Updates on the PeNCIL project

By comparing measured and expected polarization in the HI Ly α 121.6 nm coronal emission line it is possible to infer the magnetic field in the solar corona. PeNCIL is the ideal device to perform such a measurement. It is a light transmitting polarimeter optimized at 121.6 nm, completely free of mechanical moving parts, thought as part of an internally occulted coronagraph to be flown aboard a future small solar mission. Its optical components are in de Senarmont configuration: a fixed MgF _2 quarter wave retarder, a nano-wire grid polarizer (nano-WGP) and a MgF _2 variable retarder modulated through a calibrated piezo-clamp (PCVR). The nano-WGP and the PCVR represent a first-ever achievement in the history of technology development for VUV. The nano-WGP fabrication is at the edge of the current nanotechnology since the pitch between wires shall be 40 nm. The PCVR is based on a MgF _2 parallelepipedic sample refractive index variations as produced by a piezo-electric clamp. This work addresses the status of the project with particular emphasis on the design and manufacturing of the nano-WGP and the PCVR.