Bonn 2010 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 36: Postersitzung

HK 36.31: Poster

Mittwoch, 17. März 2010, 14:00–16:00, HG Aula

Plasma effects and ion transport in the KATRIN windowless gaseous tritium source. — •Nikita Titov — Karlsruhe Institute for Technology, Institute for Nuclear Physics (on leave from INR, RAS, Moscow)

KATRIN is the international experiment currently being assembled at Karlsruhe to measure the absolute value of the electron antineutrino mass at the 0.2 eV level. It will study the shape of the tritium beta decay spectrum near the endpoint with an electrostatic spectrometer with adiabatic magnetic collimation. In order to reduce the systematic uncertainties, a windowless gaseous tritium source (WGTS) will be used to produce at unprecedented number of decay electrons.

The tritium decay rate inside the WGTS is planned at the 1.2 × 10 ¹¹ sec ⁻¹ level. Together with processes of secondary ionization, thermalization and charge transport this leads to an ion / electron pair density inside WGTS at the 10 ⁷ ... 10 ⁸ cm ⁻³ level. At the operating temperature 30K these charges will behave as a plasma.

There are two main requirements related to the space charge in the WGTS:
- Electric potential inside WGTS level should be controlled below 50 meV
- Ion transport toward spectrometer should be reduced by a factor 10 ⁺⁶ ... 10 ⁺⁷ .
Both issues are addressed by numerical analysis and experimental modeling.