RGA THEORY AND OPERATION Module 300 RGA Hardware

RGA THEORY AND OPERATION Module 300: RGA Hardware and How It Works

PURPOSE • Develop and demonstrate expertise with my. RGA • Understand how RGAs function as a step toward learning how RGA’s can be used to meet customer needs RGA Hardware and How an RGA Works

OBJECTIVES Upon completion of this module, you will be able to: • List the two major items of an RGA System and describe their function • • List the two major items of an RGA and describe their function • Describe the functions of the items on the rear panel of a my. RGA electronics box List the four major sections of a typical RGA sensor and describe their function RGA Hardware and How an RGA Works

OUTLINE 1 RGA System Overview: RGA and Computer 2 RGA Hardware Overview 3 RGA Sensor 4 RGA Electronics Box RGA Hardware and How an RGA Works

1 RGA SYSTEM OVERVIEW: RGA AND COMPUTER RGA Hardware and How an RGA Works

GENERAL SCHEMATIC OF RGA SYSTEM Control Computer • Ethernet connection my. RGA Hardware and How an RGA Works

FUNCTIONING RGA SYSTEM my. RGA 2. Detect or measure the gases present in a chamber Control Computer 1. Control operation of RGA 3. Analyze, display and store results RGA Hardware and How an RGA Works

2 RGA HARDWARE OVERVIEW RGA Hardware and How an RGA Works

my. RGA Hardware and How an RGA Works

my. RGA Sensor Electronics Box RGA Hardware and How an RGA Works

ELECTRONICS BOX TO SENSOR Sensor Control voltage and current Detects gases Electronics Box Generates control voltages and currents to operate sensor RGA Hardware and How an RGA Works

SENSOR TO ELECTRONICS BOX Sensor Produces output signals that indicate amounts of gases Analog signals Electronics Box Measures the signals from the sensor RGA Hardware and How an RGA Works

ELECTRONICS BOX TO COMPUTER Sensor Electronics Box Control Computer Measured values are converted to digital format Receive data, then analyze, display and store results RGA Hardware and How an RGA Works

3 RGA SENSOR RGA Hardware and How an RGA Works

SENSOR my. RGA Sensor my. RGA Electronics Box RGA Hardware and How an RGA Works

SENSOR RGA Hardware and How an RGA Works

SENSOR DETECTOR ION SOURCE MASS FILTER RGA Hardware and How an RGA Works VACUUM FEEDTHROUGH

ION SOURCE RGA Hardware and How an RGA Works

OPEN ION SOURCE (OIS) RGA Hardware and How an RGA Works

OPEN ION SOURCE STRUCTURE • Open structure • Gas can enter easily RGA Hardware and How an RGA Works

OPEN ION SOURCE – FILAMENT ASSEMBLY Filament assembly Ion source RGA Hardware and How an RGA Works

FILAMENT ASSEMBLY – TWO FILAMENTS • • • Two semi-circle filaments Made of either: Þ Yttria-coated iridium, or Þ Tungsten Operate one at a time Filament RGA Hardware and How an RGA Works

FILAMENT IN THE IONSOURCE Filament (cathode) RGA Hardware and How an RGA Works

FILAMENT CURRENT • • Electric current in filament Filament becomes extremely hot RGA Hardware and How an RGA Works

EMISSION CURRENT • • • Electrons emitted from filament Flow of emitted electrons Emission current RGA Hardware and How an RGA Works

REPELLER • • Outer cage • Repels electrons Negative electrical potential with respect to filament Repeller RGA Hardware and How an RGA Works

ANODE CAGE (ION CAGE) • • Inner cage • Attracts electrons Positive electrical potential difference to filament Anode cage RGA Hardware and How an RGA Works

IONIZATION REGION • • • Inside the anode cage Region where ions are formed Electron impact ionization of gas molecules RGA Hardware and How an RGA Works

ELECTRON IMPACT IONIZATION Atom (He) Positive Ion (He+) RGA Hardware and How an RGA Works

ION OPTICS Focus plate Exit plate Ion path (through centers of plates) RGA Hardware and How an RGA Works

TOTAL PRESSURE PLATE The Exit Plate is also known as the Total Pressure Plate Exit plate RGA Hardware and How an RGA Works

MASS FILTER RGA Hardware and How an RGA Works

MASS FILTER (QUADRUPOLE) Straps (metal) Rods (metal) Rings (ceramic) RGA Hardware and How an RGA Works

MASS FILTER – ION PATH • • • A controlled band of ion masses will reach the detector This filters the ions for measuring one gas at a time Higher and lower mass ions will strike a rod instead ION BEAM DETECTOR RGA Hardware and How an RGA Works

MASS FILTER – ELECTRICAL CONFIGURATION RGA Hardware and How an RGA Works

QUADRUPOLE ASSEMBLY • • • Surface uniformity is essential Manufactured with precision Cleaned and manufactured in clean room RGA Hardware and How an RGA Works

DETECTOR RGA Hardware and How an RGA Works

DETECTOR TYPES RGA can have: • • FC only, or FC and EM Faraday cup (FC) RGA Hardware and How an RGA Works Electron multiplier (EM)

