Marcel Vreeswijk (NIKHEF)
AGENDAAGENDA• Xray tomograph -BOL0 results (Martin)• BOL0 and BOL2 Features (Graziano)• Discussion (All)
Features and Mysteries of BOL chambers
Features and Mysteries of BOL chambers
Marcel Vreeswijk (NIKHEF) s
BOL0 - Hypothesis
OBSERVATIONS BOL0OBSERVATIONS BOL0•Y-pitch between inner wire-layers: 20um too large•Y-Pitch between outer wire-layers: only slightly too large
•Y-Pitch between multilayers: 75um too small
HypothesisHypothesis•Glue shrimp between tubes and spacer? (2x500um glue gap)--> measured: <5um effect for 1mm gap
•Xplate deforms during gluing. In particular the flange--> presented today
Additionally:Additionally:•Re-analysis of BOL0 construction RASNIK readings: ‘cumulative effects’ lead to better agreement!
Marcel Vreeswijk (NIKHEF)
Floppy Xplate wrt tubes
s
@longbeam
Away from longbeam
=Rotation of unknown relative size
Tube direction bends flanges
Longbeam constraints body Xplate locally
‘Tube-length’ bends body
Marcel Vreeswijk (NIKHEF)
Sag Adjustment
s
=Rotation of unknown relative size
‘Tube-length’ constraints flanges
Tube direction bends flanges
Longbeam constraints body Xplate locally
Away from longbeam flange bends differently!
BOL0 is scanned with sag-adjustment (partially) on!BOL0 is scanned with sag-adjustment (partially) on! (Longbeam sag is assymetric in BOL0)(Longbeam sag is assymetric in BOL0)
When we are optimistic: deformation is symmetric for up/down ML.
Marcel Vreeswijk (NIKHEF)
Sag Compensation
s
=Rotation of unknown relative size
‘Tube-length’ constraints flanges
Tube direction bends flanges (temporary)
Longbeam constraints body Xplate locally
Marcel Vreeswijk (NIKHEF) s
XP deformation
For now, BOL2 is still equipped with gauges, located on the inner side of the HV-xplate
During BOL2 construction, the flange of the HV xplate was measured with micro-gauges:LBF: Longbeam- FlangeBF: Body- Flange
Marcel Vreeswijk (NIKHEF)
Gluing BOL-0• Stability Xplates during gluing
Start glue
Start glue
Layer 2
Layer 3
Yrasnik=2 x Sag
Start glue
Layer 1
Layer 1: dSag=7um
Layer 2: dSag=10um
•The sag of the xplates in layer 1 and 2 change in time. •Layer 3,4,5,6: Sag stable
s
Marcel Vreeswijk (NIKHEF) s
Sag Compensation
End: -38/2 um
Start: -15/2 um
Start: 30/2 umEnd: 50/2 um
During gluing of layer 1 and 2, significant changes in xplate sag were observed:•In-stable reduction valves?•Effect of glue viscosity?
Layer 1
Layer 2
1 deg
BOL2BOL2
Marcel Vreeswijk (NIKHEF) s
Conclusions
OBSERVATIONS BOL0OBSERVATIONS BOL0Y-pitch between inner wire-layers: 20um to largeY-Pitch between outer wire-layers: only slightly to large:•Effects largely explained by RASNIK measurements during construction. • Flange deformation of order 10um could be ‘baked’ in.
Y-Pitch between multilayers: 75um to small:•Flange deformations of this order are certainly observed. However these deformations appear symmetric and elastic.•Needs more study -> effects of kinematic mounts•direct -in situ- measurement dY of Frascati comb and towers
Marcel Vreeswijk (NIKHEF) s
Test @CERN inTomograph (BOL0)
Wire positionsRMS 16m
Analysis of Martin Woudstra
Marcel Vreeswijk (NIKHEF) s
Parallelogram-ness
Checks distance wrtComb @ RO side
For stability bare spacer
“BOL
rail
RO
Marcel Vreeswijk (NIKHEF) s
Landing-Tool•Problems with lowering gluing tube layers on tube layers due to glue viscosity
•Landing tool pre-aligns chamber and ensures flat landing in glue.
BOL
Tower
Effective + EasyEffective + Easy
Marcel Vreeswijk (NIKHEF) s
Cosmic Ray Stand