In the Lab
A Look at the Cluster Machine
We have built a time-of-flight machine to observe light-cluster interactions. The machine is designed to detect both electrons and ions by switching the polarity of the MCP (microchannel plate) potential. The flight tube length is about 50 cm and the acceptance angle is about +- 1 degree (limited by our MCP size ~18 mm dia). The flight tube is shielded by a Faraday cage and Mu-metal cylinder to block out stray fields. The cluster jet is first skimmed by a hydrodynamic skimmer to reduce the size distribution and only a few clusters see the intense laser light in the interaction zone. Essentially, our primary purpose for this machine is to lead the study of the effect of mid-infrared light on clusters, many atoms bound together through Van der Waals interactions. With a longer wavelength, we can reach a deeper tunneling regime (as opposed to multiphoton regime in shorter wavelength), and effectively elongate the quiver amplitude. By driving electron farther than the cluster size, we hope to observe some interesting phenomena from the multi-body interaction.