November 16, 2006

Status of Drift Chambers and Micro Drift Chambers for DIRAC.

Physicists:V. Kruglov, A. Dudarev, M.Nikitin.

Design of electronics for DC and MDC: V. Karpukhin.

Software support: L. Kruglova.

Mechanical works: V. Kudriavtsev.

November 16, 2006

November 16, 2006

Drift ChambersModule

typeNumber of modules

Active planes Active area, cm2

Total wire length, m

DC-1 2 X,Y,W,X,Y,W 2x(40x80) 1674

DC-2 3 X,Y 80x40 384

DC-3 3 X,Y 112x40 460

DC-4 3 X,Y,X,Y 128x40 998

What was done:

• all modules were revised;• all wires have been cleaned up;• HV tested;• beam tested.

November 16, 2006

Micro Drift Chambers (MDC)Scheme MDC plane

T1+T2 < T for 2 tracksT1+T2 = T for 1 track

November 16, 2006

Cathode strips and anode wires

November 16, 2006

MDC Characteristics

Item MDC

Cell size 2.54 by 2 mm

Number of planes 18 (9 double plane modules)

Plane efficiency >99%

Total thickness 0.005X0

Gate width 25 ns

Spatial resolution 22 ± 4 µm

2-track resolution 150 µm (100%)

2002 beam test: 1 module in the left arm of DIRAC setup

MDC Time SpectrumMain features

U=3.4kVIth=20µAAr(66%)+iC4H10(66%)+H20(1%)P=2atm(a)

November 16, 2006

MDC Status

Based on the results of the last DIRAC Run (2004) dedicated to MDC’s:

• preamplifiers for all MDC modules were made;

• all cathode strips were changed to increase their conductivity.

November 16, 2006

MDC Plans

• To finish job with preamplifiers and cabling;

• To continue job with fully metallized cathodes;

• To remake old MCGC gas rack for MDC.