Publications

We are actively engaged in the research and development of neutron generators, neutron generator applications, neutron optics and also neutron imaging systems. Some of our work has been published in peer reviewed journals and presented at conferences. We routinely collaborate with scientists and engineers at other companies, universities and government institutions. A list of selected publications in the fields of neutron generators, neutron optics and imaging, x-ray sources and x-ray optics are given here.

Patents

US 20140179978
Title: Neutron Source for Neutron Capture Therapy
Date: Jun 26, 2014
Inventors: Richard Harris Pantell, Charles Kevin Gary, Melvin Arthur Piestrup
Assignee: Adelphi Technology, Inc.
Abstract: A therapy apparatus for producing thermal neutrons at a tumor site in a patient has a plurality of fast neutron sources surrounding a moderator, a fast neutron reflecting media around the fast neutron sources, a gamma-ray and neutron shielding media surrounding the fast neutron reflecting media, and a patient chamber positioned inside the moderator. The fast neutron sources are positioned around the moderator to maximize and direct the neutron flux to said tumor site.

2015

High Flux Neutron Generator for Neutron Activation Analysis
Date: 12-17th April 2015
Publication type: Abstract for Marc X conference
Publication: 10th Marc (Methods & Applications of Radioanalytical Chemistry) conference
Authors: Allan X. Chen, Jaakko H. Vainionpaa, Melvin A. Piestrup, Charles K. Gary, Greg Smith, David L. Williams, David Diprete, Glenn Jones, Richard H. Pantell

Abstract: The new model DD110MB compact neutron generator manufactured by Adelphi Technology produces thermal neutron flux that is commonly achievable only by small research nuclear reactors or larger accelerator based systems. The maximum thermal neutron flux at the sample ports has been measured to exceed 4·10⁷ n/cm²/s. The DD110MB utilizes the deuteron-deuteron (D-D) reaction to produce 2.45MeV fast neutrons by bombarding a titanium target with deuteron at energies up to 120keV. Four microwave ECR ion sources are used to produce a high atomic species of deuterium ions which are then accelerated by a single gap acceleration structure to a central Ti/Cu clad target. An integrated plastic moderator serves to both moderate the fast neutrons and isolate the high voltage target from ground potential. Depending on the choice of the moderator material, the DD110MB can produce a various neutron energy spectrums that are custom-tailored to the desired applications. The total fast neutron yield of the resulting from the D-D reaction exceeds 2·10¹⁰ n/s while using less than 12kW of total beam power. Footprint of the completely shielded DD110MB measures approximately 3m x 3m x 2m, which is ideal for operating inside a modest-sized laboratory room. In contrast to research nuclear reactors and large accelerator systems, the DD110MB presents less administrative and regulatory requirements. We will present both simulation and experimental results that are used to characterize the performance of the neutron generator at the conference.

Applications for Moderated DD Neutron Generators to Support a Radio-Analytical Laboratory
Date: 12-17th April 2015
Publication type: Abstract for Marc X conference
Publication: 10th Marc (Methods & Applications of Radioanalytical Chemistry) conference
Authors: Charles K. Gary, Melvin A. Piestrup, David Diprete, Allan X. Chen, Jaakko H. Vainionpaa, Greg Smith, David W. Williams, Glenn Jones, Richard H. Pantell

Abstract: Inexpensive thermal neutron sources for nuclear physics research and training are now available from Adelphi Technology Inc. Two prototype generators have been developed and have undergone preliminary testing for feasibility with neutron activation analysis (NAA). In addition, earlier models using differing moderating designs have been used for other tasks such as prompt gamma neutron activation analysis (PGNAA) and thermal neutron radiography.

These sources can produce thermal neutron fluxes that are commonly achievable only by small research nuclear reactor or larger accelerator-based systems. For example, Adelphi model DD-110MB uses four Deuterium ion beams directed toward a central target and produces 4 x 10⁷ n/cm²-sec of thermal neutrons at the sample chamber. Advanced designs are being considered for increasing this flux to 10⁸ n/cm²-sec. NAA of Au and Cl samples have been demonstrated using the DD-110MB. Best geometries for source and detector placement for PGNAA and thermal neutron radiography will discussed, along with potential issues of thermal neutron beam contamination due to fast neutrons and gamma emission.

