Increased Neutrino Yield with the new NOvA Target Design Simulation - PowerPoint PPT Presentation

Increased Neutrino Yield with the new NOvA Target Design Simulation Study Daisy Kalra Panjab University, India Fermi National Accelerator Laboratory, USA On behalf of NOvA Collaboration HPT R&D RoadMap Workshop-2017 Fermilab May 31, 2017 Daisy Kalra Fermilab/P.U. HPT R&D RoadMap Workshop-2017, Fermilab 1

NOvA (NuMI Off-Axis ν e Appearance) NOvA looks primarily for the ν e appearance and ν µ disappearance using two detectors: the Near Detector (ND) & the Far Detector (FD). Using ν e appearance and ν µ disappearance 
 Determine the ν mass hierarchy. 
 Measure 𝜄 13 . 
 Search for CP violation. 
 Determine the 𝜄 23 octant (muon-tau asymmetry in neutrino mixing). 
 Precise measurement of atmospheric parameters 𝜄 23 and 2 ⎢ Δ m atm ⎢ . Also… 
 Neutrino cross sections at the NOvA ND 
 Sterile neutrinos 
 Supernova neutrinos 
 other exotica 
 Daisy Kalra Fermilab/P.U. HPT R&D RoadMap Workshop-2017, Fermilab 2

The NuMI (Neutrinos at the Main Injector) Beam Line NOvA Far Detector NO A Simulation ν CC / 6E20 POT / kton / 0.1 GeV On-Axis FLUKA11 14.6 mrad Off-Axis (NO A) ν 15 10 NuMI Beamline 5 120 GeV proton beam from the Main Injector collides with µ ν a graphite target, resulting in the production of many 0 5 10 15 E [GeV] ν secondary (short-lived) particles (e.g pions and kaons). The NOvA off-axis position selects quasi mono energetic neutrino beam of 2 GeV where it gives the highest probability of These particles are focused by a set of two magnetic horns: oscillation. The Horn2 is 19.18m away from the Horn1. They afterwards decay to neutrinos in a decay pipe filled with He. At the end of the NuMI beam line, we get an almost pure ν µ beam. Daisy Kalra Fermilab/P.U. HPT R&D RoadMap Workshop-2017, Fermilab 3

Motivation NOvA Preliminary 20 NO A 6.05 10 POT-equiv. ν × 120 Best fit prediction 100 Events / 0.25 GeV NOvA FD observed few events with exposure of Unoscillated prediction Data 80 6.05 e20 POTs. 60 We need more events, more POTs. 40 20 0 0 1 2 3 4 5 Reconstructed neutrino energy (GeV) Daisy Kalra Fermilab/P.U. HPT R&D RoadMap Workshop-2017, Fermilab 4

Event yield for NOvA The Event yield for the NuMI off-axis NOvA neutrino experiment is : Upgraded to 700kW for NOvA Off-Axis Running time Detector mass Event Yield (N) ∝ (Beam Power)(time) ( ν per proton) * M( ε ) Detector efficiency We focus on the efficiency ( ν per proton ) of the NuMI Target and Horn system to produce useful neutrinos (in energy range 1-3 GeV) in the NOvA detector. Getting 10% more ν per proton means 10% more event yield as if the experiment had a detector of 10% larger mass or 10% more beam power (770kW) : Interesting! So, we investigate different ways to optimize the neutrino yield per proton on the target, hence the event yield (N) of the experiment. Daisy Kalra Fermilab/P.U. HPT R&D RoadMap Workshop-2017, Fermilab 5

NuMI Target & Horn system for NOvA The NOvA target consists of 48 graphite fins (+2 budal monitors) with a total target length of 122.5 cm. Downstream End Upstream End @ -20cm Horn1 @0m The NOvA Target Beam Horn2 @19.18m ME Horn2 Y-Z View of the target configuration Medium Energy Horn2 configuration (ME): The Horn2 is at Horn2 @10.00m 19.18m w.r.t the Horn1: s tandard configuration for NOvA. LE Horn2 configuration Low Energy Horn2 configuration (LE): The Horn2 is at 10.0m w.r.t the Horn1: used in past by MINOS On-Axis Experiment . Beam Daisy Kalra Fermilab/P.U. HPT R&D RoadMap Workshop-2017, Fermilab 6

Study of neutrino yield NOvA FHC ν µ Events 90 Longer targets & targets with gaps : observed few ν µ events. 80 Reduce the number of fins from the upstream part of the NOvA 70 target, making a shorter target : observed maximum ν µ yield with 60 36-fins target. 50 40 Flugg ND,FHC, ν Using half of the target (24 fins), neutrino flux is reduced by µ 30 Flugg FD,FHC, 10^6 ν µ just 5% at the FD as compared to the whole 48 fins target. g4numi ND ν µ 20 g4numi FD 10^6 ν µ 10 The number of protons surviving a 24 fins target ( ƛ ~1.25) is 0 10 20 30 40 50 Number of fins ~30% : WASTE of protons! Events are in 1-3 GeV Energy Range FLUGG & G4NuMI Simulations We have investigated if we can use these protons elsewhere to get the increased neutrino yield!! Idea is to extend the target inside the Horn1! Daisy Kalra Fermilab/P.U. HPT R&D RoadMap Workshop-2017, Fermilab 7

Various Targets In this study, various targets are simulated to see the effect on neutrino yield. 1. Standard NOvA target (63 mm high Fins) ➞ Real 2. MINOS tall fins target (18 mm high Fins, 
 120cm long, longer than the default MINOS target ~97cm ) ➞ Almost Real 3. MINOS short fins target (7.4 mm high Fins) ➞ Concept 4. Miniaturized NOvA target (9.5 mm high Fins) ➞ Concept 5. Minimal NOvA target (17 mm high Fins) ➞ Concept 6. Simple rod (7.4 mm high fins) ➞ Idealized Concept All targets are ~122cm long. Daisy Kalra Fermilab/P.U. HPT R&D RoadMap Workshop-2017, Fermilab 8

