Fusion Message Board

In this space, visitors are invited to post any comments, questions, or skeptical observations about Philo T. Farnsworth's contributions to the field of Nuclear Fusion research.

Subject: Re: Unification (large vacuum chamber)
Date: May 07, 7:46 pm
Poster: Jim Lux

On May 07, 7:46 pm, Jim Lux wrote:

>In a room sized chamber - 20x20 feet
>how low a air presssure can one easy get?

AS big as you want, if you aren't constrained by cost. Mostly it's a matter of pumping speed, interestingly, it gets easier as it gets bigger (because outgassing from the walls is the largest source of gas (once you've found all the leaks (heh, heh,heh)).....

As a point of reference, the big chamber at JPL is about 30 feet in diameter and 60 feet long and pumps down to 1E-7 in about an hour... and costs about $20-50K/hr to operate, as I recall (although that may include LN2 costs, and operators for a normal Thermal Vac test). A set of truly enormous diff pumps does the job.