1. Calorimeter R&D at SuperNEMO Calor08 - 28 May Matthew Kauer UCL London *unofficial

2. 28 May 08Calor082 Calorimeter R&D at SuperNEMO by Matthew Kauer 2  2 and 2  0 physics Why energy resolution is key! SuperNEMO status and goals Calorimeter R&D Solid scint. Liquid scint. Solid/Liquid Hybrid Solid bar scint. Summary Conclusions Outline

3. 28 May 08Calor083 Calorimeter R&D at SuperNEMO by Matthew Kauer 2  0 Beyond SM: Total lepton number violation Most sensitive way to establish Majorana/Dirac nature of neutrino Most sensitive way to measure absolute n mass in a lab environment (for Majorana n’s) Possible access to n mass hierarchy and Majorana CP-violation phases Link to matter-antimatter asymmetry (leptogenesis) Phase space Nuclear matrix element v e effective mass Half-life 2  2 allowed in Standard Model very rare, ~ G F 4 typical T 1/2 =10 18 -10 21 years Insert new physics here

4. 28 May 08Calor084 by Matthew Kauer Calorimeter R&D at SuperNEMO M mass (g)  efficiency k C.L. confidence level N Avogadro number t time (y) N Bkg background events (keV -1.g -1.y -1 )  E energy resolution (keV) > AA M. t N Bkg.  E (y). ln2 N k C.L.. Good Energy Resolution is a MUST! 12% FWHM 8% FWHM Even with ideal M, N bkg,   2 and 0 mix at low  E

5. 28 May 08Calor085 Calorimeter R&D at SuperNEMO by Matthew Kauer NEMO-3 Currently taking data Tracker + Calorimeter Tracker offers great background suppression via particle identification SuperNEMO based on proof of concept 2  event  + 3   +  + 

6. 28 May 08Calor086 Calorimeter R&D at SuperNEMO by Matthew Kauer SuperNEMO ~ 90 physicists, 12 countries currently on 3 year R&D phase (ends late ’09) 82 Se (and/or 150 Nd if enrichment possible) 100 - 200 kg ~ 30 %  10  Bq/kg 4% FWHM @ 3 MeV    ) > 10 26 y < 0.04 - 0.11 eV Isotope Isotope Mass M Efficiency  Internal Bkgs Energy Resolution Sensitivity R&D on: Isotope enrichment Drift cell tracker Software Calorimeter UCL London CENBG Bordeaux, LAL Orsay INR Kiev, ISMA Kharkov JINR Dubna Univ. Texas Austin

7. 28 May 08Calor087 Calorimeter R&D at SuperNEMO by Matthew Kauer We can do better than NEMO3 14% @ 1MeV FWHM Not optimal scint shape Polystyrene scint. 20-25% QE PMs 3 Main Points of Calorimeter R&D < 7% @ 1MeV FWHM (4x light) Absolute calibration < 1% PMT radio-purity (Bi214 < 0.05 Bq/kg) Calibration Conventional LASER / LED configurations are difficult for so many channels. (10k-20k) 1) 1-2 PE monitoring with pulsed LED or dark noise 2) Imbedded Alpha source

8. 28 May 08Calor088 Calorimeter R&D at SuperNEMO by Matthew Kauer Barium salt used to make glass is chemically same as Radium Ra226  Rn222 into the tracker volume  Bi214 (Q  ~ 3.3MeV) Quick Comment on Radio-purity Photonis is winning with their secret recipe.

9. 28 May 08Calor089 N ph /E e x  col x QE PMT = N pe Calorimeter R&D at SuperNEMO by Matthew Kauer PMT’s: Photonis (3,5,8,9,10in) / Hi-QE (3in) ETL (5,8,11in) / Hi-QE (10in) Ham. (3,8,10in) / Hi-QE (3,8in) Ham. Ultra-QE (3in) Limitations: Low Z scint. Materials to minimize backscattering at low energies Low density reflectors High radio-purity materials Good timing resolution (Scint. and PMT’s) Scintillators:  8in Solid PVT (Bicron, Eljen) thin scint. on Lightguide thick concave scint.  8in Liquid  8in Solid/Liquid Hybrid 2m Long Scint. Bars (Bicron, Eljen) Reflectors: Tyvec (diffusive) Teflon (diffusive) Al. Mylar (specular ~90%) Vikuiti ESR (specular ~98%) ReflecTech ESR (specular ~98%)

10. 28 May 08Calor0810 Calorimeter R&D at SuperNEMO by Matthew Kauer Significant improvements on PM QE!!

