Valved Thermal Cracker Cell VTCC

Full PBN solution for corrosive materials like Te, Sb, Se, As, Zn and Mg
DN40CF ( O.D. 2.75" ) mounting flange c ompatible 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) Datasheet

Introduction

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.

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.

Application

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

General
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
Reservoir
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
Cracker
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

Crucibles

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 .

Dimensions

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 Gasketdimensions .

Product	CF flange	Nominal capacity	Lip diameter	Cooling	Shutter*	UHV dimensions*** [mm]		max. electrical [W]/[A]	Power supply product code	Crucible product code
		[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	CRU 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.