An Adelphi model DD-110MB has recently been procured by a national laboratory to replace an aging Cf-252 based neutron source. The neutron source is utilized to support a variety of nuclear measurement projects and radiochemical analyses. Specific applications of the generator within the radiochemical measurements and nuclear counting group will also be discussed.

Development of high flux thermal neutron generator for neutron activation analysis
Date: 29-Jan-15
Publication type: Peer reviewed publication
Publication: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
Authors: Jaakko H. Vainionpaaa, Allan X. Chena, Melvin A. Piestrup, Charles K. Gary, Glenn Jones, Richard H. Pantell
Abstract: The new model DD110MB neutron generator from Adelphi Technology produces thermal ( < 0.5 eV) neutron flux that is normally achieved in a nuclear reactor or larger accelerator based systems. Thermal neutron fluxes of 3–5 · 107 n/cm²/s are measured. This flux is achieved using four ion beams arranged concentrically around a target chamber containing a compact moderator with a central sample cylinder. Fast neutron yield of ∼2 · 1010 n/s is created at the titanium surface of the target chamber. The thickness and material of the moderator is selected to maximize the thermal neutron flux at the center. The 2.5 MeV neutrons are quickly thermalized to energies below 0.5 eV and concentrated at the sample cylinder. The maximum flux of thermal neutrons at the target is achieved when approximately half of the neutrons at the sample area are thermalized. In this paper we present simulation results used to characterize performance of the neutron generator. The neutron flux can be used for neutron activation analysis (NAA) prompt gamma neutron activation analysis (PGNAA) for determining the concentrations of elements in many materials. Another envisioned use of the generator is production of radioactive isotopes. DD110MB is small enough for modest-sized laboratories and universities. Compared to nuclear reactors the DD110MB produces comparable thermal flux but provides reduced administrative and safety requirements and it can be run in pulsed mode, which is beneficial in many neutron activation techniques.
Keywords: Neutron generator; Neutron source; Ion optics; Neutron moderator; ECR

2014

Prompt gamma-ray neutron activation analysis of boron using Deuterium–Deuterium (D–D) neutron generator
Date: December 2014
Publication: Journal of Radioanalytical and Nuclear Chemistry, January 2015, Volume 303, Issue 1, pp 115-121
Authors: K. Bergaoui, N. Reguigui, C. K. Gary, C. Brown, J. T. Cremer, J. H. Vainionpaa, M. A. Piestrup
Abstract: Prompt gamma-ray neutron activation analysis (PGNAA) is a nuclear analytical technique for the determination of trace and other elements in solid, liquid or gaseous samples. The method consists in observing gamma rays emitted by a sample during neutron irradiation. The PGNAA system was built using a moderated and shielded deuterium–deuterium (D–D) neutron generator. This facility has been developed to determine the chemical composition of materials. The neutron generator is composed of three major components: An RF-Induction Ion Source, the Secondary Electron Shroud, and the Diode Accelerator Structure and Target. The generator produces monoenergetic neutrons (2.5 MeV) with a yield of 1010 n/s using 25–50 mA of beam current and 125 kV of acceleration voltage. Prompt γ-ray neutron activation analysis of 10B concentrations in Si and SiO2 matrices was carried out using a germanium detector (HPGe) and the results obtained are compared with a PGNAA system using a NaI detector. Neutron flux and energy distribution from D–D neutron generator at the sample position was calculated using Monte Carlo simulation. The interaction properties of neutrons in a Germanium detector have been studied.
Keywords: PGNAA, D–D neutron generator, HPGe detector, NaI detector, Boron, MCNP6

