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More information available in User interface specification document (8.1.4); Requirement specification document (A.3.4). The user wants to measure the dispersion function of the machine. This measurement requires the implementation of BPMs and an RF master clock (set and get of the RF frequency within a narrow range around the nominal value). The measurement structure is identical to that of subsection \ref{usecase:chromaticity}. The user sets the value of the step in RF frequency ($\Delta f$, a small value of a few \unit{\Hz}) and the number of such steps. Then the RF frequency is changed between $f_0$, $f_0 - n_\text{steps}\Delta f$ to $f_0 + n_\text{steps}\Delta f$ and back to $f_0$ (we do this path to avoid any large change in the RF frequency). At each value of RF frequency, a beam orbit (horizontal and vertical local orbit positions at each BPM) is recorded. For each BPM, then a polynomial fit (usually linear) is made of the local orbit to the RF frequency. The linear coefficient of this fit (normalised by a coefficient depending on the momentum compaction factor) is a local value of the dispersion. Dispersion functions (horizontal and vertical) are then obtained at the locations of each BPM.
Due by November 15, 2025Detailed description: Use interfance specification document (8.1.2), Requirement specification document (A.3.6, A.3.6.1) The user would like to measure the orbit response matrix --- response of the horizontal and vertical beam orbit to the variation of horizontal and vertical dipole correctors. This measurement requires having BPMs to be able to measure the orbit of the beam at different locations along the ring. Another requirement is the possibility to control the strength of the dipole corrector magnets. This measurement is supposed to measure an orbit response matrix (ORM) with a given set (or subset) of dipole correctors (or steerers) and using all or a subset of BPMs. The classical way of doing the measurement involves changing sequentially the strength of each dipole corrector (horizontal then vertical, in total $(M_\text{horizontal}+M_\text{vertical})$) and recording the beam orbit (a vector ($N_\text{horizontal} + N_\text{vertical}$, number of horizontal BPMs + number of vertical BPMs)). The resulting vectors are stacked into an orbit response matrix with dimensions ($(M_\text{horizontal}+M_\text{vertical}) \times (N_\text{horizontal} + N_\text{vertical})$)
Due by September 15, 2025•5/5 issues closedWorking EPICS bindings
No due dateWorking TANGO bindings implementation
No due dateMore information available in: User specification document (8.1.1), Requirement specification document (related info in A3.6.2) The user would like to get the value of the tune and set it to a desired value (not necessarily the model one. This measurement requires having a tune monitor (diagnostics) element (see subsection~\ref{subsec:tune_monitor_element}). This element is supposed to give access to the storage ring tune or to the booster tune at a given time along the ramp. This measurement requires having a quadrupole (corrector) magnet element either in a family or not (see subsection \ref{subsec:magnet_element}). The measurement requires at least two quadrupole families (to be able to set horizontal and vertical tunes independently). To set the tune, one needs to compute a tune response matrix (or use a precomputed one), either from the machine model or from a dedicated measurement. A response matrix will be a ($2\times N$) matrix containing a response of the tune to a change of a quadrupole corrector strength/current. $N$ stands for the number of quadrupole families used. To set the tune, an inverse matrix is used to find the required strength of quadrupole correctors for a desired tune. This calculated strength are applied to the magnets to correct the tune.
Due by August 1, 2025•2/2 issues closed