Vacuum Operations
with the INDRA detector
Mise a jour : 15 Mai
1998
The vacuum operations is based on 4 units (see figure):
From Atmospheric pressure to Vacuum.
- Close the manual primary valve under the
chamber. If it is NOT closed, the vacuum system will not start.
- On the PC, go to page 2, the manual valve
is displayed below the chamber and called "Vanne Manuelle" The
red color means it's closed.
- Click on "Vide", confirm on "vide" then on "Entree"
(see figure). The slow primary valve (VPL) will open.
- Open the manual valve by about 1 turn and check both by sound and on
the manometer (on the right of the chamber) the evolution of the vacuum.
- Check on the Chamber Gas control unit that
the relitve pressure of the Ionisation Chambers does not exceed a few mbar.
- Open the manual valve gradually.
- At 20 mbar the ROOTs pump should start and the fast primary
valve (VPR) should open at 1mar. These values of the vaccum can be read
on the Balzers meter on the left of the The chamber
control rack.
- At 5 10-2 mbar, the turbo pump valve (VSPT) will open. At this
point the relative pressure of the ionisation chamber can reach 5mbar.
- At 10-3 mbar, the Cryo pump valve will open. The temperature
of this Cryo must be below 20K (this value can be read on The chamber control
rack and its state is visible on the right of the computer screen).
- At this time the primary vacuum sytem (including the root pump) will
close its valves, the pumps will stop and return to atmospheric pressure.
One should close the primary valve under the chamber.
- The biases (Caen units) on the photomultiplicators can be applied only
below 10-4 mbar.
Eric Plagnol , David
Gourio