Personnel Safety System



This sticker is placed on special PSS devices or components which are
used to prevent beam transport into an area where people may be working. An example would be
the beam stoppers in the BSY.

This sticker is placed on all PSS components and wiring conduit to
designate it as PSS equipment.  Don't touch!!!

A typical access room consists of a message display (black box),
redundant dor switches, magnetic locks, and an exchange key bank (blue boxes).  The blue strobe
over the first door is an ODH warning beacon.  The yellow strobe over the second door is a laser
shutter warning beacon.

The Controlled Area Radiation Monitor or CARM (the black box
in the upper left) is used to measure gamma and neutron dose and dose rate in areas where people
work.  If the rate ever became too high the CARM would trip off the beam.

Beam stoppers are "Critical Divices" which are used to block
beam from traveling to the experimental end stations while people are present there. Two stoppers are
used, in addition to shutting off the beam transport magnets, for redundancy.

FEL PSS racks show the electronics for the public address system (left)
and the oxygen monitoring system (right).

This is one of the two 50kW power supplies used to power the FEL
super-conducting injector.  The PSS will shut off the power supply when the tunnel is open for access.

Typical access room exchange key bank system.
When an individual accesses the tunnel while it is in Controlled Access state, they will remove the top key
(master key) and place it in the right hand slot of the bottom key bank.  At this point, the slave keys can
be removed and the master key is captured in the bottom key bank.  Each person entering the tunnel is
required to take a slave key.  As long as the master key is removed, the PSS will not allow the machine to
be switched to "Power Permit."

The ODH monitor uses ambient oxygen in a reduction-oxidation process
that produces a small curent.  The current from the sensor is directly proportional to the amount of oxygen
in the air.  Electronics upstairs compare the sensors current to present thresholds and will alarm if the level
drops below present limits.

The "Run/Safe" box has several functions.  Spread through-out the accelerators,
the "Run/Safe" is used in the tunnel sweeps as safe/unsafe indicator, and as an emergency crash station.