X-ray tubes and tube assemblies

01

Match focal spots and anode input power

Varex's A-134 is a 71 mm, 150 kV rotating anode insert for heavy-duty general radiography and fluoroscopy, with a 12° rhenium-tungsten-molybdenum target and nominal focal spots of 0.6 and 1.2 (IEC 60336). Its nominal anode input power is 32 kW on the small focal spot and 76 kW on the large one (IEC 60613), and its rating charts note that exposure power equals kV × mA, for example 70 kV × 300 mA = 21 kW. [1]

Siemens Healthineers' SV 150/40/80C-100 tube assembly, for radiography and fluoroscopy, has a 150 kV nominal voltage (110 kV for fluoroscopy), 0.6 and 1.0 focal spots, a 12° anode, nominal anode input power of 40 and 80 kW at 150/180 Hz rotation (IEC 60613:1989) and 47 and 85 kW radiographic (IEC 60613:2010), with filament currents up to 5.1 A. [2]

Editorial note: smaller focal spots give sharper images but take less power, so check the single-load and serial-load rating charts for the exposure times and kV-mA combinations you will use, not only the nominal kW.

Give the supplier the application (radiography, fluoroscopy, angiography, industrial inspection), generator type and frequency, maximum kV, focal spots needed, typical and peak exposure techniques and workload per hour, the housing and cooling arrangement, mounting to the collimator and system, and the regulatory requirements in your market.

02

Check anode and housing heat storage and cooling

Varex rates the A-134 anode at 222 kJ (300 kHU) maximum heat content. Siemens Healthineers rates the SV 150/40/80C-100 anode at 450 kJ (600 kHU) and the complete tube assembly at 1.800 MJ (2.530 MHU), with a nominal continuous input power of 300 W without a fan and 450 W with one at 20–25 °C ambient, and publishes heating and cooling curves for anode and assembly. [1] [2]

Editorial calculation: both datasheets put 1 kHU at about 0.74–0.75 kJ (222 ÷ 300 and 450 ÷ 600). A 21 kW exposure lasting 0.1 s puts about 2.1 kJ into the anode, about 1% of the A-134's 222 kJ; fifty such exposures in quick succession add about 105 kJ, almost half its capacity before cooling, which is why serial-load and cooling curves matter for busy rooms. [1] [2]

At 450 W continuous with a fan, the Siemens assembly would take about 1,800,000 ÷ 450 ≈ 4,000 s (just over an hour) to shed its full rated assembly heat if no further load were applied; the published cooling curves give the actual behaviour. [2]

03

Check which IEC editions the focal spot and power ratings follow

The Varex and Siemens Healthineers data sheets on this page quote focal spots per IEC 60336 and nominal anode input power per IEC 60613 [1] [2]. IEC 60613:2010 "applies to X-ray tube assemblies either with a rotating anode X-ray tube or a stationary anode X-ray tube, intended for use in medical diagnosis" and covers definitions and conditions of electrical and loading characteristics during and after energization; its third edition was published on 27 January 2010. IEC 60336:2020 applies to focal spots in medical diagnostic X-ray tube assemblies at tube voltages up to and including 150 kV, with nominal focal spot values from 0,1 to 3,0; its fifth edition, published on 17 December 2020, introduced digital detectors and replaced the 2005 edition. [4] [5]

Both data sheets on this page sit at the 150 kV top of IEC 60336's scope, with nominal focal spots of 0.6 and 1.2 (Varex) or 0.6 and 1.0 (Siemens Healthineers) [1] [2]. Because the 2020 edition changed the measurement to digital detectors [5], ask a supplier which edition its focal spot values were measured to, and for the measurement report if you are qualifying a replacement tube.

Nominal anode input power, such as Varex's 32 kW and 76 kW, is defined under IEC 60613 [1] [4]. When comparing tubes, ask for the power at the same exposure time and anode speed from each maker's rating charts, since Varex notes that exposure power is kV × mA and reads limits off the charts [1].

Editorial calculation: the 0.6 to 1.2 focal spot pair on the Varex insert sits within IEC 60336's 0,1 to 3,0 range; the large spot's 76 kW is about 2.4 times the small spot's 32 kW. [1] [5]

Values are from the Standard Norge catalogue pages for IEC 60613:2010 and IEC 60336:2020; the full standards were not reviewed.

04

Check leakage radiation and filtration

US rule 21 CFR 1020.30(k) limits leakage radiation from the diagnostic source assembly, measured 1 m from the source in any direction and averaged over 100 cm², to 0.88 mGy air kerma (100 mR) in one hour at the leakage technique factors. [3]

Siemens Healthineers states leakage radiation of its SV 150/40/80C-100 assembly as no more than 0.8 mGy/h at 150 kV, 450 W and 1 m (IEC 60601-1-3), with 1.5 mm Al permanent inherent filtration plus 1 mm Al removable filtration at 75 kV, and an assembly weight of about 26 kg. [2] Editorial note: ask for the leakage test conditions and certificate of the exact assembly and housing combination you will install.

05

Compare what suppliers offer

Suppliers linked to this page list X-ray tubes; each card links to the page reviewed.

Listings include metal-ceramic, glass-envelope and panoramic X-ray tubes for industrial non-destructive testing and security inspection, and X-ray tubes among X-ray machine accessories. Ask each supplier for the tube type (rotating or stationary anode), focal spots, rating and cooling curves, housing heat capacity, leakage test data and the clearances held for medical use.

06

Trace the tube assembly parts

This is a functional reference built from the sources cited; it is not one maker's specification.

07

Fill the specification fields with values for your system

An X-ray tube quotation needs values for your system and workload. The table explains each field, gives published values where a reviewed source states them, and says what to obtain from the supplier.

08

Send the application, workload and system data together

Paste it into your enquiry below or into an email to a maker, then replace every bracket.

Application: [radiography; fluoroscopy; industrial]
Generator: [type; frequency; maximum kV]
Techniques: [kV; mA; exposure times; exposures per hour]
Tube: [focal spots; anode heat capacity; housing heat capacity]
Cooling: [fan; oil; water]
Compliance: [leakage; filtration; market clearance]

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