Introduction to Health Physics: Fourth Edition - Ruang Baca FMIPA UB

% of Peak
100
80
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20
NONIONIZING RADIATION SAFETY 757
0
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0
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A Wavelength (nm)
B
Wavelength (nm)
Figure 14-10. Calibration curve for a photoelectric detector. A. Silicon diode B. In GaAs detector.
(Courtesy of Coherent, Inc, Santa Clara, CA.)
and peak power. Like most quantum electronic devices, photoelectric detectors are
highly energy-dependent and each instrument must be calibrated. A typical calibration
curve, as supplied by the manufacturer, is shown in Figure 14-10.
W Example 14.16
The output from a 60-Hz pulsed ruby laser, λ = 694.3 nm, is measured with a
photodiode-type meter. With the aid of an oscilloscope, we find rectangular pulses
as shown below:
The meter reading, which is proportional to the average power, is 35 μA. Calculate
the
% of Peak
100
(a) duty cycle (fraction of time that lasing actions occurs),
(b) average power, P , μW,
(c) peak power, P0, μW, and
(d) energy per pulse, J.
80
60
40
20