1. Made by Stanislav Hristov

2. Why Solar Neutrino?  Examining solar neutrino allows us to find what the physics of the Sun’s core is.  The Sun produces some 10 electro-neutrinos and calculations show that some 10 must pass every square meter on Earth’s surface. 38 14

3. Early Solar Neutrino Experiments and Theories.  In the 1950’s Ray Davis and John Bahcall were the first to think about the solar neutrino and detecting it. Bahcall made calculations about how many neutrinos the sun produces and Davis was trying to experimentally prove that theory.

4. Ray Davis’ Experiment  Ray Davis built an electron- neutrino detector 1500 m underground in the 1960s. The experiment took place in the Homestake Gold Mine in Lead, South Dakota. It was a huge 100, 000 gallons tank full of perchloroethylene (C ₂ Cl ₄ ). Theory showed that he will detect around 10 argon atoms every week, but he used to find only 3 argon atoms every week.

5. Kamiokande  Masaroshi Koshiba in 1983 designed an experiment in Japan, that was going to examine the rare proton decay. It was a tank 16.0 m (52.5 ft) in height and 15.6 m (51.2 ft) in width, containing 3,000 tons of pure water and about 1,000 photomultiplier tubes.

6. Super-Kamiokande  Super-Kamiokande is really big, 41.4 m tall and 39.3 m across, filled with 50 000 tons of ultra-pure water, surrounded by 11 000 photo multiplier tubes. The Super-Kamiokande Collaboration announced the first evidence of neutrino oscillation in 1998.

7. Mistake in the Standard Model!!!

8. The Sudbury Neutrino Observatory  The SNO (Sudbury Neutrino Observatory) located in Canada, built 2 km underground in the Vale Inco's Creighton Mine in Sudbury, Ontario, Canada and is the deepest experiment, of this kind. When it was built in Nov 1999 its center was the place with lowest amount of radiation in the Solar System.  Its heart is an acrylic sphere 6 meters in radius, containing 1000 tones of heavy water almost 10,000 photon detectors.

9.  For 19 months just 2000 out of 10 billion trillion neutrinos reacted with the heavy water. In June 2001 they officially announce their results about the flux of neutrinos the sun produces, taking all three types of neutrino in account. These results proved that both John Bahcall and Ray Davis are right, the Sun emits as much neutrino as John predicted but only around a third of them are electro-neutrinos when they come to us.

10.  References: R.A. Freedman, W.J. Kaufmann, Universe, 8 th edition, (Freeman) (2007), pp 413-414 http://en.wikipedia.org/wiki/Solar_neutrino_p roblem http://en.wikipedia.org/wiki/Solar_neutrino_p roblem http://en.wikipedia.org/wiki/Super- Kamiokande http://en.wikipedia.org/wiki/Super- Kamiokande "Nova" The Ghost Particle, Episode 12, Season 33, KPBS, 2006.