DUNE ND Hall Study Mike Wilking @ Stony Brook Luke Pickering and - - PowerPoint PPT Presentation

DUNE ND Hall Study

Mike Wilking @ Stony Brook
 Luke Pickering and Dan Douglas @ Michigan State

• Working conceptual layout for the hall over the past year was 55

ft “long” (beam-direction) x 140/120 ft (= 42.7/36.6 m) “wide” (off-axis direction)

• This is the +50% option that was agreed upon by the ND

group in March, 2017 (although 90° rotated relative to the initial proposal)

• Original DUNE-PRISM goal was to make measurements up to

~33 m off-axis

• But this must include non-fiducial LAr & cryostat width, etc.
• May also need additional width near on-axis position for

magnet infrastructure

• Language in ND Report Recommendation:


• Note: “experimental floor area of 35 m…”


rather than “LAr FV reach of 35 m…”

ND Hall Size Requirements

R6) The experimental floor area must be at least 35 m × 17 m and the hook height must be at least 13 m, measured from the floor. Option B: Existing + 50%

140 ft 120 ft 55 ft

+$5M

beam

DUNE-PRISM 0.5 GeV

30 m 33 m

How Far Off-Axis?

• Further off-axis = lower reach in neutrino energy
• 500 MeV flux peaks at 26 m off-axis
• To understand events at 500 MeV, we need access

lower energies at further off-axis positions

• One method to determine the lowest needed energy is to

construct a Gaussian energy spectrum at 500 MeV (10% width) using linear combinations of off-axis fluxes

• This is not the only method one could employ (see next

slides), but it should provide some useful information

• The 500 MeV Gaussian fit clearly begins to degrade

when fluxes between 30 m & 33 m are excluded

5 10 15 20 25 30 35 40 Off axis position (m) 0.5 1 1.5 2 (GeV)

ν Peak,

E

µ

ν FHC

µ

ν RHC

(GeV) 0.5 1 1.5 (GeV)

ν

E 10 20

12 −

10 × (A.U.)

ν

Φ

12 −

10 (A.U.) (GeV) 0.5 1 1.5 (GeV)

ν

E 10 20

12 −

10 × (A.U.)

ν

Φ

12 −

10 (A.U.) 0.5 1 1.5 (GeV)

ν

E 10 20

12 −

10 × (A.U.)

ν

Φ

0.5 1 1.5 (GeV)

ν

E 10 20

12 −

10 × (A.U.)

ν

Φ

per POT)

• 2

cm

• 1

(GeV

ν

Φ 10 20 30

12 −

10 ×

2

eV

• 3

10 × = 2.6

32 2

m Δ ) = 0.5,

23

θ (

2

sin Fluxes up to 40m Fit region

(GeV)

ν

E 1 2 3 4 5 6

FD (unosc.) ND - FD (osc.)

0.5 − 0.5

Oscillated Flux Fits

• We can also use linear combinations of
• ff-axis fluxes to construct an oscillated

flux seen at the far detector for any currently allowed set of oscillation parameters

• Again, this is not the definitive metric,

but it does show how well such a fit can resolve the bump below the 2nd

• scillation maximum (which peaks as

low as ~500 MeV, depending on Δm322)

• The following studies probe the 9 points

in Δm322, θ23 space shown in the top figure

• Vary off-axis range used in fits
• The next few pages show many such fits

Fluxes Up to 40 m Off-Axis

• Can even somewhat resolve the peak below the 3rd oscillation maximum

for all values of Δm322

Fluxes Up to 35 m Off-Axis

• Can still generally resolve bump below 2nd oscillation maximum for all values of

Δm322, although some fluctuations are seen in the ratio to the unoscillated flux

Fluxes Up to 33 m Off-Axis

• Can still generally resolve bump below 2nd oscillation maximum for all values of

Δm322, although some fluctuations are seen in the ratio to the unoscillated flux

Fluxes Up to 30 m Off-Axis

• Poor fits around the 2nd oscillation maximum for low Δm322 region; ability

to constrain systematics in this region may be compromised

Fluxes Up to 28 m Off-Axis

• Very poor fits around the 2nd oscillation maximum for low Δm322; limiting

to 28 m can cause harm to 2nd oscillation maximum physics

LBNF Proposal

• In response, new LBNF design provided exactly 17 m x 35 m of floor space
• Note this is 1.6 m *less* in the off-axis direction than the conceptual

design we have been working with

• Goal of this talk is to explore how much space may actually be needed

depending on off-axis reach and required space opposite the primary off- axis direction (including a 2 x 5 m space for LAr utilities)

