EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH

European Laboratory for Particle Physics

Content

  1. Introduction
  2. Conditions before starting the patrol
  3. Size and equipment of the patrol
  4. Patrol sequence
  5. Patrol sectors
  6. Patrol circuit
  7. Sector 11
  8. Sector 10
  1. Introduction

The ALICE experiment is located in the UX25 cavern at the LHC intersection point 2. Before beams can pass the UX25 cavern, a patrol has to verify that no persons are left in the cavern and all sector gates are locked.

This document specifies the conditions before a patrol and the patrol itself for the two sectors under the responsibility of the ALICE experiment.

  1. Conditions before starting a patrol

The experimental cavern UX25 comprises several zones, which have to be locked off before a patrol in order to simplify and speed up the patrol itself. These zones will be searched before any patrol and closed by doors with padlocks. The keys (one key for the areas in the detector, one different key for the gangways??) to the padlocks are kept in the ALICE control room and have to be signed out. These zones are areas where access is necessary only occasionally or where access is difficult and takes appreciable time.

There are nine such zones in UX

  • Zone 1, gangway along the crane rail on the “inside” of the cavern, see figure 1
  • Zone 2, gangways between the crane rail level and the PX24 plug on the ‘inside’, see figure 1
  • Zone 3, gangway along the crane rail on the “outside” of the cavern, see figure 2
  • Zone 4, gangways between the crane rail level and the PX24 plug on the ‘outside’, see figure 2
  • Zone 5, inside of the L3 magnet, see figure 3
  • Zone 6, FASS and muon dipole area, see figure 3
  • Zone 7, area between stations 3 and 4 of the muon arm, see figure 3
  • Zone 8, Mini-frame area, see figure 4
  • Zone 9, to top of the L3 solenoid, see figure 5

Furthermore, it is required that

  • the MAD in UP25 is closed and the emergency handle is sealed (figure 6)
  • The doors of sector 11 are closed and the emergency door handles are sealed.
  • the technical gallery between UX25 and US25 is sealed (see figure 6)
  • the shielding plug in PX24 is complete (see figure 7)
  • The two doors, YCPZ02=PX24 and YCPZ03=PX24, at the shielding plug level are sealed.
  • the PX cable chicanes at the shielding plug level are blocked
  1. Size and equipment of the patrol

The patrol of the UX25 cavern requires 2 teams of 2 persons (team A and B) and a patrol leader.

The patrol needs the following equipment

  • Three patrol keys, one for each team and the patrol leader.
  • Equipment to arm access doors and access points
  • Equipment to seal sector gates (sealing pliers, seals, sealing wire)
  • Personal protection equipment (safety shoes, helmet, light, dosimeter)
  1. Patrol sequence
  1. Before entering the sector to patrol, the patrol asks the operator in the CCC to change the status of the sector to “PATROUILLE”. This locks all doors of the sector and disarms the patrol boxes of the sector.
  2. The patrol authorizes the unlocking of the door to the sector with the patrol key. The patrol bushes the button (which, name) to operate the door lock and to inhibit the “SEARCH transfer” and then opens the sector door to enter.
  3. The sector door is sealed automatically after closing it again.
  4. The patrol searches the sector and rearms the search boxes with the patrol key.
  5. The patrol exits the sector with the help of the patrol key. Attention: a sector door, which stays open longer than 30 seconds, invalidates the search and disarms all search boxes of the sector.
  6. The patrol asks the operator in the CCC to drop the “PATROUILLE” status. The operator confirms to the patrol that the “SEARCH” status is activated.
  1. Patrol sectors

Two sectors at LHC Point 2 are under the responsibility of the ALICE experiment, see EDMS document xxxxxx, LHC-OP-SP-0002. Figures 8 to 9 (pages 13 to 15 in EDMS document 342642, LHC-Y-ES-0103) show the two sectors:

  • Sector 10 comprises the UX25 cavern, the room between the PX stairway and the PX elevator at the level of the shielding plug, the PX elevator and the area at the top of the elevator between the elevator and the PX access point
  • Sector 11 comprises the stairway in the PX shaft
  1. Patrol circuit

The patrol enters sector 10. The patrol leader and Team A descend with the elevator to the bottom of the PX shaft and wait there for Team B.

6.1Sector 11

Sector 11 has to be searched before the patrol of sector 10.

