Manipulating ionization path in a Stark map: Stringent schemes for the selective field ionization in highly excited Rb Rydberg atoms

We have developed a quite stringent method in selectivity to ionize the low angular- momentum ($\ell$) states which lie below and above the adjacent manifold in highly excited Rb Rydberg atoms. The method fully exploits the pulsed field-ionization characteristics of the manifold states in high slew-rate regime: Specifically the low $\ell$ state below (above) the adjacent manifold is firstly transferred to the lowest (highest) state in the manifold via the adiabatic transition at the first avoided crossing in low slew-rate regime, and then the atoms are driven to a high electric field for ionization in high slew-rate regime. These extreme states of the manifold are ionized at quite different fields due to the tunneling process, resulting in thus the stringent selectivity. Two manipulation schemes to realize this method actually are demonstrated here experimentally.Comment: 10 pages, 4 figure

Systematic observation of tunneling field-ionization in highly excited Rb Rydberg atoms

Pulsed field ionization of high-$n$ (90 $\leq n \leq$ 150) manifold states in Rb Rydberg atoms has been investigated in high slew-rate regime. Two peaks in the field ionization spectra were systematically observed for the investigated $n$ region, where the field values at the lower peak do not almost depend on the excitation energy in the manifold, while those at the higher peak increase with increasing excitation energy. The fraction of the higher peak component to the total ionization signals increases with increasing $n$, exceeding 80% at $n$ = 147. Characteristic behavior of the peak component and the comparison with theoretical predictions indicate that the higher peak component is due to the tunneling process. The obtained results show for the first time that the tunneling process plays increasingly the dominant role at such highly excited nonhydrogenic Rydberg atoms.Comment: 8 pages, 5 figure

Reduced-order Models of Power Systems based on Controllability and Observability

Reduced-order models for dynamic control of power systems are formulated using a modal analysis technique, based on the notion of controllability and observability. In this technique, an input/ouutput index is used to identify and rank the strongly controllable and observable modes of the system given a particular input/output pair. The system state variables that are strongly related to the retained modes are then determined by analysis of a participation factor martrix. Davison's method of reducing linear systems is then applied to formulate the desired reduced order dynamic equivalent. This technique of forming dynamic equivalents is investigated on a single machine infinite bus system. Several reduced order model equivalents are formed and evaluated on their performance and accuracy

Task-oriented groups: A motivational and confidence approach to effective decision making

Thesis (B.S.) in Psychology--University of Illinois at Urbana-Champaign, 1993.Includes bibliographical references (leaves 82-88)Microfiche of typescript. [Urbana, Ill.]: Photographic Services, University of Illinois, U of I Library, [1993]. 3 microfiches (112 frames): negative. s1993 ilun

Does the enhancement observed in γγ→DDˉ\gamma\gamma\to D\bar{D} contain two PP-wave higher charmonia?

Solved is a new puzzle raised by the observation of an enhancement structure Z(3930) in $\gamma\gamma\to D\bar{D}$. If categorizing Z(3930) as $\chi_{c2}(2P)$ suggested by Belle and BaBar, we must explain why $\chi_{c0}(2P)$ dominantly decaying into $D\bar{D}$ is missing in the $D\bar{D}$ invariant mass spectrum. In this work, we propose that the Z(3930) enhancement structure may contain two $P$-wave higher charmonia {$\chi_{c0}(2P)$} and $\chi_{c2}(2P)$. We show that this assumption is supported by our analysis of the $D\bar{D}$ invariant mass spectrum and $\cos\theta^\ast$ distribution of $\gamma\gamma\to D\bar{D}$. This observation would not only provide valuable information of two P-wave higher charmonia $\chi_{c0}(2P)$ and $\chi_{c2}(2P)$, but also serve as the crucial test of our novel proposal to the observed enhancement structure Z(3930), especially at the forthcoming BelleII and the approved SuperB.Comment: 5 pages, 2 tables, 3 figures. More contents and discussions adde

Selective Field-Ionization Electron Detector at Low Temperature of 10 mK Range (NUCLEAR SCIENCE RESEARCH FACILITY?Particle and Photon Beams)

Combined with a dilution refrigerator, selective field-ionization detection system with a channel electron multiplier optimized at 10 mK-range temperature was developed. The detection efficiency of the ionized electrons from the n~110 Rydberg states of Rb is 98% at the lowest achieved temperature of 12 mK