2008-07-08 - GSI
2008-07-08 - GSI
2008-07-08 - GSI
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TRD alignment with (German) cosmics<br />
Dariusz Miśkowiec<br />
(<strong>GSI</strong>), Eva Sicking (Uni Münster)<br />
ALICE offline week, 8-Jul-<strong>20<strong>08</strong></strong><br />
intro<br />
alignment with Münster cosmics<br />
TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, <strong>07</strong>-Jun-<strong>20<strong>08</strong></strong> 1
alignable<br />
18 TRD supermodules<br />
like /TRD/sm03<br />
aligned by survey<br />
540 TRD chambers<br />
like /TRD/sm03/st3/pl0<br />
aligned with tracks<br />
objects in TRD<br />
TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, <strong>07</strong>-Jun-<strong>20<strong>08</strong></strong> 2
Bastian Bathen<br />
Münster<br />
cosmics<br />
cosmic trigger rate 100 Hz<br />
1 M – 10 M events per SM<br />
100 k – 1 M tracks per SM<br />
TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, <strong>07</strong>-Jun-<strong>20<strong>08</strong></strong> 3<br />
phi
scintillator paddles<br />
for cosmic trigger<br />
TRD supermodule<br />
TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, <strong>07</strong>-Jun-<strong>20<strong>08</strong></strong> 4
Münster<br />
cosmics<br />
supermodule assembled reassembled inserted<br />
SM1 Heidelberg --- Nov(?) 2006 Sector 8<br />
SM2 Münster --- Jan <strong>20<strong>08</strong></strong> (?) Sector 0<br />
SM3 Münster Münster<br />
SM4 Münster CERN May <strong>20<strong>08</strong></strong> Sector 9<br />
SM5 Münster Münster May <strong>20<strong>08</strong></strong> Sector 17<br />
in this talk: 5370 tracks in SM4<br />
(now in sectior 9) btw. data looks<br />
like coming<br />
from sector 0<br />
TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, <strong>07</strong>-Jun-<strong>20<strong>08</strong></strong> 5
Münster<br />
ALICE pit view from A-side<br />
cosmics, SM4<br />
ALICE pit top view<br />
TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, <strong>07</strong>-Jun-<strong>20<strong>08</strong></strong> 6
Münster<br />
ALICE pit view from A-side<br />
cosmics, SM4<br />
ALICE pit top view<br />
TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, <strong>07</strong>-Jun-<strong>20<strong>08</strong></strong> 7
Münster<br />
ALICE pit view from A-side<br />
cosmics, SM4<br />
ALICE pit top view<br />
TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, <strong>07</strong>-Jun-<strong>20<strong>08</strong></strong> 8
alignment procedure with AliAlignmentTracks<br />
AliTrackPoints.root<br />
AliAlignmentTracks<br />
AliAlignObj<br />
PointSelector.C<br />
AliTrackFitter<br />
(Straight, Rieman)<br />
AliTrackResiduals<br />
(Chi2, Fast, Linear)<br />
AliESDs.root<br />
AliESDfriends.root<br />
TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, <strong>07</strong>-Jun-<strong>20<strong>08</strong></strong> 9
L5<br />
L4<br />
L3<br />
L2<br />
L1<br />
L0<br />
alignment procedure<br />
keep L0 and L5 fixed<br />
adjust inner ones to all (at least 4) others<br />
(iteratively)<br />
fit straight tracks<br />
use "fast" minimizer<br />
(all 6 shifts and tilts allowed)<br />
TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, <strong>07</strong>-Jun-<strong>20<strong>08</strong></strong> 10
Münster<br />
cosmics, SM4<br />
SM4, stack 1<br />
TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, <strong>07</strong>-Jun-<strong>20<strong>08</strong></strong> 11
Münster<br />
cosmics, SM4<br />
SM4, stack 2<br />
TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, <strong>07</strong>-Jun-<strong>20<strong>08</strong></strong> 12
Münster<br />
cosmics, SM4<br />
SM4, stack 3<br />
TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, <strong>07</strong>-Jun-<strong>20<strong>08</strong></strong> 13
How many tracks per stack are needed?<br />
this was with 1000 tracks<br />
tested 200,1000, 2000<br />
2000 much better (flatter) than 1000<br />
TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, <strong>07</strong>-Jun-<strong>20<strong>08</strong></strong> 14
dataset<br />
Münster<br />
Münster<br />
cosmics<br />
sim v4-11-Release<br />
sim v4-11-Release<br />
sim v4-11-Release<br />
sim v4-06-Release<br />
sim v4-06-Release<br />
cosmics, resolution<br />
what aligned to what<br />
residuals<br />
peak width<br />
L3<br />
L0,L1,L2,L4,L5<br />
L3 L0,L1,L2,L4,L5<br />
L0 TPC<br />
L5 TPC<br />
L3<br />
L9<br />
0.30 cm<br />
0.18 cm<br />
0.22<br />
cm<br />
0.80<br />
cm<br />
L0,L1,L2,L4,L5 0.<strong>07</strong> cm<br />
TPC<br />
0.11 cm<br />
TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, <strong>07</strong>-Jun-<strong>20<strong>08</strong></strong> 15
Münster<br />
cosmics, summary<br />
chamber alignment very good (typically within 0.5 mm)<br />
1000-2000 tracks per stack reasonable for alignment<br />
residuals 1.7<br />
residuals with tracklets<br />
times wider than in simulation<br />
2.2 times wider than with cluster<br />
TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, <strong>07</strong>-Jun-<strong>20<strong>08</strong></strong> 16
ackup<br />
TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, <strong>07</strong>-Jun-<strong>20<strong>08</strong></strong> 17
Münster<br />
cosmics, SM4<br />
SM4, stack 0<br />
TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, <strong>07</strong>-Jun-<strong>20<strong>08</strong></strong> 18
Why resolution worse than in sim?<br />
Might be because of the tail Xe tail cancellation applied to Ar.<br />
In this case, however, phi-dependence expected. Not seen (Eva):<br />
width of the residuals<br />
btw., different groups of tracks give<br />
within 0.1 mm the same alignment<br />
TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, <strong>07</strong>-Jun-<strong>20<strong>08</strong></strong> 19
Münster<br />
cosmics, why poor resolution?<br />
Might be because of the track cuts, wide open for cosmics<br />
Under investigation by Eva.<br />
and B=0<br />
TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, <strong>07</strong>-Jun-<strong>20<strong>08</strong></strong> 20
Münster<br />
cosmics, SM4<br />
TRD alignment with Muenster cosmics, D. Miskowiec, TRD status, <strong>07</strong>-Jun-<strong>20<strong>08</strong></strong> 21
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