Why are there different lengths of fluoroscopic test stand bars?
The shorter bars (total length including thread 39cm) are used with a smaller fluoroscopic test stand frame (28cm x 28cm). This combination is used with the test phantom ETR-1.
The longer bars (total length including thread 42.8cm) are used with a larger fluoroscopic test stand frame (30cm x30cm). This combination is used with the Primus A and Primus L test phantom.
The length dimensions have no relation to any acceptance test or constancy test standard.
The length dimensions are the result of a user-friendly balance between the greatest possible distance between the test body and the fluoroscopic test stand frame and a very good stability.