Development of a new deuterium–deuterium (D–D) neutron generator for prompt gamma-ray neutron activation analysis
Date: December 2014
Publication: Applied Radiation and Isotopes, Volume 94, December 2014, Pages 319–327
Authors: K. Bergaouia, N. Reguiguia, C.K. Gary, C. Brown, J.T. Cremer, J.H. Vainionpaa, M.A. Piestrup
Abstract: A new deuterium–deuterium (D–D) neutron generator has been developed by Adelphi Technology for prompt gamma neutron activation analysis (PGNAA), neutron activation analysis (NAA), and fast neutron radiography. The generator makes an excellent fast, intermediate, and thermal neutron source for laboratories and industrial applications that require the safe production of neutrons, a small footprint, low cost, and small regulatory burden. The generator has three major components: a Radio Frequency Induction Ion Source, a Secondary Electron Shroud, and a Diode Accelerator Structure and Target. Monoenergetic neutrons (2.5 MeV) are produced with a yield of 1010 n/s using 25–50 mA of deuterium ion beam current and 125 kV of acceleration voltage. The present study characterizes the performance of the neutron generator with respect to neutron yield, neutron production efficiency, and the ionic current as a function of the acceleration voltage at various RF powers. In addition the Monte Carlo N-Particle Transport (MCNP) simulation code was used to optimize the setup with respect to thermal flux and radiation protection.
Keywords: Neutron generator; MCNP;Deuterium–deuterium fusion reaction; Neutron yield; Shielding; PGNAA

Design, testing and optimization of a neutron radiography system based on a Deuterium–Deuterium (D–D) neutron generator
Date: January 2014
Publication: Journal of Radioanalytical and Nuclear Chemistry, Volume 299, Issue 1, pp 41-51
Authors: K.Bergaoui, N. Reguigui, C. K. Gary, J. T. Cremer, J. H. Vainionpaa, M. A. Piestrup
Abstract: Simulations show that significant improvement in imaging performance can be achieved through collimator design for thermal and fast neutron radiography with a laboratory neutron generator. The radiography facility used in the measurements and simulations employs a fully high-voltage-shielded, axial D–D neutron generator with a radio frequency driven ion source. The maximum yield of such generators is about 1010 fast neutrons per seconds (E = 2.45 MeV). Both fast and thermal neutron images were acquired with the generator and a Charge Coupled Devices camera. To shorten the imaging time and decrease the noise from gamma radiation, various collimator designs were proposed and simulated using Monte Carlo N-Particle Transport Code (MCNPX 2.7.0). Design considerations included the choice of material, thickness, position and aperture for the collimator. The simulation results and optimal configurations are presented.

2013

The Pros and Cons of Preliminary R&D of Boron Neutron Capture Therapy Based on Compact Neutron Generators: A Plan of Collaboration
Date: 23-27 September 2013
Publication: Physics Procedia, Volume 60, 2014, Pages 264–270
Authors: C.-K. Loong, Ray Sollychin, Raymond Kingwen Wong, Keith Bradley, Melvin A. Piestrup, Tianjiao Liang
Abstract: The characteristics of boron neutron capture therapy (BNCT) for cancer treatment demand, in addition to sufficient fluxes of epithermal neutrons, proper conditions of the neutron sources—compact layout, flexible operation, compatibility with hospital setting, etc. These requirements are best satisfied by compact accelerator-driven sources (CANS). We discuss the trade-offs among different CANS options and the needed R&D in order to advance BNCT to an acceptable level of practical prevalence and cancer treatment scope. We focus our attention on compact neutron generators (CNGs) which are the most compact and least expensive. We argue that the usefulness of D-D CNGs for preliminary studies, in spite of the substantial lower fluxes, can be augmented by high-performance beam-shaping assemblies and discoveries of superior 10B-containing cancer-cell seeking drugs. The plausibility of BNCT treatment of breast cancer using neutrons from a DD-109 CNG (Adelphi Technology, Inc.) is assessed by calculating the distribution of photon equivalent dose on a breast phantom using Monte-Carlo (MCNPX) simulations.
Keywords: compact neutron generator; boron neutron capture therapy; neutronics simulation; MCNPX

