1. TOTEM Collaboration Meeting, Feb. 2005, F. Haug, CERN Cooling System for TOTEM Friedrich Haug and Jihao Wu Cryogenics for Experiments CERN TOTEM Collaboration Meeting Feb. 2005

2. TOTEM Collaboration Meeting, Feb. 2005, F. Haug, CERN Subjects discussed Temporary Cooling Solution for X5 and SPS in 2004 Basic Design Principle and Lay-out for LHC Key Technologies Heat Pipes and Pulse Tube Refrigeration Design and Development Results and Outlook for 2005

3. TOTEM Collaboration Meeting, Feb. 2005, F. Haug, CERN Temporary Cooling Solution for SPS and X5 Experiments in 2004 The temporary cooling solution for the experiments at SPS and at X5 beam consisted of using liquid nitrogen as cold source withdrawn from mobile dewars, distributed and fed in parallel to the heat exchangers inside the Roman Pots. A connecting flexible thermal bridge provided extraction of the dissipated heat in the RP set-up which was cooled. The temperature was controlled with a local electric heater and a limited control loop. LN2 Lines Heat exchanger El. Heater (not visible) Flexible thermal connection Roman Pot Insert during Assembly Phase

4. TOTEM Collaboration Meeting, Feb. 2005, F. Haug, CERN Simplified Schedule 2004: First TOTEM Beam Experiments and Tests + Simple Cooling. Results: Cooling principle = versatile and useful for the purpose. Not applicable for final installation at LHC. 2005: Development Phase of Cooling System and Components 2006: Construction Phase

5. TOTEM Collaboration Meeting, Feb. 2005, F. Haug, CERN Heat pipe 1Adiabatic zone Refrigerator cold head Pulse tube refrigerator Interconnecting block Cryostat Beam centre line Horizontal roman pot Vertical roman pots Heat pipe 2 Heat pipe 3 Basic Cooling Design Principle for LHC The dissipated heat from the six RP’s is conducted by six individual heat pipes to a central cryostat housing the Pulse Tube Refigerator. -Heat Pipes are passive, effective heat transfer elements. -Pulse Tube Refrigerators are modern cryogen free coolers exhibiting low vibration noise.

6. TOTEM Collaboration Meeting, Feb. 2005, F. Haug, CERN HEAT PIPE -A heat pipe is a completely passive heat transfer device without any moving mechanical parts like e.g. circulation pumps. -It shows an extremely high effective thermal conductivity in using the high heat of vaporization (condensation) of a two- phase working fluid. -Its principle relies on a continuous evaporation / condensation process and the heat transfer is done via mass transfer of counterflowing vapor and condensate.

7. TOTEM Collaboration Meeting, Feb. 2005, F. Haug, CERN Heat Pipe Cross Section (Example) Vapor duct Longitudinal Capillaries for liquid return Courtesy IKE, University Stuttgart Mesh

8. TOTEM Collaboration Meeting, Feb. 2005, F. Haug, CERN QRL Transfer Line for LHC collider magnets Refrigerator Compressor (can also be installed at distance) Vertical and horizontal Roman Pot Units Beam vacuum pipes Heat Pipes Pulse Tube Refrigerator integrated in Cryostat Proposed Layout at LHC with Heat Pipes and Pulse Tube Refrigerator

9. TOTEM Collaboration Meeting, Feb. 2005, F. Haug, CERN Investigation of an “Ambient” Temperature Heat Pipe Operating at different angles (gravity-assist to antigravity) The results show the measured performance limits at different inclination angles and temperatures. Operation against gravity reduces the heat transfer capacity by an important factor.

10. TOTEM Collaboration Meeting, Feb. 2005, F. Haug, CERN Laboratory Set-up for Performance Measurements of Heat Pipes with Pulse Tube Refrigeration (from ambient temperature to 100 K) Pulse tube refrigerator Vacuum enclosure (inside Heat Pipe)

11. TOTEM Collaboration Meeting, Feb. 2005, F. Haug, CERN Performance Characteristics of the Pulse Tube Refrigerator (without Heat Pipes) at different Inclination Angles

12. TOTEM Collaboration Meeting, Feb. 2005, F. Haug, CERN RESULTS TO DATE - X5, SPS tests successfully completed -Preliminary results of ambient temperature heat pipes (gravity assist and anti-gravity operation) = encouraging -Laboratory set-up with Pulse Tube Refrigeration = operational -Investigations on cryogenic heat pipes has started OUTLOOK for 2005 -Thermal Model of a Roman Pot Insert: Design, Construction and Testing -Development and testing of low temperature Heat Pipes -Testing of Combination Heat Pipes and Peltier Elements -Prototype Cooling System: Design, Construction, Testing