The pulse forming network is 500 J (max) using a 700
uF, 1,350 V (max) capacitor bank and 0.5 mH inductor. Note that the Pulse length is around 3 ms which appears to
be optimal. If the flashlamp can handle a 1.5 ms
pulse length without exploding.
With the long fluorescence lifetime of ruby - about 3
ms - timing of the Q-switch is not as critical as it is for Nd:YAG with its
much shorter fluorescence lifetime (230 us). The Q-switch motor spins at 30,000
rpm or 500 rps for a period of 2 ms. So, if the flash duration is resaonably
short compared to 2 ms, there will be a high probability of a decent output
energy even if the flashlamp was triggered at random relative to the Q-switch
position! Even if the flash duration is as long as 3 ms, half the time, more
than 50 percent of the available energy will have been transferred to the rod
when the Q-switch is triggered. This is probably the main reason that faulty
Q-switch trigger circuits seemed to produce successful results, though I bet
the variation in energy due to the timing not always being optimal remained a
mystery and was probably attributed to other causes. However, with a proper design,
the pulse energy should be quite consistent
