MBE Components, Valved Thermal Cracker Cell VTCC


Valved Thermal Cracker Cell


VTCC 40-130-54-KS
VTCC 40-130-54-KS with integrated cooling shroud and shutter on DN40CF (O.D. 2.75") flange
  • Full PBN solution for corrosive materials like Te, Sb, Se, As, Zn and Mg

  • DN40CF (O.D. 2.75" ) mounting flange compatible with all MBE systems

  • Thermal cracking up to 1300°C 

  • 130 cm3 PBN reservoir 

  • Excellent thermal isolation between low temperature reservoir and hot cracking zone

  • Integrated water cooling for cracker stage

  • Integrated rotary shutter (optional)

Download IconData Sheet


The Valved Thermal Cracker Cell VTCC is a full PBN valved cell with a water cooled cracker stage. The compact design of the cell allows its implementation on the space-saving DN40CF (O.D. 2.75") flange.

It features a crucible size of 130 cm3 which is sufficient for most R&D applications.

The reservoir heater of the VTCC is designed to perform fast and precise ramps in the temperature range from 100°C  to 650°C.

Three independent heating zones for reservoir, valve and cracker allow flexible adjustment of the cell operating conditions.

This, in combination with the full PBN construction of the valve, reservoir and cracker, enables a wide variety of the VTCC applications with the numerous high vapor pressure evaporation materials.

The crucible and cracker zones are shrouded by water cooling, minimizing the thermal load on the chamber.
VTCC zones

 VTCC zones

click to enlarge image
VTCC characteristics: valve position versus Te flux over time

The VTCC characteristics figure shows the example of the valve calibration, performed with Te. The valve demonstrates wide dynamic range, allowing precise flux adjustments in the % range of the maximal material flux.

The flux is reduced by about 5000 times when the PBN valve is closed. The VTCC may be equipped with the optional integrated shutter, with can be used to reduce the material flux even further.

The VTCC has excellent thermal insulation between the low temperature reservoir and the hot cracking stage.



A source concept like this is used for high vapor pressure materials, which form atom clusters. Typical evaporation elements are As, Se, Sb, Te, Zn and Mg.

Technical data

Mounting flange DN40CF (O.D. 2.75")
In-vacuum length L 287 mm
In-vacuum maximum total length TL 307 mm
Maximum airside length OL 507 mm
In-vacuum diameter D 36 mm
Maximum airside radius AR 134 mm
Shutter distance DS 15 mm
Shutter opening angle 90° ccw
Bakeout temperature 200°C
Cooling water flow 30-90 l/h
Weight 15 kg
Maximum chamber pressure 10-5 mbar

Heater type Ta wire filament
Thermocouple NiCr/NiAl (type K)
Operating temperature 100°C – 650°C
Outgassing temperature Up to 700°C
Cooling Integrated water cooling shroud
Crucible capacity 130 cm3
Crucible material PBN

Tube / Valve
Heater type Ta wire filament
Thermocouple W5%Re/W26%/Re (type C)
Operating temperature 200°C – 800°C
Outgassing temperature Up to 850°C
Cooling None
Tube material PBN

Heater type Ta wire filament
Thermocouple W5%Re/W26%/Re (type C)
Operating temperature 300°C – 1200°C
Outgassing temperature Up to 1300°C
Cooling Integrated water cooling shroud
Cracking insert material PBN



The crucible material suitable for most evaporants is PBN. Please refer to the Selection Guide or inquire for detailed recommendations. For information on crucibles see Crucibles.



Schematic drawing VTCC Schematic drawing of the  Valved Thermal Cracker Cell VTCC

(drawing shows
VTCC 40-130-54-KS)


Specific data

For general information on CF mounting flanges see Flange and Gasket dimensions.


[cm³] [mm] [mm]/[mm] [W]/[A] Product code Product code
VTCC 40 - 130 - 54 - K S- L287D36 Reservoir 400/8
Valve 100/5
Cracker 150/8
PS 60-10
PS 36-12
PS 36-12
PBN 130-54
* rotary shutter possible on same flange
*** UHV length L=287 mm


Product code:
e.g. VTCC 40-130-54-KS-L287D36

is a Valved Thermal Cracker Cell on DN40CF-flange for an 130 cm³ crucible (lip Ø 54 mm), with integrated water cooling shroud, shutter, PBN crucible, in-vacuum length 287 mm and outer diameter 36 mm.