Like the CCR with Tail Extension a high temperature CCR is a modified low temperature system. The addition in this case is a hot-stage, which the sample is attached to, containing the heaters and separated from the standard cold-stage by thermal insulating standoffs. The standoffs thermally link the two stages at low temperatures and isolates the hot stage at high temperatures
Two new high temperature CCRs are being built. These CCrs will have a wider temperature range than existing NCNR high-temperature CCRs.
Temperature Gradient Issues
When using high temperature CCRs, one should be aware that the temperature of the sample is not always the same as that being read by the sensor on the sample block. The bottom of the can is cooler than the sample block because it is farther from the heat source. The gradient gets worse as the system goes to higher temperatures. In most cases, the gradient is negligible below room temperature.
The following tests were done by mounting an extra sensor on the bottom of the sample can and measuring the gradient across the can. Both the inner and outer heat shields were in place for these tests. Failure to use the heat shields, especially the inner shield, can cause huge gradients (up to 40K) in temperature. Always use both cans!
It is important to note that the sample and sample can take much longer to reach the set point than the sample block. A delay of about one hour can be expected in most cases for the bottom of the sample can to reach the desired temperature.
Both the time delay and the temperature gradient are dependent on the system and sample can. Below you will find test results for the individual high temperature CCR sytems. These results can be used as a guide, but may not be repeatable in your experiment.
**The names listed above correspond to the coldhead, not necessarily the compressor. Sometimes cold heads and compressors get switched, so make sure that you are looking at the right information for your coldhead.
Available Instruments:
System Description Temperature Range (K) Manufacturer Available Instruments System Drawing PID Zone Table CCR-HO1 27-650 Leybold All CCR-HO2 27-650 Leybold All CCR-HO3 27-650 Leybold All CCR-HO4 27-650 Leybold All CCR-HO5 20-800 Anticipated ARS Not in Service CCR-HO6 20-800 Anticipated ARS Not in Service More Information:
- High Temp. CCR Manual (pdf will open in new window)
