The MetalJet D2+ is the latest version in Excillum’s line of extreme brightness X-ray sources, following the success of the earlier MetalJet D1 and D2. It is similar to a standard X-ray tube, but features Excillum’s unique metal-jet anode technology and advanced electron optics. Within the 5-30 μm spot-size range, it delivers significantly higher brightness than any other available microfocus X-ray source on the market, and with an excellent spot quality. This makes it an ideal source for any microfocus application requiring shorter exposure times, higher throughput or better signal to noise.
With the introduction of Dynamic Adaptation technology in July 2019 the practical cathode lifetime has been further extended 2-4x, up to a full year of 24/7 operation depending on application.
Features and Benefits
Data Sheet in PDF
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Features and Benefits
  • Extreme microfocus source power
  • Optional shutter
  • Superior spot quality
  • Optional dual-port mode
  • Minimal maintenance
  • User variable size and aspect ratio of spot
  • LaB6 long-life cathode
  • Very stable X-ray emission and spot position
  • User-friendly Graphical User Interface
  • Controlled through GUI or TCP/IP protocol
  • Integrated radiation shielding
  • Adjustable take-off angle
  • No external cooling water requirement
  • Operated remotely from any computer
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Technical Specifications

Technical Specifications

Target material1 Ga or In rich metal alloy Min. focal spot size ~ 5 μm
Target type Liquid jet Emission stability3 < 1%
Voltage 21-70 kV Position stability3 < 1 μm
Power2 0-250 W Min. focus-object distance4 18 mm
Max current 4.3 mA Beam angle 13°/30°

Available Anode Alloys


Anode Alloy Gallium
[weight %]
[weight %]
[weight %]
ExAlloy-G1 95 5  –
ExAlloy-I1 68 22 10
ExAlloy-I26 47 37 16
ExAlloy-I3 75 25  –

1) The room temperature liquid metal alloys supplied for the MetalJet source consist mainly of gallium, indium and tin. They have low reactivity and low toxicity but should be handled according to their safety data sheets and local regulations. 
2) The actual power used is dependent on spot-size and voltage. However, maximum output power of the 70 kV high-voltage-generator is 300 W.
3) Standard deviation.
4) Without a shutter (24.8 mm with shutter).
5) Without a shutter (10.5° with shutter).

6) Operation of ExAlloy-I2 requires that the MetalJet source is equipped with a heater system since the melting point is above room temperature. Due to this requirement the MetalJet sources with ExAlloy-I2 are under limited availability. Please contact us for further information.

70 kV Performance Examples

70 kV Performance Examples

Jet material Nominal X-ray spot size6 [µm] E-beam power [W] Ga Kα (9.2 keV)  peak brightness [photons/(s mm2 mrad2)] Ga Kα (9.2 keV)  radiant flux  [photons/(s mrad2)] In Kα (24 keV)  peak brightness [photons/(s mm2 mrad2)] In Kα (24 keV)  radiant flux  [photons/(s mrad2)]
ExAlloy  G1
10 125 4.3×1010 6.3×106 6.0×108 9.0×104
ExAlloy G1
20 250 3.2×1010 1.1×107 4.7×108 1.6×105
ExAlloy I1 10 125 2.6×1010 3.7×106 1.7×109 2.6×105
ExAlloy I1 20 250 1.8×1010 6.4×106 1.4×109 4.7×105
ExAlloy I2 10 125 1.6×1010 2.3×106 2.9×109 4.4×105
ExAlloy I2 20 250 1.1×1010 4.0×106 2.3×109 7.9×105

6) Actual e-beam spot is 40×10 and 80×20 μm line focus respectively, but the apparent X-ray spot is essentially circular.



Installation and operation

Installation and operation

The source consists of the head and the pump system with dimensions shown in the drawing. The head has to be mounted essentially straight above the pump system. The coupling is semi-rigid, allowing some movement of the source head.

In addition, the MetalJet D2+ 70 kV consists of two 4U (176 mm height) 19” rack electronics boxes and a floor standing air/water chiller (69×36×62 cm), that can be mounted up to 4m from the head and pump system.

Sources operating with ExAlloy I2 furthermore have heater jackets around parts in the alloy recirculation loop as well as an additional 3U (133 mm height), 19” rack mounted controller.

The source can be remotely operated through TCP/IP or directly through the GUI. The GUI can be operated on the source itself if it is equipped with monitor, keyboard and mouse, or on most computer platforms with a TCP/ IP connection to the source.

The source cannot be operated as a standalone unit and must be integrated into a system providing the proper interlock connections.

Mains: AC, single phase, 200-240 V, 16 A, 50/60 Hz.

Ambient: 20-25°C (stable within ± 0.2°C for optimal source stability), max 85% relative humidity.

Safety & Compliance

Excillum’s X-ray sources are compliant with the Machinery Directive 2006/42/EC, RoHS Directive 2011/65/EU and Low Voltage Directive 2014/35/EU. Excillum’s X-ray sources are a sub-assembly and therefore excluded from the EMC Directive 2014/30/EU, hence also conform to the definition of partly completed machinery and so should not be CE marked. Our X-ray sources are intended for system integration into customer equipment. The system integrator is solely responsible for final certification and safety compliance. X-rays emitted from the source are harmful for the human body and it is the sole responsibility of the system integrator to comply with all regulations and to protect all personnel during operation. The X-ray source may be subject to local government radiation hazard regulations.


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