M. Dracos

1

Status of theStatus of theTarget TrackerTarget Tracker

(M. Dracos)(M. Dracos)

Nagoya, 08/03/2011 M. Dracos

M. Dracos

2

During last TT interventionDuring last TT intervention(2-9 Dec. 2010)(2-9 Dec. 2010)

•Light leaks: 23 horizontal and 16 vertical cured

Right Left

More and more difficult to scotch the light leaks, during one year they become big…

Nagoya, 08/03/2011 M. Dracos

M. Dracos

3

PMT statusPMT status

PMT replaced in Dec. and now in Strasbourg for studies

trig

ger

rate

(H

z)

Not light tight!

PA2583 PA940

PA2496PA1971 PA4086

Nagoya, 08/03/2011 M. Dracos

M. Dracos

4

PMT statusPMT statustr

igge

r ra

te (

Hz)

More than 10 PMTs suffer from this problem affecting the channels on the 3 external sides (under discussion with Hamamatsu).

Apparently, the problem comes from an electrode running only on the 3 sides and emitting more and more electons…

Nagoya, 08/03/2011 M. Dracos

M. DracosOthersOthers

• front end cards• 4 replaced• limited spares• 200 spare chips found in Bern !

• Camerops and mezzanines• 2 camerops replaced• 2 mezzanines replaced

• Problems with the basket (essential for this work)• Thanks to Mario and Mengucci, the problem has been

attenuated using a faraona.

Nagoya, 08/03/2011 M. Dracos 5

M. Dracos

6

Interaction with BMSInteraction with BMS

The BMS has "touched" the TT at many places on several walls⇒All the TT walls have been readjusted

Nagoya, 08/03/2011 M. Dracos

M. Dracos

7

SummarySummary• 39 light leaks cured,

• 2 camerops+mezzanines and 4 front end cards replaced

• spare chips found!

• More than 10 PMTs under observation (discussions with Hamamatsu),

• next intervention: end of the year

• Obviously, only one intervention at the end of the running period is not enough.

Nagoya, 08/03/2011 M. Dracos