Implement thresholds rho_at_z1 and rho_at_z2

Related Issues and MRs

Dependency of MooreOnline!586 (merged)

• Please test together

Description

Add new configurable thresholds for transverse displacements of the major axis extrapolated to two values of z.

Properties

Adds two new configurable thresholds that can be used as keys in the map property MaxAbsDeltaMap, the property that sets the change thresholds for publishing updated conditions. The keys for the new thresholds are "rho_at_z1" and "rho_at_z2". Each has a corresponding new propery, Z1ForRhoAtZ1Thresh and Z2ForRhoAtZ2Thresh respectively, that sets the z coordinate at which to evaulate the extrapolated difference.

Implementation

In the notation of 'Beamspot monitor' in the 03 Apr 2025 RTA WP4/5 meeting, given InteractionRegion statistics mean position \overline{X}_{\alpha} and spread matrix S_{\alpha\beta}, where \alpha,\beta \in \{x, y, z\}, the extrapolated major axis of the of the interaction region is a_{\alpha}(z; \overline{X}, S) = \overline{X}_{\alpha} + \frac{S_{\alpha z}}{S_{zz}}\left(z - \overline{X}_{z}\right)

For two sets of statistics, the current published InteractionRegion (\overline{X}_{c}, S_{c}) and the latest test sample, (\overline{X}_{t}, S_{t}), the transverse change in the extropolated position is evaluated as \Delta\rho(z) \equiv \sqrt{\left(a_{x}(z; \overline{X}_{t}, S_{t}) - a_{x}(z; \overline{X}_{c}, S_{c})\right)^2 + \left(a_{y}(z; \overline{X}_{t}, S_{t}) - a_{y}(z; \overline{X}_{c}, S_{c})\right)^2}

The new threshold keys compute \Delta\rho(z) at fixed values of z as configured by the corresponding ZnForRhoAtZnThresh property. If it exceeds the threshold value, then (\overline{X}_{t}, S_{t}) are published as new InteractionRegion conditions.

Example configuration

Excerpted from MooreOnline!586 (merged), the new threshold keys and accompanying properties are configured as follows

    beam_spot_moni = BeamSpotMonitor(
        name="BeamSpotMonitor",
           :
        MaxAbsDeltaMap={
            'rho': 0.01 * mm,
            'rho_at_z1': 0.01 * mm,
            'rho_at_z2': 0.01 * mm,
        },
        Z1ForRhoAtZ1Thresh=-600 * mm,
        Z2ForRhoAtZ2Thresh=600 * mm,
           :
        )

This will cause BeamSpotMonitor to publish updated thresholds if \Delta\rho(0) > 10{\mu m} ('rho': 0.01 * mm) or if \Delta\rho(-600mm) > 10{\mu m} ('rho_at_z1': 0.01 * mm) or if \Delta\rho(600 mm) > 10{\mu m} ('rho_at_z2': 0.01 * mm).

Related presentations and documents

Presentations at RTA: WP4/5 Alignment, Calibration, QA meetings

• 'Beamspot monitor' on 03 Apr 2025
  • Describes the motivation for the new configurable thresholds, and updates estimates of samples sizes required to deliver indicated precision.