1. Guide to ALICE Lasers Personal Safety System (primarily for key commissioners) Within the PI laser room and diagnostics room there are several lasers which are dangerous and require a personal safety system. Main experience a key commissioner will have is entering the PI laser room in at 8 am to prepare the PI laser for use… …or entering the PI laser room at midnight to ‘turn off’ the PI laser. But there are other scenarios that require more knowledge of the personal safety system.

2. The Basic Dangers Powerful lasers exposed in the PI laser room and diagnostics room. Many different people, key commissioners, laser people, university colleagues etc have access to these rooms. There are many different situations in which somebody could be exposed to a laser. This file outlines the dangers and the safety procedures in place to prevent harm.

3. Dangers PI laser room In PI laser room there is the ALICE PI laser and the TW laser, both are dangerous. Signs indicate “LASER BEAM ON” if either or both of these lasers is exposed SHOW PICTURES OF THE SIGNS THAT INDICATE LASER BEAMs ON. Anybody going into the PI laser room will see these signs. If anyone is already in the PI room before the laser is exposed, the person exposing the laser should warn them and get them to put on goggles

4. Dangers Diagnostic Room In diagnostic room there can be: – The TW laser ported through from the PI laser room and exposed – Another separate Class 4 laser exposed (this laser is entirely contained in the diagnostic room) – I think there is yet another Class 4 laser in that room that can be exposed. – The FEL light exposed – THz radiation exposed Signs indicate ‘Laser Beam On’ and ‘FEL SHUTTER OPEN’. ‘Laser Beam On’ indicates that ANY of the lasers (TW, class 4 etc) is exposed. Anybody going into the diagnostic room will see these signs and should put on goggles. If anyone is already in the diagnostic room before a laser is exposed, the person exposing the laser should warn them and get them to put on goggles.

5. More complicated dangers People can pass from diagnostics room to PI laser room and back again. The signs in place should warn anyone of the dangers in both rooms. Equipment access door is an alternative entrance to the diagnostic room and PI laser room, but it is not supposed to be used for general access. It will ALWAYS TRIP ALL LASERS if it is opened.

6. This was the state of the laser room lasers on 14 th Sep 2012 i.e. both PI Laser and TW laser are ON in the PI laser room, put on your goggles before opening this door.

7. FEL SHUTTER OPEN LASER BEAM ON Corridor in between laser room and diagnostics room This sign indicates if any lasers or FEL radiation are on in the diagnostics room. The fact that they are off in this picture means that no lasers are on in the diagnostics room.

8. LASER BEAM ON Equipment access door to the diagnostics room. This door ALWAYS trips ALL lasers if opened (except if sliding door is shut, it won’t trip the PI laser) This sign indicates if any lasers or FEL radiation are on in the diagnostics room. The fact that they are off in this picture means that no lasers are on in the diagnostics room. The “laser energised” sign notes that the TW laser is energised. It is important to have this warning because if this door is opened it will trip the TW laser power off and it’s difficult to turn back on again. The intent of this light is to prevent that eventuality.

9. FEL SHUTTER OPEN LASER BEAM ON Diagnostics Room This sign indicates if any lasers or FEL radiation are on in the diagnostics room. The fact that they are off in this picture means that no lasers are on in the diagnostics room.