11. 28 May 08Calor0811 Calorimeter R&D at SuperNEMO by Matthew Kauer  E/E = 6.5% at 1 MeV  3.8% at 3 MeV Outstanding result with plastic scint 207 Bi conversion electron source Hamamatsu high-QE PMT BC404 scintillator wrapped in Teflon Bicron is best so far, vs. ISMA, JINR Still need to test Eljen ~ Bicron

12. 28 May 08Calor0812 Calorimeter R&D at SuperNEMO by Matthew Kauer PMTs not ideally hemispherical “Standard” optical gel (BC-630) not ideal due to its high viscosity Solid Scintillator UCL, London CENBG, Bordeaux Less channels = less electronics More cost efficient Better Radio-purity

13. 28 May 08Calor0813 Calorimeter R&D at SuperNEMO by Matthew Kauer Measurements Try to understand with simulations 8in ETL w/ Lightguide 5x5x2cm BC404 ~ 10% FWHM 1MeV 11in ETL w/ Lightguide 5x5x2cm BC404 ~ 12% FWHM 1MeV Optical Coupling Gel Lightguide Transmittance (Bulk absorption) Surface losses (polished vs. de-polished) Lightguide reflective material Cathode uniformity Magnetic effects 1)Switch to Cargille Laboratories “fused silica fluid” Type 06350 viscosity ~ water Index of refraction ~1.48 ~400nm 2) Polished the Lightguide Only gave 1-2% increase!

14. 28 May 08Calor0814 Calorimeter R&D at SuperNEMO by Matthew Kauer Simulations University of Texas, Austin CENGB, Bordeaux ISM, Kharkov Nominal GEANT4 Inputs Scint emission spectra ALL simulation inputs are experimentally measured and wavelength dependant!! POPOP Stokes’ Shifting

15. 28 May 08Calor0815 Calorimeter R&D at SuperNEMO by Matthew Kauer 8in Measured = 8.3% 11in Measured = 9.3% 8in ETL 9354KB – w/ Lightguide 990 PEs = 7.47% 930 PEs = 7.71% 11in ETL – w/ Lightguide Optimized Simulation Polished lightguide – wrapped in Al. Mylar small (50-100um) air gap between lightguide surface and reflector 5x5x2cm BC404 – wrapped in ESR Cathode uniformity? Magnetic effects? Lightguide properties?

16. 28 May 08Calor0816 Calorimeter R&D at SuperNEMO by Matthew Kauer Scint Dimensions (solid) FWHM @ 1 MeV PMT Size and Make 5 2 x 2 cm BC4046.5 %3in Ham-SBA 9 2 x 2 cm BC40810.1 %8in Ham-SBA w/ LG 14 2 x 2 cm BC4049.2 %8in ETL w/ LG 15 2 x 2 cm BC40810.3 %8in Ham-SBA w/ LG 20 (hex) x 2 cm BC40811.2 %8in Ham-SBA w/ LG ** 20 2 x 2 cm PST (cast)8.3 %8in Photonis XP1886 ** 20 2 x 10 cm PST (cast)9.3 %8in Photonis XP1886 Solid Scint. Results ** preliminary

17. 28 May 08Calor0817 Calorimeter R&D at SuperNEMO by Matthew Kauer Liquid Scintillator CENBG, Bordeaux INR, Kiev ISM, Kharkov Bubbling Ar through liquid scint. improves resolution ~ 1% ! BONUS No lightguide needed / deeper active volume / cheaper than plastic scint. better uniformity / better radio-purity recycle to fix aging problems BUT  engineering challenge Safety hazard, especially underground

18. 28 May 08Calor0818 Calorimeter R&D at SuperNEMO by Matthew Kauer Scint Dimensions (liquid) FWHM @ 976 keV PMT Size and Make  7.6 x 5 cm 7.6 %3in Photonis XP5312  7.6 x 10 cm 8.0 %3in Photonis XP5312  8.4 x 9.2 cm 7.3 %5in Photonis XP2412  20.3 x 20 cm 11.3 %8in Photonis XP1886 23 (hex) x 9.2 cm10.8 %5in ETL 9390 Liquid Scint. Results

19. 28 May 08Calor0819 Calorimeter R&D at SuperNEMO by Matthew Kauer 23 cm Solid + Liquid Scint. Hybrid 23cm (hex scint) on 23cm (hex liquid volume) = 15.1% FWHM 5cm (square scint) on 23cm (hex liquid volume) = 12.3% FWHM Motivation Passive window has to be thin and therefore is less mechanically robust

