1. Cryostat and Magnet Status Report UIUC EDM Collaboration Meeting LANL June 20, 2005

2. Summary Cryostat Goals Progress To Do Magnet Goals Current Field Measurements Future Field Measurements

3. Crysostat goals Ensure no cryostat materials spoil magnetic field uniformity. Minimize heat load.

4. Cryostat Progress Large 3 He cell constructed, cleaned and purity-tested with a spectrometer Silicon-Bronze selected as replacement for inner vacuum vessel flange. Indium seals selected to replace conflat seals

5. Long 3 He cell

6. Cryostat to Do Replace dewar (currently being ordered) Completely rework outside plumbing Build new inner vacuum vessel Pumping lines ( 3 He and 4 He) must be replaced with thinner walled steel to reduce heat load Test/Install large 3 He cell

7. Magnet Design Ensure  B/B <5E-5 cm -1 over VOI by optimizing coil currents and spacings. Coil currents determined by number of windings and shunt resistors. Coil diameters are identical.

8. First measurement with Gantry First attempted to map coils with “gantry” from G 0 project Long term variation of order 0.1 G in the probe offsets rendered this data useless for determining gradient information

9. Current center field measurement Deviation from 5 Gauss, measured with Fluxgate magnetometer

10. Current field measurement Several gradients appear in the data, one of order 2*10 -5 cm -1 and one of order 10 -4 cm -1. Location of change in gradient value corresponds with junction of two PVC tubes used to position fluxgate. Fluxgate has time dependences that could not be completely removed. More accurate positioning and a more precise field measurement are necessary.

11. Next field uniformity measurement ~0.1 mG magneto-resistive sensor purchased To be mounted on boom of G 0 mapper