Spectrosil B Quartz Inner Window (Optistat CF/DN new style) and assembly.
Spectrosil B is a synthetic vitreous silica. The material itself is not birefringent and standard strain-relieved low temperature window mounts ensure that Spectrosil B windows do not affect polarised light. It is an excellent material for filtering out the near-mid IR room temperature thermal radiation, resulting in a low thermal load on the cryostat. The transmission data is for a 2 mm thick window. Inner window assembly, 15mm clear diameter x 2mm thick