Simulations of Multi-Gamma Coincidences From Neutron-Induced Fission in Special Nuclear Materials
Date: 11-Apr-13
Publication: Nuclear Science, IEEE Transactions on (Volume:60 , Issue: 2 ) pp 533 – 538 ISSN: 0018-9499 INSPEC Accession Number: 13428873 DOI: 10.1109/TNS.2013.2248380
Authors: Kane, S.; Gozani, T. ; King, M.J. ; Kwong, J. ; Brown, C. ; Gary, C. ; Firestone, M.I. ; Nikkel, J.A. ; McKinsey, D.N.
Abstract: A study is presented on the detection of illicit special nuclear materials (SNM) in cargo containers using a conceptual neutron-based inspection system with xenon-doped liquefied argon (LAr(Xe)) scintillation detectors for coincidence gamma-ray detection. For robustness, the system is envisioned to exploit all fission signatures, namely both prompt and delayed neutron and gamma emissions from fission reactions induced in SNM. However, this paper focuses exclusively on the analysis of the prompt gamma ray emissions. The inspection system probes a container using neutrons produced either by (d, D) or (d, T) in pulsed form or from an associated particle neutron generator to exploit the associated particle imaging (API) technique, thereby achieving background reduction and imaging. Simulated signal and background estimates were obtained in MCNPX (2.7) for a 2 kg sphere of enriched uranium positioned at the center of a 1m × 1m × 1m container, which is filled uniformly with wood or iron cargos at 0.1 g/cc or 0.4 g/cc. Detection time estimates are reported assuming probabilities of detection of 95% and false alarm of 0.5%.
Keywords: Associated Particle Imaging (API), Fission Multiplicity Detection (FMD), Liquefied Argon (LAr) scintillation detector, coincidence counting, gamma ray detection by Liquefied Argon

Neutron and X-ray Optics Authors: Jay Theodore Cremer Jr.
Date: Mar 6, 2013
Publication type: Book
Publication: Elsevier, ISBN-10: 0124071643 | ISBN-13: 978-0124071643
Abstract: Covering a wide range of topics related to neutron and x-ray optics, this book explores the aspects of neutron and x-ray optics and their associated background and applications in a manner accessible to both lower-level students while retaining the detail necessary to advanced students and researchers. It is a self-contained book with detailed mathematical derivations, background, and physical concepts presented in a linear fashion. A wide variety of sources were consulted and condensed to provide detailed derivations and coverage of the topics of neutron and x-ray optics as well as the background material needed to understand the physical and mathematical reasoning directly related or indirectly related to the theory and practice of neutron and x-ray optics. The book is written in a clear and detailed manner, making it easy to follow for a range of readers from undergraduate and graduate science, engineering, and medicine. It will prove beneficial as a standalone reference or as a complement to textbooks.

2012

Large Area Liquid Argon Detectors for Interrogation Systems
Date: August 2012
Publication type: Conference proceedings
Publication: AIP Proceedings Application of Accelerators in Research and Industry: twenty-first International Congress (August 2012)
Authors: Charles Gary, Steve Kane, Murray I. Firestone, Gregory Smith, Tsahi Gozani, Craig Brown, John Kwong, Michael J. King, James A. Nikkel, and Dan McKinsey

Liquefied Noble Gas (LNG) Detectors for Detection of Nuclear Materials
Date: 27 Jan 2012
Publication type: IEEE Transactions on Nuclear Science (TNS) (submitted)
Authors: John Kwong, Tsahi Gozani, Craig Brown, James A. Nikkel, Dan McKinsey, Steve Kane, Charles Gary,
Abstract: Based upon a presentation to be given at The Symposium on Radiation Measurements and Applications (SORMA)

Neutron and X-ray Microscopy
Date: 2012
Publication type: Book
Publication: Academic Press, ISBN 0123944228, 9780123944221
Authors: Jay Theodore Cremer, Jr.
Abstract: This special volume of Advances in Imaging and Electron Physics details the current theory, experiments, and applications of neutron and x-ray optics and microscopy for an international readership across varying backgrounds and disciplines. Edited by Dr. Ted Cremer, these volumes attempt to provide rapid assimilation of the presented topics that include neutron and x-ray scatter, refraction, diffraction, and reflection and their potential application.

