A two-stage 3He–4He fridge for bolometric photometry

✍ Scribed by T Maiani; P de Bernardis; M De Petris; S Granata; S Masi; A Orlando; E Aquilini; P Cardoni; L Martinis; F Scaramuzzi

• Book ID: 104111644
• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 180 KB
• Volume: 39
• Category: Article
• ISSN: 0011-2275
• DOI: 10.1016/s0011-2275(99)00072-7

✦ Synopsis

We describe the design, construction and performance of a double stage 3 He-4 He refrigerator, built to cool down a multiband bolometric photometer at the MITO telescope. The fridge was optimized to work without external pumps, with the main cryostat providing a 4.2 K thermostat at sea level and a 4.0 K one at high mountain pressure conditions. The measured ultimate temperature of the fridge is 290 mK, with a hold time of 81 h. The external heat input on the cold flange is ෂ35 µW, with the main bath at 4.0 K. The recycle time is 8 h with a heat input on the thermostat during recycling of ෂ6800 J. The cryostat can operate without any relevant changes to performance tilted down to 50°from the vertical position, as needed at the telescope focal plane.