Vacuum-Brazed Cooling Elements

The cooling plate was specially designed for use in a 3He – 4He cryostat. During manufacture, more than 100 precisely positioned individual parts are joined with high precision in a vacuum brazing work step.

Operating temperature: 5mK to approx. 0.5 K
Special feature: absolutely helium-tight cavities

The cooling plate consists of two highly thermally conductive copper plates that are joined in a vacuum-tight and distortion-free manner by means of high-temperature vacuum brazing. This design principle enables the inserting of any cooling channel structures in one of the two plates and thus to tailor the cooler contact area precisely to the heat loads. Consequently, area outputs of up to 2 MW/sqm can be achieved.

The refrigeration head serves as a cooling unit for a storage ring. The joints must withstand temperatures alternating from -271°C to +350°C. The specification for the perm value at the weld seams is less than 1.05. The leakage rate must not exceed the value of 1 x 10-9 mbar x l/sec. This requires a purity suitable for UHV.

The antenna is used for ion sources. Here, the component serves as a shield and as a cooling element. The vertically arranged copper rods are hollow, and they are water-cooled when in use. For the production of the antenna, we join over 30 individual components in a single vacuum brazing step.

The design principle of our round cooling plates corresponds to that of the square plates. The customised cutting of the cooling channels and connections is likewise possible here. The heat elements are characterised by a high degree of flatness and parallelism. Other material combinations such as the copper/copper combination shown are also possible (e.g. copper/stainless steel).