Flash Lamps Considerations
Optical Pumping is the second critical step. Flashlamps used for laser
pumping are usually expensive and hard to find.
Perkin
Elmer has a huge variety of flashlamps suitables for any
kind of laser rods on his catalog, but the price is quite unattainable
for the hobbist. On the other hand reliability and calculation of
Pulse Formin Network are essential for industrial usage. It's up to
you...
From my point of view, an array of
four tipical xenon flashlamps of nominal energy of 250J, are good
enough for my purpose.By the way, calculation of PFN has been a little
tricky.
I spent lof and lot of time to
understand electrical parameters of gas lamps. Fortunally there are
some irreplaceable resorces on the Net. Sam's
FAQ is the right place where you may fiind answer to any kind of
technical question.
There also are a section about
flashlamps power supply calculation and usage.
Back to our point: the Optical Pump.
This laser uses 4 photo flashlamps
model FT218, manufacturer unknown.
Electrical parameters
for FT218 flashlamps (from manufacturer)
Nominal Input Energy : 250J
Vmin
: 350V
Vmax
: 500V
Vtyp
: 450V
envelope
: quartz
That's all I got form the seller, a too few information to design a
proper PFN.
So I decided to calculate the real charcteristics startin from the
phisical diimensions. General
Xenon Flash and Strobe Design Guidelines gives the key to
understand flashlamps.
Starting from the physical
dimensions, is possible to get new electrical parameters.
Physical Dimensions of
FT218 flashlamps
Arc Lenght
(Larc)
: 160 mm
Internal Diameter (ID)
: 6mm
Discharge Area (Sarc)
: 3015 mm^2
Discharge Volume (Varc)
: 4420 mm^3
Cathode dimensions
: l=3.5mm d=2mm
New Electrical
parameters for FT218 flashlamps (calculated)
Maximun Input Energy
: 300J
Vmax
: 950V
Average Power (freeair) : 100W
Average Resistance
: 2 ohms
Dinamic Resiastance (Ko) : 24 ohm*sqr(A)
The estimated Electrical to Optical conversion is 50%, that means only
the 50% of electrical energy is converted to light.
A simple Excel
Sheet may be used to calculate FlashLamps electrical parameters
and PFN Inductor and Capacitor.