20. 28 May 08Calor0820 Calorimeter R&D at SuperNEMO by Matthew Kauer Motivation More compact design Drastically reduced # PMs Increased impact resolution (1-2 cm) Better background tagging Higher detection efficiency Decreased radio-impurities into tracker volume Long Scint. Bars UCL, London PMT's: 3” Hamamatsu SBA (~ 40% QE) 5” ETL 9390 (~ 28% QE) BC408 scintillator bar: 2m x 10cm x 1.25cm Wrapped in Mylar or ESR

21. 28 May 08Calor0821 Calorimeter R&D at SuperNEMO by Matthew Kauer BC404 – 2m x 10cm x 1.25cm ~ 12% FWHM 1MeV Measured Result

22. 28 May 08Calor0822 Calorimeter R&D at SuperNEMO by Matthew Kauer Solid 6.5% with small samples ~8% with large samples Liquid ~7% with small samples >10% with large samples Hybrid >12% with small samples >15% with large samples Bars ~12% Abandon Lightguide Cast scint. with concave end and couple directly to PMT looks very promising! - waiting on Eljen PVT samples Summary of R&D Can do better than this with PVT (6-7%) Suspect the effects of pile-up are degrading the resolution returned from the fit. Working on modifying the fit and testing against simulation to verify ~ 7% looks challenging at this point Still a big engineering and safety challenge

23. 28 May 08Calor0823 Calorimeter R&D at SuperNEMO by Matthew Kauer Conclusions Unprecedented resolution for low Z scintillator (6.5% FWHM 1MeV) We’ve exceeded our resolution requirement with small samples Technology is here to scale up: ~ 40% High-QE PMs ~ 98% specular reflectors > 10k photons / MeV scint. (low Z) Just need to find the right combination  1/2 (0  ) > 10 26 yr < 0.04 - 0.11 eV SuperNEMO will reach the projected sensitivity:

24. 28 May 08Calor0824 Calorimeter R&D at SuperNEMO by Matthew Kauer BONUS SLIDES

25. 28 May 08Calor0825 Calorimeter R&D at SuperNEMO by Matthew Kauer Simulated – 6% @ 1MeV FWHM 6.2% @ 1 MeV FWHM Verify the fit on simulated data Simulation in GEANT-3.2 includes full Bi 207 decay table E loss in air / Al filter backscattering event pile-up Fit does not yet count Backscatter Event pile-up

26. 28 May 08Calor0826 Calorimeter R&D at SuperNEMO by Matthew Kauer 2 Methods to Measure Resolution: 976 keV conversion electrons from Bi 207 source Sr 90 “Spectrometer” source, selecting 1Mev electrons 976 keV Conversion Electrons Gamma run filtering out CE’s Gamma+CE run Fit 976keV K-CE peak 1MeV Sr 90 Spectrometer Background run Electron run Fit 1MeV peak

27. 28 May 08Calor0827 Calorimeter R&D at SuperNEMO by Matthew Kauer Aluminised Mylar wrapper Scintillator block 1mm ESKA fibre S-type SMA connector Ocean Optics Spectrometer 350 – 1000 nm, resol. < 1 nm The fibre is glued into the block using BC600 optical cement. A hypodermic syringe minimised trapped air. Scintillator stimulated with pulsed Blue/UV LED (375 nm) Scintillator stimulated with pulsed N 2 laser (337 nm)

28. 28 May 08Calor0828 Calorimeter R&D at SuperNEMO by Matthew Kauer Measured Emission Spectra from BC404, BC408, BC412 ** also in the plans to set up an optical bench to test reflectivity to < 1% Reflectivities of Al. Mylar are a bit ambiguous Good to verify quoted ESR reflectivities Measured emission spectra is different from Bicron’s quoted spectra because they use a thin layer reflection test which doesn’t take bulk absorption into account.

29. 28 May 08Calor0829 Calorimeter R&D at SuperNEMO by Matthew Kauer Standard 93% Mylar Main result shown in RED 100 electrons per data point 10k = 10000 photons/MeV 12k = 10k scaled by 1.2 SBA-select QE Simulations

30. 28 May 08Calor0830 Calorimeter R&D at SuperNEMO by Matthew Kauer

31. 28 May 08Calor0831 Calorimeter R&D at SuperNEMO by Matthew Kauer Liquid Scint.FWHM @ 1 MeV LS-17.5% LS-1A8.2% LS-677.3% LS-1197.9% Teflon container  84  92 mm PMT XP2412

32. 28 May 08Calor0832 Calorimeter R&D at SuperNEMO by Matthew Kauer