Advances in Imaging and Electron Physics: Part B: 173 [Kindle Edition]
Date: 31 December 2012
Publication type: Book (eBook)
Publication: Academic Press (Amazon Digital Services, Inc.), ASIN: B0093J2Q10
Authors: Jay Theodore Cremer Jr
Abstract: This special volume of Advances in Imaging and Electron Physics details the current theory, experiments, and applications of neutron and x-ray optics and microscopy for an international readership across varying backgrounds and disciplines. Edited by Dr. Ted Cremer, these volumes attempt to provide rapid assimilation of the presented topics that include neutron and x-ray scatter, refraction, diffraction, and reflection and their potential application.

Advances in Imaging and Electron Physics: Part A [Kindle Edition]
Date: 22 December 2012
Publication type: Book (eBook)
Publication: Academic Press (Amazon Digital Services, Inc.), ASIN: B008PQAR5E
Authors: Jay Theodore Cremer Jr
Abstract: This special volume of Advances in Imaging and Electron Physics details the current theory, experiments, and applications of neutron and x-ray optics and microscopy for an international readership across varying backgrounds and disciplines. Edited by Dr. Ted Cremer, these volumes attempt to provide rapid assimilation of the presented topics that include neut

Large area imaging of hydrogenous material using fast neutrons from a DD fusion generator
Date: 21 May 2012
Publication type: Peer reviewed paper
Publication: Nuclear Instruments and Methods in Physics Research A, 675 (2012) 51-55
Authors: J.T. Cremer, D.L. Williams, G.K. Gary, M.A. Piestrup, D.R. Faber, M.J. Fuller, J.H. Vainionpaa, M. Apodaca,(Adelphi Technology Inc) R.H. Pantell, J. Feinstein (Department of Electrical Engineering, Stanford University)
Abstract: A small-laboratory fast-neutron generator and a large area detector were used to image hydrogen-bearing materials. The overall image resolution of 2.5 mm was determined by a knife-edge measurement. Contact images of objects were obtained in 5ñ50 min exposures by placing them close to a plastic scintillator at distances of 1.5 to 3.2 m from the neutron source. The generator produces 109 n/s from the DD fusion reaction at a small target. The combination of the DD-fusion generator and electronic camera permits both small laboratory and fie

High Yield Neutron Generators using the DD reaction
Date: May 17, 2012
Publication type: Conference Proceedings
Publication: 22nd International Conference on the Application of Accelerators in Research and Industry (CAARI 2012)
Authors: J. H. Vainionpaa, J. L. Harris, M. A. Piestrup, C. K. Gary, D. L. Williams, M. D. Apodaca, J. T. Cremer, Qing Ji, B. A. Ludewigt, G. Jones

Liquefied Noble Gas (LNG) detectors for detection of nuclear materials
Date: March 2012
Publication type: Journal
Publication: Journal of Instrumentation Volume 7 March 2012
Authors: J A Nikkela (Yale University), T Gozanib, C Brownb, J Kwongb(Rapiscan Laboratories), D N McKinseya, Y Shina, S Kanec, C Garyc and M Firestone (Adelphi Technology)
Abstract: Liquefied-noble-gas (LNG) detectors offer, in principle, very good energy resolution for both neutrons and gamma rays, fast response time (hence high-count-rate capabilities), excellent discrimination between neutrons and gamma rays, and scalability to large volumes. They do, however, need cryogenics. LNG detectors in sizes of interest for fissionable material detection in cargo are reaching a certain level of maturity because of the ongoing extensive R&}D effort in high-energy physics regarding their use in the search for dark matter and neutrinoless double beta decay. The unique properties of LNG detectors, especially those using Liquid Argon (LAr) and Liquid Xenon (LXe), call for a study to determine their suitability for Non-Intrusive Inspection (NII) for Special Nuclear Materials (SNM) and possibly for other threats in cargo.

