Droplet SP2-D User manual

COPYRIGHT © 2017 DROPLET MEASUREMENT TECHNOLOGIES
Single Particle Soot
Photometer (SP2)
Operator Manual
DOC-0171
Revision G-9—Describes the SP2-D
2400 Trade Centre Avenue
Longmont, CO 80503 USA

Operator Manual, Single Particle Soot Photometer (SP2)
Form DOC-0171 Rev G-9 II
© 2017 DROPLET MEASUREMENT TECHNOLOGIES
2400 TRADE CENTRE AVENUE
LONGMONT,COLORADO,USA 80503
TEL:[phone]
FAX:[phone]
WWW.DROPLETMEASUREMENT.COM
All rights reserved. No part of this document shall be reproduced, stored in a retrieval system, or
transmitted by any means, electronic, mechanical, photocopying, recording, or otherwise, without
written permission from Droplet Measurement Technologies. Although every precaution has been
taken in the preparation of this document, Droplet Measurement Technologies assumes no
responsibility for errors or omissions. Neither is any liability assumed for damages resulting from the
use of the information contained herein.
Information in this document is subject to change without prior notice in order to improve accuracy,
design, and function and does not represent a commitment on the part of the manufacturer.
Information furnished in this manual is believed to be accurate and reliable. However, no
responsibility is assumed for its use, or any infringements of patents or other rights of third parties,
which may result from its use.
Trademark Information
All Droplet Measurement Technologies product names and the Droplet Measurement Technologies
logo are trademarks of Droplet Measurement Technologies.
All other brands and product names are trademarks or registered trademarks of their respective
owners.
Warranty
The seller warrants that the equipment supplied will be free from defects in material and
workmanship for a period of one year from the confirmed date of purchase of the original
buyer. Service procedures and repairs are warrantied for 90 days. The equipment owner will
pay for shipping to DMT, while DMT covers the return shipping expense.
Consumable components, such as tubing, filters, pump diaphragms, and Nafion humidifiers and
dehumidifiers are not covered by this warranty.

Operator Manual, Single Particle Soot Photometer (SP2)
Form DOC-0171 Rev G-9 III
© 2017 DROPLET MEASUREMENT TECHNOLOGIES
Laser Safety
The SP2-D is a Class I Laser Product. STRICT OBSERVANCE OF THE FOLLOWING WARNING LABELS
IS ADVISED.
The following label appears on the back panel of the SP2:
The following laser safety label is located on the exterior of the laser frame:
The following laser safety label appears next to the interlock switches:
Laser Characteristics
Pump Laser
Main Laser
Wavelength
808 nm
1064 nm
Maximum power
4 W
.4 W

Operator Manual, Single Particle Soot Photometer (SP2)
Form DOC-0171 Rev G-9 IV
© 2017 DROPLET MEASUREMENT TECHNOLOGIES
Additional Instrument Labels:
The following identification label appears on the back panel of the SP2:
The following label appears on the back panel of the instrument:
Warning: If not properly grounded, the instrument can cause an electrical shock.
Use a three-conductor cord and a plug appropriate for the location in which the instrument will be
used. Connect the plug to a properly grounded receptacle.
CAUTION: Use of control or adjustments or performance of procedures other than specified in this
manual may result in hazardous radiation exposure.

