76,874 research outputs found
Measurement of fluence at the D-line fast neutron facility at iThemba LABS
No full textMeasurements of fluence were made for the neutron beams produced at the fast neutron beam facility of iThemba LABS, using an NE213 organic liquid scintillator detector and a 238U fission ionisation chamber. Neutron beams were produced by irradiating a 6 mm natural lithium target with pulsed proton beams obtained from the k = 200 separated sector cyclotron. Three incident proton beam energies were used in this work, namely 65.99 MeV, 99.44 MeV and 203.33 MeV. From time-of-flight measurements with the NE213 scintillator, the spectral fluence of the neutron beams was obtained. Pulse shape discrimination was used to correct for gamma ray induced signals in the NE213 detector. Simultaneous measurements of the neutron beam flux were performed at 0° and 16°. The 238U detector was used to obtain peak fluence measurements relative to the 238U(n,f) cross section
Reaction 58Ni(π+,2p) at 160 MeV
No full textData for the 58Ni(π+,2p) reaction at Tπ=160 MeV were obtained for a number of angle pairs. The resultant angular correlations for T1+T2>160 MeV (guaranteed pion absorption) peak at a separation angle corresponding to absorption on a deuteron at rest. However, simple estimates of initial- and final-state scatterings suggest that less than 50% of the absorption cross section arises from absorption on nucleon pairs. The data show little evidence for scattering of pions before absorption on nucleon pairs
Analyzing Powers It11 and T20 of Dp -> Ppn Reaction at 400 Mev Investigated at Nuclotron
No full textOne of the tools to study spin structure of short range correlations (SRCs) and three nucleon forces is the measurement of the polarization observables. Deuteron induced reactions at intermediate energies are investigated at Internal Target Station (ITS) of Nuclotron through the dp elastic and dp → ppn reactions. Analyzing powers iT11 and T20 analyzing powers of dp → ppn reaction at 400 MeV are presented
A Study of the Gamma Radiation Produced in the Alpha-Particle Bombardment of 0¹⁶
No full textThis thesis describes an investigation of gamma rays from the reaction O^(16)(α,γ)Ne^(20). The excitation function for gamma radiation has been studied for laboratory alpha-particle energies E_α from 4.8
to 9.9 Mev. Resonances were observed at E_α = 5.374, 5.94, 6.61, 6.930, 7.94, 8.17, 8.54, and 9.40 Mev, corresponding to Ne^(20) states at excitation energies of 9.029, 9.48, 10.02, 10.270, 11.08, 11.27,
11.56, and 12.25 Mev. Gamma-ray angular distribution measurements establish spins and parities of 4^+, 2^+, and
4^+ for the 9.029.-, 10270-, and 11.08-Mev states respectively. The 2^+ assignment for the 10.270-Mev state is supported by the results of triple angular-correlation studies made on the gamma-ray cascade from this state. Decay schemes have been investigated and estimates made of radiative widths and total widths. It is concluded that the 10.270-Mev state is the first T = 1 state of Ne^(20) on the basis of measurements of its excitation energy, spin and parity, total width, and M1 radiative width. The excitation function for 6.13-Mev gamma rays from the reaction O^(16)(α, α'γ)O^(16) has been studied for E_α from 8.9 to 9.9 Mev. The data indicates a resonance at E_α = 9.57 Mev corresponding to a state in Ne^(20) at 12.39 Mev. There is some evidence for a
weaker resonance at E_α = 9.25 Mev corresponding to a state at 12.13 Mev
FDG at 7.8 MeV
No full textI here report the fundamental performance of a new generation of compact medical cyclotrons for hospital-based PET tracer manufacture, exemplified with the FDG production numbers achieved by the first prototype of the GE GenTrace cyclotron. The proton energy is 7.8 MeV. After 3 years of extensive testing in a "physics lab" setting, which is door-to-door with our normal GMP production suite, I can now conclude that this cyclotron in conjunction with a standard GE Fastlab chemistry box easily achieves significant, reliable and compliant FDG output surpassing 15 GBq per batch at EOS, after 2 hours bombardment time. The details are reported below
Tissue substitutes for particulate radiations and their use in radiation dosimetry and radiotherapy
No full textPhDMost of the tissue substitute materials currently used inclinical
radiation dosimetry are designed to simulate muscle or
bone when irradiated with photons A few materials have been
developed for neutron dosimetry, but substitutes speci fically
designed for beams of high energy charged particles are not to be
found in the literature.
This thesis deals with the formulation and manufacture of,
tissue substitutes for particulate radiations and the subsequent
application of these substitutes in dlectron, pion, proton and
neutron dosimetry. The method of "elemental equivalence" was
used and over 80 solid, gel and liquid substitutes have been
produced2 which simulate the most important tissues (adipose,
blood, bone, muscle, etc), body organs (brain, lungj etc) and
tissue components (fat, protein, water). Most of these materials
are "tissue equivalent" and are useful for all types of radiations.
The compilation of selected chemical compounds (compound
library) used for the formulatign; and the computer programs
written for the theoretical evaluation of the new materials are
described and discussed. The experimental comparison of some
selected substitutes with the corresponding real tissues, using
fast neutrons, high energy protons, cobalt-60 gamma rays and
120 kVP X-rays., verified the high precision of the simulation
procedures. The results of depth dose measurements in various
tissue substitutes ý as well as water, using 7.5 MeV neutrons
150 MeV protons, 70 MeV negative pions , 10 MeV electrons and
cobalt-60 gamma rays are presented. The effect of tissue
heterogeneities on the dose distributions from thesý radiations was investigated. Isodose shift factors for air, lung, fat and bone
were derived for all the above radiation modalities and detailed
lung correction factors were measured for 7.5 MeV neutrons and
cobalt-60 gamma rays.
In view of the proposed use of the 160 MeV proton beam of
the Atomic Energy Research Establishment (Harwell, JJ. K) for
patient treatment, a complete series of pre-therapeutic measurements
was performed with this proton beam facility using the new
materials, and the results are presented and discussed in detail.
Finally, the applications of the new substitutes in other
practical clinical aspects are described and some examples of
such applications given
Cost-effective Design Options for IsoDAR
No full textThis whitepaper reviews design options for the IsoDAR electron antineutrino source. IsoDAR is designed to produce electron antineutrinos per year with an average energy of 6.4 MeV, using isotope decay-at-rest. Aspects which must be balanced for cost-effectiveness include: overall cost; rate and energy distribution of the electron antineutrino flux and backgrounds; low technical risk; compactness; simplicity of underground construction and operation; reliability; value to future neutrino physics programs; and value to industry. We show that the baseline design outlined here is the most cost effectiv
MeV-2 and MeV3 are present in different <i>M</i>. <i>euphorbiae</i> (<i>Me</i>) populations.
No full textNucleic acids from mixed developmental stages of aphids were used in RT-PCR for the detection of MeV-2 and MeV-3. Macrosiphum euphorbiae from Germany (DEU), the Netherlands (NDL), France (FR) the United States of America (USA), and Canada (CAN) were used. The population from France is WU11 colony from which the virus was identified. Arabic numerals stand for different aphid populations. FR1a and FR1b colonies are from the same M. euphorbiae population separated for at least 14 years. Aphid ribosomal gene RpL27 was used as positive control. M = molecular weight marker. The cropped two lanes of the MeV-3 gel, displays enhanced imaging of the two amplified bands.</p
Excitation function of (p, alpha) nuclear reaction on enriched 67Zn: Possibility of production of 64Cu at low energy cyclotron
No full textThe potential for production of the medically relevant 64Cu has been investigated by proton irradiation of highly enriched 67Zn targets. The excitation function of the 67Zn(p, α)64Cu a nuclear reaction was measured by the stacked-foil technique up to 30 MeV. The prediction of the TALYS code was also compared to the measured cross section results. Based on the improved database of the 67Zn(p, α)64Cu reaction, thick target yield as a function of energy was also deduced. Production possibility of 64Cu is discussed in detail, employing different energy proton beams and with regards to the 61Cu and 67Cu contamination levels as a function of the target enrichment level. By using 1 μA beam intensity, 6.3505 h irradiation time and enriched 67Zn target (64Zn ≤ 0.5%, 66Zn ≤ 9%, 67Zn ≥ 80%, 68Zn ≤ 10% and 70Zn ≤ 0.5%), the expected EOB (End Of bombardment) yields are 43.66, 88.80 and 156.14 MBq/μA at 12, 15 and 18 MeV proton energies, respectively. Application time-frames were also deduced where the total radio-copper contamination level remains below 1%
First observation of Bs → J/ψf0(980) decays
No full textUsing data collected with the LHCb detector in proton–proton collisions at a centre-of-mass energy of 7 TeV, the hadronic decay is observed. This CP eigenstate mode could be used to measure mixing-induced CP violation in the system. Using a fit to the π+π− mass spectrum with interfering resonances gives . In the interval ±90 MeV around 980 MeV, corresponding to approximately two full f0 widths we also find , where in both cases the uncertainties are statistical and systematic, respectively
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