Physics:Solar neutrino unit
The solar neutrino unit (SNU) is a unit of Solar neutrino flux widely used in neutrino astronomy and radiochemical neutrino experiments. It is equal to the neutrino flux producing 10−36 captures per target atom per second.[1] It is convenient given the very low event rates in radiochemical experiments. Typical rate is expected to be from tens SNU to hundred SNU.[2]
There are two ways of detecting solar neutrinos: radiochemical and real time experiments. The principle of radiochemical experiments is the reaction of the form
[math]\displaystyle{ ^{A}_{N}Z + \nu_{e}\longrightarrow^{A}_{N-1}(Z+1)+e^{-} }[/math].
The daughter nucleus's decay is used in the detection. Production rate of the daughter nucleus is given by [math]\displaystyle{ R = N\int\Phi(E)\sigma(E)dE }[/math], where
- [math]\displaystyle{ \Phi }[/math] is the solar neutrino flux
- [math]\displaystyle{ \sigma }[/math] is the cross section for the radiochemical reaction
- [math]\displaystyle{ N }[/math] is the number of target atoms.
With typical neutrino flux of 1010 cm−2 s−1 and a typical interaction cross section of about 10−45 cm2, about 1030 target atoms are required to produce one event per day. Taking into account that 1 mole is equal to 6.022×1023 atoms, this number corresponds to ktons of the target substances, whereas present neutrino detectors operate at much lower quantities of those.
See also
Links
- Bellerive, A. (2004). "Review of Solar Neutrino Experiments". International Journal of Modern Physics A 19 (8): 1167–1179. doi:10.1142/S0217751X04019093. Bibcode: 2004IJMPA..19.1167B.
References
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