Instrumentation and measurement

Cryogen Free sub-Kelvin ARPES System from Janis Research

October 24, 2019

Angle-Resolved Photoemission Spectroscopy (ARPES) is used to study the electronic structure of the surface of solids. The ARPES technique employs a synchrotron or laser beam to interact with a sample, resulting in emission of photoelectrons. By analyzing the energy and momentum of the photoelectrons, the Fermi surface of the material can be mapped. ARPES experiments are often performed in the 2 Kelvin – 10 Kelvin range, but recent research trends often require temperatures below 1 Kelvin (sub-K).

Janis Research delivered the world’s first continuous operating high cooling power “wet” He-3 ARPES cryostat in 2008, achieving a base temperature of 0.9 K. (https://www.tandfonline.com/doi/abs/10.1080/08940886.2012.720159) Similar systems have since been installed at leading research facilities around the world, but the recent global helium shortage has made continuous operation of these large sub-K ARPES systems costly. In response to researcher demand, Janis Research has successfully developed another world first, a continuously operating high cooling power cryogen-free (“dry”) sub-K cryostat for ARPES. This dry He-3 system eliminates the need (and cost) of liquid helium, while also simplifying the design and dramatically reducing the cryostat size.