LArSoft and Low Energy Physics Jason D. Stock Juergen Reichenbacher - - PowerPoint PPT Presentation

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LArSoft and Low Energy Physics

Jason D. Stock Juergen Reichenbacher April 26, 2019

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2 Jason Stock | DUNE & SDSMT

Alphas and Protons as Simulated in LArSoft (Low Energy Ion Physics Issues)

Simulated alphas are making less charge than simulated protons of equal kinetic energy. Fewer simulated alphas are observed than simulated gammas of the same kintetic energy.

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3 Jason Stock | DUNE & SDSMT

• ------- EEEE ------- G4Exception-START -------- EEEE -------

*** G4Exception : had005 issued by : G4HadronElasticProcess::PostStepDoIt In /scratch/workspace/nu-release-build/v2_22_02/s67- e17/prof/build/geant4/v4_10_3_p03c/source/geant4.10.03.p03/source/processes/hadronic/management/ src/G4EnergyRangeManager.cc, line 129: ===> GetHadronicInteraction: No Model found Target element argon Z= 18 A= 40 Unrecoverable error in the method ChooseHadronicInteraction of hadElastic TrackID= 22 ParentID= 1 neutron Ekin(GeV)= 0.0254441; direction= (0.947898,0.0114053,0.31837) Position(mm)= (-1351.77,-2953.69,2028.05); material LAr PhysicalVolume <volTPCActiveInner_PV> No HadronicInteractionfound out *** Fatal Exception *** core dump ***

• ------- EEEE -------- G4Exception-END --------- EEEE -------

Low Energy Hadron Physics Issues

Thanks to Maria Manrique

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4 Jason Stock | DUNE & SDSMT

Physics Lists

(New Physics List)

Standard Physics List

• Em
• FastOptical
• SynchrotronAndGN
• Ion
• Hadron
• Decay
• HadronElastic
• Stopping
• NeutronTrackingCut

SN/LE Physics List

• LowEnergyEm
• FastOptical
• SynchrotronAndGN
• Ion (IonHP)
• NeutronHP (HadronHP)
• Decay
• HadronElastic
• Stopping

Thanks to Steve Gardiner (FNAL) for helping to impliment IonHP and HadronHP so quickly.

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5 Jason Stock | DUNE & SDSMT

Charge From Tested 5MeV RadioGen particles

Simulated 5MeV Alphas produce almost no charge!

5MeV Proton signal provides a clear baseline by which to gauge minimum expected values for Alphas

5MeV Heavy Protons (FourProton) with 4 times the proton mass to approximate alphas

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6 Jason Stock | DUNE & SDSMT

Light From Tested 5MeV RadioGen particles

5MeV Proton signal provides a clear baseline by which to gauge minimum expected values for Alphas

Simulated 5MeV Alphas produce almost no Light! 5MeV Heavy Protons (FourProton) with 4 times the proton mass to approximate alphas

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7 Jason Stock | DUNE & SDSMT

FourProton as a Substitute for Alphas

Ar39/Kr85 Peak

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A Look at Alternative Rn Rquirements (Using FourProton as a stand in for Alpha)

Large background signals can cause issues for SN triggers and the overall data rate. Ar39/Kr85 Peak

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9 Jason Stock | DUNE & SDSMT

Reduction in the high PE signals is important for optical triggering

A Look at Alternative Rn Rquirements (Using FourProton as a stand in for Alpha)

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10 Jason Stock | DUNE & SDSMT

Radon?

• Radon vs the Ar39 Background
• Rn must remain

subdominant to the Ar39 Background

• Radon as a false trigger for SN
• Rn must not cause an

undue number of false SN triggers

• Radon and its impact on the

data rate.

• Rn must not saturate the

readout

• Complications of a tighter

requirement.

• Quality control on Ar-39

suply.

• Emanation from detector

materials

• Diffusion from the FD

cavern into the detector.

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11 Jason Stock | DUNE & SDSMT

Summary/Discussion

• All low energy ions are currently

misshandled in LArSoft/dunetpc.

• Workarounds can be found to

avoid using the Ion physics.

• Appropriate Low Energy physics

factories have been generated and are being tested right now.

• The impact of radon on low

energy triggers could be much larger than previously estimated.

• Having started with a very

generous Radon requirement leaves room for a more stringent requirement.

• In all cases, the signal

from Radon and its daughters are likely to produce much brighter signals that we have previously believed.

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Backup

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13 Jason Stock | DUNE & SDSMT