X-Y View (Beam View Of the Targets) All Targets are shown at the same scale Daisy Kalra Fermilab/P.U. HPT R&D RoadMap Workshop-2017, Fermilab 9

Y-Z View of the Targets NOvA NOvA NOvA Rod Miniaturized Minimal Standard All targets (~122cm) ending @40cm Std. NOvA Rod is the idealized concept @ -20cm s o t h e r e i s n o t a n y supporting structure, cooling tubes, Be window… z Details of the targets are in backup slides. y Daisy Kalra Fermilab/P.U. HPT R&D RoadMap Workshop-2017, Fermilab 10

Strategy Using FLUGG software • Simulate targets at target position -20 cm. • Simulate various targets at different positions to find the best possible target position. • Simulate targets at the best target position. Daisy Kalra Fermilab/P.U. HPT R&D RoadMap Workshop-2017, Fermilab 11

Simulation Results with different Targets (Targets Length ~122cm) Target Downstream end @ -20 cm 93.1 91.4 90.8 ν µ Event yield (Un-oscillated ν µ ) for FD in 1-3 GeV energy range 86.4 83.9 81.1 At -20cm, Standard NOvA target is the best target.. 
 (Rod is the ideal one…). Daisy Kalra Fermilab/P.U. HPT R&D RoadMap Workshop-2017, Fermilab 12

Choosing the best target position and configuration Simulate Minos short target of different lengths at various target positions. FD Events (1-3 GeV energy range) ν µ Magenta: 24 fins ~64cm long POTs/kton 48 fins target (~122cm 100 Blue: 36 fins long) configuration ~93cm long 90 20 @40cm position seems CC+NC events/6X10 Red: 48 fins 80 to be the best one. ~122 cm long 70 Black: 60 fins ~147cm long 60 µ 50 ν -20 -10 0 10 20 30 40 50 60 Target Position [cm] We checked this further using different targets and they all showed maximum yield with target positioned @+40cm (inside the Horn1). Daisy Kalra Fermilab/P.U. HPT R&D RoadMap Workshop-2017, Fermilab 13

Simulation Results with different Targets (Targets Length ~122cm) Target Downstream end @ +40cm Std. NOvA is always @-20cm 107.2 ν µ Event yield (Un-oscillated ν µ ) for FD in 1-3 GeV energy range 101.8 100.1 98.2 : E T O N 95.6 We are back to 48 fins target 91.4 configuration and are not wasting protons. At +40cm, NOvA Minimal target proves to be the best target configuration. Event gain with Minimal NOvA is 11.4% as compare to the Std. NOvA. Daisy Kalra Fermilab/P.U. HPT R&D RoadMap Workshop-2017, Fermilab 14

Minimal NOvA Target simulation Minimal NOvA target @+40 cm inside the Horn1 Beryllium fins Graphite fins ME Horn2 Configuration (Horn2 @19.18m) 
 ME Horn2 Configuration (Horn2 @19.18m) 
 *FHC & RHC 
 *FHC & RHC 
 LE Horn2 Configuration (Horn2 @10.0m) 
 LE Horn2 Configuration (Horn2 @10.0m) 
 *FHC & RHC *FHC & RHC Compare these results with the Std. NOvA target *FHC: Forward Horn Current, 200kA (focussing 𝜌 + ) *RHC: Reverse Horn Current, -200kA (focussing 𝜌 - ) Daisy Kalra Fermilab/P.U. HPT R&D RoadMap Workshop-2017, Fermilab 15

Results (Std. NOvA & graphite fins Minimal NOvA target: FHC) (FHC) NOvA Simulation 12 Std. NOvA(ME:C): FD ME Horn2 configuration 
 FD Events are in 1-3 GeV POT 10 Minimal NOvA(ME:C): FD Energy range (Horn2 @19.18m) 20 CC+NC/6x10 8 11.4 % gain with 6 106.0 Minimal NOvA Target 4 µ 101.8 ν 2 LE 0 ME 0 2 4 6 8 10 Energy[GeV] NOvA Simulation 91.4 LE Horn2 configuration 
 12 (Horn2 @10.0m) Std. NOvA(ME:C): FD 10 POT Minimal NOvA(LE:C): FD 8 20 15.9 % gain with CC+NC/6x10 6 Red: Standard NOvA Minimal NOvA Target 4 Blue: Graphite (C) Fins µ ν 2 Minimal NOvA Target % is w.r.t Std.NOvA 0 0 2 4 6 8 10 Energy[GeV] Daisy Kalra Fermilab/P.U. HPT R&D RoadMap Workshop-2017, Fermilab 16

On-axis behavior is very different from Off-axis behavior NOvA Simulation 30 NOvA (ME) OnAxis FD NOvA (ME) OffAxis FD 25 POT Minimal NOvA:C (ME) OnAxis FD Minimal NOvA:C (ME) OffAxis FD 20 20 CC+NC/6x10 15 10 µ ν 5 0 0 2 4 6 8 10 12 14 16 18 20 Energy[GeV] Off-axis spectra is fairly constant (no shift in the peak), just the number of events changes. On-axis spectra for Standard NOvA shifts towards higher energy as compare to the on-axis spectra for Minimal NOvA because we have removed the fins from upstream part in Minimal NOvA which leads to higher energies. Daisy Kalra Fermilab/P.U. HPT R&D RoadMap Workshop-2017, Fermilab 17