SN trigger requirement changes and latency Pierre Lasorak & - PowerPoint PPT Presentation

SN trigger requirement changes and latency Pierre Lasorak & Simon Peeters 1

Outline • SN requirement changes in the TDR • SumADC problem • Future work Pierre Lasorak 2 13/09/2019

SN requirement change • The requirement for SN triggering efficiency was changed: • Old: > 90% efficiency for SNB within 100 kpc • New: > 95% efficiency for a SNB producing at least 60 interactions with neutrino energy > 10 MeV in 12 kT of active detector mass during the first 10 seconds of the burst. • Getting rid of the model dependance: • What is the distribution of probability for SN to happen within 100 kpc • How many neutrino events at 100 kpc Pierre Lasorak 3 13/09/2019

Sensitivity 60 events - real spectrum Caveats: • Sum ADC PDF integrated over 10 seconds: • Neutron background is at 40 Hz • Note that these plots are for the full MCC11 signal statistics, not with (could be as high as ~400 Hz) • Neutron spectrum is wrong the extra high-rate background-only samples (probably low impact) • Note the integral of these histograms is the number of cluster you • Radon quenching is wrong expect to see: (probably low impact) • No Beta-Alphas correlations • Background rate x 10 seconds (right) (Bismuth/Polonium) • Background rate x 10 seconds + 60 SN events x efficiency (left) PDF PDF 4 1.4 3.5 1.2 3 1 2.5 0.8 2 0.6 1.5 0.4 1 0.2 0.5 0 0 0 20 40 60 80 100 120 140 160 180 200 0 20 40 60 80 100 120 140 160 180 200 SADC SADC Signal+Background Background only Pierre Lasorak 4 13/09/2019

Likelihood distributions 60 events - real spectrum • Throw according to the 2 histograms from previous slide, and build a likelihood to compare with the background-only hypothesis. • Black line → 1 fake trigger per month • With 60 events, it’s very hard for the 2 plots on previous slide to look the same. • Triggering efficiency is excellent. Pierre Lasorak 5 13/09/2019

Sensitivity 60 events - 10 MeV neutrinos • PDF of the Background and Signal+Background. • Again the normalisation corresponds to the number of event you’d expect (with the efficiency at 10 MeV). • You need to be very “unlucky” to get no events after sum ADC = 100 and have L background ~ L signal PDF 3 PDF 1.4 2.5 1.2 2 1 0.8 1.5 0.6 1 0.4 0.5 0.2 0 0 0 20 40 60 80 100 120 140 160 180 200 0 20 40 60 80 100 120 140 160 180 200 Sum ADC SADC Signal+Background Background only (unchanged) Pierre Lasorak 6 13/09/2019

Likelihood distributions d e t a c e r p e D • As can be anticipated the likelihoods look very different and good separation can be achieved. Pierre Lasorak 7 13/09/2019

Comment PDF • The reason this works well is because the 4 distribution of sum ADC doesn’t change much. 3.5 • Red: ~10 MeV neutrinos (i.e. ~5MeV electrons) 3 2.5 • Blue: full spectrum 2 • This is weird as Josh was pointing out: 1.5 • Left: SumADC for single electrons at the cathode 1 0.5 • Right: SumADC for neutrino events 0 0 20 40 60 80 100 120 140 160 180 200 • The SumADC should be roughly the same! SADC Pierre Lasorak 8 13/09/2019

Investigating this discrepancy Gamma multiplicity Gamma multiplicity • Neutron gamma spectrum Count 500 400 • True captures on LAr: 300 Gamma individual energy Gamma individual energy • On average: 200 Count 800 700 • 3 gammas 100 600 • ~2 MeV 500 0 0 5 10 15 20 400 n gamma • Summing up to 300 Highest energy gamma Highest energy gamma ~6 MeV (or 8.8 200 160 Count MeV if the 100 capture was on a 140 0 different isotope 0 2 4 6 8 10 12 14 16 18 20 120 Energy [MeV] of Argon) Summed gamma energy Summed gamma energy 100 Count • Highest photon 1200 80 energy 3-4 MeV. 60 1000 40 800 20 600 0 0 2 4 6 8 10 12 14 16 18 20 400 Energy [MeV] 200 0 0 2 4 6 8 10 12 14 16 18 20 Energy [MeV] Pierre Lasorak 9 13/09/2019

