Tenders Are Invited For Refrigerators – He3-He4 Based Mk Cooling System

Refrigerators – He3-He4 Based Mk Cooling System. Quantity To Be Purchased  1 Dry He3-He4 Cooling System With Sample Holder (Or Equivalent)  1 Superconducting Vector Magnet With Power Supply Unit (Or Equivalent)  He3-He4 Mixture (Or Equivalent) General Description: The Devices Subject To Procurement Are Ultra-Low Quantum Circuits They Will Be Used To Investigate Transport In The Presence Of Temperature And An External Magnetic Field Of Any Direction In A Frequency Window From Direct Current To 20 Ghz. The Proposed Instruments Must Meet These Requirements: Minimum Technical Requirements: A) 1 Pc Dry He3-He4 Cooling System With Sample Holder  He3-He4 Cooling System With <15Mk Base Temperature And >250Uw Cooling Power At 100Mk.  Operation Without Liquid Helium, With Pulsating Tube Cooler (Cooling Power At Least 1.8W At 4.2K)  Oil-Free Pumps In The Mixture Circuit.  Safety Function That Protects The Mixture In Case Of Possible Pressure Increase.  Built-In Flow Meter For Monitoring The Mixture Flow.  Pre-Cooling Circuit With Liquid Nitrogen, Built-In Heating Resistors With Power Supply For Fast Cooling And Heating  Computer Control Of The System, With A Program Capable Of Automatic Cooling And Cold Keeping And Logging Of Temperature, Pressure And Heating Power Values.  Calibrated Thermometer Set For Monitoring Different Parts Of The System.  At Least 40 Dc Lines To Mixing Chamber Level.  14 Semi-Rigid Coax Cables With >20Ghz Bandwidth Up To The Level Of The Mixing Chamber With Thermal Contacts Through Dampers At Each Level.  From The 14 Semi-Rigid Coax, An Rf Line Made Of Superconductor To The 4K Plate.  Sample Holder, Which Allows Sample Insertion Without Disassembling The Cooling System. Sample Holder Diameter At Least 72Mm. Wiring From The Temperature Measurement Room To The Sample Area (At Least 48 Twisted Pairs, Heat Trapped Shielded Dc Wires). A Connection Mechanism That Allows Wires That Are Thermalized In The Mixing Chamber To Be Connected To The Sample Space. The Sample Holder Should Be Equipped With Calibrated Thermometers, Built-In Heating, Computer Control And An Insertion Mechanism. The Cooling Time Of The Sample Holder Should Be A Maximum Of 9 Hours To 100Mk. The Cooling Capacity Of The Sample Holder Should Be Min. 100Uw At 100Mk With Full Wiring. Minimum Temperature <= 20Mk.  A Separate Shield That Allows The Fridge To Cool Down Without The Magnet. B) Superconducting Magnet That Can Be Integrated Into The A) System, 12T  Maximum Magnetic Field At Least 12T  Minimum Internal Diameter 90Mm  The Magnet Must Be Able To Be Integrated Into The A) Cooling System And The Sample Holder Of Point A) Must Reach The Center Of The Magnet.  The Magnet Must Have A Safety Function That Protects The Magnet And The Cooling System From Sudden Quench.  Magnet Stand For The Superconducting Magnet. The Power Supply Computer Must Be Controllable Via Gpib And Usb Or Serial Port. The Cables Required For Connection Are Also Mandatory Components. C) C) Other Needs In B