1 / 9

Gain Studies

Gain Studies. Jason for the SB Tent Crew. Oct 10, 2006. HBD east Gain Curves. Reminder of “standard” gain test: pad C2 measured (~8kHz) for 20 min gain map, 56 pads (1 min/pad) again, pad C2, (8kHz), 20 min C2 curve fit to saturating exp used to correct gain map.

millieh
Download Presentation

Gain Studies

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Gain Studies Jason for the SB Tent Crew Oct 10, 2006

  2. HBD east Gain Curves • Reminder of “standard” gain test: • pad C2 measured (~8kHz) for 20 min • gain map, 56 pads (1 min/pad) • again, pad C2, (8kHz), 20 min • C2 curve fit to saturating exp • used to correct gain map. • also used as “quality” check. • Features: • gain rises to some plateau w/ time. • when source is away from pad: • gain increases • when source is returned: • gain drops • approaches original plateau.

  3. “long” Gain Curves • Stack 25 • Gain was measured while rate was varied. • called “long” test. • Test box filled with clean ArCo2, then closed off. • P/T = R*n/V = constant. • gain curve looked very similar 12 hours later 10Hz 500Hz 500Hz 4kHz 8kHz 4kHz 8kHz 8kHz 500Hz 8kHz voltage off, gas refreshed

  4. Gain Curves • Stack 26 • (nearly) identical set-up/test • curves have much larger tau’s • inconsistent time constants. • gain still looked funny after the long test 10Hz 8kHz 500Hz 8kHz 500Hz 4kHz 500Hz 8kHz 8kHz 8kHz 4kHz voltage off, gas refreshed voltage off, gas refreshed

  5. Gain Curves • Stack 26 • 12 hours later, performed similar test • only first half of test, 90 min intervals • similar odd results. • initial “standard” test curve looked normal 10Hz 8kHz 500Hz 4kHz 8kHz voltage off, gas refreshed

  6. Time Constants • Stack 25 • time constants: • rate independent • different for rising and falling curves • Temperature was held constant at 32C. • Stack 26 • time constants: • no clear, discernable pattern • Temperature was slowly rising: • Thurs 1pm, “standard” test @ 32C • Thurs 2:30pm, heat on, T=32C • Thurs 3pm began “long” test • Fri 8am, T=36 • Fri 10am, began 2nd “long” test. • Fri 2pm, T=40 • Fri 5pm, T=42 • However, during testing, box was sealed.

  7. Gain Curves • Stack 26 • The “normal” test shows a tau consistent with other stacks. • taken before heating! • It seems as though heating affects the measurements: • time constants and plateaus!! • We don’t flow ArCo2, box is sealed: • P/T = R*n/V = constant!! • Possibly, heat contributes to gas contamination. • A few degrees increase of ambient T drives “crap” off GEMs, etc • known from HBD west. • (although stainless steel box should be pretty clean.)

  8. Gain Plateaus • Stack 25 • gain plateau is rate dependant. • however, only <10% • Stack 26 • gain plateau could be rate dependant. • flat? or 30% effect?? • maybe more like 10%? points taken immediately after gas flush Consider gas contamination… 2nd “long” test Friday morning 1st “long” test Thursday afternoon

  9. Conclusions • All stacks inside HBD east look similar and reasonable • New “long” gain tests reveal: • rate dependant plateau • rate independent time constants • different rising and falling time constants. • Heating seems to have affected both: • time constants • and plateaus • Longer time constants may lead to larger rate dependence of time constants… • however, maybe not… • Data isn’t conclusive yet… • once HBD east ships, we plan to perform more tests!

More Related