Particle Counting, T a l C o u n t a c c u r a c y | Teledyne 651

C H A P T E R 7

Particle Counting

This chapter discusses particle counting and particle count measurements performed using the Ultrafine Particle Monitor - Model 651.

The Model 651 has two modes for particle counting:

∙Concentration mode, where data is presented as particle concentration in particles/cm3, updated each second on the display (the maximum time resolution is one second).

∙Totalizer mode, where total particle counts are accumulated and presented each second.

Concentration mode is commonly used for most applications and for averaging over a period of time. Totalizer mode is used at very low particle concentrations and includes live-time corrections.

Particles can be accumulated until a desired statistical accuracy is achieved.

In the concentration mode, the Model 651 operates in the single count mode with continuous, live-time correction over the range between 0 and 1 × 106 particles/cm3.

The instrument can display up to 106 particles/cm3. The Model 651 must be calibrated against a concentration reference (e.g., an aerosol electrometer or another Ultrafine Particle Monitor with a dilution bridge with a known dilution ratio) in the range from 3 × 105 to 106 particles/cm3 in order to provide a single dead-time correction calibration (DTC) factor.

T o t a l C o u n t A c c u r a c y

At very low concentrations, the accuracy of the measurement in the single-particle-counting mode is limited by statistical error. If the total number of particles counted in each time interval is very small, the uncertainty in the count is large. The relative statistical error of the count σr is related to the total count n by

σr = nn .

07506C DCN6727

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Teledyne 651 operation manual Particle Counting, T a l C o u n t a c c u r a c y

Contents

Model Page Trademarks This page intentionally left blank F e t y M e s s a g e s R N I N G Laser Safety R r a n t y This page intentionally left blank V i s i o n H i s t o r y O u t T h i s M a n u a l Viii Contents Particle Counting Maintenance, Service, and Troubleshooting SFC Set Flow Rate Calibration Constant G u r e s Table A-1 B l e s Xiv How This Manual is Organized R p o s eG a n i z a t i o n T t i n g H e l p L a t e d P r o d u c t L i t e r a t u r e Product Overview O d u c t D e s c r i p t i o nA P T E R Parameter Specification Specification s Water System Parameter W i t W o r k s Physical Features 2illustrates the flow system of the Model Model 651 Flow System Schematic C k i n g L i s t Unpacking and Setting Up the Model P a c k i n g Model 651 Maintenance Kit PN DU0000169 Remove Protective Caps InstallationConnecting the Water Supply Equipment Bracket Screw Connecting the Water Supply Connecting the Aerosol Supply Connecting the Water Exhaust Tube Connecting the Aerosol Supply Nozzle Securing Inlet Screen Assembly in Place Installing the Model 651 in a Rack Connecting Power and Warming up the Model Connecting the USB Cable Warm-up Screen Moving and Shipping Model Moving the Model 651 Short DistancesPreparing the Model 651 for Shipping and Storage 07506C DCN6727 Instrument Description O n t P a n e lDisplay Status Messages Indicator Light C k P a n e l T e r n a l I n s t r u m e n t C o m p o n e n t s Optics ModuleVacuum Supply Internal Clock Water SystemFans Circuit Boards RS-232 Serial Connections Data Communication Ports Ethernet Communication Port 07506C DCN6727 C o m m e n d e d O p e r a t i o n P r o c e d u r e s Outdoor Operation ProceduresInstrument Operation E r a t i n g P r e c a u t i o n s Standard Operation Procedures Home Screen ∙ Status ∙ Setup ∙ TotalR m u p S p l a y / U s e r S e t t i n g s Status Description Setup Screens On After WarmupOFF SET Time Address Mask Total Screen 07506C DCN6727 E o r y Technical Description Sensor S i g n o f t h e M o d e l 6 5 Pulse Height Critical Flow Flow System Inlet Pressure Measurement Temperature Control Water Removal System Page 07506C DCN6727 T a l C o u n t a c c u r a c y Particle Counting Concentration = Total counts V e T i m e C o u n t i n g Concentration = N × t N c e n t r a t i o n M e a s u r e m e n t 07506C DCN6727 T a l i z e r M o d e 07506C DCN6727 Computer Interface Commands, and Data Collection M p u t e r I n t e r f a c eEthernet Programs and Features Choose Turn Windows features on or off Flash Drives Line Flash Memory Data Files Example of data record RS-232 Serial Communications USB Communications Parameters Terminal Communications M m a n d s ReadSET 07506C DCN6727 07506C DCN6727 U t i o n Maintenance, Service Troubleshooting P l a c e m e n t P a r t s K i t s M o v i n g t h e C o v e r M o v i n g a n d Install i n g t h e W i c k T e A n g i n g t h e F i l t e r s R o s o l F l o w C h e c k s Model 651 Flow Schematic E a n i n g t h e W a t e r B o t t l e E a n / R e p l a c e t h e O r i f i c e s S p e c t i n g a n d C l e a n i n g t h e F a n s S p e c t L i q u i d L i n e s A t u s M e s s a g e s Troubleshooting Troubleshooting INLET/DRAIN T u r n i n g t h e M o d e l 6 5 1 f o r S e r v i c e C h n i c a l a s s i s t a n c e W S t a t i c C h a r g e s a r e C r e a t e d Primer on Electro Static Discharge Static Generation Voltages for Typical Activities Sensitivity of Electronic Devices to Damage by ESD M m o n M y t h s a b o u t E S D D a m a g e General Rules S i c P r i n c i p l e s o f S t a t i c C o n t r o l 07506C DCN6727 Working at an Anti-ESD Work Bench Working at the Instrument Rack Transferring Components from Rack to Bench and Back Opening Shipments from Teledyne API’S Customer Service Packing Components for Return to TAPI’s Customer Service 100 07506C DCN6727 Read SET Commands Command Explanation Read Commands A D C o m m a n d s RAI Read Analog Input VoltageRAI Rall Rall Read Operating Condition RCT Read Current Time RD Read Displayed ConcentrationRCT RIF RIE Read Instrument ErrorsRIF Read Aerosol Flow Rate RIE RIS Read Instrument Status RL Read Laser CurrentRIS RPV Read Vacuum Pressure RLL Read Liquid LevelRPA Read Absolute Pressure Transducer RPN Read Nozzle Pressure Transducer RRD RRD Read Data Record RRS RTA Read Cabinet TemperatureRTC Read Conditioner Temperature RRS Read Status Record RTG Read Growth Tube Temperature RTO Read Optics TemperatureRV Read Firmware Version Number T C o m m a n d s SM Set Mode SA Set Auxiliary Flow Valve SFC Set Flow Rate Calibration ConstantSFC SR Set Real-time Clock SP Set Pump Vacuum Sstart Sstart Starts a New Sample ST Set Transport Flow T a R e p o r t i n g R e c o r d s Record CNTPstd Tinlet Record Status Aerosol inlet 43, 45 Index External vacuum source Orifice Teledyne Contact Information Index-5