1. Meson Test Cherenkov Measurements Michael Backfish Dec 2015

2. Reason for Studies The sequencer uses the equation below to set F:MT4W for the desired Magnetic field F:MT4WH = 57.92*Momentum (This equation was found using the relationship found from the save files) F:MT4WH = 58.098 * Momentum + 16.453 (This equation was from Geelhoed’s Spreadsheet) F:MT4WH = 57.937 * Momentum + 16.453 (This equation was from “Notes on Mtest Energy Scale and hall Probes” Coleman Oct 3, 2014 A new method for Zeroing hall probes was used for getting rid of the DC offset next we check the slope

3. FTBF Equipment for Verification Lead glass Calorimetry (lead glass is currently not large enough to contain a full electron shower……another idea is brewing) Minerva’s New Time of Flight System (Before Christmas we ran a few days worth of studies….a hardware problem in one of the TDCs needs resolved though it seems we have good data. Analysis continues) Cherenkov Detector (appearance of light is determined by pressure, particle type and momentum…..This talk will elaborate)

4. There are 2 Cherenkov Detectors Upstream has only 1 PMT light is seen at 0 mRad The Downstream has an Inner and Outer PMT Light is seen at 0 mRad on inner and 7 mRad on outer Image from http://ftbf.fnal.gov/cerenkov-detectors/

5. FTBF Documentation https://web.fnal.gov/experiment/FTBF/Cerenkov%20Information/Forms/AllItems.aspx

6. Using Python to Efficiently Analyze the Cherenkov Data http://dbweb5.fnal.gov:8080/ECL/test_beam/E/index

7. Fit(x) is the integral of a Gaussian Fitting the pressure scan data with this equations provides an analytic method for determining at what pressure the light appears (the parameter mu). The width of the derivative of this function (sigma) is impacted by both the momentum spread and beam divergence. Fit(x) = A*(sqrt(3.14/2.0))*sigma*erf( (x - mu) / (sqrt(2.0)*sigma) ) +const Derivative(fit(x))=Gaussian(x) = A*e^(-(x-mean)**2/(2.*sigma**2)) For this analysis (mu-2*sigma) is used as the point where light first appears (mu-2*sigma)

8. These plots show (mu-2*sigma) or the pressure where Cherenkov light is first seen for both positive and negative particle momentums Positive particles are Red and Negative are Green The theoretical value shown in blue and comes from the equation below This equation is derived on the next page

9. These 2 equations found at https://web.fnal.gov/experiment/FTBF/Cerenkov%20Information/cc_mtest.pdf From Weidemann “Particle Accelerator Physics” pg 14 Insert Beta there to get this