Steps:

Note: DO NOT CONNECT the purity meter to the white tube until you reach to Step (4).

1. Check whether MV11, MV12, and the rotatable hand valve are closed (see the picture).
   Note: ensure MV11 is kept closed when you perform the following steps.
2. Open the rotatable hand valve and then bleed from MV12 a few times (open-close MV12 multiple times to flush), then leave the MV12 cracked open (to have only a little flow).
3. Connect the white tube's one end to the port after MV12 and let gHe flush through the other end before connecting to the purity meter.
4. Connect the other end of the white tube to the purity meter inlet while there is a little gHe flow.
5. Measure the purity, and take a picture of the reading (send it to the target group if possible), make a elog entry (with date, time, location, and purity).