Transcript Helium Bag Readiness

Helium Bag Readiness
Scattering chamber
Clamshell flange (not here yet)
Electron
Beam
20 H target
“Coffee can” collimator
E Plane
E Plane
0.005” Polyurethane Balloon
(sides only)
10 m mylar foil
Front wire chamber
10 m Mylar Balloon
Upgraded Rear wire chamber
Transport of low energy protons (200-600 MeV/c) from
target through BigBite to MWDC
• Transport protons using helium a few mm above atmospheric
pressure. Almost as good as using vacuum. More convenient and
cheaper.
• Use company that makes polyurethane helium filled balloons of all
shapes and sizes. Polyurethane skin 0.15 - 0.005 “ thick. Will lose helium
slowly over a few days. Test leakage rate.
• Flexible enough to have limited angular movement of BigBite. Show
sample material.
• Stretched over circular snout fixed to scattering chamber and hot
glued
• Stretched over rectangular angle aluminum attached to wire chamber
frame and hot glued
• Investigate stability of the system and radiation damage of
polyurethane and glue and measure helium loss rates.
Stretch over aluminum
support frame and hot
glue poly and terminate
with 10 m mylar
Shape of Polyurethane Helium Filled Balloon
Stretch over “coffee
can” collimator and
hot glue
157.8 cm
18 Deg
Side view
33.8 cm
18 Deg
82.3 cm
5 cm
122.9 cm
5 cm
33.1 cm
2 Deg
44.0 cm
25.2 cm
Bottom
view
206.2 cm
38.7
cm
Test on Balloons
• Need to always keep inflated above atmospheric pressure
• Monitor during the experiment. This is crucial.
• Mechanical stability of of joints and seams and leak rates
• On the polyurethane balloons and mylar balloons
• Conduct radiation damage test on both types.
– Effects on hot glue joints
– Effects on seams
– Effects on polyurethane
Balloon Milestones
• March
– Design/Draft shape of polyurethane helium containment balloon
– Design Coupling balloon to chamber
– Order sample polyurethane balloon material
• April
– Order prototype polyurethane balloon ( 0.005” thick) and prototype
and 10 m mylar “pillow shape” balloon.
- Order two extra balloons for protecting PMTs from helium leaks
- Design Helium gas handling system for balloon
• May
– Test all prototype balloons for helium leak rate and radiation damage
– Test gas handling system.
• June-July
– Evaluate test results and make modifications. Decide on many balloons
and type. Purchase final balloons
• August
– Assemble flanges, collimator, window, gas handling system, and balloon
for further testing.
• September , November, and December
– Continue checking out system and measure loss rates over long term