Region 2 Drift Chambers

1
Region 2 Drift Chambers

• Status Report
• Qweak Collaboration Meeting
• April 2005

2
Prototype I

• 40cm X 40cm
• 32 20mm Gold-plated Tungsten Sense Wires
• 33 100mm Gold-plated Beryllium-copper Wires

3
Prototype I

• Soldering wires
  Epoxying wires

4
Prototype I Tests

• 10 CO2 90 argon gas
• Nanometrics N-277 Amplifier/Discriminator cards
• Threshold set at 1mamp
• Scintillators above and below chamber
• Efficiency (Scint1 Scint2 Any wire)/(Scint1
  Scint2)

5
Prototype I Efficiency
6
Current
7
Singles Rate
8
Prototype II
9
Design Parameters

• Four chambers with six planes each
• Wire pitch 6 - 7mm
• 20mm gold-plated Tungsten sense wires
• 75mm gold-plated Be-Cu field wires
• 1664 electronics channels
• Nanometrics preamp/descriminators
• 100 x 16 channels/board 35k

10
Qweak Side View
11
End View
12
Beam View
13
Plans for 2005

• Evaluate electronics and measure drift velocity
  using Prototype I
• Build and test a chamber with the final
  dimensions
• xuv sense planes
• four cathode planes
• 208 electronics channels