Output pulse

Fig. 6. Output pulse from reading a transition in the longitudinal recording mode.

A commercial fs-laser (CPA-10 Clark-MXR, MI, USA) was used for ablation. The parameters used for the laser output pulses were central wavelength 775 nm pulse energy -0.5 mj pulse duration 170-200 fs and repetition rate from single pulse operation up to 10 Hz. In these experiments the laser with Gaussian beam profile was used because of the lack of commercial beam homogenizers for femtosecond lasers. 

In the phosphor-photoelectric detector used as just described, the x-ray quanta strike the phosphor at a rate so great that the quanta of visible light are never resolved they are integrated into a beam of visible light the intensity of which is measured by the multiplier phototube. In the scintillation counters usual in analytical chemistry, on the other hand, individual x-ray quanta can be absorbed by a single crystal highly transparent to light (for example, an alkali halide crystal with thallium as activator), and the resultant visible scintillations can produce an output pulse of electrons from the multiplier phototube. The pulses can be counted as were the pulses-from the proportional counter. 

In the pulse counting method, each photoelectron pulse arriving at the phototube anode is processed. The pulses are amplified and then used to trigger a pulse generator. The output pulses from the generator are integrated and displayed on a recorder. 

The y-detector of a Mossbauer spectrometer converts the incident y-photons into electric output pulses of defined charge (see Sect. 3.1.6). The detector signals are electronically amplified and shaped by an amplifier network to obtain strong needle pulses with well-defined rise time, so that the pulse height is proportional to the energy of the incident photon. The amplifiers are usually adjusted to obtain... 

The detector signal is conditioned through a single channel pulse height analyzer whose output pulses are fed to a scaler-timer in the single crystal controller. 

Another important property of PMTs is the pulse height distribution. The amplification of individual photoelectrons by the PMT is a stochastic process that causes variations in the gain of individual photoelectrons. As a result significant jitter in the amplitude of the output pulses is observed, see Fig. 3.6. These pulse height variations can be more than a factor of 10. The lowest pulse heights mainly consist of (thermal) noise, indicated by the dashed line in Fig. 3.6. The pulse height distribution exhibits a peak corresponding to detected photons. The threshold level of the... 

The single channel analyzer has two dial settings a LEVEL dial and a WINDOW dial. For example, when the level is set at 2 volts, and the window at 0.2 volts, the analyzer will give an output pulse only when the input pulse is between 2 and 2.2 volts. The output pulse is usually a standardized height and width logic pulse, as shown in Figure 11. 

If the discriminator is set at 2 volts, then any input pulse > 2 volts causes an output pulse. 

The radiation detector is located some distance from the readout. A shielded coaxial cable transmits the detector output to the amplifier. The output signal of the detector may be as low as 0.01 volts. A total gain of 1000 is needed to increase this signal to 10 volts, which is a usable output pulse voltage. There is always a pickup of noise in the long cable run this noise can amount to 0.001 volts. 

A discriminator circuit selects the minimum pulse height. When the input pulse exceeds the discriminator preset level, the discriminator generates an output pulse. The discriminator input is normally an amplified and shaped detector signal. This signal is an analog signal because the amplitude is proportional to the energy of the incident particle. 

Figure 32 illustrates input and output signals and how the discriminator acts to eliminate all pulses that are below the preset level. The output pulses of this circuit have the same relative amplitudes as the input pulses. 

Range Resolution. Let r represent the output pulse length and Tr the pulse repetition interval. Pulses travel along the slant range and interact with the ground through the mainbeam as well as the sidelobes of the antenna array as shown in Fig. 13. 

These instruments feature keyboard entry of instrument parameters which combined with digital displays, simplifying instrument operation. A high-output pulsed xenon lamp, having low power consumption and minimal ozone production, is incorporated within the optical module. 

In pulse fluorometry, we take advantage of the fact that the amplitudes of the output pulses of the TAC are proportional to the times of arrival of the fluorescence photons on the photomultiplier. Selection of a given height of pulse, i.e. of a given time of arrival, is electronically possible (by means of a single-channel analyzer) and allows us to record the fluorescence spectra at a given time t after the excitation pulse. This is repeated for various times. The method described above for phase fluorometry can also be used in pulse fluorometry. 

Organic dye lasers are especially useful for nanosecond absorption spectroscopy since their wavelength can be tuned continuously over a range of several hundred angstroms and their output pulses reach several megawatt at pulsewidths down to 10" sec with mode-locking techniques. 

Lipchik et al. (1972) reported no significant acute changes in cardiac output, pulse rate, pressure or left ventricle volumes, or clotting time in dogs injected intravenously with up to 1 ml of Thorotrast/kg (1.9nCi/kg = 70 Bq/kg). 

This is how the output pulse looks with time. 

Photoexcitation was achieved by using a triggerable nitrogen gas laser (LGI-21). The laser output pulse was of duration 8ns at a wavelength of 337nm. 

Cardiovascular system Decreased peripheral vascular resistance increased heart rate, stroke volume, cardiac output, pulse pressure high-output heart failure increased inotropic and chronotropic effects arrhythmias angina Increased peripheral vascular resistance decreased heart rate, stroke volume, cardiac output, pulse pressure low-output heart failure ECG bradycardia, prolonged PR interval, flat T wave, low voltage pericardial effusion... 

You can also set RETOL=0.01. Figure 9.13 shows the waveform results of the breadboard at three different test conditions. The top picture shows the input pulse and the output pulse overlapped so the delay and turn-off ring can be examined. The middle picture shows the input (top) and output (bottom) waveforms when the duty cycle is 5%. The bottom picture shows the input (top) and output (bottom) waveforms when the duty cycle is 95%. 

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