A Magnetic Tracking Calorimeter for a Neutrino Factory ...dpnc.unige.ch/users/blondel/0509_cern_iss_nelson.pdf · A Magnetic Tracking Calorimeter for a Neutrino Factory - Ideas &

DoE Review June 26, 2000

NOνA

A Magnetic Tracking Calorimeter for a Neutrino Factory - Ideas & Issues

Jeff NelsonWilliam & Mary

Williamsburg, Virginia

1st Meeting, Detector Working Group International Neutrino Factory & Super-beam Scoping Study

CERN22, September 2005

NuFact ISS CERN 9/05J. Nelson

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Outline

• Preamble• Some history

> Studies of sampling trackers for super beams> Reminder: comments from my nufact05 talk

• Making a large device> Ideas from MINOS, NOvA & MINERvA> A concept I think we can build as a starting point

• Thoughts for moving forward


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What Should It be Able to Do?

• Goal: map the oscillations down to the 2nd dip > Down to 2 GeV neutrinos

• Want to get …> Good muon charge ID > Good hadronic calorimetry for neutrino energy

• Harder as Ehad goes down

• Can get …> Good electron counting (without charge ID)

• Is this useful?• What resolution is useful?

• Can we get do tau ID/counting like NOMAD?> How pure is useful?


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Starting Out

• How should we develop a iron tracking detector for the neutrino factory?

• My thoughts …> Start with things we know well from other detector

development projects> Take something we can build, see its performance

& optimize• Needs iteration with physics working group

> If substantial extrapolation from current devices is suggested by optimization, then we’d want to try a real device in a particle beam


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Other Good Starting Places

NuFact Workshops> S. Wojcicki (Nufact01)

• Review of many options – analytic calculations• No obvious reason why an iron/scintillator tracker not adequate

> A. Cervera (Nufact04)• Review of large magnetic detectors

FNAL Proton Driver Studies> Exploration of off-axis detectors in 2 GeV – 1cm steel & scintillator> e.g. hep-ph/0204208, hep-ex/0206025, hep-ex/0304017

NOvA> Electrons & muons with a 2 GeV neutrino beam> Both sampling version and totally active version> Sampling version (2004 version) & final proposal hep-ex/0503053> Prior work: P Border, et al, NIM A463 194-204, 2001

MINERvA> High resolution scintillator device for few GeV neutrinos> hep-ex/405002 and CDR (12/04)


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A MINOS Scintillator Plane

• Strips assembled into “modules”

• 8m diameter• 192 strips per plane


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FD Steel PlaneMake from 2m-wide pieces


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Steel Plate

• Bigger device will be composite like MINOS FD> Widest single sheet of steel in US is 3.9m

wide> ~15m longest length to cheaply ship (in

US)> Suggests a 4 element laminate like the

MINOS FD


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First MINOS FD beam event

A 13GeV stopping muon measured by range & curvature


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Defocused rock muon event

4 GeV stopping track (defocused)


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Near Detector Event

MINOS PreliminaryEtrack approx. 1.5 GeV

Low-energy track from fiducial region


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Additional Near Detector Events

MINOS PreliminaryEtrack approx. 3.1

GeV

Medium energy track from near peak in “pseudo-medium”beam


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Cost Scaling

• Want massive device• Do not break the budget• Can we get an upper limit on the cost?


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Making a Magnetic Field

• Full geometry FEA simulations including all gap structures

• Plot of |B| (T)

• Field is an average of slices through a FD plane

• Average field is roughly 1.3T

• Modest drop off in corners


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B-H Curve for MINOS Steel

0

5000

10000

15000

20000

050

0010

000

1500

020

000

2500

0

H (Amp/m)

B (G

auss

)

• How strong a field? • MINOS used 1006

low-carbon steel> Mass produced for

stamping auto panels> We can use reject

grade steel at discount

• Can get somewhat above 1.5T with a reasonable current> That is about the limit


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Making a Bigger Torus

• FEA by R. Wands (Fermilab) & J.K. Nelson > No inherent limitations in current> I = 40kA * (r/10m)> Recall MINOS

ND is 40kA• Perfectly feasible


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Readout Options

• RPC vs Solid Scintillator>Costs are indiscernible>[NOvA 11/03 proposal appendix & PAC

presentation from 11/03 (next slide)]• Solid vs Liquid

>Active components 33% cheaper for liquid


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50kt NOvA Sampling Detector

The sampling design had ~400m2 and 1000 samples

Not fully loaded costs – only to show relative scaling

Use absolute costs from NOvA Proposal (summary in a later slide)

Solid PMT

Solid APD

Liquid APD

Scintillator 22.3 27.3 14.2 optical fibers 12.0 12.0 12.0 Scintillator Assembly 25.7 21.4 13.5 Photodetector 7.5 1.7 1.7 Electronics (not DAQ) 15.3 8.4 8.4 Sum 82.8 70.8 49.8 ($M)


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MINOS has too much light(& works too hard to get it!)

Distance along the scintillator (m)

Num

ber o

f obs

erve

d ph

otoe

lect

rons

APDs vs PMTs• Cost dramatically

lower per channel• 8× quantum efficiency

of a M16/M64 PMTAPD relaxes the light

yield requirements > Allows longer cells> Allows smaller fibers


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NOvA Far Detector

• Liquid scintillator cells> 1984 planes of cells

• Cell walls> Extruded rigid PVC> 3 mm outer; 2 mm inner

• Readout > U-shaped 0.8 mm WLS fiber> Acts like a prefect mirror > APDs (80% QE)

0.8 mm looped fiber

15.7 m


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Full costs from NOvA TASD (3/05)

• NOvA instrumented area is huge> 30kt of instrumentation> 1984 planes of 246m2 -> 55k$/250m2

• For not to much cost can make a much more massive detector by adding Fe> Structure & iron (~M$/kt)

Installation

Shipping

Electronics and DAQ

Active detector

Far Detector

Installation

Shipping

Electronics and DAQ

Active detector

Far Detector

14

7

13

80

Total Cost M$

14

7

13

80

Total Cost M$


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MINERvA Optics (Pioneered by DØ Preshower)

Particle

• Significantly enhance position resolution for wider strips

• Could make the same cell geometry for liquid cells too


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A Strawman Concept for a NufactIron Tracker Detector

• 15m diameter polygon> 4 piece laminate> Can be thin if planes

interconnected• e.g. down to 1cm

> Idea from 1st NOVA Proposal

• 60kA-turn central coil> 0.5m x 0.5m> Average field of 1.5T> Extrapolation of MINOS

• Triangular liquid scintillator cells> Structure based on NOvA

using MINERvA-like shapes> 4cm x 6cm cells (starting

point)> 3mm thick PVC walls> Looped WLS fibers & APDs

• A sample would look like> 1 cm Fe> 0.7 cm PVC> 3.3 cm LS> 2/3rds Fe; ρ ≈ 2> Based on 175M$ for 90kt


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Summary

• Detector is feasible> Large area toroidal fields can by directly extrapolated from

MINOS design> Can now make an affordable large are scintillator readout

with NOvA APD technology> Enhanced position resolution with MINERvA-like triangles> Costs are all from 2004/2005

• Optimize sampling to get lower tracking threshold for charge ID> Would also give good electron counting

• Come up with parameterization of resolutions, efficiency/fake rate, & costs for optimization

Documents

A Magnetic Tracking Calorimeter for a Neutrino Factory ...dpnc.unige.ch/users/blondel/0509_cern_iss_nelson.pdf · A Magnetic Tracking Calorimeter for a Neutrino Factory - Ideas &