- Bayard-Alpert type ionization gauge
- Compatible with AML gauge controllers
- Mounting flange DN40CF (O.D. 2.75")
- Linear gauge head positioning
- Standard linear travel 150 mm
- Bakeable up to 200°C Datasheet
Introduction
In many MBE applications the beam equivalent pressure (BEP) of the atomic or molecular beams from effusion cells can be used to determine flux ratios and growth rates near or at the sample position. Our Beam Flux Monitor BFM has been designed and optimized for this purpose.
The basic component of the BFM is the Bayard-Alpert type ionization gauge, that is mounted on a linear motion feedthrough with edge-welded bellows. By means of this feedthrough, the gauge can be shifted linearly between a measurement- and a standby-position.
The design of the BFM includes the shielding of the gauge head, inhibiting contamination of a substrate behind the gauge head during flux-monitoring. The shielding parts can be seen on the right hand figure.
Application
Typical applications for the BFM beam flux monitor are:
- flux calibration of effusion cells vs. source temperature
- fast check of flux ratios from different sources before growth (e.g.
As/Ga in III-V MBE)
The BFM series has been designed to be pin-compatible with ion gauge controllers of the PGC-series from AML. The electrical 12-pin feedthrough of the BFM mates with a standard AML gauge head connection cable. If other ion gauge controllers shall be used, adaptability to the pin-out shown on the left and match with the characteristics of the ion gauge head (see below) is required.
Technical Data
| Mounting Flange | DN40CF (O.D. 2.75") [mm / inch]; port I.D. >= 38mm |
| In‑vacuum dimensions | 100...500 mm, others on request |
| Airside dimensions | 311...726 mm (depending on linear travel length) |
| Electrical feed-through | pin-compatible with AML controller cables |
| Bakeout temperature | up to 250 °C |
| Extended length E | depending on linear travel length |
| Measurement range | 10 -3 mbar to 4x10 -11 mbar total pressure or BEP |
Specific Data
For general information on CF mounting flanges see Flange and Gasketdimensions.| Product | Flange [CF] | Linear travel [mm] | UHV dimensions [mm] specify L with order | |
|---|---|---|---|---|
| BFM | 40 | 150 | LxxxD37 | |
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| BFM | 40 | 200 | LxxxD37 | |
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| BFM | 40 | 250 | LxxxD37 | |
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| BFM | 40 | 300 | LxxxD37 | |
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| BFM | 40 | 400 | LxxxD37 | |
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Example: BFM 40-200-L100D37 is a Beam Flux Monitor on DN40CF-flange with 200 mm shift, retracted in-vacuum length L = 100 mm and extended length T+L = 300 mm. The center of the active quartz surface is located at T+L-30 mm = 270 mm. The surrounding tube has to have an inner diameter ≥37 mm.
