Alba synchrotron accident

The afternoon of November 13th, the Alba synchrotron has had an accident. As it has been officially mention by an email to all the staff, during the machine start up after a week shutdown, and accident have vent the vacuum in the storage ring.

Having a 3GeV beam with a current of around 100mA some beam studies were on going. It looks that the vertical orbit have suddenly change (+-5mm). The machine protection was off because it was necessary for the works on going and the orbit interlock protection hasn't being triggered to kill the beam. This protection has been design to avoid the beam hits the cavity when the beam goes out of a safe region.

The first indicator of the issue can be saw in the machine status because usually the operation pressure is rounding the 1e-9 mbar (in the Ultra-High Vacuum range) and in the picture taken the evening of that day this pressure is at 6e-2 mbar, where this is medium vacuum.

Even that this pressure value is not in one position, is an average. There where out-gassed sectors and sectors where the pressure has been contained:

In the bottom plot is possible to see where this accident have vent the cavity and where the pressure is very far than UHV. Notice that the scale is logarithmic in this plot, and we have already start work to fix that. When the accident has happen, some sectors have raised up to atmospheric pressure...

Now the machine status informs a little bit about this and is not giving a pressure value:

Update: Current user run cancelled. Due to the vacuum accident, the current 3 week run with beam for users has been cancelled. We hope to get it back up and running as soon as possible.

Update 20121116: We are recovering the vacuum. Yesterday we where at 0.39mbar on average in the storage ring, and today we are at 0.074mbar (on average).

Update 20121117: Yesterday we've been informed that the breakdown was less than can be thought, if it's possible to say like that. As far as I understood, the electron beam haven't hit the vacuum chamber; the damage has come from synchrotron photons have hit flanges downstream some bending magnets, the feebleest element on the path.

The vacuum technicians are working this weekend to speed up as much as possible the recovery of the machine operation. And today, on average we are at 0.0024mbar having only 4 places with pressures in the medium vacuum range (the others are already in UHV).

Update 20121119: Back from the weekend It look like the people that work this free days did an incredible work:

Sector 12 have 2 reading of 2.7e-3mbar, but as is show in the plot, the others are below the 1e-8mbar. Sector 7 looks to be in an incredible good 1e-12mbar...

Update 20121119, afternoon: the machine status gui recovers the pressure value

The Vacuum Controls gui (vacca) is also showing much better look: