Thursday, May 10, 2007

Red tape can damage labs

The university bureaucracy threatened to damage my lab recently. We use an excimer laser to generate the UV laser light used in our laser ablation system. Like most excimer lasers, this unit contains fluorine gas, and this gas is purified by circulating it through a liquid nitrogen cold trap. If the cold trap warms up during laser operation, damage to the internal components is possible, and damage to the windows of the resonator is likely.

I recently had a professor who was using the instrument get stuck in a meeting for so long that the cold trap, which is designed to hold 6-8 hours of LN2, ran dry, putting the laser at risk.

Now, I realize that senior academics do need to communicate with each other. And I know that sometimes the timing of these meetings can have a much higher relative error than, say, the age of the Earth. But still. If a meeting is going to run hours and hours over time, have a thought for the direct consequences of keeping people tied up, in addition to the lost productivity, disenchantment, etc. I wouldn’t be so foolish to ask admin to buy us new mirrors- my money is better spent on lottery tickets. But giving researchers enough time to temporarily tread water would be nice.


EliRabett said...

My general experience is that you don't gain much with a cryotrap. Unless you are running Xe, the cost of a boost fill is less than the cost of the LN2. YMMV depending on the laser of course.

Chuck said...

Neon isn't produced in Australia, so we need to get the tanks in from overseas, for a cool 4 grand a pop.

And the LN2 comes from the Wollongong steel mill, so it is fairly managable, and mostly paid for by the stable isotope and noble gas guys anyway.

I'm told it is easier on the resonator windows and electrodes as well, and new resonators are $$.

Are you a laser bunny?

EliRabett said...

Amazing that neon is not produced in the air separation plants but it must keep down the glitz a la las vegas. And yes, Eli even owned and operated a Tachisto, the pieces are still in the basement along with Lambda and Questek parts.

My understanding is that you don't need the cryotrap, you do a circulation of unionized gas at a slight overpressure between the windows and the discharge to preserve the expensive optics.