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Detecting Neutrinos

8 Background for Detectors

This is section 8 of 13.

The systems designed to detect neutrino use different materials.

Those materials are described in this preceding section so the length of those detector descriptions is reduced.

8.1 Deuterium

Deuterium is used in the Sudbry Neutrino Observatory.

Here is a description of deuterium.

Deuterium (or hydrogen-2, symbol 2H also known as heavy hydrogen) is one of two stable isotopes of hydrogen (the other being protium, or hydrogen-1). The nucleus of a deuterium atom, called a deuteron, contains one proton and one neutron, whereas the far more common protium has no neutrons in the nucleus. Deuterium has a natural abundance in Earth's oceans of about one atom in 6420 of hydrogen. Thus deuterium accounts for approximately 0.0156% (0.0312% by mass) of all the naturally occurring hydrogen in the oceans, while protium accounts for more than 99.98%. The abundance of deuterium changes slightly from one kind of natural water to another (see Vienna Standard Mean Ocean Water [below]).


8.1.1 Deuterium Stability

Deutereium has odd counts of both protons and neutrons, with 1:1

Most odd-odd isotopes are not very stable, or not having a long half-life.

Deuterium is considered stable.

However, some neutrino detection instruments are trying to detect the break in deuterium between the 1 proton and 1 neutron.


8.1.2 Vienna Standard Mean Ocean Water

Although each water molecule (H2O) contains two hydrogen atoms and one oxygen atom, VSMOW composition is given in terms of the atoms and is indifferent to the isotopic combinations in molecules. The particular molecular combinations do not affect the properties of VSMOW, and in fact the molecules in a water sample exchange atoms rapidly and continuously.



This known behavior of heavy water is crucial when deuterium is the basis for a system seeking neutrinos by their change to deuterium.

8.2 liquid scintillator

Lliquid scintillators are used in KamLAND.

Here is a basic description.

Liquid scintillation counting is the measurement of radioactive activity of a sample material which uses the technique of mixing the active material with a liquid scintillator (e.g. zinc sulfide), and counting the resultant photon emissions. The purpose is to allow more efficient counting due to the intimate contact of the activity with the scintillator. It is generally used for alpha particle or beta particle detection.



The topic describes alternative elements for this technique.

8.2.1 Efficiency

There is a separate topic about the efficiency of this technique.


8.3 perchloroethylene

Perchloroethylene is used in the HOMESTAKE experiment

Here is its description.

British physicist and chemist Michael Faraday first synthesized tetrachloroethylene in 1821 by thermal decomposition of hexachloroethane.

C2Cl6 to C2Cl4 + Cl2

Most tetrachloroethylene is produced by high temperature chlorinolysis of light hydrocarbons. The method is related to Faraday's discovery since hexachloroethane is generated and thermally decomposes. Side products include carbon tetrachloride, hydrogen chloride, and hexachlorobutadiene.



The HOMESTAKE experiment detected the results of chlorine atoms executing a beta plus decay.

The conclusion was only a neutrino could initiate this particular step in radioactive decay when deep below Earth's crust.

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last change 04/04/2022