Before entering the vault, inform the operator in charge so that the beam is being stopped and the RadSafety wall plug and scintillator for S3 are inserted, otherwise the cyclotron's RF will trip as soon as the door to the vault is being opened (please check also this link).
The S3 vault has three levels (see picture below), the top level, the middle level, and the bottom level. The different levels and sections within these levels are locked off by rad safety chains. Whenever a chain is unlocked, the area behind it needs to be checked and secured. When going around to the buttons, check the vault for other people, especially those working in areas not directly visible from where you stand.
On the bottom level, two buttons need to be pushed to secure the area. One is located in the north-east corner of the vault, behind the spectrograph (see left picture below). The second one is located under the stairs next to the elevator (see central picture below). The bottom level is locked off with the chain on the stairs on the middle level (see right picture below). All lights have to be turned off before closing the chain.
The middle level is separated into two areas: (1) the beam line section west of the intermediate image chamber, leading to the S800 object station, and (2) the middle level of the spectrograph with the staircase. The button for area (1) can be found at the western-most end of the vault at the S800 object (see first picture from left to right), where the beam line enters the vault from the transfer hall. This section is locked off from the remaining part by a chain at the intermediate image chamber (see second picture from left to right). Make sure that the lights in this section are off before locking he chain. Area (2) has one button on the frame of the spectrograph, between the two big spectrograph dipoles on the east side of the structure (see third picture from left to right). This section is secured by closing the chain on the staircase to the top level (see fourth picture from left to right).