Spatial Variation of Light Yield with Reflector Foils Daniel Cookman 16 July 2018 DUNE Photon Detector Simulation Meeting Daniel Cookman
Methodology • Used the dune10kt_v1_1x2x6_withfoils_lib.root file obtained from Diego Garcia-Gamez (had to modify to reconcile a missing job) • Contains photon visibility data for both direct VUV & reflected visible light: proportion of photons generated in a given voxel that hit a given optical channel 2 16 July 2018 DUNE Photon Detector Simulation Meeting Daniel Cookman
Empty region: Voxels 1458000 – 1458499 inclusive Overlap region: Voxels 1459500 – 1459999 inclusive [Slide courtesy Diego Garcia-Gamez!] 3 16 July 2018 DUNE Photon Detector Simulation Meeting Daniel Cookman
Methodology • Built a “toy - MC” simulation to look at Light Yield as a function of drift-distance, x • Generated 10 MeV energy depositions randomly within a 3D region of the geometry: • x = [10, 330] cm • y = [-600,600] cm z = [300, 1000] cm • • This is the “middle - third” of the simulated geometry, typical for most of the DUNE detector. 4 16 July 2018 DUNE Photon Detector Simulation Meeting Daniel Cookman
Methodology ● From photon library, determined number of photons hitting the detectors by: 𝑂 𝛿 = 𝑄𝑝𝑗𝑡𝑡𝑝𝑜 𝑊𝑗𝑡𝑗𝑐𝑗𝑚𝑗𝑢𝑧 ⋅ 𝐹 ⋅ 24,000𝛿 𝑁𝑓𝑊 ⋅ 𝑅𝐹 • Assumed (unless specified otherwise) that the detectors have same sensitivity to VUV & visible light • Binned into x-voxel-planes; used mean & stdev for plots • Varied cathode reflector foil coverage, as a limited coverage might be needed to allow for neutralisation of +’ve ions 5 16 July 2018 DUNE Photon Detector Simulation Meeting Daniel Cookman
Light Guide Bars 6 16 July 2018 DUNE Photon Detector Simulation Meeting Daniel Cookman
≈ 2.2p.e/MeV ≈ 0.3 p.e/MeV 7 16 July 2018 DUNE Photon Detector Simulation Meeting Daniel Cookman
≈ 1.8p.e/MeV 8 16 July 2018 DUNE Photon Detector Simulation Meeting Daniel Cookman
≈ 1.6p.e/MeV (Within uncertainties for 80%) 6 16 July 2018 DUNE Photon Detector Simulation Meeting Daniel Cookman
ARAPUCAs (Estimates from same photon library) 10 16 July 2018 DUNE Photon Detector Simulation Meeting Daniel Cookman
ARAPUCA Transmission Possibilities • ARAPUCAs can be covered with a WLS or left uncovered (as in SBND) • For covered detectors, the extreme possibilities are that it is equally sensitive to visible light & VUV, or that it doesn’t let visible through at all. • Truth lies somewhere between! Planning tests with VUV spectrometer. No WLS WLS Visible VUV (direct) VUV (direct) Visible (Reflected) Visible (Reflected) ? 11 16 July 2018 DUNE Photon Detector Simulation Meeting Daniel Cookman
Option 1: WLS VUV (direct) Visible Visible (Reflected) 1) – Inclusive 12 16 July 2018 DUNE Photon Detector Simulation Meeting Daniel Cookman
1) – Inclusive 13 16 July 2018 DUNE Photon Detector Simulation Meeting Daniel Cookman
1) – Inclusive 14 16 July 2018 DUNE Photon Detector Simulation Meeting Daniel Cookman
1) – Inclusive 15 16 July 2018 DUNE Photon Detector Simulation Meeting Daniel Cookman
Option 2: WLS VUV (direct) Visible Visible (Reflected) 2) – Exclusive 16 16 July 2018 DUNE Photon Detector Simulation Meeting Daniel Cookman
2) – Exclusive 17 16 July 2018 DUNE Photon Detector Simulation Meeting Daniel Cookman
2) – Exclusive 18 16 July 2018 DUNE Photon Detector Simulation Meeting Daniel Cookman
Bonus: Plots if ARAPUCA sensitivity is up to 2.5% 19 16 July 2018 DUNE Photon Detector Simulation Meeting Daniel Cookman
1) – Inclusive 20 16 July 2018 DUNE Photon Detector Simulation Meeting Daniel Cookman
2) – Exclusive 21 16 July 2018 DUNE Photon Detector Simulation Meeting Daniel Cookman
Summary ● Looked at Light Yield response vs. distance when cathode reflector present for bars; notable improvement in LY at large 𝑦 (~7 × for 100% cathode) ● Estimated similar plots for ARAPUCAs with various parameters; can obtain roughly-uniform LY in either WLS scenario by having coverage at 30-40%, though total LY is decreased ● If ARAPUCA sensitivity is boosted to 2.5% LY passes enhanced technical requirement of 10 p.e./MeV even with conservative parameter estimates ● I have selected a few plots here, but have numerous more pre- generated if asked for! 22 16 July 2018 DUNE Photon Detector Simulation Meeting Daniel Cookman
Backup 16 July 2018 DUNE Photon Detector Simulation Meeting Daniel Cookman
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