High Temperature Interfaces
- 800 K
- 450 K
This interface allows the cryocooler to operate up to 800K. Except as indicated in low power coolers such as DE-202 with 50 Hz power supply. The maximum and minimum temperature ratings of the cryocoolers is shown in table below.
The 800K interface design includes a thermal impedance which acts as a thermal isolator at very high and very low temperature (Below 8K). So it is not advised to use this with 4K systems. It will increase the sample temperature by approximately 1 K at no load for a 4K cooler.
It is mechanically fragile and must be treated with care during sample installation. The 800K interface is only supplied with ARS cryocoolers.
At 800K most sensors including Pt and thermocouples will anneal and the calibration will change from time to time. The annealing is a function of the cooldown and heat up rate. The accuracy at the low temperature (4 to 30K) is affected as the response curve (dmV/dT) is generally flatter at this section of the curve.
Standard system
The 800K interface includes the following:
- 800K interface with 50 ohm Cartridge Heater.
- High Temperature safety cut off (heater circuit).
- 1 ea. T/C (E-Type) for control in the range 4K to 800K.
Accuracy ~2K - 3K - Silicon Diode Diagnostic Sensor for re-calibration capability of T/C’s.
- Temperature Controller with dual sensor and dual T/C capability.
- Pt sensor for accurate sample temperature reading between 70K and 800K.
Temperature Ramp Rates
Using a CS-202 with 800K interface the following rates were obtained:
Cool down (Initial) 300K to 10K < 50 minutes
Heat up 10K to 700K < 10 minutes
Cooldown (Subsequent) 700K to 10K < 70 minutes
Construction and Specifications
Cartridge Heater = 0.2 Gauss at 1 cm. and 0.02 G at 2 cm.
OFHC copper C-101 Alloy.
Stainless Steel 304.
Stainless Steel 8-18
Vacuum Level Achieved: 5E-11 Torr. (Aarhus Univ)
Not electrically isolating
700K in lower cooling power coolers.
Mechanically fragile due to sapphire construction. Caution when using with heavy loads or high torsional or cantilevered forces.
The 450K interface uses a sapphire switch and stainless brace to keep it robust. It is Not electrically isolating.
The silicon diode sensors are accurate and maintain the accuracy after repeated cycling.
The 450K interface design includes a thermal impedance which acts as a thermal isolator at very high and very low temperature (Below 8K). So it is Not advised to use this with 4K systems. It will increase the sample temperature by ~0.5K at No load for a 4K cooler. Heat load of 0.5Watts on the sample will raise the sample temperature by 2K.
In the high cooling power systems this can be pushed up to 500K for short periods of time (Few Hours).
Standard system
The 450K interface includes the following:
- 450K interface.
- 1 ea. Silicon Diode for control in the range 2K to 450K.
- 1 ea. Silicon Diode for accurate sample temperature monitoring in the range 2K to 450K. Model DT-670A.SD (Accuracy +/- 0.25K from 1.5K to 100K; 0.5K from 100K to 450K)
- Thermofoil heater for control.
- Controller with dual channel capability.
Temperature Ramp Rates
Using a CS-202 with 450K interface the following rates were obtained:
Cool down (Initial) 300K to 10K < 50 minutes
Heat up 10K to 450K < 8 minutes
Cooldown (Subsequent) 450K to 10K < 50 minutes
Construction and Specifications
Sapphire rod with stainless bracing (NCt electrically isolated).
Will work at 500K but NCt continuous duty.
Thermofoil Heater – Kapton foil with Manganin Wire filament
OFHC copper C-101 Alloy.
High Temperature Epoxy.
Some adhesive (Some initial outgassing expected)