Rapiscan Systems Laboratory, Yale University Physics Department, and Adelphi Technology are collaborating in the investigation of the suitability of LAr as a scintillation material for large size inspection systems for air and maritime containers and trucks. This program studies their suitability for NII, determines their potential uses, determines what improvements in performance they offer and recommends changes to their design to further enhance their suitability. An existing 3.1 liter LAr detector (microCLEAN) at Yale University, developed for R&}D on the detection of weakly interacting massive particles (WIMPs) was employed for testing. A larger version of this detector (15 liters), more suitable for the detection of higher energy gamma rays and neutrons is being built for experimental evaluation. Results of measurements and simulations of gamma ray and neutron detection in microCLEAN and a larger detector (326 liter CL38) are presented.

2011

Liquefied Noble Gas (LNG) Detectors for Detection of Nuclear Materials
Date: November 2011
Publication type: Conference Presentation
Publication: Journal of Instrumentation, C03007, November, 2011.
Authors: Tsahi Gozani , Craig Brown, John Kwong, James A. Nikkel, Dan McKinsey, Steve Kane, Charles Gary

2010

Long-Lifetime HIgh-Yield Neutron Generators using the DD reaction and application of PGNAA
Date: May 2009
Publication type:
Publication: IAEA Publication
Authors: Michael Fuller, Melvin Piestrup, Charles Gary, Ted Cremer, Jack Harris, Glenn Jones, J. Hannes Vainionapaa, David L Williams (Adelphi Technology, Inc.) A. Bell, G. McRae (Carleton University), Daniel Faber (Heliocentric Technologies), B.A. Ludewight, J.W. Kwan, J. Reijonen, K.-N. Leung (E.O. Lawrence Berkeley National Laboroatory)
Abstract: The Lawrence Berkeley National Laboratory and Adelphi Technology Inc. have developed a series of high-yield neutron generators using the D-D reaction with an axial geometry. They operate with a single ion beam and can have a small origin size useful for immediate moderation and a high concentration of thermal neutrons. The generator uses RF induction discharge to efficiently ionize the deuterium gas. This discharge method provides high plasma density for high output current, high atomic species from molecular gases, long life operation and versatility for various discharge chamber geometries. These generators are open systems that can be actively pumped for a continuous supply of deuterium gas further increasing the generatorís expected lifetime. Since the system is open, many of the components, including the target, can be easily replaced. Pulsed and continuous operation has been demonstrated. In either mode of operation these generators have been used for Prompt Gamma Neutron Activation Analysis (PGNAA) and neutron activation analysis (NAA). Carleton University and Heliocentric Technologies are developing an Elemental Analyzer based on this neutron source.

2009

2008

High Intensity, Pulsed D-D- Neutron Generator
Date: 10-15 Aug 2008
Publication type: Conference publication
Publication: Proceedings Applications of Accelerators in Research and Industry, Twentieth International Conference
Authors: D.L. Williams, H.H. Vainionpaa, G. Jones, M.A. Piestrup, C.K. Gary, J.L. Harris, M.J. Fuller, J.T. Cremer (Adelphi Technology Inc), B.A. Ludewight, J.W. Kwan, J. Reijonen, K.-N. Leung, R.A. Gough (Lawrence Berlekey National Laboratory)
Abstract: Single ion-beam RF-plasma neutron generators are presented as a laboratory source of intense neutrons. The continuous and pulsed operations of such a neutron generator using the deuteriumdeuterium fusion reaction are reported. The neutron beam can be pulsed by switching the RF plasma and/or a gate electrode. These generators are actively vacuum pumped so that a continuous supply of deuterium gas is present for the production of ions and neutrons. This contributes to the generator’s long life. These single-beam generators are capable of producing up to 1E10 n/s. Previously, Adelphi and LBNL have demonstrated these generators’ applications in fast neutron radiography, Prompt Gamma Neutron Activation Analysis (PGNAA) and Neutron Activation Analysis (NAA). Together with an inexpensive compact moderator, these high-output neutron generators extend useful applications to home laboratory operations.

