ATLAS SCT H8 Testbeam Safety, Interlock, Access and Magnet Usage Notes

These are informal notes on safety and interlocks at the Atlas H8 Testbeam.
Please also consult the official ATLAS/H8 Safety page.
These notes apply to H8 at CERN; similar rules apply at the KEK PS Pi-2 beamline. Make sure you acquaint yourself with all appropriate safety information.

File Badges MUST BE WORN AT ALL TIMES

Film badges (temporary or permanent) can be obtained from the Individual Dosimetry Service at CERN by registered Users.
You should bring to CERN a medical certificate of the type approved by the Dosimetry Service, or alternatively you can try to pursuade them to give you an appointment at the CERN Medical Centre for same.
If you are allocated a permanent badge, it will probably live in the slots on the stairs near the Atlas Secretariate where it can be routinely exchanged. Remember to return it there once your duties at H8 are complete.

Film badges are occasionally checked by TIS responsibles, so please do not be caught without one (Atlas already has a poor record, but within Atlas, SCT has a good record.)

Interlocks and Access to the beamline area

Brief rules for Controlled Access:

• No spectators - only enter the beamline area with good reason.
• Always take a yellow key
• Do not rush, especially going in or out the door or anywhere near where modules maybe exposed.
• Do not lose the key
• Plan the work to be done, and by whom, before going in.

If this door is on "FREE ACCESS" (green light illuminated) you can enter freely at any time. Do not take a key. The beam cannot be switched on until the control room releases the interlock after sending someone down to check that noone remains in the area.

If the door is on "CONTROLLED ACCESS" (yellow light) you must press the button "Key", and then take one of the 8 yellow keys. Use this to enter the door, turning the key carefully before turning the handle. Do not "Force" the door by being too quick, or too slow. If the door is forced (eg, for emergency exit) or left open for more than 1 minute it switches automatically to Free Access. This means a delay of anything up to a half an hour before the beam can be restored by CRN.

Do not lose the yellow key, and always return it immediately upon leaving the area. When several groups are using the area, keep an eye on who's going in or out, and tally the keys. A lost key can mean a stop of several days because the interlock control panel must be physically exchanged for another, a procedure which is not at all favoured by the responsibles concerned.

At the end of a Controlled Access, when all keys have been returned, press the "Fin d'Acess" button. This is a good idea even if you have no immediate need of beam but wish to be ready to start ASAP since it keeps out users from other groups.

If the door has "BEAM ON" (flashing lights) then access is not permitted.

To gain access to the beamline area during Beam On:

• If SCT are main users, notify any other users (eg, Pixels,, TRT, Tiles, NA45) that an access will commence shortly. Where reasonable, find a time in the near future that suits all users, eg, after their runs have finished.
• If SCT are co-users, the same applies, but we decide with the other co-users when we would like access.
• If SCT are not main or co-users, find the main users and request an access. They may ask you to wait for anything up to several hours until their run is finished. When performing the access, take all reasonable care to be prompt and efficient so that data taking can recommence as soon as possible. Even the briefest access takes at least 10 minutes due to the time it takes to stop and then to restore the beam.
• To request access (which should only be done as and when agreed by the current main user), go to the SPS run control terminal. The terminal used by the SCT is located at the far (downstream) end of our control room. Using the "eanorth> RUN TREE" window, follow the menu chain for ACCESS, DOORS, etc. Our door is 158. You request "OPEN" to gain a controlled access, "BEAM ON" to finish a controlled access, or "FREE" to go to free access (but only do this for a stop of a day or more). Wait at the terminal until it prompts you for a user name (for the access log), and then make sure the messages displayed seem to show that something is happening, i.e., that the system hasn't hung. Any problems, ring CRN (75566) (they can speak English even if they answer in French).
• Lately (2000) the process for closing the interlocks and restoring beam ("Beam On") has been failing at the first attempt (with a message "Veto on chain H8"). This seems to be some timeout problem or the like. Try again to do "Beam On" - it usually starts at the second attempt.

MAGNET

Brief rules for using the magnet

• The magnet should only be used with explicit agreement of one of the sub-detector link persons (in 2000, Gareth Moorhead or Anatoly Romaniouk). This is because some removable beamline equipment can be seriously damaged if not parked correctly first.
• Do not enter the beamline area unless the magnet is completely ramped down.
• Do not leave tools, power supplies, or anything else which may be ferromagnetic anywhere in or near the magnet unless securely fastened down.
• Do not approach the magnet if you have any iron-mongery implanted (pins, pacemaker etc.), even when it is ramped down, as there is a strong residual field.
• It's probably a good idea to leave any magnetic swipe cards (credit cards etc.) outside the beamline area if the magnet has been used, again because of the strong residual field.

gareth