Student Lecture on Neutrino Detectors

1. Student Lecture onNeutrino Detectors • Basics : Neutrino Source & Interactions • Survey of Detection Techniques • Projects Experimentalists Theorist Henry T. Wong / 王子敬 Academia Sinica / 中央研究院 @ THU / 清華大學 November 2002

2. Nobel Prize in Physics (2002)50% for n astrophys. : Ray. Davis Jr. (U. Penn) : “Classic” Chlorine Expt. Masatoshi Koshiba小柴昌俊(U. Tokyo) : Kamiokande & SuperK Citations leave room for future prizes on n physics !!! • 50% to Riccardo Giacconi, in X-Ray Astronomy

3. Neutrino History • 1914: continuous b-spectra (Chadwick) • 1930: postulation of neutrinos (Pauli) • 1934: theory of b-decay (Fermi) calculation of s(np) (Bethe,Peierls) • 1956: observartion reactor ne(Reines,Cowan) • 1957: measurement of n helicity (Goldhaber) • 1962: discovery of accelerator nm(BNL) • 1968: observation of solar neutrinos (Davis) • 1974: discovery of weak neutral currents (CERN) • 1987: observation of supernova SN1987a n’s (IMB,Kamiokande) • 1989: three families of light neutrinos (CERN) • 1998: evidence of atmospheric neutrino oscillation (Super-Kam., …) • 2000: observation of nt(Fermilab) • 2001: evidence solar neutrino oscillation (SNO+SK+GALLEX ……)

4. Neutrino Sources Observed window • n‘s everywhere: 300 per c.c. • from sun, supernovae, cosmic rays, reactors, accelerators, astrophysical sources, & relic Big Bang …

5. Neutrino Physicist :

6. Cross Sections Strong Electro-magnetic • Challenges of Neutrino Experiments : “How to Beat the Small Cross-Section?” i.e.By building Massive Detectors  while keeping cost/background Low ! Weak l(H2O)  250 light years ! BUT ….. En~ 1015 eV, L~Earth’s diameter

7. Neutrino Detection : Summary • ※ 0.1-1 keV Neutrinos: • R&D:Cryogenic techniques ※ keV-MeV Neutrinos: • Proven: Radiochemical Techniques (solar neutrinos with Cl, Ga) • R&D : World efforts to develop counter/real time+energy methods • TEXONO on Reactor Neutrinos: Crystal Scintillator, Solid-State Device • ※ MeV-GeV Neutrinos: • R&D:Water Cherenkov Detector, Liquid Scintillator ※ GeV-TeV Neutrinos: • Proven: multi “high energy physics” detector systems ※ Astrophysical UHE Neutrinos: • Projects: Water/Ice Cherenov, Radio/Sound Waves, Cosmic-Ray Showers ..

8. Radio-chemical Experiments – extracting 30 atoms from 30 tons (1029 atoms) of target materials. e.g. GALLEX: ne+71Ga71Ge, detected by EC X-rays

9. Favorite Technique for Massive Detector:Cherenkov Radiation Permits one Sensor to see Area of Λ2atten E. Kearns, BU

10. Super-Kamionkande ※ Water Cerenkov detector: 5k tons, viewed by 11,000+=50 cm PMTs in 1000 m underground site in central Japan ※ Physics: solar n, atmospheric n , long baseline accelerator n, proton decays .. ※ Accidents (PMTs imploded) Nov 01, 50% PMT data again end of 02 !!!

12. SK >5 MeV e-ring from ne+e scattering The Sun IS Burning !!

13. SK sub-GeV events from atmospheric n interactions m-ring from nmN e-ring from neN NC events with p02g

14. Sudbury Neutrino Observatory (SNO) ※ Heavy Water Cerenkov detector: 1k ton, shielded by 7k ton of water viewed by 9456 PMTs located 2000 m underground in Canada. ※ Physics: Solar n …

15. Actual measurements : only detect e- (a burst of light) : deconvolute the channels

16. (also Cl, Ga, diff. E) (also SK) ( 5s effect )

17. “Reines’ Reaction” for ne Detection :ne+pe++n • detect e+ then delayed n-capture • modern version : liquid scintillator (proton target) Discovery of Neutrinos , Reines 1956

18. KamLAND • Long Baseline Reactor n (sensitive to 20% of world’s reactors !) • ave. flight path of 160 km • 1 kton liquid scintillator in old Kamiokande site • probe “LMA” for solar n • first results “any time” (only 5 years from approved !!!!)

19. Accelerator n (1-10 GeV) Experiments : typical high energy physics techniques -  tracking m for Q/p,  calorimetry for em/had. Showers CC: nm+Nm-+X(shower) NC: nm+N nm +X(shower)

20. CHORUS NOMAD

21. Historic Bubble Chamber Neutrino Interaction Events nm+Nm-+X(shower) nm+e-nm+e- nm e- nm m-

22. Modern “Bubble Chamber” : Liquid Argon Time Project Chamber

23. DirectObservation of ntwith Nuclear Emulsion nN Interaction @ Emulsion Events from DONUT@FermiLab nt Field of View : 100 mmX120 mm

24. Optical CherenkovNeutrino Telescope Projects Gaols: detect astrophys. n at 1012-1015 eV ANTARES La-Seyne-sur-Mer, France BAIKAL Russia NEMO Catania, Italy DUMAND Hawaii (cancelled 1995) NESTOR Pylos, Greece AMANDA, South Pole, Antarctica

25. IceCube – km3n Telescope ※ To detect high energy (1012-1015 eV) n’s South Pole AMANDA IceCube

26. IceCube 1015 eV ntN event (sim.) “Double Bang Event” AMANDA “upward-going” m event τ Decay length O(100 m) at 1015 eV ντ

27. Radio Chenrenkov Detectors : for > 1015 eV neutrinos; target- Moon, Antartic Ice, Salt mine ……

28. En > 1015eV : using surface of Earth as target

29. En > 1019 eV: Detection of Cherenkov/florescence light from space

30. Summary & Outlook • Neutrinos are important but strange objects history of n physics full of surprises ! • Strong evidenceS of massive n’s & finite mixings Physics Beyond the Standard Model ! • More experiments & projects coming up EVEN MORE EXCITEMENT ! • TEXONO is also a (modest) part of it

31. How Science Makes Progresses ……….