1. Absorber R&D and Test Results CM16 at RAL, Oct 8-11, 2006 Shoji Suzuki & Shigeru Ishimoto KEK

2. 1)Absorber Test Cryostat 2)Instrument and DAQ 3)H2 Cooling Test Results 4)He Cooling Test Results 5)20 L Absorber Cooling Test Results 6)Summary OUTLINE

3. Absorber Test Cryostat & Test Absorber

4. LH2/He Level Sensor KF40 + 48 pin Feedthrough KF40 L=100 Extension Tube CX-1050-SD X5 (serial) CX-1050-SD X1 calibrated (4 wires) 2 cm

5. 1 st stage Heat Exchanger HEAT EXCHANGER ~60K H2 or He GAS INLET Cryocooler Condenser

6. Mini-Flange Test Mini Rotation Flange Mini-Flange S-S Aluminum KF16 1mm dia. Indium KF Flanges + Helicoflex Condenser 48 Pin

7. Instrument and DAQ

8. LakeShore 218S Keithley 2700 DMM Cernox x8 MKS 0-2000 Torr Level #1-5 VAC. Gauge... MONITOR (LabView) LakeShore 218 Keithley 2700 DMM Absorber DAQ System

9. Wiring diagram of DAQ

10. Software front panel for data-logger

11. Software front panel for Cernox readout

12. Software front panel for data-logger Cernox LH2 level indication

13. A part of software block diagram (data-logger)

14. A part of software block diagram (Cernox readout)

15. H2 Cooling Test G-H2 was supplied to the Cryocooler from the 2 m 3 tank at 1.3~1.0 atm.

16. L-H2; 0.368 l/h (w/o)  0.973 l/hr (MICE 20 l ; 57 hr  22 hr ) Improvement by the Heat Exchanger 2,000 l Tank -0.193 l/hr ~1.7 W 0.973 l/hr ~8.6 W COOLING STOP

17. L-H2 Level Sensor Test IN LIQUID(#2) IN LIQUID(#1) IN GAS(#5) IN GAS(#4) IN GAS(#3) (#2) (#1) (#3) (#4) (#5) 48 PIN

18. L-H2 Level Sensor Test R TH

19. L-H2 Level Sensor Test R TH

20. LHe Cooling Test G-He was supplied to the Cryocooler directly from a cylinder at 1.4 atm.

21. He ~3.7K ~ 0.6 atm He ~4.6K ~ 1. 4 atm VAC; 10 -7 ~10 -8 Torr (No Leak) LHe 4 K Leak Test (Mini-Flanges and 48 Pin Feedthrough)

22. LHe Condensation and Evaporation Speed ID=4cm 2cm LHe 1.5 atm; 0.207 l/h (MICE 20 l ; 97 hr) 48 PIN

23. LHe Level Sensor Test R TH

24. Calibrated Cernox vs. LHe Vapor Pressure dT=10 mK He Condensation ~ 4.6 K (1.4 atm) T min ~ 3.7 K (0.6 atm) CX-1050SD-1.4D

25. Absorber Cooling Test 20 L Absorber was filled ~1.4 L L-H2.

26. 20 l Absorber cooling test at KEK (1) Assemble *Level sensors at bottom, 2 Cernox and 1 PtCo on body *Lead wires pass through at the LH2 condenser *window seal; d=1 mm Indium (1 loop) *8 G10 (t=5) supports *MLI set; Al-Mylar 9  x5 + Nylon Mesh x6 1 layer on windows and G10 supports 4 layers on body ~2 layers on flexible pipes. (2) Vacuum and Leak Test *Leak at 300K  disassemble  found pinhole at a Helicoflex KF25  changed  recovered *vacuum; 3 x 10^(-6) Torr after 3 days, 300K

27. (3) Cooling Test #1 Sep-14, ‘06 *cryocooler cooling 82 hrs; 300  20K *solid air blocking at the 1 st stage heat exchanger  H2 impurity after 2 years operation for LH2 target  changed gas-H2 1.5 atm in the 2,000 L tank (4) Cooling Test #2 (same assemble) Sep-22, ‘06 *restart with LN2 pre-cooling  leak from N2 to vac. at ~200K  stop LH2 filling *restart cryocooler w/o LN2 from 230K, takes 60 hrs from 230K to 20K *liquefied ~1.5 l H2 ( 1.5  0.9 atm 2,000 L tank) *measured H2 condensation and evaporation speed 20 l Absorber cooling test at KEK (continued)

28. Temperature sensors inside 20 l Absorber Level (5 Cernoxes) Cernox calibrated Cernox abs.1 Cernox abs.2 & PtCo LH2 outlet LN2(LHe) inlet

29. Level (5 Cernoxes) 5 4 3 2 1 5 4 3 2 1 Cernox calibrated

30. Attachment for Cernox abs.2 & PtCo

31. 20 l Absorber assembled LH2 inletLH2 outlet LN2(LHe) outlet LN2(LHe) inlet G10 support

32. 20 l Absorber MLI wrapped MLI --- 1 layer Al-Mylar 9  x5 + Nylon Mesh x6 Window 1 layer Body 4 layers

33. Cryocooler Top flange and warm bore

34. 20 l Absorber inserted to warm bore and piping LN2(LHe) outlet LH2 inlet LN2(LHe) inlet LH2 outlet

35. Bottom view of H2 condenser LH2 supply LH2 return LN2(LHe) return LN2(LHe) supply Kyocera 48 pin From LH2 supply line (from Absorber) To Bendix 18 pin

36. Insert to Vacuum Chamber Pipes with MLI ~2 layers

37. 20 l Absorber H2 liquefaction test at KEK (LH2 1.425 l liquefied) H2 Press. (Torr) CX REF. 2nd.(ohm) CX REF. 1st. (ohm) CX0-calib. (K) *10 LH2 Temp_P. (K) *10 PtCo Abs. (K)*10 L-H2 in bodyL-H2 in pipe

38. 20 l Absorber H2 liquefaction test at KEK LH2 GH2 Level sensors In LH2 at same time?  G10 support was turned down?

39. Cernox vs. H2-pressure In LH2 Condenser Temperature measurements by H2 pressure is possible within error. Cernox vs. H2-pressure In Absorber Temperature by H2 pressure

40. Liquefaction and Vaporization of LH2 in 20 l Absorber 0.30 l / h, 2.6 W 1.33 l / h, 11.7 W 2000 l tank Cooling stop LH2 1.43 l  68 hrs to fill 20 l

41. (1) Cooling time (300K  20K) > 82 hrs by cryocooler only (not yet tested with LN2 pre-cooling)  Needs LN2 pre-cooling (2) Condensation speed; 0.30 l / h, 2.6 W  68 hrs to fill 20L  Needs better insulation to obtain shorter filling time (3) Evaporation speed ~ heat leak; 1.33 l / h, 11.7 W (2)+(3) = 14.3 W ; net cooling power at absorber LHe absorber required Q L (heat leak) < 1.5 W@4.2K  LHe Absorber needs additional L-He supply ? Summary 1/2 (Absorber Cooling Test)

42. (1) Cooling test with LN2 pre-cooling > Cold leak test and fix the LN2 channel > Open the window and check the level sensors  repair if it needs > Add PtCo thermometer on the dummy bore and in the condenser (2) Improvement of absorber insulation > design G-10 support, MLI.... * Until Q L < 1.5 W@4.2K for the LHe absorber, if possible ? * Larger cooling power margin makes shorter filling time and easier operation for the LH2 absorber. Summary 2/2 (Future Plan)

43. Thank you