Transcript 55x272.8 mm² (M3/R4)

Wire Pad Chambers
PNPI design for regions R4 in Stations M2,M3,M4
 4 gas gaps of
 Active area:
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5mm±70µm;
1224x252.8 mm²
1320x272.8 mm²
1416x292.8 mm²
Wire pad sizes: 51x252.8 mm²
55x272.8 mm²
59x292.8 mm²
Number of wire pads: 24/plane
Wire pitch
2mm±50µm;
Gold-plated tungsten wire Ø 30µm;
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(M2/R4) – 192+10% spare
(M3/R4) – 192+10% spare
(M4/R4) – 192+10% spare
(M2/R4)
(M3/R4)
(M4/R4)
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GENERAL VIEW OF WIRE PAD CHAMBER
.
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Main design principles
 The design assumes final glueing of the chamber planes.
 Decision on the final glueing is taken only after full tests
of the preassembled chamber (PA chamber) operating
with the nominal Ar/CO2/CF4 gas mixture.
 These tests include:
- Initial HV scans;
- Scans with gamma-source;
- One week stability test;
- Final HV scan.
 After tests are completed with positive results, the final
glueing of the chamber is performed without reopening the
chamber.This procedure guarantees performance of the
finally assembled chamber to be identical to that of the
tested PA chamber.
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PRECISION GLUING OF BARS TO PANELS
Precision gluing is used both for
anode and cathode bars.
This provides uniform gas gap and also
important for preliminary assembling
and final gluing.
One chamber contains:
2 double side anode panels;
1 double side cathode panel;
2 one side cathode panels.
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DOUBLE SIDE WIRING OF ANODE PLANES
Some advantages of double side wiring:
 Symmetric load of the panels;
 Fixed position of the two anode bars
allowing to install before assembling the HV capacitors from both
anode planes on the outer anode bar with easy reach for replacement
(if needed) in the finally assembled chamber.
 Also installed are the HV resistors
and grounding strips interconnecting the two cathodes
After this the anode panel is ready for assembling
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ORING OF TWO ANODE PLANES
Each wire pad in each anode plane has a HV capacitor and a HV resistor.
The anode bars are divided into 3 sectors (8 pads in each)
All the HV capacitors are placed on the outer anode bars.
All the HV resistors are on the inner anode bars.
The signals from the inner bar pads as well as HV are
transported to the outer bar via capacitor legs.
Oring of the pads is arranged after the HV capacitors.
The Ored signals from one sector are transported
to the protection board through one 17 pins connector.
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Preliminary WPC assembling with external O-rings
Preliminary assembling uses:
four temporary assembling studs
in the reference holes at the panel corners and
four 3mm diam. external O-rings
pressed by 18 clamps around the chamber perimeter.
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Preliminary WPC assembling with external O-rings
External O-ring provides sufficient gas tightening
allowing to use the nominal Ar/CO2/CF4 gas mixture
in all subsequent tests with small gas consumption.
If needed,electronics readout can be also implemented.
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Final glueing
Final glueing is performed only after positive results
from all tests of the preliminary assembled chamber.
NO REOPENING OF THE CHAMBER during this process.
Temporary studs are replaced by permanent ones;
O-rings are removed;
Glue is distributed over perimeter side by side.
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GROUNDING
Grounding strips, already installed on each panel,
are interconnected after final glueing.
Also, these strips are connected to the grounds
on the HV bars.
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Electric shielding
2.5 mm metallic shield
is screwed to the panels
with Parker screws.
It is also used for supporting
structure.
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Gas input/output
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ASSEMBLING AREA
Assembling area ( 400 m2 ) is prepared at PNPI
for production of the M2/R4 and M3/R4 chambers.
Designed production rate:
1 chamber per day.
Total number of the chambers:
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400
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MAIN TOOLING
Four glueing tables
Wiring machine
Wire pitch&tension measuring machine
Automated soldering machine
To be ready in June 2003
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PRODUCTION SHEDULE
First chamber to be produced at PNPI
July –August 2003
30 chambers should be produced by the end of 2003
384 chambers
by Oct,2005
40 spare chambers
by the end of 2005
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Conclusion
 Chamber design is fixed excluding
(1) the gas inlet/outlet, (2) electric shield,and
(3) chamber support structure designs.
 List of materials is not completely finalized
(types of the glue, HV protection cover).
 Module 0 will be constructed accordingly the
travelers in July 2003 and has to be tested.
 PRR for PNPI production site is scheduled for
September 2003.
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