Gas-discharge XeF* (B→X) laser with high specific output energy

The discharge characteristics of the XeF* (B→X) laser are investigated. The NF3 and Xe partial pressure of the laser gas mixture and the total gas pressure have been varied. A highest specific output energy of 4.7 J/l with an efficiency of 0.5% was obtained from a X-ray preionized Ne/Xe/NF3 gas mixture at 6 bar with single-pulse excitation through a multichannel spark gap

Discharge studies with a high-efficiency XeCl excimer laser

Results on a high efficiency excimer laser operating according to the prepulse-mainpulsetechnique are reported. The laser volume of about 90 cm is X-ray preionized. The mainpulse obtained from a PFN 2 swiched onto the discharge by means of a racetrack saturable inductor (magnetic switching) connected to the laser head with low inductance. Laser output energy has been measured as a function of gas mixture and delay between X-ray and prepulse

Strong Structural Controllability of Systems on Colored Graphs

This paper deals with structural controllability of leader-follower networks. The system matrix defining the network dynamics is a pattern matrix in which a priori given entries are equal to zero, while the remaining entries take nonzero values. The network is called strongly structurally controllable if for all choices of real values for the nonzero entries in the pattern matrix, the system is controllable in the classical sense. In this paper we introduce a more general notion of strong structural controllability which deals with the situation that given nonzero entries in the system's pattern matrix are constrained to take identical nonzero values. The constraint of identical nonzero entries can be caused by symmetry considerations or physical constraints on the network. The aim of this paper is to establish graph theoretic conditions for this more general property of strong structural controllability.Comment: 13 page

Magnetic pulse compression in the prepulse circuit for a 1 kW, 1kHz XeCl excimer laser

Using high quality low loss ferrite, a single stage magnetic pulse compression network has been demonstrated working at 1 kHz PRF. A pulse compression factor of 4 has been achieved, delivering a 50 ns pulse as prepulse in the excitation circuit for a high power XeC1-excimer laser

Discharge technology for excimer lasers of high-average power

The self-sustained discharge of excimers is analyzed. Several excitation schemes that have been successfully applied are compared. For high repetition rate operation not only the discharge stability and its efficiency are important selection criteria but more important is the potential of fast discharge switching with minimum pulse energy. Pulse compression plays a key role in the laser performance. A technology for low energy compression is described

A Unifying Framework for Strong Structural Controllability

This paper deals with strong structural controllability of linear systems. In contrast to existing work, the structured systems studied in this paper have a so-called zero/nonzero/arbitrary structure, which means that some of the entries are equal to zero, some of the entries are arbitrary but nonzero, and the remaining entries are arbitrary (zero or nonzero). We formalize this in terms of pattern matrices whose entries are either fixed zero, arbitrary nonzero, or arbitrary. We establish necessary and sufficient algebraic conditions for strong structural controllability in terms of full rank tests of certain pattern matrices. We also give a necessary and sufficient graph theoretic condition for the full rank property of a given pattern matrix. This graph theoretic condition makes use of a new color change rule that is introduced in this paper. Based on these two results, we then establish a necessary and sufficient graph theoretic condition for strong structural controllability. Moreover, we relate our results to those that exists in the literature, and explain how our results generalize previous work.Comment: 11 pages, 6 Figure

Fault detection and isolation for linear structured systems

This paper deals with the fault detection and isolation (FDI) problem for linear structured systems in which the system matrices are given by zero/nonzero/arbitrary pattern matrices. In this paper, we follow a geometric approach to verify solvability of the FDI problem for such systems. To do so, we first develop a necessary and sufficient condition under which the FDI problem for a given particular linear time-invariant system is solvable. Next, we establish a necessary condition for solvability of the FDI problem for linear structured systems. In addition, we develop a sufficient algebraic condition for solvability of the FDI problem in terms of a rank test on an associated pattern matrix. To illustrate that this condition is not necessary, we provide a counterexample in which the FDI problem is solvable while the condition is not satisfied. Finally, we develop a graph-theoretic condition for the full rank property of a given pattern matrix, which leads to a graph-theoretic condition for solvability of the FDI problem.Comment: 6 pages, 1 figure, 1 tabl

Optimisation of the pulse duration of a discharge pumped XeF (B-X) excimer laser

In an x-ray preionised XeF(B→X) discharge-excited laser driven by a magnetic-spiker sustainer circuit with a magnetic pulse compressor the influence of the various parameters on the optical pulse duration was experimentally investigated. Laser pulses at λ = 351 nm with a duration of 212 ns (FWHM) have been achieved in a NF3/Xe/Ne mixture by using very low (0.25 mbar) NF3 partial pressures in a total gas pressure of 2.5 bar and with a high-reflecting output coupling mirror