CDC Design
Design Principle
- CDC covers angular region from 15 degrees to about 90 degrees 
    for good trigger efficiency to detect pion and proton pairs from 
    lambda particle decay.
    All particles come to the angular region go through the outer window 
    of CDC to achieve good trigger efficiency for low energy protons.
- No sense wire at the forward angle to avoid irradiation by high rate 
    scattered protons.
    An absorber also helps to reduce charged particles hit CDC at 
    the forward angle.
- CDC has 2 groups of axial layer and 2 groups of stereo layers.
    Every axial layer group has 4 layers of sense wires, and every 
    stereo layer group has 3 layers.
- Ratios of width and thickness of cells in the 1st stereo layer are 
    smaller than 2.5.
- Typical cell thickness is 1 cm.  The potential between sense and 
    potential wires can be obtained with an ordinary HV system.
Drawings and Photos