LAr Configuration

A-A

A A

Assembly_ND 1 1

3/14/2018 rohaenni

A3 4.2 m 3.5 m 6.4 m 6.4 m 0.7 m 0.7 m 4.0 m 5.0 m

Extra 50 cm volume required on either side

• f the active ArgonCube modules

LAr Detector Parameters

• Cryostat walls are 0.7m thick
• 50 cm of inactive LAr is required on either side of the ArgonCube

modules (inside the cryostat) for cryo-coolers, pumps, and instrumentation (previous slide)

• The pictures that follow show a detector that is 8 m wide, rather

than 4 m wide (for illustration purposes), but the conclusions do not depend strongly on the detector width

• The FV considered in this study has a 1.5 m of active area on

either side of the detector in which event vertices are not allowed

• This is to make the efficiency due to hadronic shower

containment uniform across the fiducial volume

• This value has not yet been optimized, but 1.5 m is almost

certainly sufficient (may be able to shrink this somewhat)

• We are also including a 2 x 5 m platform next to the LAr detector

for cryogenics and electronics systems that can move with the detector

Veto region Vertex selection region

μ

• Hadr. shw.

x y

Vertex desert

Best Efficiency Worse Efficiency Worse Efficiency

Position 1 Position 3 Position 2 Position 4 … Efficiency

Layout Diagrams

• The following are keynote “engineering drawings” for the ND hall

with LAr detector & utilities platform

• The numbers are rounded, but the figures should be accurate to

±1 pixel (15 pixels per meter)

• The following modifications to the LBNF proposal are considered in

various combinations

• Shortening the distance between the beam center & the wall in

the shorter off-axis direction

• Lengthening the distance between the beam center & the wall in

the longer off-axis direction (to achieve measurements up to 30 m & 33 m off-axis)

ND Hall Layout (LBNF Hall Proposal)

42.6 m (15 px/m) 17 m (15 px/m)

Egress Primary Shaft Support Space Secondary Shaft

• n-axis

beam

FV FV

1 m x 1 m

23.7 m

• ff-axis

7.6 m
 (25 ft) 3.7 m
 (12 ft) 35.0 m
 (115 ft) max off-axis beam

ND Hall Layout (LBNF Hall Proposal)

42.6 m (15 px/m) 17 m (15 px/m)

Egress Primary Shaft Support Space Secondary Shaft

• n-axis

beam

FV FV

1 m x 1 m

23.7 m

• ff-axis

7.6 m
 (25 ft) 3.7 m
 (12 ft) 35.0 m
 (115 ft) max off-axis beam

LAr Utils (2x6.4)

w/ LAr Utility Platform

ND Hall Layout (LBNF Hall Proposal)

42.6 m (15 px/m) 17 m (15 px/m)

Egress Primary Shaft Support Space Secondary Shaft

• n-axis

beam

FV FV

1 m x 1 m

25.7 m

• ff-axis

5.7 m
 (18.6 ft) 3.7 m
 (12 ft) 35.0 m
 (115 ft) max off-axis beam

LAr Utils (2x6.4)

w/ On-Axis Beam Shift

ND Hall Layout (+4.4m Hall)

47 m (15 px/m) 17 m (15 px/m)

Egress Primary Shaft Support Space Secondary Shaft

• n-axis

beam

FV FV

1 m x 1 m

30 m

• ff-axis

5.7 m
 (18.6 ft) 3.7 m
 (12 ft) 39.4 m
 (129 ft) max off-axis beam

LAr Utils (2x6.4)

w/ On-Axis Beam Shift

ND Hall Layout (+7.4m Hall)

50 m (15 px/m)

Egress Primary Shaft Support Space Secondary Shaft

• n-axis

beam

FV FV

1 m x 1 m

33 m

• ff-axis

5.7 m
 (18.6 ft) 3.7 m
 (12 ft) 42.4 m
 (139 ft) max off-axis beam

LAr Utils (2x6.4)

w/ On-Axis Beam Shift

ND Hall Layout (+9.3m Hall)

51.9 m (15 px/m)

Egress Primary Shaft Support Space Secondary Shaft

• n-axis

beam

FV FV

1 m x 1 m

33 m

• ff-axis

7.6 m
 (25 ft) 3.7 m
 (12 ft) 44.3 m
 (145 ft) max off-axis beam

LAr Utils (2x6.4) LAr Utils (2x6.4)

Layout Study Summary

• The longest option considered was +9.3 m relative to LBNF proposal,

and +7.7 m relative to previous LBNF conceptual drawing (i.e. our working assumption over the past year).
 Notation: (+9.3/+7.7)

• Preserves 25 ft space to the left of the beam, and provides

measurements up to 33 m off-axis

• Shortening to (+7.4/+5.8) is the minimum to allow measurements up to

33 m off-axis, as long as the short off-axis dimension can be shrunk to 5.7 m (18.6 ft)

• Further shortening to (+4.4/+2.8) further limits the off-axis measurement

range to 30 m, which begins limit the ideal off-axis range

• Although not addressed here, are we confident 17 m along the beam

direction will be sufficient?