Transcript Cooling Systems Adopted For the Use in the Elementary Particle

Cooling System(s) for the Roman Pots
of TOTEM experiment
V. Vacek
AGENDA:
1. Scope of the Research activities (TFP and DAQ group at the Dept.
of Applied Physics – F. of Mechanical Engineering, CTU in Prague)
2. TOTEM Roman POT cooling system development
3. Application of the efficient heat exchangers
4. Commissioning matters (ATLAS, TOTEM RP or any other system)
5. What we have learned so far
LHC cooling forum, CERN, October 30, 2008
V. Vacek, CTU Prague
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Scope of the Research activities over the last 10 years
 Main research program :
 Cooling system design for electronics application:
 ATLAS Inner Detector cooling circuit
 Pixel and SCT structures testing (with CPPM Marseille)
 Design, assembly and commissioning of the cooling system realized
at CERN in SR1 facility
 Commissioning measurements in the PIT (ATLAS cavern)
 TOTEM Cooling system for the Roman POTs
 Overall design, prototype development and verification of the Roman
POT thermal mockup
 Commissioning measurements of the 24 RP, prior to the installation
in the LHC tunnel; final system commissioning
LHC cooling forum, CERN, October 30, 2008
V. Vacek, CTU Prague
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Scope of the Research activities over the last 10 years
 Associated research program:

Fluid property research:
 Thermophysical properties of fluoroinert fluids we studied, both theoretically
(simulations – MD and MC methods) and experimentally
 Databases, individual thermophysical property fitting functions and engineering
diagrams were prepared at the CTU for the most of the fluoroinert

DAQ systems and various type of the sensors
 Mobile DAQ systems (based on ELMB and PVSS use) development and their
implementation was completed
 Calibration and verification of the great variety of sensors was done
 Most of the commissioning measurements for ATLAS and TOTEM cooling
systems were performed with our DAQ systems

Heat transfer modeling for the heat exchangers design

Two phase flow studies (capillary flow modeling)

