Beam Line Data Analysis of the PMT and Quartz Coupling Zak Arcara

Trigger Source – “The Notch” The initial trigger by this device, the notch, initializes the data capturing for the PMT 2 Notch Triggered The initial trigger by this device, “the notch”, initializes the data capturing for the PMT

PMT HV: 1200V Example of a typical two pulse curve detected by the PMT 3 Notch Triggered Example of a typical 2 pulse curve

Threshold 4 The Threshold is set at -0.4V to disregard background – eyeballed the best threshold The Threshold explains why there is a 2 pulse system In order for another pulse to be detected, the return needs to drop below the threshold value Offline Threshold in the Software that can be changed quickly Notch Triggered

PMT HV: 1200V Peak Number, Threshold of -0.4V 5 Two pulses dominate the frequency of peaks (85.8%) There are zero triggers 7% of the time Acceptance * efficiency = 93% Everything right of red line, or 0 triggers, is counted into (acceptance * efficiency) value

PMT HV: 1300V Peak Number, Threshold of -0.4V 6 4.5% of the time, there are zero triggers that are recorded Acceptance * efficiency = 95.5%

PMT HV: 1400V Peak Number, Threshold of -0.4V 7 Zero triggers occur 12.4% of the time when the Notch triggers Acceptance * Efficiency = 77.6 %

PMT HV: 1500V Peak Number, Threshold of -0.4V 8 There are never any zero triggers for this voltage Acceptance * Efficiency = 100%

Acceptance * Efficiency 9 VoltageAcceptance * Efficiency 1200V93% 1300V95.5% 1400V77.6% 1500V100% Acceptance * Efficiency is anytime there is any data capture; at least one pulse detected

PMT HV: 1200V, -0.4V Threshold 10 Interesting Double Peak Structure The two different groups of double peaks are not fully understood yet The time between peaks is the proton beam structure

PMT HV: 1200V Time Between Peaks 11 This histogram is an exact representation of the 37MHz beam structure The 37 MHz structure gives a 24 ns time between blasts

PMT HV: 1300V, -0.4V Threshold 12 Same double peak structure formed Both double peak structures occurred around the same time as 1200V The second peak decreased in frequency Threshold is the explanation

PMT HV: 1300V Time Between Peaks 13 This histogram is an exact representation of the 37MHz beam structure The 37 MHz structure gives a 24 ns time between blasts

PMT HV: 1400V, -0.4V Threshold 14 The Double Peak structure is vanishing Explained by Threshold value Time between peaks matches with the 37MHz structure

PMT HV: 1400V Time Between Peaks 15 There are under 10 data points that recorded a 3 pulse graph The time difference shows the majority around 24 ns where expected The other points are the difference between the 3 point curves

PMT HV: 1500V, -0.4V Threshold 16 Double Peak structure is even less evident Threshold value altered the amount of the second peak recording frequency

PMT HV: 1500V Time Between Peaks 17 The chart has the majority of the data points around 24 ns There is a cluster around 70 ns, which maybe explained by 3 pulse curve Increased the threshold and it gives graphs almost identical to the 1200V

Booster Structure 18 The proton beam structure looks like the figures above It has a distinct 1600 nsec time period between each proton burst That time in between should be no pulsing above a certain background amount The PMT and Quartz crystal coupling need to be able to detect the short time between each burst Selection Window, defined at center plane of the tracker

Afterpulsing 19 Notch Trigger Afterpulsing is an issue because it allows possibility of “fake” data Afterpulsing was tested with a Peak Counter algorithm – same as used for regular, non-delayed data points The 1 ms time window allows the determination to see if there is after pulsing occurring far down the time line PMT Triggered After Pulse 1.6 us in between pulses

1 ms Delay Data To understand the background, a 1 ms delay was integrated The threshold had to decrease in order to see any activity from the beam line From -0.4V to -0.15V Did the change of voltage by eye, new system is being implemented for later data This gives data above the majority of the background noise 20

1200V, 1 ms Delay, -0.15V Threshold 21 This is 1 ms after the Notch triggered This could be the single proton triggers

1300V, 1 ms Delay, -0.15V Threshold 22 Interesting to see multiple pulses after the delay window No double peak structures were seen at 1200V

1400V, 1 ms Delay, -0.15V Threshold 23 Has almost identical structure to 1300V, but there are more entries for this High Voltage

1500V, 1 ms Delay, -0.15V Threshold 24 A couple triple peaks detected for first time

Signal Graph at -1300V

Summary The PMT can detect the 37MHz structure consistently PMT double peak structure varies in time Afterpulsing doesn’t seem to be a real issue after 1 ms At -0.4V, lower the threshold and frequency increases There are visible electron quantum levels that can be used to set appropriate thresholds PMT looks effective at speeds that are needed for Mu2e 26