John

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/05

Tracking in KamLAND?Tracking in KamLAND?

CAN WE USE OPTICS TO IMAGE TRACKS AND WHAT WOULD IT GET US?

John LearnedUniversity of Hawaii

At KamLAND Collaboration meeting

Gatlinburg, Tennessee, 4/05

Byron Dieterle has done optical studies, thought about problem,and been a great help in developing this idea.

John

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Basic Idea: a Scintillator “Bubble Chamber”

• If we can design the optics with enough

light collection

adequate depth of field• and not much rescattering of light

• Reconstruct tracks and precise vertices.Reconstruct tracks and precise vertices.

John

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/05

KamLAND Physics ApplicationsKamLAND Physics Applications

• Accelerator neutrinos: superior recognition of electron events and rejection of πos.

• PDK: excellent K mode resolution.• SN: resolution of direction.• Reactors: better e+-n direction resolution.• Solar Nu’s: Some directionality.• Muons: very accurate track reconstruction,

increased rejection of backgrounds.• Nuclearites, Q-Balls, etc. : not presently

recorded in SK or KL (?)… opportunity.

John

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/05

Sensitivity & ImplicationsSensitivity & Implications

• Aperture: assume 8 x 17”PMTs (~1.2m pupil)• Similar QE, efficiency• Assume 8 wide field cameras• ~2.4 PE/cm track in each camera• 40 MeV track yields ~200 pixels• 1 MeV yields ~10 pixels• Aim for resolution ~4 mm• Implies camera with ~4M pixels => commerically available CCDs

John

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/05

Starting point: ASHRA Imaging Particle Detector

Pixel Cost Reduction by Pixel Cost Reduction by O(10O(1044))

Key TechnologyKey Technology

9M-pix. CMOS Sensor Covering 50deg-FoV9M-pix. CMOS Sensor Covering 50deg-FoV

PMT-array PMT-array CameraCamera

CMOS Sensor CMOS Sensor ChipChip

4,500x3,000 (14M) pix.

Commercial CMOS Camera

Ideas and leader: Makoto Sasaki, ICRR

John

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/05

Design of Ashra Optics

F/0.74

Details can be found in

M.Sasaki et al, NIM A492 (2002) 49

• Schmidt-type optics• Spherical segment mirror• Spherical focal surface• 3-element corrector lens

Advantage: a large degree of freedom for optimization of lens surface shape to cancel1. spherical aberration2. chromatic aberration.

pupil : 1m

Modified Baker-Nunn

John

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/05

Performance of Ashra Optics

wavelength

inci

den

t an

gle

4 largest peaks in air-fluorescence spectra

incidentangle

Spot diagram after optimization

John

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/05

performance of Ashra Optics

Spot size = 0.0167°(1 arcmin)

using ZEMAX by A.Okumura

incidentangle

from weighted sum of several wavelength

Ashra Optics has capability to achieve 1 arcmin resolution

within the whole FOV of ± 25°

John

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/05

3mφmirror3mφmirror1 deg/Pix1 deg/Pix

3mφmirror3mφmirror1 deg/Pix1 deg/Pix

3mφmirror3mφmirror1 deg/Pix1 deg/Pix

3mφmirror3mφmirror1 arcmin/Pix1 arcmin/Pix

3mφmirror3mφmirror1 deg/Pix1 deg/Pix

3mφmirror3mφmirror1 deg/Pix1 deg/Pix

3mφmirror3mφmirror1 deg/Pix1 deg/Pix

3mφmirror3mφmirror1 arcmin/Pix1 arcmin/Pix

What this does for ASHRAWhat this does for ASHRA EAS air fluorescence angular resolution EAS air fluorescence angular resolution

1arcmin1arcmin

ASHRAASHRAAngular ResolutionAngular Resolution

• < 1 arcmin at E > 1018.5eV

• 0.3 arcmin at E ~ 1020eV

John

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/05

R&D R&D 状況ー状況ー 2/32/3 モデル望遠鏡モデル望遠鏡

• I.I.

• 補正レンズ• ミラー

2/3 scale prototype

John

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/05

Image Intensifier Pipeline

• 46 Lp/mm => σ~7μm ~ CCD pix. size46 Lp/mm => σ~7μm ~ CCD pix. size• magnification factor = 1magnification factor = 1

• 4.6 Lp/mm =>σ~70μm @ input surface4.6 Lp/mm =>σ~70μm @ input surface• de-magnification factor de-magnification factor ～ ～ 1010

photocathode

photon

gate pulse >5ns

phosphor screen

Proximity focused I.I.

Focal sphere => => CMOS Sensor

Minimum modification of

focal surface

commercial ASHRA I.I.

Lens I.I.

Incident photons

John

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/05

Large Diameter Image Intensifier

Existing

16” (400mm)φphotocathode

photocathode resolution 3.4 line pair/mm

(largest and finest resolution in world) 　

24“ under development (but maybe 20” limit)

John

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/05

Prototype Image PipelineNot needed for KL application

John

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/05

Add Cameras to KamLAND?Add Cameras to KamLAND?

Would require drainingthe detector: stopper?

Present idea based onASHRA size camera.

Maybe smaller camera which replaces 1 PMTand requires no cutting steel, but then need More cameras.

John

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/05

Beam4 CalculationsBeam4 Calculations

• 9 surfaces sas16.opt

Diameter dia index Zvx Curv A4 A6 A8 shape Mir/Lens --------------:--------:----------:---------:----------------:------------------:---------------:--------------:---------:------------:• 2.400 : : : -.22 : -0.0 : 0. : 0. : 0. : 1. : lens : L1• 2.400 : : 1.414 : -.195 : -0.0013394: 0.07467649 : 0.0011911: 0. : 1. : lens : L1• 2.000 : : : -.05 : 0.0130258:-0.06570667 :-0.0011347:-0.000453 : 1. : lens : L2• 2.000 : : 1.414 : 0.0 : -0.0 : 0. : 0. : 0. : : iris : L2

2.000 : : 1.414 : .05 : -0.0130258: 0.06570667 : 0.0011347: 0.000453 : 1. : lens : L2 2.400 : : : .195 : 0.0013394:-0.07467649 :-0.0011911: 0. : 1. : lens : L3

• 2.400 : : 1.414 : .22 : -0.0 : 0. : 0. : 0. : 1. : lens : L3• 2.400 : : :1.50 :-.667 : : : : 1. : mirror : M• 0.400 : : :0.694 :-1.441 : : : : 1. : other : D

Simple setup, easy to get started Start with Sasaki design

Can do simple optimization

Example of card file below:

Calculations by Byron Dieterle

John

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Byron has done some Beam4 Sims for KL-like GeometryByron has done some Beam4 Sims for KL-like Geometry

Conclude: resolutions of order of mm are achieved at IIT.Conclude: resolutions of order of mm are achieved at IIT.

John

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/05

Image of a Track

Use tomographic methods to reconstructout of focus image.

John

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/05

ConclusionConclusion

• Idea to add imaging to KamLAND needs study…. optics, design practicality, sensitivity, reconstruction.

• How about small camera in place of a neck 6” PMT? Could do muon tracks, nuclearites?

• Biggest question: does it buy us something really important?

• Should we pursue it? Anyone interested?