2007

Extreme ultraviolet emission from non-relativistic electrons penetrating a multilayer nanostructure
Date: January 2007
Publication type: Peer reviewed journal
Publication: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Volume 254, Issue 2, January 2007, Pages 259ñ267
Authors: N.N. Nasonova, 1, , A.S. Kubankina, P.N. Zhukovaa (Laboratory of Radiation Physics, Belgorod State University), M. Goldsteinb, D.L. Williams (Intel Corporation), b, M.A. Piestrupc, H. Parkc, (Adelphi Technology, Inc.)
Abstract: The spectral and angular distributions from parametric X-radiation (PXR) from non-relativistic electrons penetrating a multilayer nanostructure are calculated while accounting for contributions of ordinary and diffracted transition radiation. The PXR emission mechanism is shown to be the dominant emission mechanism. The calculation also demonstrates the possibility of a tunable quasi-monochromatic extreme ultraviolet (EUV) source using only non-relativistic electrons whose efficiency can be large enough for practical applications.

Development of Advanced Neutron/Gamma Generators for Homeland Security and Imaging Applications
Date: 2007
Publication type: Conference proceedings
Publication: Optics and Photonics in Global Homeland Security III. Proceedings of the SPIE, Volume 6540, pp. 65401P (2007).
Authors: J. Reijonen, N. Andresen, F. Gicquel, R. Gough, M. King, T. Kalvas, K.-N. Leung, T.-P. Lou, H.Vainionpaa, A. Antolak, D. Morse, B. Doyle, G. Miller and M. A. Piestrup (affiliations: Lawrence Berkeley National Laboratory, Sandia National Laboratory, Tensor Technology Inc., Adelphi Technology Inc.)
Abstract: We report here on the development of neutron and photon sources for use in imaging and active interrogation applications, where there is a growing urgency for more advanced interrogation tools. These devices include high yield D-D, D-T and T-T fusion reaction based neutron generators and also low energy nuclear reaction based high-energy gamma generators. One common feature in these various devices is the use of a high-efficiency, RF-induction discharge ion source. This discharge method provides high plasma density for high output current, high atomic species from molecular gases for high efficiency neutron or gamma generation and long lifetime. Predictable discharge characteristics of these plasma generators allow accurate modeling for both the beam dynamics and for the heat loads at the target spot. Current status of the neutron and gamma generator development with experimental data will be presented.

Simple microscope using a compound refractive lens and a wide-bandwidth thermal neutron beam
Date: 2007
Publication type:
Publication: Appl. Phys. Letts. 90 (2007).
Authors: J. T. Cremer, H. Park, M. A. Piestrup, C. K. Gary, R. H. Pantell, R. Flocchini, H. P. Egbert, M.D. Kloh, R.B. Walker (affiliations: Adelphi Technology Inc., Dept Electrical Engineering, Stanford University, Davis McClellan Nuclear Radiation Center).
Abstract: The results of imaging experiments using biconcave, spherical compound refractive lenses (CRLs) and a wide-bandwidth thermal neutron beam are presented. Two CRLs were used, consisting of 155 beryllium and 120 copper lenses. The experiments were performed using a thermal neutron beam line at McClellan Nuclear Radiation Center reactor. The authors obtained micrographs of cadmium slits with up to 5◊ magnification and 0.3 mm resolution. The CRL resolution was superior to a pinhole camera with the same aperture diameter. The modulation transfer function (MTF) of the CRL was calculated and compared with the measured MTF at five spatial frequencies, showing good agreement.

2006

Measured operational neutron energies of compound refractive lenses
Date: October 2006
Publication type: Refereed Journal
Publication: Nuclear Instruments and Methods in Physics Research Section B, Volume 251, Issue 2, p. 507-511.
Authors: H. Park, J.T. Cremer, M.A. Piestrup, C.K. Gary (Adelphi Technology Inc), Rex P. Hjelm, W.C.L.J. Sellyey, R.H. Pantell (Los Alamos Neutron Science Center LANSCE, Los Alamos National Laboroatory) R. H. Pantell (Stanford University)
Abstract: The characteristics of two compound refractive lenses (CRLs) have been measured using a broadband spallation neutron source. One CRL consists of a stack of 98 biconcave, spherical lenses made of MgF2, and another consists of 198 biconcave, spherical lenses made of Al. The bandwidth of the spallation source included wavelengths from 1.5 ≈ to 15.7 ≈ that we could use to test the CRLs. The MgF2 CRL was found to be useful from 9 to 15 ≈ with the maximum transmission around 13 ≈, whereas the Al CRL was found to give good transmission around 5 15 ≈, with the maximum transmission around 8 ≈. Spectra with Al lens and MgF2 CRLs show multiple transmission dips due to Bragg diffraction of the microcrystal structure of the lens materials (Al or MgF2). These measurements helped characterize the CRLs for possible applications at shorter wavelengths than previously used.

