The use of flowing water coolant is common with many high-powered devices. In this lab the use of this cooling method will be investigated with a large-frame argon-ion laser (a Coherent Innova-90).
Review the I-90 Operations Manual
Leave the laser OFF. Start the cooling water and adjust for a flow of 8 lpm (litres per minute). Allow the water to run for ten minutes to achieve a constant temperature - measure it with the thermometer at the water outlet. This will be the inlet temperature.
Start the laser by turning the key on and pressing the ON button (see the SOP for operation details). The laser will start after a one minute delay to preheat the cathode after which the current through the plasma tube will be indicated on the front panel. Adjust the LIGHT control fully clockwise (maximum output) then adjust the CURRENT control for 35A of current. Wait ten minutes for the outlet temperature to stabilize then read the thermometer (This will give the temperature increase at a flow of 8 lpm). Now, decrease the flow rate by carefully closing the water supply valve until the flowmeter reads 7.2 lpm. Once again, wait for the temperature to stabilize then record it. Repeat for flow rates of 6.4 lpm and 5.6 lpm. Do not go below 5.0 lpm or the outlet temperature will climb dangerously high and the power supply will shut off automatically due to an overheat condition. The laser also features an flowswitch interlock for cooling water flow - the lower limit for this flowswitch was purposely lowered to allow low flow rates as used in this experiment but it still has a minimum flow requirement.
For reference, the I-90 Operations Manual lists details such as utility requirements. It also provides a brief overview of operating principles in chapter 7 for the curious.
For this experiment, an abbreviated lab report is required (word processed, never hand-written) with the same format as PHTN1300. Answer each question in the form "4a., 4b., 4c. ..." with each new question (#4, #5, etc) beginning on a new page. Do NOT answer an entire question (e.g. question 4) as a single paragraph without identification of sub-parts ('a', 'b', etc). Submit the lab report in a bound folder NOT simply a pile of loose, stapled papers nor a thick binder!
Each student must submit a unique lab report - no portion other than the results must be shared between lab group members.