1. HARPS... North HARPS-N PDR Harvard CfA, 06/07-12-2007 Thermal enclosure

2. 3-level concept Spectrograph room: +- 0.2 K Isolation Box: +- 0.01 K Spectrograph: +- 0.001 K 15°C 17°C T-sensor

3. Spectrograph room Model : YORK YEB 3S Serial Nr. : 135.157.DN003

4. Room thermal control

5. Isolation Box

6. Temperature control ✓ Lakeshore 331S T-controller + diode sensors + heaters ✓ 60 mm polyurethane panels with 1 mm Al skin ✓ Floor isolated by 100-mm foam ‘carpet’ ✓ Thermal load on external room: about 10 W/K

7. Performances, but...

8. Lessons learned Concept works well and is simple Changing thermal load through feet produces gradient and seasonal effects ➡ Thermal isolation of feet ➡ Heater below feet, Tref = vacuum vessel e.g. using Lakeshore controller