Sourcing photomultiplier tubes from China

Duty on photomultiplier tubes

Read from the UK Trade Tariff on 7 November 2026, photomultipliers under 8540 20 80 91 carried 0% duty for goods from China. The supplied tariff record lists no anti-dumping or countervailing duty, suspension or attached import control for this line.

Heading 8540 covers thermionic, cold cathode and photocathode valves and tubes. The table shows photomultiplier design options sharing the same commodity line, rather than separate tariff subdivisions. See the wider valves and tubes guide.

Confirm the commodity code against the actual goods and datasheet, especially when ordering an assembled detector rather than a bare tube.

Specify the photocathode and test conditions

Specify the photocathode material, spectral response, window material, active area, envelope dimensions and pin arrangement. State whether the tube has an end window or side window, and whether separate anode outputs are needed. Agree substitutions before production.

Set acceptance criteria for gain, dark current, sensitivity, pulse response and linearity. Define the supply voltage, divider circuit, temperature, light source and dark-conditioning procedure used for testing. Ask for results traceable to each tube.

Official guidance excludes component parts sold business to business from the RoHS Regulations. For components incorporated into electrical products sold in the UK, obtain material compliance information and identify any exemption relied upon, as discussed in the wider guide. Use testing and certification support to review the evidence for the intended equipment.

Worked duty example

Illustrative example, not a quote: Illustrative batch of photomultiplier tubes for a small instrument manufacturer under 8540 20 80 91, invoiced at £30,000 free on board, with £900 of freight and insurance to the UK. The customs value is £30,900. Duty at 0% is £0. Import VAT at 20% is charged on the customs value plus duty, £30,900, so it is £6,180. With no duty, the only import tax is the VAT, which a VAT-registered importer can usually reclaim. The import duty and VAT guide explains each step.

Inspection checklist

Identity: check tube markings, batch records, dimensions, window orientation and pin arrangement against the approved drawing.

Performance: compare gain, dark current and sensitivity with agreed limits using the agreed test circuit and conditioning procedure.

Condition: inspect the glass envelope, optical window and pins for cracks, contamination, scratches or distortion.

Packing: check individual cushioning, protected pins and separation from loose accessories. Plan sampling with the quality inspection guide.

What goes wrong

A nominally equivalent tube can have a different spectral response, window material or pin arrangement. A gain figure measured with a different divider circuit or supply voltage may not predict performance in your instrument.

Dark-current comparisons become unreliable when temperature and conditioning differ. Transit damage and dirty windows can also undermine otherwise acceptable tubes. Agree the test method and packing before dispatch, then retain arrival results against the supplier's records.

Cambridge China Bridge sources these products for UK businesses, checking the factory and the documents before shipment. See factory verification. For components and parts, see sourcing for manufacturers.