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

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

• John Learned
• University 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.
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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.

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KamLAND Physics Applications

• Accelerator neutrinos superior recognition of
  electron events and rejection of pos.
• PDK excellent K mode resolution.
• SN resolution of direction.
• Reactors better e-n direction resolution.
• Solar Nus Some directionality.
• Muons very accurate track reconstruction,
  increased rejection of backgrounds.
• Nuclearites, Q-Balls, etc. not presently
  recorded in SK or KL (?) opportunity.

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Sensitivity Implications

• Aperture assume 8 x 17PMTs (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
• gt commerically available CCDs

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Starting point ASHRA Imaging Particle Detector
Ideas and leader Makoto Sasaki, ICRR
Key Technology 9M-pix. CMOS Sensor Covering
50deg-FoV
Pixel Cost Reduction by O(104)
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Design of Ashra Optics
Modified Baker-Nunn

• 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 cancel
• spherical aberration
• chromatic aberration.

F/0.74
pupil 1m
Details can be found in M.Sasaki et al, NIM A492
(2002) 49
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Performance of Ashra Optics
Spot diagram after optimization
wavelength
4 largest peaks in air-fluorescence spectra
incident angle
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performance of Ashra Optics
Ashra Optics has capability to achieve 1 arcmin
resolution within the whole FOV of 25
Spot size 0.0167(1 arcmin)
from weighted sum of several wavelength
using ZEMAX by A.Okumura
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What this does for ASHRA EAS air fluorescence
angular resolution
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RD ???2/3??????

• I.I.
• ?????
• ???

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Image Intensifier Pipeline
Focal sphere gt
gt CMOS Sensor

• 46 Lp/mm gt s7µm CCD pix. size
• magnification factor 1

• 4.6 Lp/mm gts70µm _at_ input surface
• de-magnification factor 10

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Large Diameter Image Intensifier
Existing 16 (400mm)fphotocathode

• photocathode resolution 3.4 line pair/mm
• (largest and finest resolution in world)
• 24 under development (but maybe 20 limit)

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Prototype Image Pipeline
Not needed for KL application
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Add Cameras to KamLAND?
Would require draining the detector stopper?
Present idea based on ASHRA size camera. Maybe
smaller camera which replaces 1 PMT and requires
no cutting steel, but then need More cameras.
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Beam4 Calculations
Simple setup, easy to get started Start with
Sasaki design Can do simple optimization Example
of card file below

• 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

Calculations by Byron Dieterle
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Byron has done some Beam4 Sims for KL-like
Geometry
Conclude resolutions of order of mm are achieved
at IIT.
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Image of a Track
Use tomographic methods to reconstruct out of
focus image.
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Conclusion

• 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?