Si$\Lambda$ViO: A Trigger for $\Lambda$-Particles

Abstract

The production of bound kaon-nucleon-states (kaonic-cluster) in the reaction $p+p\to [ppK^{-}] + K^{+}$ should be investigated in a dedicated measurement at the FOPI detector system at the SIS-accelerator of GSI, by looking for the decay $ppK^{-} \to p + \Lambda \to p + p + \pi^{-}$. To select the final states, the detector system Si$\Lambda$ViO has been build up as a trigger for $\Lambda$-Hyperons. This detector consists of two layers of segmented silicon-strip-detectors, which are able to measure online the particle multiplicity. These two layers are arranged such, that most of the $\Lambda$-Hyperons will decay between them. The trigger signal is generated by comparing online the hit multiplicity on the two layers.