Laser FuzzyMuzzle.com (Ruby

Flashlamps

The flashlamps are one of the most important and probably the second hardest part to get. For this reason you want to design your laser around it and your Ruby rod.

Deciphering Variables

The variables required in the following formulas are measurements of your flashlamps. Below is a summary of each measurment:

d = flashlamp inside diameter; usually 75% - 80% of the outside diameter (mm)

i = flashlamp current (amps)

Ko = flashlamp dynamic impedence; can be considered the same as resistence (ohms)

l = flashlamp arc length between the two electrodes (mm)

p = flashlamp fill pressure (torr)

t ^ 1/3 = laser pulse width (ms)

u = flashlamp explosion energy; lamps should be run at 30% of this (joules)

x = 450 for Xenon flashlamps; 805 for Krypton flashlamps

v = flashlamp operating voltage (volts)

Explosion Energy

Explosion energy is the amount of energy in Joules that your flashlamp can handle before dangerously exploding. It's generally good practive to run your flashlamp at 30% of this value for long life and safety.

u = 90 * d * (0.039 * l) * (t ^ 1/3) ^ 1/2

Credit goes to "Sam's Laser FAQ" for the original version of this formula.

Example for the Ruby project:

u = 90 * 4 * (0.039 * 90) * (1.671) ^ 1/2

Explosion Energy = 1633.4199 Operating Energy = 490.03 joules

Ko Variable

Ko is the dynamic impedence of the flashlamp, it's a similar concept to the resistence of a resister, so for our sake you can consider it the flashlamp's resistence. Impedence will help you determine the amount of current needed for your lamp.

Ko = 1.28 * (l / d) * (p / x) ^ 1/5

Credit goes to "Sam's Laser FAQ" for this formula.

Example for the Ruby project:

Ko = 1.28 * (90 / 4) * (450 / 450) ^ 1/5

Ko = 28.8 ohms

Questions

Below are questions asked by various users, if you have a question or an answer send it here.

Question: I know flashlamps operate off of DC, so can somebody tell me why this is impedence and not resistence?

Answer: One reason is that Ko is a function of current. It's a non-linear resistance and doesn't obey Ohm's law. - Sam Goldwasser

Question: What pulse width and pulse rate should I setup my Ruby laser for?

Answer: Your pulse width and pulse rate are greatly determined by the current available from your home wiring, the available transformers, and the lasers application. Most home wiring can only supply up to 15A, transformer selection is usually limited to 9000V 30ma neon sign transformers, and cutting laser require a high pulse rate and width, while holography doesn't. - Michael Robinson

Next - Pulse Forming Network (PFN)