The Linac interlocks and controls are divided into two separate systems connected in series. The first set of interlocks is the ‘Linac Chain’ (DWG. 4034). The second set of interlocks is the ‘Linac HV Power Supply Control’ (DWG.4150)
Linac Ready Chain:
The primary personnel safety interlocks are included in the ‘Linac Chain’ which is located in the CESR control room. This chain of PPS interlocks include:
- Light beams
- Area Resets
- Machine keys (except CHESS)
- CHESS area status
- Radiation monitors
- Shielding blocks
- Interlock SET SWITCH
- LS1/LO Lead shielding Door
Also included are hardware interlocks we require just to put beam into the synchrotron.
- Foam Generator
- Synch Mag. Safety switches
- Synch. Vacuum Gate Valves
- Substation relays (Accel Crash relays)
- Diffusion Pumps
The output of the ‘Linac Chain’ produces only a ‘Linac Enable’. You cannot turn on the Linac HV at this point, only enable the power supply.
Linac HVPS Chain:
This set of interlocks is quite complicated and spans across two supplies which both have 25% and 75% settings. The interlock chain includes hardware interlocks from the supply such as door switches, temps, water flow, 480VAC power, inductrol flybacks, and inputs from sub chains. The sub-chains include the eight modulators, e- optics, external interlock and computer ready.
The turn ON of the supply is divided into three sections.
- All PPS interlocks are Reset and hardware interlocks are ready.(Linac Chain)
- The Linac is Enabled.
- A 15 sec timer is started
- Linac Alarm is sounded
- Synchrotron ON light in all Machine Status Sign boxes comes ON.
- Lights go out in the Tunnel and LS1
3. High Voltage is turned on based on the position of the 25%-75% power switches and -24vdc from the Linac Interlock Chain OR the Test Bypass Plug.
Enabling and turning on the Linac HVPS effects our PPS interlocks and Radiation Warning system.
After turning on the Linac HVPS the following steps happen:
- ‘LINAC ON’ signs light. (Three in LS2 and one on the catwalk.)
- Rotating RED beacon on the west wall of L0 lights
- Two RED spots light on west wall of L0
- 480vac is checked after the main contactor (for alarm status)
- Signal to Trouble Light #39 if HV is ON when synch. Magnet is OFF
- Lights RED ‘ON’ buttons in CESR control room Linac panel
PPS Interlock affected:
- White KEY Bypass Boxes are disabled
- Gray Key Bypass Boxes are disabled
- Tunnel perimeter now active in Linac chain