Following the adsorption test we evaluated the recovery of gas adsorbed onto the porapak at approximately -20$^\circ$C by freezing into the cold finger for a period of time, isolating and measuring the amount of recovered gas. Freezing was continued in time increments of 300s until full recovery had been attained. The data, plotted in Figure 2(b) show that a minimum time of 1800s is required before 100% recovery is attained.