The manual version of the RTTA is supplied with an innovative, user-friendly system to align the arm with the desired ports.
Fitted to the top of the thimble ring are a number of adjustable position stops. These engage with a pair of spring-loaded bearings that can be withdrawn while the drive is rotated into position then re-engaged to hold the drive firmly in position by using a simple lever. Each stop can be individually aligned with a port axis to define default angular positions which are very reproducible.
True UHV rotation with no oil, slip rings, bellows or differential pumping. The Radial Telescopic Transfer Arm is actuated by the MD64LB and MD40 magnetically-coupled MagiDrive rotary feedthroughs. They provide true UHV performance, without any bellows, oil, slip rings or differential pumping. The larger MD64LB has a break-away torque of ~40Nm, providing an extremely stiff coupling, ideal for rotating the arm assembly. The smaller MD40 actuates the mechanisms to drive the arm in and out.
An issue with many radial distribution chambers system designs is the issue of the rotating arm motion causing the arm extension assembly to move (often described as the axis cross-talk). Therefore, rotation of the arm also causes the sample to be driven in and out, losing its position. To overcome this, complex software programming is required to unwind the secondary drive during rotation of the arm. UHV Design recognises this to be an unwanted feature and has, therefore, removed this as an issue through a unique mechanical design used on many other UHV Design manipulators over the years. In brief, this links the rotary motion of the MD64 arm to the motor mounting of the smaller MD40, mechanically unwinding the undesired motion, without the need for complex software.