Heike R2012-09 R67

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Revision as of 16:36, 17 September 2012 by Rothfuss (talk | contribs)
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NEW

  • Renewed and improved noise thermometer.
  • The wiring for four Double-Channel-Squids is installed.
  • Two more stainless steel Coax-Cables are installed with their own port at room-temperature. The are numbered #5 and #6. Up to now they end at the mixing chamber and are connected to each other.
  • Two semi-rigid coax-cables were installed, too.
  • Filter-boxes I, II and VI were improved by adding a second coil at the input (cryo-end) of the filter circuit. The coils were manufactured by Würth Electronik, Part No. 744221, 2000H; 600mA; 0.42


TEST

  • Testing Pt-NMR. Coax #1 and #3 is connected with a special box. Inside this box the inner conductor of coax #1 is grounded and the inner conductor of #3 is feed through. For details see Pt-NMR Log-Book page 20. At first glance it seems like the device works at Curie-Mode.
  • In spite of many attempts with different setups it isn't possible to measure in the Korringa-Mode with the PLM-4 so far.
  • Heating by RF-Signal causes a significant parasitic heat input on the mixing chamber and on the Cu-Stage. Several tests were done to prove this. See e.g. logbook: 16.03. or 22.03.2012.
  • NEW LOWEST TEMPERATURE ACHIEVED: TNMR ~ 85 K (14.03.)
  • New Filter-Design for some Boxes.


TIME TABLE

Icy transfer tube with a sub-prime vacuum :)
  • 28.02.2012: FIRST DAY - CLOSING, CLEANING & PRECOOLING
    • Closing cyrostat and dewar. Cleaning/pumping lines.
    • Precooling with 50l LN.


  • 29.02.2012: SECOND DAY - LIQUID HELIUM
    • 07:50 : Status = TDewar=207K, TMC,Si=216K, TMagn,l=217K, pVC=2.15mbar
    • 09:55 : Start filling LHe
    • 17:00 : Status after two cans (188.8l LHe) =TMC,Si=80K, TMagn,u=50K, pVC=0.45mbar


  • 01.03.2012: THIRD DAY - MIX IN
    • 08:00 : Status = TDewar=78K, TMC,Si=80K, TMagn,u=81K, pVC=0.67mbar, connect 3rd can LHe
    • 11:45 : TMC,Si=4K, start pumping vacuum vessel.
    • 14:00 : Start condensing mix. T1=688mbar, T2=700mbar, T3=0mbar, p4=774mbar.
    • 14:10 : 100% He-Level. Total consumption to reach this level: 428.2 litres (Five cans) .
    • 16:20 : Close Heat-Switch (IPCS#4=1.5A, IH=0.5mA) @ TRuOx=700mK
    • 17:20 : All mix is in, all pumps are running. ISTILL=3.0mA, TRuOx=90mK


  • 02.03.2012: 4th DAY
    • Testing FPD
    • Connecting and Testing Pt-NMR


  • 05.03.2012: 1st RAMP MAGNET
    • Satus : Heat switch is closed.
    • 12:40 : IM= 40 A, heat switch closed (1,5 A)
  • 07.03.2012: 1st DEMAG
    • 11:04 : Open HS, Ti= 19.6 mK (corresponding to Noise Thermometer), Bi= 3.96 T
    • 19:06 : IM= 0.6 A, TNMR ~ 389 uK, NT was disturbed by additional noise contribution in the frequency spectrum.


PLM-4 display shows temperature after demag (Curie-Mode)(14.03.12).
  • 08.03.2012: 2nd RAMP MAGNET
    • 12:00 : IM= 40 A, heat switch closed (1,5 A)
  • 14.03.2012: 2nd DEMAG
    • ! Changed setup of PLM-4! See NMR-textbook page 23
    • 11:04 : Open HS, Ti= 14.95 mK (corresponding to Noise Thermometer), Bi= 3.96 T
    • 19:06 : IM= 0.1 A, TNT ~ 300uK ( caused by disturbances !!! ), TNMR ~ 85 K (!!!) in Curie Mode.


  • 17.03.2012: 3rd RAMP MAGNET
    • 13:05 : Closing heat switch.
    • 13:38 : IM= 40 A, heat switch closed (1,5 A)
  • 21.03.2012: 3rd DEMAG
    • 10:43 : Open HS, Ti= 19.23 mK (corresponding to Noise Thermometer), TNMR= 19.045 mK, Bi= 3.96 T
    • 10:59 : Start Demag: TNT= 17.80 mK
    • 16:16 : Stop Noise-Thermometer read-out due to massive external distributions by additional noise (SQUID-Radio Moscow :) ).
    • 18:50 : IM= 0.3 A, TNMR ~ 240 K in Curie Mode.
  • 22.03.2012: MIX OUT
    • Some rf-heating tests
    • 14:30 : Start putting mix in tank 1 and 2.
    • 18:00 : After using babypump :T1=688mbar, T2=700mbar, T3=0mbar, p4=1032mbar.
    • ALL MIX IS DUMPED IN OUR TANKS


TO DO

  • Find correct setup of the PLM-4 Korringa-Mode.
  • Improve Filter-Design!
  • Reduce parasitic heating by rf-signals.
  • Get rid of SQUID-Radio Moscow :)
  • Remove partially plugged flow of cooling water