Girard Perregaux

chippyfly
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G-P Gyromatic ref: 7317 dilemma

On this forum I had expressed my concerns about the radioactivity emanating from my G-P ref: 7317 Gyromatic.  I store most of my small watch collection on cushions in individual wooden boxes with hinged transparent lids that all fit neatly together, twelve at a time in desk draws.  All my manufacturers’ watch boxes are stored elsewhere in archive.  The innocuous looking luminous hands and indexes of my Gyromatic indicate “off the clock” readings on my little Geiger counter, which has a maximum register of 9.99µSV/hour.

From calculations based on a few measurements at varying distances (using inverse square law) from my Gyromatic, the true “spot” radiation is approximately between 13.0µSV/hour and 15.0µSV/hour, which is quite high and probably harmful to my wrist and body over time.  So last weekend as an experiment I lined one watch box internally with six panels cut from some scrap lead sheet 1.8 mm thick to completely screen my environment from most of the stored Gyromatic’s radiation.  The transparent lid is now blocked with lead so the dial is hidden from view.

Below are two photographs of the results.  The first is the open lead-lined box containing the Gyromatic on its cushion close to the Geiger counter, which reads 9.99µSV/hour maximum as expected.  The second photo shows the box's lid closed and the closely positioned Geiger now reading 0.90µSV/hour.  My home’s background radiation is between 0.12µSV/hour and 0.14µSV/hour so with the box closed, only approximately 0.78µSV/hour radiation is escaping to do me “harm” at my desk.  I think I can live with that.

However from 1960’s back to 1920’s many watch dials were painted with radium-powered luminosity.  What accumulated harm did they inflict on those watch wearers?  After all, wearers in likely ignorance were happy to wear their luminous watches.  Of course a single watch on a wrist is a point source of radiation.  Retailers and manufacturers with a large number of radium powered luminous watches held in store or on display must have been detrimentally affected by the multiple sources of radiation where they worked.

Are there any records of the harm caused to individual wearers, which perhaps precipitated the change in the law in 1960’s?

How harmful is my Gyromatic to wear and should I have the Gyromatic’s dial renovated with the removal of the luminous paint, which will down-value and lose the dial's wonderful current patina?

Best

Clive

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