Testing of the HARpy Application with a View to Replacing SUSSIX in the OMC Software

Presented here is an investigation into the suitability of the HARpy application as a replacement for SUSSIX in the Optics Measurement and Corrections (OMC) software. Comparisons have been made between the abilities of SUSSIX and two operating methods of HARpy (BPM and SVD) to identify optics parameters of the LHC — namely amplitude, tune, phase advance and horizontal and vertical coupling of the betatron oscillations of the beam — from real turn-by-turn BPM data. The accuracy and precision of all three methods are compared as a function of number of turns present in the data. A study has also been conducted into the accuracy of both SUSSIX and the HARpy-BPM method when analysing simulated data containing known excitation parameters and several levels of random noise. The HARpy application was found to perform similarly to SUSSIX when analysing real AC Dipole data, showing high accuracy and precision, particularly for the mainline amplitude, tune and phase advance. The analysis of the simulated data did not show such high accuracy; results taken with zero random noise show uncertainties of an order of magnitude similar to those found when real data was used, but for higher levels of noise the uncertainties were several orders of magnitude higher. Simulated data plots also did not show the expected trend of uncertainties decreasing as a function of number of turns.