Standard Equipment:
|
Description |
Model |
Company |
|
Radiometer |
RK-5100 |
Laser Precision Corp. |
|
Light Intensity Detector |
RKP 545 |
Laser Precision Corp. |
|
Lock-In-Amplifier |
Dynatrac 3 |
Ithaco |
|
Chopper |
194A |
EG&G Park |
|
Gold Mirror |
52-54 |
J.A. Noll Co. |
|
Pressure Gauge |
8L-320 |
Matheson |
|
Pressure Gauge |
3491 |
Matheson |
|
Stepper Motor Power Supply |
1210 |
Transistorized Power Supply |
- Remove plastic coverings.
- Start vacuum pump to remove oxygen –make sure toggle switch is thrown open.
- Place glow plate and black light in front of laser (output end).
- Make sure power lines are connected to the two ends of the laser tube (DON’T TOUCH THE HIGH VOLTAGE WIRE).
- Turn on water at a slow, but steady rate… check draining pipe for flow
- Turn on large power source and slowly increase voltage… staying within these boundaries…
|
Voltage Range |
Current Range |
|
0-18,000 V |
0-20mA |
- Ramp up voltage until lasing is seen in the tube.
- Slowly open gas flow (4kPa – 5kPa)…. Increase voltage once again until lasing.
- Should see a dark spot on the glow plate, where the laser strikes it… you are now lasing.
- Warm up laser and begin lasing
- Calibrate the stepping motor and measure stepping speed (um/s) with a stopwatch.
- Place the light intensity detector in front of the laser and make sure you’re seeing a reading on the radiometer.
- Open ‘CO2_input.vi’ in LabView and make sure the analog input (1) is connected to the Radiometer.
- Begin the stepping motor around 3.5um and step up until 8um, all the while collecting data in LabView (see instruction on separate page for VI description).
- Export the data into excel and find the correct position (um) according to stepping rate.
- Warm up laser and begin lasing.
- Fill CO2 chamber with gas.
- Align chopper, chamber, mirror, and light intensity detector, so that the light passes through to the detector –not easy to do. See picture for graphical interpretation.
- Connect light detector meter to radiometer.
- Connect CO2 chamber to the lock-in-amplifier. The lock-in-amplifier and the chopper must be set to the same frequency.
- Output the radiometer into LabView’s analog 1 input and output the lock-in-amplifier to LabView’s analog two inputs.
- Measure the rate of the stepper motor with a stopwatch.
- Open ‘CO2_input.vi’ and begin collecting data once the stepper motor begins.
- Export data to excel… dividing the chamber output with the light intensity detector’s measurements. This will normalize that data for different laser intensities.