Neues
Termine
Konferenzen
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SANS-Workshop 21./22. Juni
21. Juni - 22. Juni
Seminare
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Commissioning of the CASCADE detector at MIRA
04. Juni 14:45 - 15:45
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Structural and dynamic study of several magnetic systems by means of Neutron Resonant Spin Echo techniques
11. Juni 14:45 - 15:45
- “ZETA” is a Neutron Resonant Spin Echo (NRSE) option which is currently installed on the thermal...
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Macromolecular crystallography at the European Spallation Source
18. Juni 14:45 - 15:45
- The structure determination of biological macromolecules by X-ray crystallography is a key...
Sputtering machine for producing supermirrors
The optical functional coatings of supermirrors used for the neutron guides are produced in a dc-magnetron sputter process. This process offers the advantage of a homogeneous large area coating in the final production. Within the sputtering process gas ions out of a plasma are accelerated towards a target consisting of the material to be deposited. Therefore negative voltage is applied to the target. Due to the bombardment with ions material is detached (’sputtered’) from the target and afterwards deposited on a substrate in the vicinity. The process is realized in a vacuum chamber, which is pumped down to 10-7 mbar before deposition starts. To enable the ignition of a plasma argon is feed into the chamber up to a pressure in the low mTorr region.
At our facility the sputter machine is divided in three large chambers (see fig. ): the first one is used for heating and preparing (cleaning) the substrate for deposition, the second one is the deposition chamber, and the third one is used for taking out the plate. Through the chambers the glass substrate is moved by an electric movement system. The sputter process is controlled by a software written in LabView.
The supermirrors for the neutron guides consist of Ni/Ti-bilayers with thicknesses varying from 20 to 800Å. This layer system is produced by a sputtering machine equipped with two targets (Ni and Ti). The material of the layer is chosen by applying the voltage to one of the targets. The thickness of the layer is achieved by moving the substrate with the right velocity through the particle shower below the active target. This velocity is inverse propotional to the estimated layer thickness. The whole coating process runs automatically. Currently we are producing supermirrors consisting of more than 100 layers which leads to an m-factor of 2. We are able to produce supermirrors up to a size of 220 mm by 1050 mm.
