Speaker
Description
EPURE Facility (standing for “Expériences de Physique Utilisant la Radiographie Éclair”, i.e Physics Experiment using Flash radiography), located at the CEA Valduc site, is a joint French-British experimentations facility. The key purpose of the Facility is to X-ray dense in-motion objects simultaneously with three radiographic axes. The radiographic images are thus captured over very short timescales (a few nanoseconds), hence the term Flash X-ray imaging.
The radiographic machines implemented in the EPURE Facility use two different technologies. Two of them are Linear Induction Accelerators (LIA) and the third one is a diode-equipped inductive voltage adder (IVA) generator. Each radiographic axis (from the end of the machine end to a detector) is over 80 meters in length.
Due to the facility’s geometry, when an experiment is underway, the detector for the third axis is not visible from most of the Laser Tracker measuring stations. Moreover, limited access makes it
complicated for a station to be positioned behind it. In an effort to optimize technical operations, and
with the aim to obtain a remotely operated a single Laser Tracker station, a solution needed to be found to measure the detector which is out of view.
The solution opted for consists in a fiducialized mirror device fixed on a wall ensuring a line of sight from most of the possible stations to the third axis detector. This mirror device consists in a mirror mounted onto 6 degrees of freedom positioning system and at least three SMRs. The mirror is situated in terms of the three SMR positions.
The associated measuring method (for a single target in this case) is carried out using the four steps
listed below:
- Definition of the mirror plane and its associated frame within the nominal frame;
- Measurement reading for a virtual target in the symmetry of the real target in the mirror
frame;
- Transformation from the virtual target to the real target using the symmetry’s matrix;
- Frame transformation from the mirror frame to nominal.
This method is still in development and given the results and laser beam behaviour, still requires further optical corrections.
