Neutrino detection Neutrino detection

Neutrino detection Neutrino detection

Laura Rossetto Laura Rossetto

Follow–up questions

Follow–up questions

• Homestake experiment  detection of solar ν

emitted by the decay of

B and

Be in the Sun via the reaction

Cl + ν



Ar + e

E

= 0.814 MeV

• GALLEX and SAGE experiments  detection of solar ν

via the reaction

Ga + ν



Ge + e

, E

= 0.233 MeV

• GALLEX  Gran Sasso laboratory, Italy, 1991–1997

30.3 tons of gallium as GaCl

in an aqueous HCl solution

• SAGE  Soviet–american Gallium Experiment, Baksan underground observatory, Caucasus

~ 50 tons of gallium

I – I – Explain how energy thresholds for neutrino Explain how energy thresholds for neutrino

detection depend on the absorbing medium detection depend on the absorbing medium

I – I – Explain how energy thresholds for neutrino Explain how energy thresholds for neutrino

detection depend on the absorbing medium detection depend on the absorbing medium

GALLEX, SAGE E

> 0.233 MeV

Homestake Homestake

E

> 0.814 MeV

• Because of the low energy threshold, the gallium experiments (GALLEX,

• At E > 10

eV  GZK neutrinos produced when cosmic ray protons

interact with the cosmic microwave background photons  rate 1 event km

yr

• ν

+ N  X + l  leptons may propagate for 20 – 30 km before being detected in the optical Cherenkov array

II –

II – Describe radio detection of neutrinos Describe radio detection of neutrinos

ν

+ N  X + l

hadronic shower  π

, π

, π

electromagnetic shower

electrons produce Cherenkov radio emission

radio spectrum

~ 100 MHz – 1 GHz

• RICE (Radio Ice Cherenkov Experiment)

 16 antennas installed in the AMANDA part of IceCube  peak sensitivity at 200 – 500 MHz

 upper limit on the flux of high relativistic magnetic monopoles  GZK neutrino detection limit set to E = 10

eV

• ANITA (Antarctic Impulsive Transient Antenna)

 balloon experiment which twice circled Antarctica at 35 – 37 km altitude  radio range 200 – 1200 MHz

 field of view = 1.5 · 10

km

 16 cosmic ray events of mean energy of 1.5 · 10

eV

originating from the interaction of

II –

II – Describe radio detection of neutrinos Describe radio detection of neutrinos

• GLUE (Goldstone Lunar Ultrahigh energy neutrino Experiment)  two radio telescopes separated by 22 km and linked by optic fiber  search for microwave pulses ≤ 10 ns from the lunar regolith

 such pulses would arise from subsurface electromagnetic cascades induced

by interactions of neutrinos in the lunar regolith, E

≥ 10

eV

II –

II – Describe radio detection of neutrinos Describe radio detection of neutrinos

• other experiments at the South Pole: ARIANNA, IceRay, AURA 22 km

Earth Moon

III –

III – During one phase of operations, salt was added During one phase of operations, salt was added

to the heavy water in SNO. Why? to the heavy water in SNO. Why?

• In June 2001 about two tonnes of NaCl were added to the heavy water volume to give a concentration of 0.002 g(NaCl)/g(D

O)

Neutral current reaction ν_x + D  p + n + ν_x

IV –

IV – Why is a Cherenkov ring a ring and not a disk ? Why is a Cherenkov ring a ring and not a disk ?

θ θ

x

x = β · c · t β = v / c

cos θ = 1 / β · n

in water c / n < v < c

0.75 · c ≤ v < c

n = 1.33

β ≥ 0.75

β = 0.75  γ = 1.5

E

= ( γ – 1) m

c

~ 53 MeV

m

c

= 105.6 MeV for µ

Bibliography Bibliography

Articles:

• J.N. Abdurashitov et al., Measurement of the solar neutrino capture rate with gallium metal, arXiv:0901.2200v3, 2009

• J. Kiko, The GALLEX solar neutrino experiment at the Gran Sasso Underground Laboratory, Astrophysics and Space Science 228, 107–112, 1995

• R. Davis, A review of the Homestake Solar Neutrino Experiment, Prog. Particle Nuclear Physics 32, 13–32, 1994

• D.P. Hogan et al., Relative magnetic monopoles flux constraints from RICE, arXiv:0806.2129v2

• S. Hoover et al., Observation of ultra-high -nergy cosmic rays with the ANITA balloon-borne radio interferometer,

arXiv:1005.0035v2, 2010

• P.W. Gorham et al., Experimental limit on the cosmic diffuse ultrahigh energy neutrino flux,