Initial Conditions in a vessel: P~my unknown, but ~100torr, V=5000cc, T=35C, gas is 50/50 N2/He
Laser drill a hole in the initial volume of diameter=10mils through a chamber wall thickness of 0.75mm.
Expand gas into sampling chamber (where pressure gauge is) of V=100cc, P before expansion=vacuum 10E-6 at highest, T=20C. I've previously been assuming the T was constant and only using P1V1=P2V2 to back calculate pressure in the original vessel, but now I'm questioning, how fast does the gas temperature equilibrate with the sampling chamber where my pressure gauge is. It takes minutes for the gas pressure to equilibrate (~3-5min) through the orifice. Do I need to be taking the temperature of the sample chamber into account? How can I calculate the rate of temperature decrease? Is it gas species dependent?