Session M18 - Ion Sources, Plasma, Chaos and Sonoluminescence and Biomedical Physics.
CONTRIBUTED session, Monday morning, April 21
Room 27, Conv. Center

[M18.01] High-Current Production of Highly-Charged Titanium and Gold Ions from a Z-MeVVA Ion Source.

Conventional Metal Vapor Vacuum Arc (MeVVA) ion sources(I.G. Brown, Rev. Sci. Instrum. 65, 3061 (1994).) produce up to hundreds of milliamps or more of several-times-ionized metal ions (e.g., uranium 3+). Recent results from Batalin et al.(V.A. Batalin et al. ITEP, Moscow, Reprints 18-93 (1993), 33-94 (1994); Proc. EPAC 1994, p. 1453.) indicate that the addition of an energetic electron beam (E-MeVVA) may lead to considerably higher charge states (e.g., uranium 17+). We report here our recent results on Z-MeVVA, in which a Z-discharge plasma is used to enhance multiple ionization. As the vacuum arc plasma plume expands into a magnetized drift region, a Z-discharge (1 to 2 kV) is triggered in the drifting metal plasma. The ions are then extracted and analyzed using a time-of-flight system. The motivation for this work is to develop a new approach for (a) heavy ion beam injection (e.g., into the Relativistic Heavy Ion Collider [RHIC] at BNL), and (b) heavy-ion implantation (to greatly reduce the cost, size, complexity and safety-hazard level over current technology).

[M18.02] Automated, Computer Controlled ``DC Batch'' Mode Production with an Electron Beam Ion Source

The CRYEBIS at Kansas State University is operated in a batch mode to produce high yields of highly charged ions. The extraction of the ion beam is accomplished by slowly raising the trap voltage to the height of the dam voltage. The time dependence of the extracted ion beam current is governed by the temperature distribution of the ions in the trap and, towards the end of the extraction cycle, by the decrease of the number of ions still left in the trap. To counter this effect the ions are not extracted with a linear ramp of the trap voltage but the trap voltage is altered by a rate that is inversely proportional to the ion temperature distribution. The trap voltage is further modified to compensate for the effect of the decrease in the number of ions left in the trap.(Martin P. Stöckli, Rev. Sci. Instrum. 67), No. 3, 892 (1996). The goal of this improvement is to increase the effective duty cycle of very highly charged ion beams, which is important for coincidence experiments. The computer control is implemented using LabView(LabView is a registered trademark of National Instruments.) in an effort to provide a simple to use system for internal and external users.

[M18.03] Particle Size Distribution by Light Scattering

Experimental results of size distribution of wood ash particles determined from small angle sacttering of laser light by wood ash particles is presented. Comparison of experimental results with theoretical predictions using the Mie Scattering theory is discussed.

[M18.04] Chaotic Scattering and Result Steering.

This abstract was not submitted electronically.

[M18.05] Chaotic Scattering on a Billiard

We have investigated classical scattering of a point particle on a particular billiard shape potential. The dynamics of such a system is studied via a standard billiard mapping consisting of the position and the tangential momentum at each intersection. Escape rates and scaling information are calculated. We observe that the scattering map space structures are essentially independent of the particle energy so that the dynamics is driven by the bound particle map. This is shown to be true for a large class of scattering potentials. We use this connection to determine qualitative and quantitative information about the scattering system.

[M18.06] Exact analytic treatment of the Schrodinger equation for the Standard Map in the Classical Limit.

This abstract was not submitted electronically.

[M18.07] Sonoluminescence as a cooperative many body effect

We propose that sonoluminescence occurs due to the cooperative interaction of matter with a radiation field in a cavitating bubble. In the scenario presented, we show that the collective spontaneous emission of population inverted atomic or molecular states leads to a timescale of the radiated light pulse which is consistent with that observed in experiments. Pumping by an ultrasound source provides the necessary condition for the inverted states to be correlated over a small volume to trigger sonoluminescence. The role of trace impurities is made evident in this picture.