2004

Large area x-ray and neutron imaging using three-dimensional arrays of microlenses
Date: 2004
Publication type: Peer reviewed article
Publication: Review of Scientific Instruments 75, 4769 (2004)
Authors: Y. I. Dudchik, N. N. Kolchevsky, and F. F. Komarov
Institute of Applied Physics Problems, Kurchatova , Minsk, Belarus), M. A. Piestrup, J. T. Cremer, C. K. Gary, and H. Park Adelphi Technology, Inc.), A. M. Khounsary (Argonne National Laboratory)
Abstract: Linear arrays of biconcave microlenses have been shown to be capable of imaging small objects using either x rays or neutrons. Because these lenses have small apertures and finite lengths, they are limited in their field of view (FOV). To increase the FOV, we propose that two sets of three-dimensional arrays of these microlenses be used. The spacing of the microlenses is calculated to achieve a complete image with uniform brightness. General design criteria are discussed in situations where either a one-to-one image or a magnified image is required.

Biological Imaging with a Neutron Microscope
Date: May 2004
Publication type: Refereed Journal
Publication: Appl. Phys. Lett., 85(3), 494-496, (19 July 2004).
Authors: J. T. Cremer, M. A. Piestrup, C. K. Gary (Adelphi Technology, Inc.), R. H. Pantell (Stanford University), and C. J. Glinka (National Institute for Standards and Technology)
Abstract: A simple microscope employing a compound refractive lens (CRL) composed of 100 biconcave lenses was used to image a biological sample with a 9.4◊ magnification using 10 cold neutrons. The microscopeís resolution, 0.5 mm, was primarily determined by the neutron detector 5.0 mm pixel size. Unlike previous work the CRLís field of view was large (44 mm) and increased as the distance between the exit of neutron-waveguide and the specimen decreased. Short source-to-specimen distances allowed the 1.2-cm-diam CRL to view a biological sample with this field of view.

2002

X-ray focusing with compound lenses made from beryllium
Date: 2002
Publication type: Refereed journal article
Publication: Optics Letters, Vol. 27, Issue 9, pp. 778-780 (2002)
Abstract: We have measured the intensity profile and transmission of x rays focused by a series of biconcave spherical unit lenses fabricated from beryllium. The use of beryllium extends the range of operation of compound refractive lenses, improving transmission, aperture size, and gain. The compound refractive lens was composed of 160 biconcave unit lenses, each with a radius of curvature of 1.9 mm. Two-dimensional focusing with a gain of 1.5 was obtained at 6.5 keV with a focal length of 93 cm. The effective aperture of the compound refractive lens was measured as 600 µm , with 9% peak transmission.

A simple neutron microscope using a compound refractive lens
Date: Nov 2002
Publication type: Refereed article
Publication: Appl. Phys. Lett., 81, 4290 (2002)
Authors: H. R. Beguiristain, I. S. Anderson, C. D. Dewhurst, M. A. Piestrup, J. T. Cremer, and R. H. Pantell
Abstract: Images obtained with a high-magnification simple neutron microscope using a compound refractive lens are presented in this letter. The short focal length of the stack of Al biconcave lenses facilitated the setup of a simple neutron microscope at the D22 small angle scattering beam line at the Institut Laue Langevin, Grenoble, France that achieved a 35◊ magnification and a 214 µm resolution. Higher-resolution images could be obtained using improved neutron lens systems that enhance beam delivery from neutron sources and produce high-quality images in combination with higher resolution two-dimensional neutron detectors. © 2002 American Institute of Physics.