. 2024 Jan 12;24(1):36–43. doi: 10.1089/ast.2023.0002

Table 2.

Results of ⁴He Measurements Performed at Room Temperature for Six Flight-like Sample Tubes, Integrated Over Various Accumulation Times to Determine He Leak Rates

Tube No.	⁴He (ncc^*)	⁴He ncc (corrected)	Accumulation time (h)	Leak rate (scc/s)
SN144	0.12	0.11	47.5	6.6E-16
	0.37	0.36	92.5	1.1E-15
	0.17	0.16	24.5	1.8E-15
	0.08	0.07	24.5	8.4E-16
SN180	0.02	0.02	24.0	2.0E-16
	0.06	0.05	72.5	2.0E-16
	0.06	0.05	72.8	2.0E-16
SN193	0.02	0.01	22.5	1.1E-16
	0.03	0.03	73.5	9.3E-17
	0.03	0.02	74.0	8.8E-17
SN196	0.03	0.03	26.5	2.7E-16
	0.05	0.05	46.0	2.7E-16
SN251	0.14	0.14	23.5	1.6E-15
	0.22	0.22	47.0	1.3E-15
	0.44	0.43	96.5	1.2E-15
	0.18	0.18	22.0	2.2E-15
	0.23	0.22	26.5	2.3E-15
	1.01	1.01	118.0	2.4E-15
	0.23	0.22	26.5	2.3E-15
	0.43	0.42	47.8	2.5E-15
SN282	3.57	3.56	22.0	4.6E-14
	15.66	15.65	96.5	4.5E-14
	3.51	3.50	21.5	4.6E-14
	4.04	4.03	25.5	4.5E-14
	7.26	7.26	45.5	4.5E-14

The measured ⁴He amounts were corrected by subtraction of blank values. Exact accumulation times (>12 h) were chosen for convenience.

^{^*}

nano (10⁻⁹) cubic centimeters