53 research outputs found
On the plume splitting of pulsed laser ablated Fe and Al plasmas
No full textA time resolved imaging study of pulsed laser ablated Fe and Al plasma plumes with specific interest in the splitting of plumes into the slow and fast moving components as they expand through the background argon gas at different pressures is reported. The material ablation was achieved using a Q-switched Nd:YAG (yttrium aluminum garnet) laser operating at 532 nm with a pulse duration of ~ 8ns full width at half maximum and a fluence of 30 µJ.cm-2 at the target surface. Typical time resolved images with low magnification show that the splitting occurs at moderate background gas pressures (0.5 and 1.0 mbar for Fe, and 0.2 mbar for Al plasma plumes). The plume splitting did not occur for higher background gas pressures
Ion-beam studies and isotope production using dense plasma focus
No full textThe objective of this project is to investigate the production of Positron-Emission-Tomography
(PET) [II isotopes (11C, 13N, 150, 18F) in the dense plasma focus. We aim to test the feasibility of replacing costly present-day cyclotron isotope production facilities for PET, with simpler, cheaper and easily maintainable repetitive plasma focus devices. PET is a rapidly growing bio-medical imaging modality. It is now well established as an essential imaging technique in the fields of oncology, cardiology and neurology. Some common diagnostic applications of PET imaging are given in the table below. PET scanners produce three-dimensional images of radio-pharmaceuticals that have been injected into a patient prior to the scan. These radio-pharmaceuticals are labeled with a positron emitting isotope - usually 11C, 13N, 150, or 18F. The half-lives of these isotopes are short – ranging from 2 to 110 minutes - hence the production of isotopes must be local to the PET facility, The principle underlying PET is that each emitted positron annihilates with an electron creating two gamma-rays travelling in diametrically opposite directions from the point of origin (where the radiopharmaceutical s is localized). From the positions of these detected gamma-ray pairs the three dimensional image of the radio-pharmaceutical distribution in the patient is reconstructed.RP 2/0
Title Multiple perspectives on meeting the challenges of PBL in the scientific disciplines Author(s)
No full textBiotech Innovation in Europe's Food and Drink Processing Industry: Promise, Barriers and Exploitation
No full textEarly optimism about the potential of biotechnology to contribute to "the production of food with improved quality and nutritional content" (ACOST, 1990) has waned in the face of consumer resistance to the use of genetically modified organisms in food. The European food and drink sector has not abandoned biotechnology, however, but it is being very selective in its use. Some of the current applications of biotechnology were not recognized in early predictions about the application of biotechnology to the food and drink sector.
Backward high energy ion beams from plasma focus
No full textHigh energy neutrons, more than 2.45 MeV from deuteron-deuteron fusion reaction, have been measured in backward direction of plasma focus devices in many laboratories. However the experimental evidence for high energy deuterons responsible for such neutrons has not been reported so far. In this brief communication, backward high energy deuteron beam from NX2 plasma focus [M. V. Roshan et al., Phys. Lett. A 373, 851 (2009)] is reported, which was measured with a direct and unambiguous technique of nuclear activation. The relevant nuclear reaction for the target activation is 12C (d, n)13N , which has a deuteron threshold energy of 328 keV.Published versio
Neutron anisotropy measurements in dense plasma focus device by means of deuteron beam obstacle
No full textAbsolute measurements of fast neutrons using yttrium
No full textYttrium is presented as an absolute neutron detector for pulsed neutron sources. It has high sensitivity for detecting fast neutrons. Yttrium has the property of generating a monoenergetic secondary radiation in the form of a 909 keV gamma-ray caused by inelastic neutron interaction. It was calibrated numerically using MCNPX and does not need periodic recalibration. The total yttrium efficiency for detecting 2.45 MeV neutrons was determined to be ƒn∽4.1 x 10-4 with an uncertainty of about 0.27%. The yttrium detector was employed in the NX2 plasma focus experiments and showed the neutron yield of the order of 108 neutrons per discharge.Published versio
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