TOTEM Collaboration Meeting, Feb. 2005, F. Haug, CERN

Cooling System for TOTEM

Friedrich Haugand

Jihao WuCryogenics for Experiments

CERN

TOTEM Collaboration Meeting Feb. 2005

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

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temporary cooling solution for the experiments at SPS and at X5 beam consisted of using liquid nitrogen as cold source withdrawn from mobile dewars, distributed and fed in parallel to the heat exchangers inside the Roman Pots.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

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

TOTEM Collaboration Meeting, Feb. 2005, F. Haug, CERN

Heat pipe 1 Adiabatic 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.

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.

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

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

TOTEM Collaboration Meeting, Feb. 2005, F. Haug, CERN

Investigation of an “Ambient” Temperature Heat Pipe Operating at different angles (gravity-assist to antigravity)

0

10

20

30

40

50

60

290 300 310 320 330 340 350 360

temp in K

Po

wre

r in

W

angle=0

angle=90

angle=180

angle=30

angle=120

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.

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)

TOTEM Collaboration Meeting, Feb. 2005, F. Haug, CERN

Performance Characteristics of the Pulse Tube Refrigerator (without Heat Pipes) at different Inclination Angles

0

20

40

60

80

100

120

140

160

0 50 100 150 200 250 300

Temp.in K

Po

we

r in

W

gravity assisted

horizontal

antigravity

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