 |
Pictured to the left are the various electronic gadgets responsible for
the spectrometer operation. From the top we have:
an oscilloscope (used for
tracking the position of the cavity modes so as we can move the mirrors
to achieve resonance at a particular frequency).
On top of the scope is a
pressure gauge for the sample handling manifold.
To the right of the scope is
the analog-digital converter that is connected to the computer.
Below this
is the mirror box which controls the positioning of the mirrors. The mirrors
are moved (via software commands) by a small stepper motor connected to one
of the mirrors.
Below the mirror control box is the master oscillator, a
Hewlett Packard 8671 frequency synthesizer. This is responsible for
generating the polarizing microwave radiation as well as providing a 10MHz
reference signal that allows synchronization of all other electronic
equipment.
Next is the pressure gauge - the chamber pressure shown on the right
hand gauge is
about 2 ×10-7 torr (indicating the diffusion pumps are
working fine!)
Next comes the all important timing box. This is responsible
for making sure that
everything fires in the correct sequence. It controls the sequencing
of the gas pulse, microwave pulse, when the switch to the detector is opened
and so on. Incorrect timing could lead to poor signal quality or even
possible damage to the electronics.
Next comes the local oscillator
which provides a radiofrequency signal that is used in the
detection process to mix the microwave frequencies (of the molecular
emission signal, typically several GHz) down to radiofrequency (~2.5MHz).
Under the local oscillator is the heater control box for
controlling the heated nozzle.
Next is the Iota One valve controller. This
controls the General Valve solenoid valve and is connected to the
computer so that the various valve settings can be changed in
the operating software.
Finally, the box at the bottom supplies power
to the microwave circuit.
|