PH-Instruments DosiTorr SRG Rotational Vacuum Gauge
| Brand | PH-Instruments |
|---|---|
| Origin | Germany |
| Model | DosiTorr SRG |
| Measurement Principle | Gas molecule adsorption/desorption-induced rotor deceleration, quantified via rotational decay rate |
| Pressure Range | 10 mbar to 5×10⁻⁷ mbar |
| Vacuum Interface | Designed for direct replacement of ionization gauges with plug-and-play electrical compatibility |
Overview
The PH-Instruments DosiTorr SRG is a process-grade rotational vacuum gauge engineered for high-precision, long-term stable pressure measurement in ultra-high vacuum (UHV) and aggressive industrial environments. Unlike thermal conductivity (Pirani) or ionization-based gauges, the DosiTorr operates on the fundamental physical principle of rotational drag: a magnetically levitated stainless steel rotor spins at high speed within the vacuum chamber; residual gas molecules collide with the rotating sphere, inducing a measurable deceleration proportional to local gas density—and thus, pressure. This passive, non-intrusive sensing mechanism eliminates thermal radiation, electron emission, and chemical interaction with the process medium, making it uniquely suited for high-purity semiconductor fabrication, plasma etching, thin-film deposition, and sterile pharmaceutical vacuum systems where contamination, drift, or gauge poisoning must be avoided.
Key Features
- True 1:1 drop-in replacement for standard ionization gauges—mechanically and electrically compatible with KF25, KF40, CF40, 8VCR, and 1/8″ NPT flanges
- Full-range linearity across 10 mbar to 5×10⁻⁷ mbar without gas-species correction—output is intrinsically independent of gas composition
- Zero-drift architecture: <1.5% annual drift, verified under continuous operation per ISO 3567 and ASTM E1971 calibration traceability protocols
- Corrosion- and deposit-resistant sensor core fabricated from EN 1.4404 (AISI 316L) and EN 1.4034 stainless steels—no internal electronics or fragile filaments exposed to vacuum
- Integrated temperature compensation via embedded Pt100 sensor, enabling real-time thermal drift correction in dynamic process conditions
- Enhanced magnetic shielding and optimized magnetic suspension system mitigate external field interference (compliant with EN 61326-1 for industrial EMC)
- 24 VDC power input with configurable 0–10 VDC analog output; supports Modbus RTU, ASCII, and LabVIEW-compatible drivers via USB Type-C or HD-15 interface
Sample Compatibility & Compliance
The DosiTorr SRG exhibits universal compatibility with reactive, corrosive, and condensable process gases—including Cl₂, NF₃, SF₆, O₂, H₂, Ar, and hydrocarbon vapors—without performance degradation or calibration shift. Its all-metal, bakeable construction (up to 150 °C with elastomer seals; 450 °C with metal seals in CaliTorr variant) meets UHV system conditioning requirements per ISO 20483 and SEMI F20 standards. The device conforms to EU directives 2014/30/EU (EMC) and 2014/35/EU (LVD), carries CE marking, and supports audit-ready data integrity through optional timestamped digital logging aligned with FDA 21 CFR Part 11 principles for GMP/GLP environments.
Software & Data Management
The DosiTorr integrates seamlessly into supervisory control systems via standardized industrial protocols. Its firmware supports adaptive measurement timing (1–30 s intervals or auto-select mode), configurable averaging windows, and dual-channel diagnostics (rotor speed + temperature). Optional PC software provides real-time waveform visualization, trend logging, and export to CSV or HDF5 formats. All configuration changes are recorded with user ID and timestamp, satisfying traceability requirements for ISO/IEC 17025-accredited laboratories and semiconductor fab QC workflows.
Applications
- Replacement of aging or poisoned hot-cathode ionization gauges in ion implanters and plasma etch tools (e.g., Lam Research, Applied Materials platforms)
- In-situ vacuum insulation monitoring for cryogenic systems and superconducting magnet enclosures
- Process endpoint detection in reactive sputtering and ALD reactors where Pirani gauges fail due to film deposition
- High-reliability vacuum monitoring in aseptic filling lines and lyophilizer chambers requiring zero outgassing and non-invasive sensing
- Primary transfer standard for on-site verification of other vacuum instrumentation per ISO 20483 Annex B
FAQ
Is the DosiTorr SRG suitable for oxygen-rich or oxidizing environments?
Yes—the entire wetted path is constructed from passivated austenitic stainless steels (1.4404 / 1.4034), which maintain structural integrity and metrological stability in O₂ partial pressures up to 100%.
Can it be installed vertically or at an angle?
Installation is rated for horizontal orientation ±5° only; off-axis mounting compromises magnetic suspension stability and introduces systematic bias in decay-rate measurement.
Does it require periodic recalibration?
No scheduled recalibration is mandated under normal operating conditions; however, users may perform optional factory-traceable verification using reference SRG standards per ISO 20483 Clause 7.2.
How does it handle vibration-prone environments?
The DosiTorr incorporates active vibration damping algorithms and higher operational rotor speeds (>10,000 rpm), reducing sensitivity to mechanical perturbations compared to conventional SRG implementations.
Is remote firmware update supported?
Yes—field-upgradable firmware is delivered via signed binary packages over USB or RS485, with SHA-256 hash validation and rollback protection to ensure system integrity.
