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Some updates on water and other items…

Some updates on water and other items…. Stony Brook HBD Crew…. Assumptions:. The water evolves from the interior. Many proofs of this…it is a certainty. The gas evolution rate is STRONGLY dependent upon temperature. This is why we heat…to drive off the water.

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Some updates on water and other items…

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  1. Some updates on waterand other items… Stony Brook HBD Crew…

  2. Assumptions: • The water evolves from the interior. • Many proofs of this…it is a certainty. • The gas evolution rate is STRONGLY dependent upon temperature. • This is why we heat…to drive off the water. • While heating strongly we flowed vigorously (off scale…likely > 6 l/min). • We have taken “breaks” from high temp and high flow to provide baseline points.

  3. Assumptions II: • If the gas/gas-system has a baseline water content this should be an additive constant to the total • In the above equation…w if the water content at any moment, w0 is that start rate, and g0 is the baseline of the gas/gas-system. • We assume that w0 is a constant if measurements have same flow and temperature. • We have made two careful measurements 9 heating-days apart at 3 l/min flow and T=24 C

  4. What is the baseline water? • We measured the baseline of the gas system is ~ 5.1 ppm at 1.0 l/min. • Also measured 5 ppm at 3 l/min!! • We can bracket the truth by using 0-6ppm as the baseline contribution w/o the HBD. • Using these assumptions, we can solve the equations for the cleaning of the HBD and extrapolate into the future how long it takes to solve the problem with present techniques.

  5. The two accurate measures. • Two data conditions: • 3 l/min • 24 C (accelerator off) • Overnight to plateau. • We’ll do 3 cases: g0=0, g0=5.1, g0=6 • t(10 ppm) is time when CHAMBER ALONE is 10 ppm

  6. What if the flow is reduced??? • We’re using today to get some more baseline measurements at lower flow. • We’ll again calculate chamber alone. • We make a simple model that assumes that the contribution of the HBD itself is constant rate:

  7. Flow DOES NOT scale as expected! • Reducing flow from 3 l/min to 1.5 l/min increases water concentration from 16.5 ppm to 23 ppm. • Would have predicted: • We have not discovered the source of this discrepancy on our calculations… • We looked for differences in the gas (different flow rate through purifier?) and found none. • Direction of discrepancy in the good direction.

  8. “Staged” turn on of the heat… • With 1.5 l/min flow (23 ppm) we turned on ONLY the bottom row of preamps without cooling flow... • Note with detector on its side, this is 6 preamp boards. • Water content rises to 38 ppm… • Additionally turned on side heaters. • At first water rises REALLY fast (headed over 50) so heaters turned down to 33 C. • Water content stable at 48 ppm. • Water rise at same DT would have been much higher due to side heaters. • Both heat sources are still quite effective in driving water…

  9. What if the running temp is increased? • Turning on the preamps is our minimal heat input to the chamber. • The pre-amp heat pushes water up. • The pre-amp cooling takes water down. • Equilibrium T is orientation-dependent. • VERY HARD TO ESTIMATE FULL EFFECTS!!! • My bottom line belief is that we need to schedule 1-2 months of heating in the hall prior to the run to ensure success. • We have the time, if we can expedite: • Turn on of electronics & electronics cooling. • Turn on of thermofoil heaters.

  10. Heater placement/Window supports: • Six heaters: • 2 North, 2 South, 2 mid • 7 Window Supports • Thick middle one. • 3 thin to each side. • Cheese-head window screws • Given “no-go” with taller screws. • Cheese heads flush with frame. • GO!!! Last thing a Au nucleus sees before death

  11. Cooling System: • Electronics Cooling System installed. • Thin (0.010”) mylar straws. • Lucite hold downs. • Measured P=2.5” water, F=5 cfm (perfect)

  12. Transportation • Designed and built transport frame. • Rich Hutter & Matt Durham built the frame on Saturday. • Two-“L” design: • Top “finds” detector (not other way around) • VERY VERY rigid. • Snakes into west with detector uprighton backupright gets west of all rails. • Front L removed (maybe one piece, probably many) • Detector lifts onto rails, slides east to beampipe. • We will install the detector into frame today. • Frame & gas cart strapped onto a palette to allow simple on/off of truck. • Delivery to hall at ~9:30 AM (we cannot pick up truck on Labor Day!!!)

  13. All Pairs Combinatorial Pairs Signal Pairs HV >100x e+ e- Relativistic Heavy Ion Group • PHENIX Experiment at RHIC has finished its 6th run! • Time for Upgrades!! • g*e+e- provides direct radiation from plasma phase • Huge combinatorial background mostly due toγ+Xe+e-+X & π0g+e+e- (small angle pairs). • New detector vetoes small angle pairs to reduce background: • Direction tagging Cherenkov detector reduces background by a factor of 10-30 X. • Beyond present State of the Art… • Triple-Stacked Gas Electron Multipliers (GEM) made photosensitive by evaporated CsI coating. photon charged ionization photoelectron CsI GEM GEM GEM Cherenkov light forms “blobs” on an image plane (rBLOB~3.36cm) Readout

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