Transient digitizer recorder

Fig. 13.4 Diabatic field ionization signals for i changing under increasing incident beam intensities. For clarity the successive curves are displaced upward by one scale unit. Data points are taken from the transient digitizer records, and a small sloping background has been subtracted. Full curves are fits to the model of MacAdam et al. (from ref. 8).

Fig. 5.5. The electrical response of piezoelectric polymers under shock loading is studied experimentally by placing the thin PVDF element on the impact surface of a standard target, either the polymer, Kel F, z-cut quartz, or z-cut sapphire. The im-pactor is typically of the same material. The current pulse is recorded on transient digitizers with frequency responses from 250 to 1000 MHz.

Pulse radiolysis was performed using e from a linear accelerator at Osaka University [42 8]. The e has an energy of 28 MeV, single-pulse width of 8 nsec, dose of 0.7 kGy, and a diameter of 0.4 cm. The probe beam for the transient absorption measurement was obtained from a 450-W Xe lamp, sent into the sample solution with a perpendicular intersection of the electron beam, and focused to a monochromator. The output of the monochromator was monitored by a photomultiplier tube (PMT). The signal from the PMT was recorded on a transient digitizer. The temperature of the sample solution was controlled by circulating thermostated aqueous ethanol around the quartz sample cell. Sample solution of M (5 x 10 -10 M) was prepared in a 1 x 1 cm rectangular Suprasil cell. 

The final point of comparison between the two techniques concerns the time required to record the data. A decent time resolution on the signal requires data to be taken at perhaps 100 time points following photolysis, and this is done in a facile manner by use of a transient digitizer, as described for... 

Laser flash photolysis was performed with a Nd-YAG Laser from Quantel which was frequency doubled with a KDP-Crystal. Samples were excited at 532 nm and the transients formed monitored with a pulsed 250 W Xenon lamp and recorded using a monochromator and an R128 photomultiplier connected with a transient digitizer linked to a PDP11-73 minicomputer. 

The other transient recorders, or perhaps more correctly transient digitizers, capture and store the waveform in a digital form in a computer-type memory. These can be further divided into two classes, those that digitize and write directly into the memory, e.g. the Biomation series of waveform recorders, and those that first write on an intermediate target from which it is then read, digitized and stored, e.g. the Tektronix series of transient digitizers. Although they share some features, the operations of these two types of transient recorder are quite different and they will be discussed separately. 

The spectrometer described in the last section (V.C.2.) uses a CAMAC system with mostly commercial components. It consists of a crate with 25 slots, two of which are taken up with a crate controller to interface with a Data General NOVA 1200 computer. The essential modules in the crate, in addition to the controller, are two transient digitizers (each stores 1024 8-bit words recorded at rates up to 20 MHz), one timing module, a GPIB interface, and one X-Y driver. Together with other modules which are primarily used for utility and... 

A fast transient recorder was introduced into the data acquisition in order to digitally record the pulse shapes, and a neural network was trained to recognize true a events and to distinguish these from PP-pileup and Py-pileup events (Eangrock et al. 2002 Eberhardt et al. 2002). 

Fig. 12.1 la,b. Quantum-beat spectroscopy of atomic or molecular ground states measured by time-resolved polarization spectroscopy (a) experimental arrangement and (b) Zee-man quantum beat signal of the Na 3 Si/2 ground state recorded by a transient digitizer with a time resolution of 100 ns. (Single pump pulse, time scale 1 rs/div, magnetic field 1.63 X 10-4 T) [12.40]... 

All Electrochemical measurements were accomplished using an EG G PAR Model 173 potentiostat/galvanostat in conjunction with a PAR 175 programmer. Transients were recorded with a Nicolet 2090 digital oscilloscope. Cyclic voltammograms were recorded on a Houston Instruments Model 2000 X-Y recorder. Simulated data were calculated using a Compaq Portable II computer. 

Examples of atomic excited-state decay curves recorded with the transient digitizer technique for a sequence of states in sulphur are shown in Fig. 9.20. The lifetimes increase with a r oc trend as expected for a Rydberg sequence... 

Fig. 9.20. Time-resolved laser-induced fluorescence recordings in a sequence of sulphur, employing the transient digitizer technique [9.122]...

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