Cold box with controlled atmosphere for the AIRFLY project was developed and used
during measurements (Frascati, It; Chicago, USA)
LHC cooling forum, CERN, October 30, 2008
V. Vacek, CTU Prague
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TOTEM Cooling system for the Roman POTs
TOTEM Experiment - its main goal is to measure the total cross section, elastic
scattering and diffractive processes at the LHC on both sides of the CMS detector.
The diffractive processes are detected by two types of tracking telescopes (T1
and T2). To measure the cross section and the elastic and quasielastic
interactions a special instrument had to be introduced: The Roman Pot (RP).
24 Roman Pots located in 8 positions around the beam pipes are capable of
detecting particles diverted by extremely low angles
Roman Pots
LHC cooling forum, CERN, October 30, 2008
The inner structure of the Roman Pot consists
of 10 silicon detectors, each of them is
positioned in an electronic board called the
“hybrid” with four embedded readout chips.
Operation of the detectors requires
temperatures below –10 °C. The dissipated
heat from the chips reaches ~ up to 3 W per
plane.
V. Vacek, CTU Prague
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TOTEM Cooling system for the Roman POTs
We have been asked to develop CS for TOTEM RP in MAY 2006, once the
system based upon the heat pipes and pulse tube refrigerator has been
ruled out since the changes in specs and strategy
Our task was extremely difficult since we
have inherited some fixed baselines, time
for development was extremely short and
nearly no resources were available at the
beginning of the work
A new system has been developed by
the team of the CTU Prague and the
final system for the PIT was designed
and installed by TS/CV of CERN
Close cooperation of the CTU and CERN - TS/CV resulted in
successful commissioning of the whole system and it is still
going on
LHC cooling forum, CERN, October 30, 2008
V. Vacek, CTU Prague
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TOTEM Cooling system for the Roman POTs
An evaporative cooling system circulating fluorocarbon C3F8 in 4 main
closed loop has been chosen and designed to guarantee a total cooling
capacity of 1.2 kW and supply a global mass flow rate of 40 g/s to be
uniformly shared between the 24 TOTEM Roman Pots.
Basic phases of the development:
• Evaluation of the principle (2006-2007)
• Thermal mock-up development and testing (2007)
• Small commissioning CS design and assembly for individual RP
testing at H8 facility at CERN was successfully finished in 2007/08
and is being used.
IN PARALLEL:
• Final CS has been designed by TS/CV (2007-2008)
• RP TOTEM CS is installed and being commissioned right now
LHC cooling forum, CERN, October 30, 2008
V. Vacek, CTU Prague
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TOTEM Cooling system for the Roman POTs
• Evaluation of the principle (2006-2007)
• Thermal mock-up development and testing (2007)
LHC cooling forum, CERN, October 30, 2008
V. Vacek, CTU Prague
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Cooling Circuit in Building 887/H8 - CERN
The cooling has been designed, assembled and adjusted by the team from the
Department of Applied Physics of the CTU in Prague in 2007 and 2008. It
consists of two oil-free compressors, a set of chilled water heat exchangers, a
pump and a condenser with PID controlled temperature. The circuit is filled
with fluorinert refrigerant R218. The circuit is presently prepared to cool down
up to three Roman Pots simultaneously. Several tuning and control devices
implemented within the circuit enable to vary a large scale of operational
parameters.
LHC cooling forum, CERN, October 30, 2008
V. Vacek, CTU Prague
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Schematics of the Cooling Circuit with single POT
DATE
HEX
LHC cooling forum, CERN, October 30, 2008
V. Vacek, CTU Prague
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CTU Prague
Performance of the Cooling Circuit with single POT
LHC cooling forum, CERN, October 30, 2008
V. Vacek, CTU Prague
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Success with elimination of the insulation = DATE-HEX
provided to TOTEM and to us by TS/CV
 DATE-HEX is compact heat
exchanger capable due to the
enhanced heat transfer between
liquid on one side and vapor on the
other side. The device provide
possibility to increase vapor
temperature over the short distance
and still keep pressure drop of
vapor at relatively small values
 It could possibly, after modification
and some more testing, replace
„problematic“ heating elementsheaters in several applications
elsewhere since the device does
not require too complex control
system and it can be considered as
the self-tuning device
LHC cooling forum, CERN, October 30, 2008
V. Vacek, CTU Prague
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Implementation of the HEX into the cooling circuit
Instrumentation
around the HEX,
P, T and flow
sensors
The Date–Hex
prototype
installed into
the circuit with
installed
pipelines
LHC cooling forum, CERN, October 30, 2008
Arrangement for the nominal refrigerant mass flow
up to 5 g/s; water flow measured standard with use
of float device, while vapor flow was monitored via
SWISS-FLOW meters (frequency principle) calibrated
prior to measurements
V. Vacek, CTU Prague
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Performance of the HEX
LHC cooling forum, CERN, October 30, 2008
V. Vacek, CTU Prague
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Performance of the HEX (other applications?)