FARADAY CUP (FC) • • • Simple metal electrode Positive ions strike surface Produces electrical output current Faraday cup Ion path Output current RGA Hardware and How an RGA Works

ELECTRON MULTIPLIER (EM) Made of glass doped with specific impurities to form a semiconducting surface EM RGA Hardware and How an RGA Works

ELECTRON MULTIPLIER (EM) • • Bias voltage attracts ions Boosts signal by large gain factor Ion Path EM Output Current Bias Voltage EM RGA Hardware and How an RGA Works

GAIN OF ELECTRON MULTIPLIER EM Gain = EM Current FC Current EM Current = FC Current x EM Gain RGA Hardware and How an RGA Works

GAIN OF ELECTRON MULTIPLIER • • • Gain can range from 10 to 10 million Depends on bias voltage applied Depends on condition of EM RGA Hardware and How an RGA Works

CHANGES TO ELECTRON MULTIPLIER GAIN Gain can decrease due to: • • • Surface degradation Contamination Usage (dosing) Gain can be increased by increasing the bias voltage. Increasing the voltage allows the user to recover for gain losses. This allows the user to maintain constant sensitivity over time. RGA Hardware and How an RGA Works 44

EM IMPACT ON RGA PERFORMANCE • • • Improves sensitivity Improves signal-to-noise ratio Improves minimum detectable partial pressure RGA Hardware and How an RGA Works

APPLIED EM PERFORMANCE The EM can be used to improve: • • • Detection of small leaks Detection of trace contaminants Measurement speed RGA Hardware and How an RGA Works

WHEN TO OPERATE FC OR EM FC: EM: • Does not boost the signal • Boosts the signal • Use to detect small leaks, trace background gases or contaminants • Use when gases are present at high levels RGA Hardware and How an RGA Works

my. RGA EM OPERATING LIMITS my. RGA EM Specifications • • 150°C maximum operating temperature 1 x 10 -6 Amperes maximum output current Exceeding these limits will: • • • Damage the EM Degrade RGA performance Shorten the useful lifetime of the EM Target Output Current for EM Protection • 2 x 10 -7 Amperes RGA Hardware and How an RGA Works

LIMITING EM CURRENT If the EM output current exceeds the specified limit, then either: • • • Decrease the EM voltage Decrease the gas pressure Turn off the EM RGA Hardware and How an RGA Works

VACCUM FEEDTHROUGH VACUUM FEEDTHROUGH RGA Hardware and How an RGA Works

FEEDTHROUGH AS VACUUM SEAL Vacuum Atmosphere RGA Hardware and How an RGA Works

FEEDTHROUGH AS ELECTRICAL INTERFACE Electrical connections Sensor feedthrough Electronics box RGA Hardware and How an RGA Works

VACUUM FEEDTHROUGH CF 40 vacuum flange Electrical feedthrough pins RGA Hardware and How an RGA Works

FEEDTHROUGH PINS Pin 1: • • Center Pin Sensor output signal Pins 2 – 13: • Control currents and voltages from electronics box to sensor RGA Hardware and How an RGA Works

PUTTING IT ALL TOGETHER DETECTOR ION SOURCE MASS FILTER RGA Hardware and How an RGA Works VACUUM FEEDTHROUGH

4 RGA ELECTRONICS BOX RGA Hardware and How an RGA Works

ELECTRONICS BOX my. RGA Sensor my. RGA Electronics Box RGA Hardware and How an RGA Works

FRONT PANEL Connector to mate with sensor pins Locking nut to secure the sensor to the electronics box RGA Hardware and How an RGA Works

BACK PANEL WITH CONNECTORS EXT I/O Emission indicator Ethernet port AUX I/O Power indicator Latching power connector Cooling fan, air intake RGA Hardware and How an RGA Works

STANDARD I/O CAPACITY 15 Pin AUX I/O • One analog input for pressure Connector gauge support (interlock kit) • One 24 volt supply (valve supply) • One relay (emission status, or valve control) • One pair of digital remote inputs (emission on/off control) RGA Hardware and How an RGA Works

OPTIONAL EXTENDED I/O CAPABILITY • • • 62 Pin EXT I/O 4 Analog Inputs Connector 4 Analog Outputs 4 Relays 12 Digital Inputs/Outputs 1 Gauge Support 24 Volt Supply RGA Hardware and How an RGA Works

ELECTRONICS BOARD RF board CPU board Power supply board RGA Hardware and How an RGA Works

ELECTROMETER ASSEMBLY Electrometer assembly RGA Hardware and How an RGA Works

SUMMARY In this module, you have learned: • • • The two major items of an RGA System, and their function The two major items of an RGA, and their function The four major sections of an RGA sensor, and their function The overview design of the my. RGA electronics box The rear panel functionality of the my. RGA electronics box RGA Hardware and How an RGA Works

THANK YOU! You have completed the RGA Hardware and How an RGA Works module! You may come back and review the content of this module at any time. RGA Hardware and How an RGA Works