[M18.08] Intensity Correlation Experiments in Sonolumines- cence

Sonoluminescence is the conversion of sound into light in a bubble of air in water. The light is produced when the lowest order acoustic wave in a flask causes dramatic collapse to \mum size, but the mechanism of the energy conversion is still not understood. We have begun to measure the light source's size using the Hanbury Brown - Twiss effect(S. Trentalange and S. Pandey, J. Acoust. Soc. Am. 99), 2439 (1996).^,(R. Fliller et al.), BAPS, 41, 1057, WC1 (1996).. The light from the bubble passes through an interference filter (\Delta\lambda=20~nm centered at \lambda=480~nm) into a set of 50~fibers (\approx1~mm~diam.) having various lengths and arrayed to subtend several angles at the source, and is then recorded by a set of photomultiplier tubes (PMTs). Using the temporal resolution capabilities of our PMTs and CAMAC data acquisition system, we exploit the various fiber lengths to measure correlations at several angles simultaneously, spanning the range from 2~to 75~mrad in just a few sets of measurements by changing the fiber array placement. We have measured the second order correlation function g^(|\vec\delta k|), from which the size of the emitting region can be extracted.

[M18.09] NMR of Laser-Polarized ^129Xe in Blood Foam

NMR of laser-polarized ^129Xe and ^3He have important biomedical and materials science applications. We have investigated laser-polarized ^129Xe dissolved in fresh human blood. The NMR signal of ^129Xe dissolved in blood was enhanced by creating a foam in which the dissolved ^129Xe exchanged with a large reservoir of gaseous laser polarized ^129Xe. The dissolved ^129Xe T_1 in this system was found to be significantly shorter in oxygenated blood than in deoxygenated blood. We determined the T_1 of ^129Xe dissolved in oxygenated blood foam to be approximately 21~(\pm5)~s; and in deoxygenated blood foam to be greater than 40~s. To understand the oxygenation trend, T_1 measurements were also made on plasma and hemoglobin foam preparations. The measurement technique using a foam gas-liquid exhange interface may also be useful for studying foam coarsening and other liquid physical properties.

[M18.10] Accidental Discovery of an Oral Drug for Diabetes Treatment First/Preliminary Evidence of Oral Semide Lasix/Water-Pill Diuretic as Oral-Insulin Like in Lowering/Control Blood Glucose/Sugar- Dec'96 Tested good for Self-case of Type II Adult Diabetes; Now Rest for its Universality and also for Type I/Juvenile Diabetes.

This abstract was not submitted electronically.

[M18.11] A Model of the CO_2 Optogalvanic Effect in Human Breath

A model calculating the expected optogalvanic signal of a weakly ionized sample of human breath stimulated by a carbon dioxide laser is discussed. This model has applications to diagnostic breath testing, in which a particular metabolic process or medical condition in a patient is investigated by administering an isotopically labeled substrate and measuring the amount of the label present in the patient's exhaled breath. Concerns for patient safety have focused most efforts on developing tests using stable isotopes, such as ^1^3C, as labels. The laser assisted ratio analysis technique employs the optogalvanic effect to determine the ratio of ^1^3CO_2:^1^2CO_2 in a weakly ionized breath sample stimulated by two lasers, one tuned to a ^1^3CO_2 lasing transition and the other to a ^1^2CO_2 lasing transition. The measured optogalvanic signals are related to the amount of each isotopic species in the sample. The development of a model simulating laser, plasma, and molecular collisional processes occurring in the gas discharge is discussed. A finite difference approach is employed to model these processes in both space and time in order to calculate the expected optogalvanic signals.

[M18.12] Collisions of Biological Objects Using Optical Tweezers

We have developed a new functional assay in which two mesoscale particles are caused to collide using two independently controlled optical tweezers. This assay involved measurement of the probability of adhesion on collision. Since the components of the solution, the orientation, and the relative collision velocity are all under the user's control, this assay can mimic closely a range of types of collisions involving biological objects. We illustrate the utility of our assay by evaluating the probability of adhesion of a single erythrocyte to a virus-coated microsphere, in the presence of a sialic acid-bearing inhibitor(M. Mammen, et al., Chemistry and Biology 3: 757-63 (1996).). This probability as a function of the concentration of the inhibitor is a measure of the effectiveness of the inhibitor; most of the inhibition constants obtained using optical tweezers agree well with those obtained from other techniques. Inhibition constants for the most effective inhibitors could not be measured using other types of assays; however, they were readily obtained using our optical tweezers based assay. The best inhibitor is the most potent inhibitor of attachment of influenza virus to erythrocytes ever measured.

Part M of program listing