COLLISIONAL FREQUENCY-SHIFTS AND LINE BROADENING IN THE CRYOGENIC DEUTERIUM MASER

We study the spin-exchange frequency shifts and line broadening of the deuterium maser in the temperature range from 0 to 10 K. We consider both a version operating on the beta-epsilon transition at B = 3.0 muT and one operating on the beta-delta transition at B = 3.9 mT. For the first transition, a comparison is made with our earlier results based on the degenerate-internal-states approximation and its first-order c orrections [E. Tiesinga, H. T. C. Stoof, B. J. Verhaar, and S. B. Cram pton, Physica B 165&166, 19 (1990)]. We find cusp structures due to ch annel thresholds and also resonance structures, both of which disappea r almost completely after thermal averaging in the temperature range c onsidered.