1. Noble Gas Purifiers and Purity Monitors Xenon Workshop LBL Nov 16-18, 2009 A. Odian, C. Prescott, P. Rowson SLAC

2. CONCEPTS HOW HIGH A PURITY IS NEEDED? Energy Resolution – Z Correction may not be enough WHERE DO ALL THE IMPURITIES LIE? In the Metal Walls and in Plastic insulators GAS VS LIQUID FOR FIXED MASS Arguments in Both Directions, Assume Same

3. PURIFIERS SAES HOT ZIRCONIUM TITANIUM SPARK PURIFIERS FREE ELECTRON DRIFT PURIFIER GETTERS RADON REMOVAL

4. cathode anode FET charge sensitive preamp and shaper grids drift region photo-emission from goldplated cathode via laser XPM uses 266nm laser (quadrupled YAG). Synchronous operation  better S/N. XPM at SLAC : schematic laser fiber Liquid Xenon Purity Monitor (XPM) at SLAC

5. Gas Purity Monitor (GPM) SPACE CHARGE LIMITED CURRENT HOT WIRE WITH NEGATIVE POTENTIAL ON AXIS OF HOLLOW CYLINDER 200 MICRON DIAMETER W WIRE12.5 CM LONG HEATED BY 4.0 AMPS ~10 V FLOATING POWER SUPPLY WITH NEGATIVE BIAS OF 18 V, 2-9V BATTERIES BATTERY CURRENT READ BY OP AMP CURRENT LIMITED BY SPACE CHARGE

6. GPM PARTS

7. GPM INSTALLED

8. TEN VOLUME CHANGES AN HOUR

10. GPM THEORY

11. ISSUES Pressure Dependence Fluctuations Calibration Difficulties Using With Liquid Xenon

12. PRESSURE DEPENDENCE

13. WAVEFORM

14. O2 INJECTION GAS ONLY

15. LIQUID GAS PURITY

17. GPM AND XPM

18. SUMMARY SAES HOT ZIRCONIUM PURIFIER MAY BE GOOD ENOUGH FOR ~ 100KG. IF NOT THERE MAY BE AFTERBURNER SOLUTIONS THE GPM MAY BE GOOD ENOUGH FOR ~100 KG. IF NOT WE HAVE ANOTHER VERSION WITH MUCH HIGHER SENSITIVITY. THESE STUDIES APPLY TO ARGON THE GPM DOESN’T TELL US WHAT KIND OF IMPURITIES ARE PRESENT

19. THINGS WE DON’T KNOW Electric Field, Microphonics, Reflectivity, Non Linearity