Speaker
Description
The European Synchrotron Radiation Facility (ESRF) was established in 1988 as the world’s first 3rd generation light source. Alignment was critically important. The quadrupole and sextupole magnet alignment tolerances were 100 µm in both the horizontal and vertical directions perpendicular to the beam.
The vertical tolerance was achievable with high precision levelling, but in the late 1980’s only very specialised instruments could achieve precision like this in the horizontal plane. Two instruments that could achieve these tolerances under specialised conditions were the distinvar and ecartometer, which were the instruments used to install and measure the initial Storage Ring in 1992.
Things have evolved considerably since 1992. In 1992 it took 57-man days to do a survey with 2700 observations. Uncertainty in the horizontal direction perpendicular to the beam was 220 µm. In 2024, 8 man-days (i.e. 4 teams of 2 people in one 8-hour shift) can make a survey with 9600 observations and uncertainty in the horizontal direction perpendicular to the beam is 50 µm.
This paper follows the evolution in the techniques, instrumentation, software and particularly the quality of the measurement results achieved at the ESRF over the past 32 years.