LHC cooling forum, CERN, October 30, 2008
V. Vacek, CTU Prague
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What is needed for smooth commissioning ?
Reliable and robust DAQ system – it is a „must“ for the commissioning
Calibration comparison - Pt1000s, 1000 Ohm dummy resistors
0.5
Internal calibration
No calibration
Calculated Temperature [ºC]
0
-0.5
External calibration
-1
Channel 0
Channel 2
Channel 4
Channel 6
Channel 8
Channel 10
Channel 12
Channel 14
-1.5
-2
-2.5
15:43:12
15:50:24
15:57:36
• Simple version of the mobile DAQ system for commissioning:
• 64 channels (but expandable; low cost per channel)
• Type of the sensors:
• PT 100, PT1000, NTC
• Pressure sensors (voltage signals)
16:04:48
16:12:00
16:19:12
Enhanced
accuracy due to
the „internal and
„external ELMB
calibration and
proper sensor
handling
• Humidity sensors (capacitance principle+voltage converter)
LHC cooling forum, CERN, October 30, 2008
Channel 1
Channel 3
Channel 5
Channel 7
Channel 9
Channel 11
Channel 13
Channel 15
V. Vacek, CTU Prague
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ATLAS ID Cooling system commissioning
DAQ system and PVSS project – well
tested
Type of sensors: NTC (kapton coated, pearl type); pressure
sensors Huba and Sensortechnics (both HP and LP); mass
flow meter Bronkhorst for the gas phase; 3 out of 6 available
ELMB´s were used. All parts of the DAQ were verified and
calibrated before the measurements.
LHC cooling forum, CERN, October 30, 2008
V. Vacek, CTU Prague
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TOTEM Cooling system commissioning
Main problems in the case of TOTEM:
• very often – some delays (both in hardware and software
for the final system deliveries)
• What had to be prepared in addition:
• For the H8 use
• Multichannel DAQ and DCS system
• For the PIT use
• Several dummy loads – due to the final RP shifted
delivery
• Mini DAQ and DCS system for the PIT commissioning
LHC cooling forum, CERN, October 30, 2008
V. Vacek, CTU Prague
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CTU Prague
Modifying and tuning Prevessin CS for commissioning purposes
• Cooling System at H8/in Building 887
prepared was prepared
• DAQ and control system was verified
and handed to TOTEM
• Patch panel with valves has been
added to the system to separate the
rack for the Roman POT installed for
eventual commissioning
• Patch panel will allow:
1. an individual manipulation of
the RP,
2. its leak checking
3. pumping down the separated
part of the cooling lines
• and when ready,
• it can be connected to the CS
circulation just through 2 valves
LHC cooling forum, CERN, October 30, 2008
V. Vacek, CTU Prague
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Prevessin CS – commissioning results of the RP No. 2
Conditions inside Roman Pot 'final' #2 placed at Beam test area, 30.07.2008, Prevessin H8
Mass flow through RP final #2 ~ 1.4 g/s
-14
10
High liquid pressure 9.8 bara
Full operation
8
-18
Slight response of the
evaporator temperatures
-20
-22
Temperatures on 'hybrids'
12.9 A
T1 RACK
OFF mode
6
13.1 A
Stand by
4
-24
T3 RACK
-26
T2 RACK
-28
T4 RACK
vapor pressure 1.27 bara
-30
13:30
2
0
14:00
14:30
15:00
T P8 Hyb Pt100
T3 RACK Pt1000
Swissflow 2 RP fin
LHC cooling forum, CERN, October 30, 2008
15:30
16:00
16:30
17:00
Time [hh:mm]
T P3 Hyb Pt100
T4 RACK Pt1000
CORI mass
17:30
T1 RACK Pt1000
p liq bef RP fin
IST-flowmeter GAS
18:00
18:30
19:00
T2 RACK Pt1000
p vap out RP fin
V. Vacek, CTU Prague
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Pressure [bara]; massflow [g/s]
Temperature [°C]
-16
Commissioning set up for single POT at H8:
Three POTs already
commissioned
Fluid INLET (liquid) and OUTLET
(vapor) available
Patch panel for an easy handling
Environmental protection of the
upper part solved
Once upper part is connected
(two tubes with refrigerant,
electrical services and DAQ
wires), RP is leak checked and
pumped down, we can proceed
with fast runs at H8 installation
Two major valves
LHC cooling forum, CERN, October 30, 2008
V. Vacek, CTU Prague
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Production of the dummy loads for the PIT and their verification at
Prevessin
LHC cooling forum, CERN, October 30, 2008
V. Vacek, CTU Prague
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Production of the dummy loads for the PIT and their verification at
Prevessin
1. Pressure drop verified
2. Leak tested
3. Electrical connection tested
4. Prepared for insulation
5. Installed within the final
cooling plant
Verified during the refrigerant
circulation in the closed
loops
LHC cooling forum, CERN, October 30, 2008
V. Vacek, CTU Prague
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Commissioning in the PIT:
Roman Pot
station in the
LHC tunnel
with one RP
and two
Dummy loads
Sensors are monitored independently by the PLC
and by the ELMB based mini DAQ system
LHC cooling forum, CERN, October 30, 2008
Sumary of the last results from the PIT
V. Vacek, CTU Prague
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SUMMARY
 Overall scope of the research activities was outlined – covering last
few years
 Activity within the ATLAS ID cooling system development were
mentioned
 TOTEM Roman POT cooling system was described and relevant
experience from CS design, running and commissioning were
presented
 Heat exchanger use for the efficient vapor warm up was described
and experimental results were introduced
 General comments related to CS of the RP detector applications
were introduced
LHC cooling forum, CERN, October 30, 2008
V. Vacek, CTU Prague
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