Magnets
Particular care must be taken in working in the vicinity of the
magnetic elements of the polarimeter as they can have large currents
running in them. Only members of the Møller polarimeter group are
authorized to work in their immediate vicinity, and only when they are
not energized. The quadrupole magnets and the leads for the dipole magnet
are protected with Plexiglas shields. As with all elements of the
polarimeter which can
affect the beamline, the magnets are controlled by MCC. There are four
red lights which indicate the status of the magnets. The dipole has two
lights which are activated via a magnetic field sensitive switch placed
on the coils of the dipole. One light is placed on the floor on beam left,
and the other is placed on the raised walkway on beam right. The quadrupoles
have similarly placed lights (one on the floor on beam left and one
on the walkway), and are lit up when any one of the Møller quads is
energized. The status of the quadrupole power supplies is on the
checklist for
closing up Hall A. Lock and tag training is required of all personnel working
in the vicinity of the Møller magnets.
The power supply for
the dipole is located in the Beam Switch yard Building (Building 98).
The maximum current for the dipole is 450A.
The quadrupole power supplies are located in Hall A electronics rack 13,
2 supplies connected in parallel per one quadrupole. The maximum
current per one power supply is 60A at about 20V.
Vacuum System
One must be careful in working near the downstream side of the dipole
magnet, as there are two 2 by 16 cm, 4 mil thick titanium windows.
Only members of the Møller polarimeter group should work in this
area.
High Voltage
There are 38 photomultiplier tubes within the detector
shielding hut, with a maximum voltage of 3000 V. The detector is serviced
by sliding it back on movable rails. The high voltage must be turned
off during any detector movement. Only members of the Møller group
should move the detector.
Target
To avoid damage to the Møller target, the target should not be in the beam
if the beam current is greater than
5 
A. Only MCC can move the target, but the experimenters
are responsible for ensuring that it is properly positioned.