I am not so sure that the solution is so very simple! The TCDD is
a mask made of two "u" shaped jaws. The "closed" position with
gap on the anti-collision switched correspond to a "protect"
position with verical aperture of +/-22mm and horizontal aperture
of +/-35mm. Se details here:
<https://edms.cern.ch/file/633431/1.0/LHC-TCDD-ES-0001-10-00.pdf>
I would be surprised if it was the source of background (I remind
you that the TDI - 7 m upstream of the TCDD - in "open" position
was kept at +/-10mm and apparently nothing was seen).
On the other hand, there were alignment issues about the TCDD, which
were supposed to be solved the week of the first sector test.
To be checked...
Next time we have beam we should try to open/close it to see
what happens.
Stefano
The TCDD.4L2 has been checked and alignment is OK. A problem was reported on the Eleta of the TED downstream TI2, but I think we can leave with it. It looks that the water flow is too limited !! Problem of balancing the flow once all the magnets are connected !! to be checked and re-balance in the future !! I am sending an email in this respect
Cheers and all the best for this week-end !!
Yacine