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Lectures on geometrical properties of nuclei

Description: Material concerning the geometrical properties of nuclei is drawn from a number of different sources. The leptodermous nature of nuclear density distributions and potential wells is used to draw together the various geometrical properties of these systems and to provide a unified means for their description. Extensive use is made of expansions of radial properties in terms of the surface diffuseness. A strong case is made for the use of convolution as a geometrical ansatz for generating diffuse surface distributions because of the number of simplifications that arise which are of practical importance. 7 figures. (auth)
Date: November 1, 1975
Creator: Myers, W.D.
Partner: UNT Libraries Government Documents Department


Description: The increasing availability of short lived gamma and positron emitting isotopes, coupled with the importance of dynamical studies and better imaging, has generated the need for an improved {gamma}-ray camera. The authors discuss a new type of {gamma}-ray camera which makes use of electron avalanches in liquid xenon. A configuration currently under development is shown in Figure 1. The successful operation of a liquid xenon proportional counter was recently reported. The liquid xenon camera promises better spatial resolution and higher counting rate than the existing NaI(Tl) scintillation camera. The spatial resolution for {gamma} rays is in principle limited only by the range of photoelectrons in liquid xenon, which is < 0.2 mm for energies < 1 MeV. A counting rate of 10{sup 6} C/s or more appears possible. As a result of the better resolution and high counting rate capability, the definition of the picture is improved. In addition, the high counting rate capability makes possible dynamic studies which were previously unfeasible. Although they expect the energy resolution with liquid xenon to be superior to that of NaI, the preliminary measurements show 17% FWHM for 279 keV {gamma}'s. Improvements are expected by using better geometry and smoother wire.
Date: February 1, 1972
Creator: Zaklad, Haim.; Derenzo, Stephen E.; Muller, Richard A.; Smadja,Gerard.; Smits, Robert G. & Alvarez, Luis W.
Partner: UNT Libraries Government Documents Department

An investigation of the components of the neutral beam produced by high energy protons at NAL using the 30 inch bubble chamber

Description: We wish to search for new neutral particles by investigating the composition of a wide angle neutral beam produced by high energy protons on a Be target. Photons in the beam will be removed by a Pb converter. The resultant neutral beam will be incident on the 30 inch bubble chamber. The composition of the beam will be determined from the kinematic analysis of selected interactions in the bubble chamber, through the decays of neutral particles and through possible anomalies in the hydrogen interactions. As a byproduct we will measure the K-Long flux through the process K-Long + P {yields} K-Short + all. By a slight change in the geometry we can look at a region immediately downstream of the target and measure the characteristics of neutral particles arising from the decay of hyperons and other particles produced in the Be target. We do not require any external equipment besides beam monitoring equipment. We request an initial exposure of 20,000 pictures.
Date: April 1, 1971
Creator: Benvenutti, a.; Camerini, U.; Fry, W.F.; March, R.; Reeder, D.D. & /Wisconsin U., Madison
Partner: UNT Libraries Government Documents Department

Geothermal reservoir engineering research in New Zealand: A simplistic model and the Wairakei geothermal reservoir

Description: Although nowadays much of the New Zealand geothermal reservoir research effort is still being concentrated on the older fields of Wairakei and Broadlands there has been a definite advance over recent years in our approach to the studies. On the practical side, long term reinjection trials are now in progress at Broadlands, and drilling, for field evaluation, is well underway at Ngawha, a field characterized by a steam discharge coupled with a hydrostatic pressure gradient. On the theoretical side, well pressure transient analysis and reservoir behavior modeling are probably the primary interests. For the former both multi-element computer modeling programs and two-phase pressure diffusion analysis (Grant, 1978, Grant and Sorey, 1979) are being used by M.A.Grant, E.Bradford and F.Sutton (AMD*) and M.L.Sorey (PEL). Geometry and boundary influences are dominant and estimated steam flows are higher than are consistent with the Corey (1954) expressions for relative permeability. Both of these effects are probably due to the fracture permeability of the reservoirs. A.McNabb (AMD) is currently taking this into account by determining the response to discharge in a fracture-block medium. He is working with 100 meter blocks, consistent with data from lumped parameter models and from well records, with a block permeability of 10{sup -15} m{sup 2}. Reservoir behavior modeling is probably the research area of greatest current interest with most research groups here involved to some extent. The models range over a wide spectrum, from extreme simplification to sophisticated detail. At the simpler extreme is the model of J.Elder (AU). This consists of two resistors and a condenser in electrical analog form but is coupled with models of the well system and the above surface plant to enable overall system effects and interactions to be assessed.
Date: January 1, 1978
Creator: Donaldson, Ian G.
Partner: UNT Libraries Government Documents Department


