Helium Bag Readiness

Scattering chamber

Clamshell flange (not here yet)

“Coffee can” collimator

0.005” Polyurethane Balloon(sides only)

10 m Mylar Balloon

Front wire chamber

Upgraded Rear wire chamber

E Plane E Plane

20 H targetElectron Beam

10 m mylar foil

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.

Shape of Polyurethane Helium Filled Balloon

206.2 cm

44.0 cm

33.1 cm

38.7 cm

Bottom view

2 Deg

5 cm

25.2 cm

18 Deg

18 Deg

Side view

122.9 cm

33.8 cm

157.8 cm

82.3 cm5 cm

Stretch over aluminum support frame and hot glue poly and terminate with 10 m mylar

Stretch over “coffeecan” collimator and hot glue

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