1. Calibration of 6000 Thermometers
J.P. Thermeau1, T. Junquera1, F. Chatelet1, C. Joly1, F. Mellac1
J. Casas-Cubillos2, C. Balle2, N. Vauthier2
1 Institut de Physique Nucléaire, CNRS-IN2P3, Orsay, France
2 CERN, ACR Division, CH-1211 Geneva 23, Switzerland
LHC Inauguration : 31 May - 1 June 2007

2. LHC Inauguration : 31 May - 1 June 2007
Summary
LHC thermometry requirements
Calibration facility
Calibration sequence description
Production rate of the LHC calibrated thermometers
Conclusions
LHC Inauguration : 31 May - 1 June 2007

3. Engineering specifications
For the temperature range 1.6 K – 300 K :
- each thermometer needs an individual calibration,
- several sensor models could be used → program tests.
Program tests to select the sensors :
- CERN : thermal cycling → long term stability,
- CNRS/IN2P3 : neutron irradiation test in liquid helium (1015 neutron/cm²) → radiation hardness.
 CERN have chosen CERNOX sensors produced by Lake Shore
LHC Inauguration : 31 May - 1 June 2007

4. LHC Inauguration : 31 May - 1 June 2007
LHC requirements
6000 thermometers units are required, including 500 spare units :
thermometers for vacuum condition are mounted on long thermometric blocks,
 -  2200 thermometers for liquid helium environment are mounted on short thermometric blocks,
 -   500 thermometers are used on cold fingers,   
Thermometers overall accuracy requirements :
range
1.6 K K
2.2 K - 4 K
4 K - 6 K
accuracy
± 10 mK
± 20 mK
± 30 mK
range
6 K - 25 K
25 K - 50 K
50 K K
accuracy
± 1K
± 5 K
LHC Inauguration : 31 May - 1 June 2007

5. View of the calibration facility
Calibration Insert
Helium vapor heater
Cryostat
Dewar LN2, LHe
LHC Inauguration : 31 May - 1 June 2007

6. Calibration under vacuum condition
75 thermometers to calibrate
Calibration and thermalization blocks are cooled down with the liquid helium loop.
T > 30 K :
no temperature regulation,
T < 30 K :
temperature regulates by Proportional Integral regulator using a heater.
7 days to realize a calibration run in vacuum condition
LHC Inauguration : 31 May - 1 June 2007

7. Mounting of thermometer with connector
Measuring wires sold on RF connector
Thermometric block slides under RF connector to realize the electrical connections
LHC Inauguration : 31 May - 1 June 2007

8. Insert for liquid helium calibration
- Copper plate on which 100 thermometers can be fixed.
A pressure regulator is used to regulate the temperature of liquid helium,
Measurement sequence is the same that in vacuum condition.
2 days to realize a calibration run in liquid helium
LHC Inauguration : 31 May - 1 June 2007

9. Calibration procedures
PROCESSUS
DIREC
DIRECT
Réception
Cyclage
Préparation
Étalonnage
Sous VIDE
Démontage
Après
Analyse
Conditionn t
Expédition
LIQUIDE 1 2 3 4 5 6 7 8 9 10
Maintenance
Des
Équipements
D'étalonnage 12
Exploitation
de la Base
de Données 13
PROCESSUS SUPPORTS ET CONTRÔ
PROCESSUS SUPPORTS ET CONTRÔLE
Contrôle
Électrique
Unitaire 11
CALIBRATION
PROCESS
Reception
Cycling
Vacuum
Calibration
Setting-up
Dismounting
after
Analysis
Tests
Shipping
Liquid
Equipments
Data Base
CONTROL AND MAINTENANCE
Electrical
Test
and
Quality Assurance Plan
Calibration sequence for thermometers used in liquid
Calibration sequence for thermometers used in vacuum
LHC Inauguration : 31 May - 1 June 2007

10. IPNO Calibration Cryostat
Network of the calibration facilities
IPNO Calibration Cryostat
IPN Network
Local
Data Base
CERN Network
Internet
CERN PC
Calibration
Analysis
Control & Command
PLC
Back-up
LHC Inauguration : 31 May - 1 June 2007

11. Number of LHC calibrated thermometers since january 2001
1 vacuum insert
1 liquid insert
2 vacuum inserts
2003
2004
2005
2002
2001
LHC Inauguration : 31 May - 1 June 2007

12. Production rate of LHC calibrated thermometers
Pre-serie
LHC Inauguration : 31 May - 1 June 2007

13. LHC Inauguration : 31 May - 1 June 2007
Conclusions
In five years (2001 – 2005), more than six thousands thermometers have been successfully calibrated for the CERN.
129 calibrations runs in vacuum condition, 44 runs in liquid helium.
Two thousands five hundred thermometers can be calibrated per year with three calibration inserts,
High calibration accuracy :
  7 mK for T < 2.2 K,
  10 mK for 2.2 K < T < 30 K,
0.25 % for T > 30 K.
Now, the calibration facility is part of SUPRATECH a technological platform for superconducting cavities at Orsay, and can be used for new projects such Spiral2, FAIR, ITER, …
LHC Inauguration : 31 May - 1 June 2007