[Dsg-rich] RICH - reflectivity test station calibration stability results

Wed Jul 19 08:40:51 EDT 2017

Hi Tyler,
thank you
marco


Il 2017-07-19 14:36 Tyler Lemon ha scritto:
> Hello Marco,
> 
> My answers to your questions are below:
> 
> 1.) Did you ever turn off the lamp after each measurements?
> No, we did not turn off the lamp between measurements. We left it on
> all day because we did not turn the lamp off between measurements of
> the mirror.
> 
> 2.) Did you take note of the voltage supplied to the lamp?
> 
> The lamp has 10.65 V and 3.84 A. This was not changed throughout the
> day and is matches what settings we recorded on 6/29/2017.
> 
> 3.) Did you ever turn off the picoamperometer?
> No. As with the lamp, we left it on because we did not turn the
> picoamperometer off either between measurements of the mirror.
> 
> 4.) Did you redo the zeroing before the measurements?
> Yes. The LabVIEW program Peter Bonneau wrote for the test station's
> data acquisition zeros the meter at the start of every set of
> measurements.
> 
> We will start with step 2 of the plan today.
> 
> Best regards,
> 
> Tyler
> 
> -------------------------
> 
> FROM: "Mirazita Marco" <Marco.Mirazita at lnf.infn.it>
> TO: "Mindy Leffel" <leffel at jlab.org>
> CC: "dsg-rich" <dsg-rich at jlab.org>
> SENT: Wednesday, July 19, 2017 8:04:57 AM
> SUBJECT: Re: [Dsg-rich] RICH - reflectivity test station calibration
> stability results
> 
> Hi all,
> I did some plots of the data you took, it seems in fact that the
> system
> is very stable if nobody touches anything. From the plots, we can
> assume
> about +/-1% systematic uncertainty.
> There are a couple of things I forgot to mention in the measurement
> plan:
> - Did you ever turn off the lamp after each measurements? Did you take
> 
> note of the voltage supplied to the lamp?
> - Did you ever turn off the picoamperometer? Did you redo the zeroing
> before the measurements?
> I think we can now move to step 2 of the plan, that I copied below.
> Thank you to everybody,
> Marco
> 
> 2) Verification of the stability of the reflectivity measurements
> using
> the control mirror
> Repeat the cycle of calibration and reflectivity mesurerement few
> times
> during one day:
> - align the system for the calibration run
> - take calibration data
> - install the control mirror and align the system for reflectivity run
> - take a reflectivity run
> Once the mirror has been installed the first time, it should not be
> touched anymore for the next measurements, the alignment procedures
> should involve only the photodiode B. Again, please take note of the
> times.
> ==>> For each measurement, take also note of the lamp voltage supply.
> <<==
> 
> Il 2017-07-19 13:00 Mindy Leffel ha scritto:
>> I see highlighting:
>> 
>> On 7/18/2017 6:28 PM, Amrit Yegneswaran wrote:
>> 
>>> good work tyler.
>>> 
>>> w.r.t. line #8: (see below, i reformatted your e-mail), i don't see
>>> any highlighting in the excel sheet.
>>> don't understand where you come up with the <1% error you quote?
>>> 
>>> fix your significant figures, do let excel decide!
>>> 
>>> w.r.t. line #13: perhaps initially the calibration may be dependent
>>> (you didn't take a measurement as soon as you turned it on, did
>>> you?), but once the lamp has warmed up, the calibration doesn't
>>> change.
>>> 
>>> finally, calculate the confidence level of your measurement.
>>> 
>>> amrit
>>> 
>>> am
>>> 
>>> w.r.t. #13
>>> 
>>> -------------------------
>>> 
>>> FROM: "Tyler Lemon" <tlemon at jlab.org>
>>> TO: "dsg-rich" <dsg-rich at jlab.org>
>>> SENT: Tuesday, July 18, 2017 4:43:39 PM
>>> SUBJECT: [Dsg-rich] RICH - reflectivity test station calibration
>>> stability results
>>> 
>>> Hello Marco Mirazita,
>>> 
>>> * Attached in "_2017-07-18_calibration_stability_tests.xlsx_" are
>>> the results from today's calibration stability of the reflectivity
>>> test station.
>>> * In the Excel sheet, there is a table of all the raw data for the
>>> calibration runs.
>>> 
>>> * At the end of the data, there are statistics for the data.
>>> * For the stability test, we turned on the lamp source at 8:00AM
>>> to allow it to heat up.
>>> * We aligned the test station's optics for a calibration run and
>>> took data on every hour starting at 10:00AM until 4:00PM (total of
>>> seven calibration runs).
>>> 
>>> * After the initial alignment, the dark box was not opened and the
>>> position of the photodiodes was not changed.
>>> * The results support that the calibration measurements do not
>>> vary over the course of a few hours if the test set-up is not
>>> modified in any way.
>>> * The calibrations for each wavelength has a calculated error of
>>> less than 1%, with the exception of the 300nm wavelenth
> (highlighted
>>> in yellow).
>>> 
>>> * The 300nm-wavelength calibration results from 10:00AM are also
>>> highlighted in yellow. This measurement seems to be the source of
>>> the larger error for the 300nm wavelength calibration.
>>> * Also attached in "_all_calibrations.xlsx_" is data for all
>>> calibrations we used for all reflectivity tests, including the ones
>>> from today.
>>> * The data is arranged in the same way as the stability test
>>> results with statistics at the end.
>>> 
>>> * Using all calibration run data, the calculated error of the
>>> calibration is much higher (~10% to ~17%). This most likely is due
>>> to the realignment that takes place between calibrations and
> between
>>> the testing of mirrors.
>>> * In conclusion, the calibration does not seem to depend on the
>>> amount of time the lamp source is on.
>>> 
>>> * Using the data from all calibrations, the main source of error
>>> appears to be the realignment of test station optics.
>>> 
>>> Best regards,
>>> 
>>> Tyler
>>> 
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>> 
>> 
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