Comments on the CLEO-III drift chamber support

Dan Peterson, Cornell 2010-07-01

CLEO-III took data at CESR from ~1998 to ~2008 and evolved from CLEO-I and CLEO-II starting in 1979.

Included a drift chamber 82cm O.R., 2.2m length, 10,000 cells

The drift chamber was directly inside the Ring Imaging Cherenkov particle ID, which is relevant because the RICH had little provisions for supporting the drift chamber.

Drift Chamber

82 cm outer radius2.2 meter length

10,000 lb wire load (1 lb = 4.45 N)

500 lb total weight

Load held at 4 pointson each side: 2 lower points2 upper points.

The outer skin holds the wire load and maintains the internal alignment. It is a thin laminate; 2 layers of 1/32inch (0.75mm) aluminum separated by 1/4 inch (6mm) polycarbonate honeycomb.

The chamber will twist (but not break) if not uniformly supported.

The lower support points support 1/8 of the chamber weight, are hard contact points provide vertical alignment provide horizontal alignment and attach to the RICH,

The upper support points attach to the magnet iron though the funny shaped bar, support 1/8 of the chamber weight, supports the weight through a spring which allows adjusting the load by watching the spring length and provides no horizontal constraint.

Installation starts with all load on the upper supports.