2015 January: the construction of SPIRou is progressing

Following the successful Final Design Review (FDR) in 2014 April, SPIRou has entered the manufacturing phase on all sites involved in the construction. 

More specifically, the spectrograph, polarimeter and fore optics were ordered last fall.

This includes in particular a number of critical components among which: 

• a 35-kg monolithic zerodur parabolic collimator cut from a 880-mm parent, built in France;  
• a 5-lens f/3 camera offering a free entrance aperture of 280 mm, built in Canada;  
• a double-pass prism-train cross-disperser made of 2 large ZnSe prisms and one even larger silica prism, built in the UK
• a pupil-slicer at spectrograph entrance, allowing to maximize spectral resolution without compromising throughput, built in France;  
• highly-purified fluoride fibers offering optical transmission throughout the whole spectral window, built in France;  
• a pair of ZnSe quarter-wave Fresnel rhombs offering nominal retardation to an extreme precision, built in France;  
• an evacuated thermally-controlled Fabry-Perot unit acting as RV reference, built in Switzerland.  

All mechanical components are also currently under fabrication, in particular: 

• the 6-m³ cryogenic vessel along with the bench and mounts holding the spectrograph optics that it will host, built in Canada; 
• the polarimeter & Cassegrain interface cylindrical structures with inner optical supports, built in France; 
• the Calibration Unit and its facilities, built in France.  

Most additional components of the control system have also been purchased, including: 

• all motorized mechanisms, e.g., the tip / tilt unit stabilizing the input image from the telescope;  
• the cold-stop cell used to block the thermal emission from the telescope;  
• the vacuum pumps and cryocoolers associated with the cryogenic dewar;  
• the high-precision temperature sensors and controllers to thermally regulate the spectrograph.