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UHV-24/UHV-24p Ionization Gauge 

14

DRAF

T

Figure 2 Typical Gauge Characteristics Graphs

Application Notes

Measurement of ultra-high vacuum is not a trivial undertaking. There are many factors that 
contribute to measurement problems. Some other concerns include that:

The gauge sensitivity factor is based on nitrogen and very little, if any, nitrogen is 
present in UHV systems that are leak tight

There are no convenient primary pressure standards that exist for UHV calibration.

A grounded conductive wall near the tube raises the sensitivity by as much as 30%. 
This is typical of gauges mounted in tubulations attached to the system.

However, these three concerns are usually theoretical in nature and most problems fall 
under the following areas:

All ion gauges are pumps, (likewise, all ion pumps are gauges). The difference is that 
gauges are designed primarily to measure pressure and have relatively small 
pumping speeds. However, given the right conditions it is possible for the gauge to 
pump the gas that being measured, especially if the chamber pump is small. 

Summary of Contents for UHV-24

Page 1: ...D R A F T Vacuum Products Division UHV 24 UHV 24p Ionization Gauge Manual No 699905505 Revision F January 2014 INSTRUCTION MANUAL...

Page 2: ...D R A F T 1 6 1 4 Copyright 2014 Agilent Inc UHV 24 UHV 24p Ionization Gauge...

Page 3: ...representatives of Seller which are inconsistent or in conflict with the terms of this warranty shall not be binding upon Seller unless reduced to writing and approved by an officer of Seller Warrant...

Page 4: ...UHV 24 UHV 24p Ionization Gauge This page intentionally left blank D R A F T 1 6 1 4...

Page 5: ...ts Preface 7 Hazard and Safety Information 7 Contacting Agilent 9 UHV 24 UHV 24p Ionization Gauge 11 Principles of Operation 11 Installation 12 Operating Specifications 13 Maintenance Filament Replace...

Page 6: ...UHV 24 UHV 24p Ionization Gauge This page intentionally left blank D R A F T...

Page 7: ...OTE Notes contain important information Before operating or servicing equipment read and thoroughly understand all operation maintenance manuals provided by Agilent Be aware of the hazards associated...

Page 8: ...1 Ion Gauge and Vacuum System Connections Use with Combustibles and Mixtures WARNING As with all ionization gauges this device is not intrinsically safe Exercise extreme care when using this vacuum g...

Page 9: ...x is not compatible with aluminum and will cause damage NOTE Normally it is unnecessary to use vacuum grease However if it must be used do not use silicone types and use it sparingly Apiezon L grease...

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Page 11: ...HV 24 UHV 24p Nude Ionization Gauge contains three elements Filament The filament serves as a source of electrons Grid The grid functions as the electron collector operating at a positive potential ty...

Page 12: ...r is 10 10 A Installation Agilent ionization gauges can be operated with any ion gauge control unit capable of supplying the necessary operating voltages and currents Degassing of this gauge is by ele...

Page 13: ...tage Vg 180 VDC Degas Power Requirements 40 W Grid Voltage 600 VDC max Emission Current total 67 mA DC Filament Voltage 7 V Measurement Specifications Sensitivity 25 Torr UHV 24 nominal 20 Torr UHV 24...

Page 14: ...pressure standards that exist for UHV calibration A grounded conductive wall near the tube raises the sensitivity by as much as 30 This is typical of gauges mounted in tubulations attached to the syst...

Page 15: ...rent is only 10 pA And that assumes that the gauge sensitivity factor of 20 Torr is somewhat accurate most likely it is lower than that Only rarely is the sensitivity factor higher than expected such...

Page 16: ...uch as several days or will be baked for an extended period of time degassing the gauge has a negligible affect Considering that the e beam degas system used runs at a high emission current it may not...

Page 17: ...Carefully loosen all six set screws and pull the old filament support brackets out CAUTION Handle the gauge only by its ceramic base to prevent damage to the delicate wires Wear nylon gloves to preven...

Page 18: ...to the delicate wires Wear nylon gloves to prevent placing fingerprints on the gauge The oil from fingerprints extends pumpdown time 2 Carefully remove the stabilizing bar by very carefully cutting b...

Page 19: ...S CORR When the gas constant is entered the gauge divides the result by the gas correction constant and displays the correct adjusted value A proper understanding for the transformation of the result...

Page 20: ...UHV 24 UHV 24p Ionization Gauge 20 D R A F T Table 2 Gas Correction Factor Table...

Page 21: ...UHV 24 UHV 24p Ionization Gauge D R A F T 21 Table B 0 Gas Correction Factor Table Continued...

Page 22: ...UHV 24 UHV 24p Ionization Gauge This page intentionally left blank D R A F T...

Page 23: ...e product e g inlet screens vent valves x Prior to shipment drain any oils or other liquids purge or flush all gasses and wipe off any excess residue x If ordering an Advance Exchange product p please...

Page 24: ...or been exposed to any toxic or hazardous materials OR HAS pumped or been exposed to the following toxic or hazardous materials If this box is checked the following information must also be filled out...

Page 25: ...ther Vacuum leak Other Section 6 ADDITIONAL TERMS Please read the terms and conditions below as they apply to all returns and are in addition to the Agilent Technologies Vacuum Product Division Produc...

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Page 28: ...ilent com Italy Agilent Technologies Italia S p A via F lli Varian 54 10040 Leini Torino ITALY Tel 39 011 997 9111 Fax 39 011 997 9350 Toll Free 00 800 234 234 00 vpt sales agilent com vpt customerser...

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