نتایج جستجو برای: epithermal process
تعداد نتایج: 1312995 فیلتر نتایج به سال:
An epithermal neutron camera based on energy-filtered imaging with gas electron multipliers was developed. Epithermal neutron imaging is achievable without time-of-flight detection of neutrons by using a resonance filter and a thermal neutron absorber. This technique is applicable to compact accelerator-based neutron sources. Blurring of epithermal neutron images caused by neutron scattering in...
Introduction: In recent years, a number of studies [1,2,3] have been published using data from the Lunar Prospector Neutron Spectrometer (LP-NS) to identify and quantify anomalously high hydrogen abundances near the poles of the Moon, which may be in the form of water ice. If water ice is indeed present at the lunar poles in high enough abundance, this could provide a critical resource for futu...
INTRODUCTION The term epithermal derives from the genetic classification scheme for hydrothermal ore deposits proposed by Lindgren (1933). On the basis of stratigraphic relationships in volcanic sequences, and by analogy with mineral and metal occurrences and mineral textures in active hydrothermal systems, Lindgren inferred that epithermal deposits formed at <200°C and <100 atmospheres (~100 b...
Nowadays neutron capture therapy looks very promising method of cancer treatment, especially for brain tumors by reason of selective damage cancer cells. Treatment effect of this method based on neutrons nuclear reaction with nuclides B, Gd. These nuclides have high cross-section of interaction with thermal neutrons. Unfortunately, thermal neutrons could enter only in near surface tissue and co...
Maps of epithermal- and fast-neutron fluxes measured by Lunar Prospector were used to search for deposits enriched in hydrogen at both lunar poles. Depressions in epithermal fluxes were observed close to permanently shaded areas at both poles. The peak depression at the North Pole is 4.6 percent below the average epithermal flux intensity at lower latitudes, and that at the South Pole is 3.0 pe...
Molybdenum-99 is one of the most important radionuclides for medical diagnostics. In 2015, the International Atomic Energy Agency organized a round-robin exercise where the participants measured and calculated specific saturation activities achievable for the 98Mo(n,γ)99Mo reaction. This reaction is of interest as a means to locally, and on a small scale, produce 99Mo from natural molybdenum. T...
Boron Neutron Capture Therapy (BNCT) can be performed at a facility with a nuclear reactor or at hospitals that have developed alternative neutron sources. A beam of epithermal neutrons penetrates the brain tissue, reaching the malignancy. Once there the epithermal neutrons slow down and these low-energy neutrons combine with boron 10 (delivered beforehand to the cancer cells by drugs or antibo...
Accurate neutron flux values in irradiation channels of research reactors are very essential to their usage. The total neutron flux of the Ghana Research Reactor-1 (GHARR-1) was measured after a beryllium reflector was added to its shim to compensate for excess reactivity loss. The thermal, epithermal and fast neutron fluxes were determined by the method of foil activation. The experimental sam...
Accelerator-based neutron sources are an attractive alternative to nuclear reactors for providing epithermal neutron beams for Boron Neutron Capture Therapy. Based on clinical requirements and neutronics modeling the use of proton and deuteron induced reactions in 7Li and 9Be targets has been compared. Excellent epithermal neutron beams can be produced via the 7Li(p,n)7Be reaction at proton ene...
Boron Neutron Capture Therapy (BNCT) [4, 5] is a form of a radiation therapy used for treatment of some kinds of cancer (mainly glioblastoma multiforme) which, due to their character, are hard to be extracted with surgical methods. The BNCT method involves the delivery of a capture compound − the B isotope is usually used – which preferentially concentrates in the cancer tissue, followed by the...
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