I want thank

Aldo Covello for the 11 Spring Seminars

on Nuclear Physics in nice areas of the Sorrento Peninsula and the Islands.

I was participating in 7 of them.

At places like: Sorrento, Ischia, Capri, Amalfi, Ravello, Paestum

Thanks go also to Angela Gargano and coorganizers for

the organisation of the 11th. Meeting.

Search for the Cosmic Neutrino Background

Amand Faessler, Ischia 15. May 2014

With thanks to: Rastislav Hodak, Sergey Kovalenko, Fedor Simkovic;Publication: arXiv: 1304.5632 [nucl-th]

11. Dec. 2013.

1) Cosmic Microwave Background Radiation

2) Cosmic Neutrino Background

3) Cosmic Gravitational Wave Background

1) Decoupling of the photons from matter about 380 000 years after the Big Bang, when the electrons are captured by the protons and He4 nuclei and the universe gets neutral. Photons move freely.

Planck Satellite Temperature FluctuationsComic Microwave Background (Release March 21. 2013)

Fingerprint of the Gravitational Waves of the Inflationary Expansion

of the Big Bang in the Cosmic Background Radiation.

On 18. March 2014 the BICEP2 Collaboration published in the arXiv:

1403.3985v2 [astro-ph.CO]

Gravitational Waves are Quadrupole Oscillations of Space not in Space.

BICEP2 Detector at the South-Pole

1.5 to 4 degrees;

2) Estimate of Neutrino Decoupling

Universe Expansion rate: H=(da/dt)/a ~ n Interaction rate: = G ne-e+<svrelative>

H = = O( T2) [1/time]

G ~ (1/a3) <GF2 p2 c=1> ~ T3 <GF

2 T2c=1> ~ GF2 T5 [1/time]

with: Temperature = T ~ 1/a = 1/(length scale); = h/(2p) = c = 1

Stefan-Boltzmann

(Energy=Mass)-Density of the Universe

log r

a(t)~1/T

Radiation dominated: r ~ 1/a4 ~ =Stefan-Boltzmann

Matter dominated: r ~ 1/a3 ~ T3

Dark Energy

1/Temp1 MeV~1sec n

dec.

1 eV5x104y today

3000 K380 000 yg dec.

8x109 y g 2.7255 Kn 1.95 K

How can one detect the Cosmic Neutrino Background?

Electron-Neutrino capture on Tritium.

3. Search for Cosmic Neutrino Background CnB by Beta decay: TritiumKurie-Plot of Beta and induced Beta Decay: n(CB) + 3H(1/2+) 3He (1/2+) + e-

Electron Energy

2xNeutrino Masses

Emitted electron

Q = 18.562 keV

Infinite good resolution

Resolution Mainz: 4 eV mn < 2.3 eV

Resolution KATRIN: 0.93 eV mn < 0.2 eV 90% C. L.

Fit parameters: mn

2 and Q value meVAdditional fit: only

intensity of CnB

Tritium Beta Decay: 3H 3He+e-+nc

e

Neutrino Capture: n(relic) + 3H 3He + e-

20 mg(eff) of Tritium 2x1018 T2-Molecules: Nncapture(KATRIN) = 1.7x10-6 nen/<nen> [year-1]Every 590 000 years a count! for <nen> = 56 cm-3

Problem: 56 e-Neutrinos cm-3 too small

• Gravitational Clustering of Neutrinos estimated by Y. Wong, P. Vogel et al.:

nne(Galaxy) = 106*<nne> = 56 000 000 cm-3

1.7 counts per yearIncrease th source strength: 20 micrograms 2 milligrams

170 counts per year every second day a countSpeakers of KATRIN: Guido Drexlin and Christian Weinheimer

20 microgram 2 milligram Tritium

• Such an Increase of the Tritium Source Intensity is

with a KATRIN Type Spectrometer is difficult,

if not impossible!

Three important Requirements:

1) The Tritium Decay Electrons are not allowed to scatter with the Tritium Gas.

2) The Magnetic Flux must be conserved in the whole Detection System.

3) The Energy resolution must be of the order of 1 eV.

Source

1) The decay electrons should not scatter by the Tritium gas.

Beam

Column length dBase 1 cm2

Tritium Gas

Number of Tritium-Atoms in Column d = Column-Density

Magnetic Field3.6 Tesla

Optimal Column Density slightly below r*dfree /2Troitsk: 30%; Mainz: 40%; KATRIN: 90%

Only 36% have not scattered

2) Conservation of Magnetic Flux

If one cant increase the intensity per area, increase the area by factor 100 from 53 cm2 to 5000 cm2.

Magnetic Flux: (Ai=5000 cm2) x (Bi=3.6 Tesla) =

18 000 Tesla cm2 = Af x (3 Gauss);Af = 6 000 m2 diameter = 97 meters

3) Energy resolution of DE~ 1 eV

Energy resolution: Ef(perpend.) = Efp = DE

Angular Momentum of the Spiraling Electrons must be conserved

Energy resolution: Ef(perpend.) = Efp = DE = 1 eV

L = |r = m const = L ~ []i =[ Bf = 3 Gauss

20 microgram 2 milligram Tritium

• Such an Increase of the Tritium Source Intensity with a KATRIN Type Spectrometer is difficult,

if not impossible.

Summary 1• The Cosmic Microwave Background allows to

study the Universe 380 000 years after the BB.

• The Cosmic Neutrino Background 1 sec after the Big Bang (BB).

• The Cosmic Background of Gravitational Waves 10-31 Seconds in the Big Bang

2xNeutrino Masses

Emitted electron

Kurie-Plot

Electron Energy

Summary 2: Cosmic Neutrino Background

1. Average Density: nne = 56 [ Electron-Neutrinos/cm-3] Katrin: 1 Count in 590 000 Years Gravitational Clustering of Neutrinos nn/<nn> < 106

and 20 micrograms Tritium 1.7 counts per year. (2 milligram 3H 170 counts per year. Impossible ?)2. Measure only an upper limit of nn

THE END