Optical Track Imaging in KamLAND: Enhancing Track Reconstruction and Vertex Localization

1. Tracking in KamLAND?CAN WE USE OPTICS TO IMAGE TRACKS AND WHAT WOULD IT GET US? John Learned at Gatlinburg 4/05 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.

2. 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. John Learned at Gatlinburg 4/05

3. KamLAND 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 Learned at Gatlinburg 4/05

4. Sensitivity & 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 Learned at Gatlinburg 4/05

5. 4,500x3,000 (14M) pix. Commercial CMOS Camera PMT-array Camera CMOS Sensor Chip Starting point: ASHRA Imaging Particle Detector Ideas and leader: Makoto Sasaki, ICRR Key Technology 9M-pix. CMOS Sensor Covering 50deg-FoV John Learned at Gatlinburg 4/05 Pixel Cost Reduction by O(104)

6. Design of Ashra Optics Modified Baker-Nunn • Schmidt-type optics • Spherical segment mirror • Spherical focal surface • 3-element corrector lens John Learned at Gatlinburg 4/05 • Advantage: a large degree of freedom for optimization of lens surface shape to cancel • spherical aberration • chromatic aberration. pupil : 1m F/0.74 Details can be found in M.Sasaki et al, NIM A492 (2002) 49

7. incident angle Performance of Ashra Optics Spot diagram after optimization wavelength 4 largest peaks in air-fluorescence spectra John Learned at Gatlinburg 4/05 incident angle

8. incident angle 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) John Learned at Gatlinburg 4/05 from weighted sum of several wavelength using ZEMAX by A.Okumura

9. 3mφmirror 1 deg/Pix 3mφmirror 1 deg/Pix 3mφmirror 1 deg/Pix 3mφmirror 1 deg/Pix 3mφmirror 1 arcmin/Pix ASHRA 3mφmirror 1 arcmin/Pix Angular Resolution 1arcmin • < 1 arcmin at E > 1018.5eV • 0.3 arcmin at E ~ 1020eV What this does for ASHRA EAS air fluorescence angular resolution John Learned at Gatlinburg 4/05

10. 2/3 scale prototype R&D 状況ー2/3モデル望遠鏡 • I.I. • 補正レンズ • ミラー John Learned at Gatlinburg 4/05

11. Proximity focused I.I. Lens I.I. photocathode Incident photons photon phosphor screen gate pulse >5ns commercial ASHRA I.I. Minimum modification of focal surface Focal sphere => => CMOS Sensor Image Intensifier Pipeline John Learned at Gatlinburg 4/05 • 4.6 Lp/mm =>σ~70μm @ input surface • de-magnification factor ～ 10 • 46 Lp/mm => σ~7μm ~ CCD pix. size • magnification factor = 1

12. Large Diameter Image Intensifier Existing 16” (400mm)φphotocathode John Learned at Gatlinburg 4/05 • photocathode resolution 3.4 line pair/mm (largest and finest resolution in world) • 24“ under development (but maybe 20” limit)

13. Prototype Image Pipeline Not needed for KL application John Learned at Gatlinburg 4/05

14. 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. John Learned at Gatlinburg 4/05

15. 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 John Learned at Gatlinburg 4/05 Calculations by Byron Dieterle

16. Byron has done some Beam4 Sims for KL-like Geometry John Learned at Gatlinburg 4/05 Conclude: resolutions of order of mm are achieved at IIT.

17. Image of a Track John Learned at Gatlinburg 4/05 Use tomographic methods to reconstruct out of focus image.

18. 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? John Learned at Gatlinburg 4/05