Zeev's Turnips Patch-No Politics (ZEEV)

[tantal]

Liquid nitrogen is fantastically cold, but it is actually a fairly inefficient coolant, because it does not absorb much heat per unit volume per unit temperature (low specific heat). IOW, you may be anticipating that it would behave simialarly to water cooled by the same amount, but it really wouldn't. You would need a fairly large amount of liquid nitrogen to get a significant cooling effect.

Might be worth a try, though.