In the early 1950's the possibility of detecting non-magnetic mines by
using the nuclear magnetic resonance of protons was
researched. Various types of coils to produce a strong steady magnetic field and a weaker
probing radio frequency wave were tried for "magnetic resonance imaging".the
buried mine. Another aspect of detecting buried objects was the use of the free precession of protons in a water
sample to detect any anomaly in the value of the earth’s magnetic field.
A programme of work in the new field of Quantum Electronics,
brought about by the discovery of the Maser (Microwave Amplification by Stimulated
Emission of Radiation) by scientists in the U.S. was undertaken. Part of this work was to
produce maser action at the microwave frequencies used in communications and this
required an understanding of the Quantum Physics of Paramagnetic Crystals, a field of
study which had been extensively researched by scientists at the Clarendon Laboratory,
Oxford University. The Three-Level Maser
was used for amplifying weak signals in satellite communication links. The Two-Level Maser with a swept magnetic field
provided low noise amplification of pulsed microwave radiation at millimetere wavelengths.
TheAmmonia Maser
obtained from the excited states of the ammonia molecule was developed as an
‘Atomic Clock’ and subsequently installed in Australia.
The Basic Physics Division was also concerned with the generation of
optical radiation by Laser Action in Ruby
crystals and Neodymium doped glass rods. A novel method of detecting infra-red was devised
using Quantum Counter action in
rare-earth crystals.
The division also had a Cryogenic facility
with a Collins helium liquifier and a liquid nitrogen machine.