TABLE 2.

Amount of cryogenic coolant required for cold mass cooling [9].

Fluid	Helium				Hydrogen				Nitrogen
Initial metal temperature K	300		77		300		77		300
	σ2	Liters	σ	Liters	σ	Liters	σ	Liters	σ	Liters
		per lb		per lb		per lb		per lb		per lb
Using latent heat of vaporization only
A1	8.3	30.2	0.4	1.45	0.38	2.42	0.018	0.12	0.83	0.46
SS	4.2	15.1	0.18	0.65	0.2	1.28	0.0085	0.05	0.43	0.24
Cu	3.9	14.1	0.27	0.98	0.17	1.08	0.012	0.08	0.37	0.21
…. and using the enthalpy of the gas
A1	0.2	0.73	0.028	0.1	0.075	0.48	0.0097	0.06	0.51	0.29
SS	0.1	0.36	0.013	0.05	0.037	0.24	0.0045	0.03	0.27	0.15
Cu	0.1	0.36	0.02	0.07	0.037	0.24	0.0065	0.04	0.23	0.13

²σ = weight of fluid required to cool the same weight of metal to the fluid boiling temperature.