor

Future directions of positron annihilation spectroscopy in low‐k dielectric films

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