  • Team B enters sector 11 with the help of the patrol key, descends the stairway and arms the three patrol boxes, see figure 9, one at each door. Team B leaves sector 11 at the bottom and joins the patrol leader and Team A at the bottom of the PX.

6.2Sector 10

  • The patrol leader and Team A proceed on the “inside” to the RB26 side of the cavern whereas team B proceeds on the “outside”.
  • Team A and the patrol leader descend to level 0 in area C. The patrol leader searches the C area under the muon dipole and arms patrol box YZBB03=UX250 while the team members stay at the stairway watching that nobody descends. The team leader returns to the stairway and watches that nobody descends to level 0. The team members searchthe “inside” of level 0 (look also behind the ventilation units into the pit in front of L3) and arm the patrol box YZBPB02=UX250. Then they search the “outside” of level 0 and arm patrol box YZBPB01=UX250. During this time Team B watches that nobody descends the crinoline to level 0 on the ‘outside’ near to L3.
  • The patrol leader and team A ascend to level 1.
  • Both teams and the patrol leader search level 1 in the area C. One team member watches that nobody descends from level 2 to the muon platform. The other team members check that the access points to the FASS and dipole magnet at station 4 are pad-locked and search level 1 (look also between the muon chambers and at the gangways on L3 doors). Both teams proceed to level 2.
  • The patrol leader arms the patrol box YZBPB02=UP25 and proceeds to the RB24 side of the cavern.
  • Teams A and B search the gangways along the cavern wall on the inside and outside.
  • One member of each team ascends to level 4. They meet on the gangway along the RB26 wall of the cavern and search the ventilation platform, the top of the muon arm and dipole. They return each to their lateral gangways and arm the patrol boxes YZBPB01=UX254 and YZBPB02=UX254. They search the lateral gangways, check on the ‘inside’ that the access to the roof of L3 is pad-locked, and proceeding towards the stairways on the A side. They remain at the stairway on level 2 till the other team member has reached the stairway at level 2.
  • The other member of each team searches the lateral gangways at levels 2 and 3 proceeding towards the stairways on the A side.
  • When both team members have reached the stairways, the team member at level 2 remains at the stairway whereas the team member at level 4 ascends to level 5, checks that the doors at level 5 are pad-locked (door for the crane gangway and door on the crinoline towards the PX24 plug) and arms the patrol box YZBPB01=UX255 or, respectively, YZBPB02=UX255. Both team members meet at level 2.
  • The teams search the low beta platform and level 1 on their side on the way to level 0 making sure that nobody ascends the stairway.
  • One member of each team remains at the bottom of the stairway on the A side. The other team member and the patrol leader search level 0 on the A side starting at the L3 solenoid. Team A checks that the access hole to L3 is pad-locked. The patrol leader checks that the access to the mini frame is pad-locked, searches the laser hut and arms patrol box YZBPB04=UX250.
  • Both teams and the patrol leader converge from both sides on the safe room at the bottom of the PX and enter. They arm patrol box YZBPA01=PX24.
  • The patrol leader and both teams take the elevator to the shielding plug level, search the room at this level and arm patrol box YZBPA04=PX24.
  • They ascend to the top of the PX, search the area one floor down in front of the access to the stairway, arm patrol box YZBPA01=PX24, search the area at the top of the elevator and arm patrol box YZBPC01=PX24.
  • The patrol leader and both teams leave sector 10 via access point YAC01=PX24, ask the CCC to drop the “PATROUILLE” status and to confirm the search status

Figures

1Inside wall of UX25 cavern

2Outside wall of UX25 cavern

3Zones inside the ALICE magnets

4Mini frame zone

5Zone on top of L3 solenoid

6UX-US technical gallery and MAD in UP25

7Shielding plug in PX24

8Sectorisation access machine LHC, Points 2 & 3.2 – SX2

9Sectorisation access machine LHC, Points 2 & 3.2 – escaliers PX24

Photos

Figure 1,“inside” wall of UX25 cavern

Figure 2,“outside” wall of UX25 cavern

Figure 3,zones inside the ALICE magnets

Figure 4,Mini-frame zone

Figure 5,zone at the top of the L3 solenoid

Figure 6,UX-US technical gallery and MAD in UP25

Figure 7,shielding plug in PX24

Figure 8

Figure 9

Figure 10