High average power dissipation in helix tubes

By precisely shrinking the glass envelope around the helix to a controlled depth, thus providing an exceptionally low thermal impedance to the outside of the envelope, and passing a suitable coolant over the envelope, it has been found that the power dissipation capability of helix circuits can be extended by more than one order of magnitude. A qualitative analysis indicates that the heat transfer characteristics should be as good as the experimental results indicate.