Description: Atmospheric pressure and temperature excursions at constant volume for oxidation of high temperature sodium are investigated analytically. Data under both the adiabatic condition and the time dependent transient heat transfer condition are reported. The analyses represent parametric cases involving variations in containment geometry, variations in sodium conditions, and variations in contained gas conditions including oxygen concentrations of 0 to 21 vol%. The objective is to obtain data for design of containment for the Fast Flux Test Facility. Design of containment requires a knowledge of maximum temperatures and pressures to be expected as a consequence of the unlikely occurrence of a high volume sodium leak. This information is presented in graphical and tabular form.
Date: March 7, 1970
Creator: Shire, PR
Partner: UNT Libraries Government Documents Department


Description: The rate of hexose transport was compared in normal and virus-transformed cells on a monolayer and in suspension. It was shown that: (1) Both trypsin-removed cells and those suspended for an additional day in methyl cellulose had decreased rates of transport and lower available water space when compared with cells on a monolayer. Thus, cell shape affects the overall rate of hexose transport, especially at higher sugar concentrations. (2) Even in suspension, the initial transport rates remained higher in transformed cells with reference to normal cells. Scanning electron micrographs of normal and transformed chick cells revealed morphological differences only in the flat state. This indicates that the increased rate of hexose transport after transformation is not due to a difference in the shape of these cells on a monolayer. The relation between the geometry of cells, transport rates, and growth regulation is undoubtedly very complex, and our knowledge of these relationships is still very elementary. In a recent review on the influence of geometry on control of cell growth, Folkman and Greenspan (1) pointed out that the permeability of cells in a flat versus a spherical state may indeed be very different. The growth properties of cells on a surface and in suspension have been compared often (1-5). However, with one exception. little is known about the changes in transport properties when cell shape is changed. Foster and Pardee (6) demonstrated that the active transport of a-aminoisobutyric acid was reduced 2.5 times in suspension cultures of Chinese hamster cells with respect to the cells grown on a coverslip. They attributed this to the smaller surface area of suspended cells. While it is not clear why active transport should be dependent on the surface area available, it is possible that once the cells assume a spherical configuration, the carrier proteins are ...
Date: July 1, 1976
Creator: Bissell, M.J.; Farson, D. & Tung, A.S.C.
Partner: UNT Libraries Government Documents Department

Measurement of the Kaon Form Factor

Description: The authors propose an experiment to measure elastic kaon scattering from electrons at a beam energy of 250 GeV. This measurement provides the first experimental value for the charge radius of the kaon. The anticipated error on the determination of the radius is 0.03 Fermi. The experiment can be performed by the present E216 spectrometer in the M1 beam line. A drift chamber system will be added to improve the spectrometer resolution and minor modifications of the trigger hodoscope and shower counter geometry will be required. The experimental design incorporates their experience in performing {pi}-e elastic scattering at 50 GeV/c at Serpukhov and at 100 GeV/c in E216 at Fermilab (data taking completed on October 1, 1975). The analysis of the E216 results is well underway and they anticipate that a definitive value for the pion radius will soon be obtained (anticipated error {+-} 0.03 F). All apparatus is designed with the goal of measuring a 1% absolute cross section. To cleanly identify elastic events and reject background, the angles and momenta of both the scattered K and e are measured. Proportional chambers and drift chambers upstream and downstream of the hydrogen target measure angles to high accuracy. Two 8-24-72 analysis magnets are used, followed by a set of six 0.5 x 1.5 m{sup 2} spark chambers, to determine momenta. A lead glass shower counter hodoscope provides electron shower identification. In the trigger there is only one veto counter used which is sensitive to target interactions. It helps to suppress non K-e background and its effect on K-e elastic events is small and well understood. A time request for 200 hours of testing and 600 hours for data taking is made in the proposal. Their continued interest in pion form factor measurements at energies much higher than 100 GeV is ...
Date: October 1, 1975
Creator: Dally, E.; May, C.; Hauptmann, J.; Stork, D.; U., /California; Ioan, I. et al.
Partner: UNT Libraries Government Documents Department