| 1. |
- Jenkins, D. G., et al.
(författare)
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Proof-of-principle for fast neutron detection with advanced tracking arrays of highly segmented germanium detectors
- 2009
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Ingår i: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 602:2, s. 457-460
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Tidskriftsartikel (refereegranskat)abstract
- Recent advances in germanium detector technology have promised much higher efficiency for gamma-ray detection through tracking the interaction of 7-rays in the crystal using pulse shape analysis. We present a related approach where the unique characteristics of the excitation and delayed decay of the excited 0(+) state in Ge-72 within a highly segmented germanium detector may be used as a very sensitive tag for fast neutrons by making use of pulse shape analysis. A proof-of-principle of this technique is presented and an efficiency for fast neutrons of up to 1.5% for a 4 pi tracking array is deduced, Neutron interactions may be localised with the unprecedentedly high angular resolution of 0.5 degrees for a compact (20-cm radius) array. The application of these properties as a novel approach to a broad class of important transfer reactions such as (d,n) and (He-3,n) is presented. (C) 2009 Elsevier B.V. All rights reserved.
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| 2. |
- Lehman, Eberhard, et al.
(författare)
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Neutron radiography with 14 MeV neutrons from a neutron generator
- 2005
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Ingår i: IEEE Transactions on Nuclear Science. ; 52:1, s. 389-393
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Konferensbidrag (refereegranskat)abstract
- Neutrons with the initial energy of 14 MeV produced by the neutron generator of the Department of Reactor Physics, Chalmers Univ. of Techn., were detected by a camera system in connection with scintillator screens. Images were prodiced for 14 MeV and moderated neutrons with suited scintillator screens. Qualitative and quantitative evaluations were made to characterize the performance of the experimental setup.
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| 3. |
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| 4. |
- Mattsson, Håkan, 1969, et al.
(författare)
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Collimation and background in the pulsed neutron activation method for determination of water flow in pipes
- 2007
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Ingår i: International Journal of Nuclear Energy Science and Technology. - 1741-637X .- 1741-6361. ; 3:1, s. 12-
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Tidskriftsartikel (refereegranskat)abstract
- In a Pulsed Neutron Activation (PNA) flowmeter, the water in a pipe is bombarded with neutron pulses, which introduce activity into the pipe. The activity is mixed with the flow, and gamma radiation emitted from the activity is measured with a detector downstream. The average velocity of the water is then calculated using the time-resolved detector signal. In this paper, the effect of collimation of the neutron radiation has been investigated. Such a collimation would increase the accuracy of the measurement, but the use of a collimator requires the distance between the pipe and the neutron source to be increased, with a corresponding loss in count rate. The results show that this loss makes neutron collimators in PNA of little use. In addition, a method to identify and subtract the background originating from stationary sources in a PNA measurement was developed.
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| 5. |
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| 6. |
- Mileshina, Larisa, 1970, et al.
(författare)
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Design and performance of the pulsed positron beam at Chalmers University of Technology
- 2009
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Ingår i: Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 267:17, s. 2934-2937
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Tidskriftsartikel (refereegranskat)abstract
- A slow monoenergetic pulsed positron beam at Chalmers University of Technology has been built. The system consists mainly of chopper, buncher and accelerator. The achieved positron energy range is in range between 230 eV and 15 keV. The FWHM of the beam resolution function is around 700 ps. The beam intensity is around 10(3) cps. (C) 2009 Elsevier B.V. All rights reserved.
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| 7. |
- Skarnemark, Gunnar, 1948, et al.
(författare)
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A Unique Master´s Program in Combined Nuclear Technology and Nuclear Chemistry at Chalmers University of Technology
- 2009
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Ingår i: AIP Conference Proceedings. - 1551-7616 .- 0094-243X. ; :1164, s. 78-84
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Tidskriftsartikel (refereegranskat)abstract
- The need for engineers and scientists who can ensure safe and secure use of nuclear energy is large in Sweden and internationally. Chalmers University of Technology is therefore launching a new 2-year master´s program in Nuclear Engineering, with start from the autumn of 2009. The program is open to Swedish and foreign students. The program starts with compulsory courses dealing with the basics of nuclear chemistry and physics, radiation protection, nuclear power and reactors, nuclear fuel supply, nuclear waste management and nuclear safety and security. There are also compulsory courses in nuclear industry applications and sustainable energy futures. The subsequent elective courses can be chosen freely but there is also a possibility to choose informal tracks that concentrate on nuclear chemistry or reactor technology and physics. The nuclear chemistry track comprises courses in e.g. chemistry of lanthanides, actinides and transactinides, solvent extraction, radioecology and radioanalytical chemistry and radiopharmaceuticals. The program is finished with a one semester thesis project. This is probably a unique master program in the sense of its combination of deep courses in both nuclear technology and nuclear chemistry.
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| 8. |
- Tengborn, Elisabeth, 1978, et al.
(författare)
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Effect of the misorientation of the 4H-SiC substrate on the open volume defects in GaN grown by metal-organic chemical vapor deposition
- 2006
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Ingår i: Applied Physics Letters. ; 89:091905, s. 3-
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Tidskriftsartikel (refereegranskat)abstract
- Positron annihilation spectroscopy has been used to study GaN grown by metal-organic chemical vapor deposition on misoriented 4H-SiC substrates. Two kinds of vacancy defects are observed: Ga vacancies and larger vacancy clusters in all the studied layers. In addition to vacancies, positrons annihilate at shallow traps that are likely to be dislocations. The results show that the vacancy concentration increases and the shallow positron trap concentration decreases with the increasing substrate misorientation.
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