
TY  - JOUR
A1  - Bogle, GS 
A1  - Gardner, FF 
T1  - Cross-Relaxation Effects in a Ruby L?Band (1440 Mc/s) Maser at Low Magnetic Fields
JF  - Australian Journal of Physics
JO  - Aust. J.  Phys.
Y1  - 1961
VL  - 14
IS  - 3
SP  - 381
EP  - 402
KW  - 
UR  - https://doi.org/10.1071/PH610381 
N2  - The reversals of maser behaviour which occur in ruby at low fields on cooling from 80° to 4 oK are explained in terms of cross-relaxation transitions (resonant interchanges of energy between neighbouring paramagnetic ions). For an angle of 29° between the magnetic field and the crystal axis a cross-relaxation process has been demonstrated which involves groups of three ions and has a transition probability of 700± 100 per second in 0·013% ruby. The profile of the cross-relaxation resonance has a half-width of 190±30 Mcts at half-intensity, and has an approximately Gaussian shape. It should be possible to obtain useful low-field L-band maser action at 4 oK by pumping V41 with the magnetic field nearly perpendicular to the crystal axis, and also at 80 oK using a concentration ten times higher, i.e. 0·13% 
ER  -

