1. 16/04/20031PNPI / LHCb Muon EDR Wire Pad Chambers PNPI design for regions R4 in Stations M2,M3,M4  4 gas gaps of 5mm±70µm;  Active area: 1224x252.8 mm² (M2/R4) – 192+10% spare 1320x272.8 mm² (M3/R4) – 192+10% spare 1416x292.8 mm² (M4/R4) – 192+10% spare  Wire pad sizes: 51x252.8 mm² (M2/R4) 55x272.8 mm² (M3/R4) 59x292.8 mm² (M4/R4)  Number of wire pads: 24/plane  Wire pitch 2mm ±50µm;  Gold-plated tungsten wire Ø 30µm;

2. 16/04/20032PNPI / LHCb Muon EDR GENERAL VIEW OF WIRE PAD CHAMBER.

3. 16/04/20033PNPI / LHCb Muon EDR 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.

4. 16/04/20034PNPI / LHCb Muon EDR 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.

5. 16/04/20035PNPI / LHCb Muon EDR 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

6. 16/04/20036PNPI / LHCb Muon EDR 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.

7. 16/04/20037PNPI / LHCb Muon EDR 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.

8. 16/04/20038PNPI / LHCb Muon EDR 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.

9. 16/04/20039PNPI / LHCb Muon EDR 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.

10. 16/04/200310PNPI / LHCb Muon EDR 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.

11. 16/04/200311PNPI / LHCb Muon EDR Electric shielding 2.5 mm metallic shield is screwed to the panels with Parker screws. It is also used for supporting structure.

12. 16/04/200312PNPI / LHCb Muon EDR Gas input/output

13. 16/04/200313PNPI / LHCb Muon EDR 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: 400

14. 16/04/200314PNPI / LHCb Muon EDR MAIN TOOLING Four glueing tables Wiring machine Wire pitch&tension measuring machine Automated soldering machine To be ready in June 2003

15. 16/04/200315PNPI / LHCb Muon EDR 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

16. 16/04/200316PNPI / LHCb Muon EDR 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.