Resonance Scanners

Definition and scope

Resonance Scanners are the standard instruments by which the Tower's standing and emergent resonance is detected, measured, and recorded. They are employed across the floors for the purposes of Resonance Measurement, the compilation of Resonance Alerts, and the general calibration of a floor's ambient condition prior to cataloguing. A scanner does not produce resonance; it reports it, and the distinction between reporting and producing has been the subject of more Concordance amendments than any other single question in the instrument's history. The standard instrument comprises a tuning slug of inert alloy, a detection coil, a graduated drum for the recording of amplitude, and a housing of variable length depending on the floor's rating. Handheld units are issued to Resonance Technicians on rotation; larger fixed installations are mounted at floor-edges and stairheads.

Classification

Resonance Scanners are classified by the Guild into four series, distinguished by the range of amplitudes they are certified to report: - Sigma series. Required by Third Concordance Amendment 14-f for the mapping of non-Euclidean geometries. Units of this series carry a doubled coil and a slower drum. - Kappa series. The general-issue instrument. The Kappa-7 is the current standard pattern, superseding the Kappa-5 after the incident of the West Stairhead. - Rho series. Fixed installations for continuous monitoring. These report to Resonance Alert stations. - Epsilon series. Short-range instruments issued for the inspection of shelving, apertures, and documents in confinement. A fifth series, the Omega, is listed in the Harmonic Resonance Protocols but has not been issued since the dissolution of the lower scriptorium. Guild inventory for the present cycle records eleven Omega units, all noted as "unaccounted for in transit," a status that has persisted for four consecutive cycles without amendment.

Operation

A scanner is prepared before use by the application of Resonance Foil to the coil face, a step supervised under Guild authority and inspected by Resonance Damping before the instrument descends below the mid-landings. The foil is renewed after every fourth reading, or immediately if the drum skips. A skipped drum is not, in itself, grounds for an alert; it is grounds for a second reading, and the second reading is the one that is recorded. Readings are entered in the floor's resonance ledger against the local amplitude scale. Where the amplitude exceeds the floor's registered profile, the reading is escalated to the Bureau of Coincidental Resonance, which maintains the reference profiles used to inscribe Resonance Dampeners. Where the amplitude falls below the registered floor of detection, the reading is entered as zero and the instrument is checked against a known source before the shift concludes. Visitors may handle an Epsilon-series scanner under supervision. They may not handle a sigma-rated scanner, and they may not enter a mapped non-Euclidean gallery with an unmapped one.

The Kappa revision

The Kappa-7 pattern entered service in the winter of the Long Landing, replacing the Kappa-5 following a dispute now recorded as the Western Resonance Spire Incident. The Kappa-5 had been found to under-report amplitudes in the presence of Spiral Resonance, a deficiency the Guild attributed to coil geometry and the Bureau attributed to the foil. The two offices exchanged nine memoranda over the question, of which the seventh is the only one that cites a measurement rather than a prior memorandum. The Kappa-7 corrected the coil geometry. It did not correct the foil. The Bureau's position, recorded in its own annex and never formally withdrawn, is that the deficiency was in the foil all along and that the Kappa-7 now reports accurately for reasons unrelated to its redesign. The Guild's position is that the instrument was rebuilt and the matter is closed. Both entries remain in the ledger.

Scholarly disagreement

The principal unsettled question concerns what a resonance scanner measures when it is itself resonating. Under Resonance Measurement, an instrument at rest relative to a floor reports the floor; an instrument in motion reports a compound of floor and motion. This is uncontested. What is contested is whether an instrument mounted permanently to a vibrating wall — as the Rho series is mounted — reports the wall or reports itself, and whether the distinction is meaningful. The Third Concordance treats the question as settled by Amendment 14-f, which specifies sigma-rated scanners for non-Euclidean mapping but is silent on fixed installations. The Harmonic Resonance Protocols assume the instrument reports the wall. The Office of Experimental Resonance has argued, in three successive reports, that a fixed scanner reports a standing condition that is neither wall nor instrument but a property of the mounting point, and has requested permission to unmount three Rho units to test the claim. The request has been before the Guild for six years. Meanwhile the Rho units continue to report, and their reports continue to be entered in the ledgers, and the ledgers continue to be cited.

Maintenance and custody

Scanners are returned to the Guild's annexe at the end of each rotation for inspection, re-foiling, and drum replacement. Instruments not returned within the stated interval are entered in the missing-property roll, where they are cited thereafter as precedent in disputes about custody. The roll currently includes forty-one scanners, nineteen of which are recorded as last seen in the possession of clerks whose own transfers were never confirmed. Drums collected from decommissioned scanners are retained indefinitely. They are stored in the sub-annexe beneath the Ledger Hall, and it is noted in the maintenance record that the sub-annexe floor vibrates at an amplitude that would, if reported by a Rho unit, generate a standing alert. No Rho unit is mounted there. The drums are counted annually and the count is entered without comment.