Down the GEANT4 tree… • Compton scattering producing electrons: • At least a 3 MeV Compton electron on average for the neutron capture. Highest energy electron Highest energy electron Electron individual energy Electron individual energy Count Count 3000 500 2500 400 2000 300 1500 200 1000 100 500 0 0 0 2 4 6 8 10 12 14 16 18 20 0 2 4 6 8 10 12 14 16 18 20 Energy [MeV] Energy [MeV] Pierre Lasorak 10 13/09/2019

Comparing spectra Highest energy electron Highest energy electron 9.5 MeV < E < 10.5 MeV ν Count Counts 500 60000 400 50000 40000 300 30000 200 20000 100 10000 0 0 0 5 10 15 20 25 30 35 40 45 50 0 2 4 6 8 10 12 14 16 18 20 E MeV Energy [MeV] e neutron neutron • Reweighted the SumADC distribution from ELep neutron neutron Count to the highest energy Compton electron Entries 4.995448e+07 Entries 4.995448e+07 Entries 4.995448e+07 0.14 Mean Mean Mean 65.96 64.83 64.83 Std Dev Std Dev Std Dev 30.97 31.24 31.24 0.12 • Blue is what neutrons should look like with the same SumADC vs ELep dependance as SN 0.1 neutrino events. 0.08 0.06 • Red is what the neutrino events at 10 MeV are… 0.04 0.02 0 0 20 40 60 80 100 120 140 160 180 200 SumADC Pierre Lasorak 11 13/09/2019

Mini production • I redid a small production to get the SumADC distribution out of 10MeV neutrinos. • “True SumADC” of all the hits in the events that are backtracked to SN: • Left: mini production with 1 SN neutrino per event • Right: MCC11 (3 neutrinos per events) from the analyser • In the process of understanding where the bug is coming from. • Mapping of neutrino interaction → hits looks good • Of course the Likelihood distributions now don’t look so great. E <10MeV ν SADC SumADC SumADC Counts Count Entries 1000 Entries Entries 425 425 80 300 Mean 29.62 Mean Mean 59.95 59.95 Std Dev 12.96 Std Dev 47.82 Std Dev 47.82 70 250 60 200 50 40 150 30 100 20 50 10 0 0 0 20 40 60 80 100 120 140 160 180 200 0 20 40 60 80 100 120 140 160 180 200 SumADC SumADC Pierre Lasorak 12 13/09/2019

Future work • The requirement for the energy can be changed (up to 15 MeV). DRivera • David Rivera has shown at DAQ Physics performance meeting that you can find at the trigger level 5 MeV electrons with 30% efficiency by taking into account: • The wire span of the cluster • The time span of the cluster • Planning to include these variables in the trigger and hope to achieve the efficiency that was quoted: • Creating a “range variable”/size of the track DRivera variable (like David Rivera) • Using all the variables in the Likelihood (multi- dimensional PDFs) • A selection on these variables can achieve good efficiency for solar neutrinos as well!! Pierre Lasorak 13 13/09/2019

Conclusion • Reprocessing the 10 MeV sensitivities needed due to a problem in the production. • Investigations are on going to get to the bottom of this. • There are ways to improve the clustering and burst trigger that should make it meet the requirement. Pierre Lasorak 14 13/09/2019

ENu-ELep correlations MeV 45 e E 40 35 30 25 20 15 10 5 0 0 5 10 15 20 25 30 35 40 45 50 E MeV ν 50 MeV 70000 45 e E 40 60000 35 50000 30 40000 25 20 30000 15 20000 10 10000 5 0 0 0 5 10 15 20 25 30 35 40 45 50 E MeV ν Pierre Lasorak 15 13/09/2019