Neutron backgrounds in DUNE Aran Borkum 1 Overview Update on - - PowerPoint PPT Presentation

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Neutron backgrounds in DUNE Aran Borkum 1 Overview Update on - - PowerPoint PPT Presentation

Oct 02, 2022 236 likes •342 views

Neutron backgrounds in DUNE Aran Borkum 1 Overview Update on neutron capture rates in LAr Comparison with work by JBeacom The issue with the current background production model Thought on improvements to the background model

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SLIDE 1

Neutron backgrounds in DUNE

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Aran Borkum

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SLIDE 2

Aran Borkum 15/03/2019

Overview

  • Update on neutron capture rates in LAr
  • Comparison with work by JBeacom
  • The issue with the current background production model
  • Thought on improvements to the background model

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SLIDE 3

Aran Borkum 15/03/2019

Neutron capture rate

  • Generated a sample of supernova events with

radiological from MCC11


prodmarley_nue_spectrum_radiological_timedep_hudepohl_11.2M_3perevent_dune10kt_1x2x6_mcc11

  • Results:
  • Neutron capture rate: 46 ± 5 Hz
  • Result from JBeacom: 81 Hz (is this close enough?)
  • Neutron capture probability, : 1.21%
  • Is this good news; hard to say for sure
  • Question: are we sure we’re simulating neutrons properly
  • More importantly, are we simulating the geometry properly

3 neutrons captured neutrons produced

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SLIDE 4

Aran Borkum 15/03/2019

Rate calculation

  • With 1000 events, we got ~25

captures

  • Are we sure that the volume ratio

being used is giving us the right thing?

4 CPA CPA APA

Rate = 25 0.12 × 1000 × 2 × 0.002246s

Event generation time Scale factor From radio-gen #Events Volume ratio

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SLIDE 5

Aran Borkum 15/03/2019

Where the neutrons are coming from

  • Silver sides are where the

radiological neutrons are being sourced from

  • Issue: This does not lend

itself to trivial scalability from a 1x2x6 module to a 10kT module

  • Also, are we producing

too many active sides?

  • Is there a better setup for

the generator to use?

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SLIDE 6

Aran Borkum 15/03/2019

Approach without having to scale by volume

  • Build up the full 10kT out of segments
  • Model each 4 separately and then combine results

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SLIDE 7

Aran Borkum 15/03/2019

Segmented approach

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4 corner pieces 4 short side pieces 4 long side pieces 4 central pieces

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SLIDE 8

Aran Borkum 15/03/2019

The problem with the segmented approach

  • No accounting for neutrons that travel between segments
  • In current scheme these neutrons are considered to have

“escaped the detector”

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n

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SLIDE 9

Aran Borkum 15/03/2019

What we should do

  • Simulate the full geometry of a 10kT detector
  • Run the radiological generation
  • Run the GEANT4
  • With this we can then see if the scaling is leading us

down the wrong path

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