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CONTENTS
1.0 Introduction ...................................................................................................... 7
1.1 Specifications......................................................................................................................... 7
1.2 Electrical Specifications ......................................................................................................... 9
1.3 Physical Specifications........................................................................................................... 9
1.4 Operating Limits .................................................................................................................... 9
2.0 Theory of Operation ........................................................................................ 10
2.1 Laser Characteristics............................................................................................................ 12
2.2Optical Detectors.................................................................................................................13
2.3 Control Board Inputs ........................................................................................................... 14
3.0 Unpacking and Setup....................................................................................... 14
3.1 Unpacking............................................................................................................................ 14
3.2 Set Up ..................................................................................................................................14
3.3 Turning On the System ........................................................................................................16
3.4 Turning Off the System........................................................................................................ 22
4.0 Flow System .................................................................................................... 22
5.0 Typical Operating Parameters.......................................................................... 23
6.0 Laser Safety Interlocks..................................................................................... 23
7.0 Routine Maintenance ...................................................................................... 25
7.1 SP2-D: Procedure to Calibrate the Laminar Flow Element.................................................. 26
7.2 Procedure for Alignment of the YAG Laser ......................................................................... 26
7.3 Cleaning the Laser Optics ....................................................................................................26
8.0 Calibrating the Instrument with Aerosol Black Carbon ..................................... 27
8.1 Required Equipment............................................................................................................ 27
8.2 Calibration Procedure.......................................................................................................... 27
9.0Troubleshooting .............................................................................................. 28
Appendix A: Revisions to Manual.................................................................................. 29
Appendix B: SP2 YAG Pump Laser Storage and Handling Instructions............................. 30
Storing the SP2 YAG Pump Laser..................................................................................................... 30
Handling the SP2 YAG Laser ............................................................................................................31
Appendix C: Configuring and Testing the SP2’s Four Analog Input Channels .................. 32
Configuration................................................................................................................................... 32
Testing the Input Voltages...............................................................................................................34
Appendix D: Plumbing Diagram..................................................................................... 35
Appendix E: SP2-D System Schematic............................................................................ 35

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Figures
Figure 1: Front View of the SP2 Analyzer ....................................................................... 10
Figure 2: Rear View of the SP2 Analyzer Chassis ............................................................ 11
Figure 3: Schematic Diagram of the YAG Laser in the SP2............................................... 12
Figure 4: SP2 Optical Diagram ....................................................................................... 13
Figure 5: Connecting SP2 and SP2 Pump Exhaust Valves ................................................ 14
Figure 6: Connecting SP2 Purge Valve to Drierite Cartridge............................................ 15
Figure 7: Connecting SP2 Pump Purge Port to Drierite Cartridge .................................... 15
Figure 8: Connecting the SP2 Purge Valve to the SP2 Pump Purge Port .......................... 16
Figure 9: Verifying the Config File on the Config Tab...................................................... 17
Figure 10: Loading a New Configuration File.................................................................. 18
Figure 11: Sample Pump Power Switch.......................................................................... 19
Figure 12: Sample Flow Stabilizing................................................................................. 19
Figure 13: Turning on the Laser from the Control Tab .................................................... 20
Figure 14: Verifying Particle Response........................................................................... 21
Figure 15: Turning the Laser Off .................................................................................... 22
Figure 16: SP2 Key in the Locked (left) and Unlocked (right) Positions............................ 24
Figure 17: Laser Interlocks (Circled in Lower Left and Upper Right of SP2)...................... 24
Figure 18: Interlock Jumper........................................................................................... 25
Figure 19: Schematic Diagram for SP2 Calibration with DMA ......................................... 27
Figure 20: SP2 Pump Laser in Protective Box ................................................................. 30
Figure 21: Shorting Plug Detached (left) and Attached (right) to Power Connector......... 31
Figure 22: Protective Cap and SMA Fiber Connector (above); Cap Attached to Connector
(below) .................................................................................................................. 31
Figure 23: Configuring Analog Input (AI) Channels in the SP2-D ..................................... 33
Figure 24: Control Tab Display of Newly Added AI Channels .......................................... 34

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1.0 Introduction
The SP2 directly measures the black carbon, known as soot, in individual aerosol particles. Its high
sensitivity, fast response, and specificity to elemental carbon make it the premier instrument for the
following tasks:
•Characterizing pollution sources
•Characterizing soot in snow, ice or water
•Calibrating Aethalometers
•Documenting thin, atmospheric layers of contamination
This manual describes revision D of the instrument.
1.1 Specifications
Measured Parameters
Single-particle laser incandescence Single-particle light
scattering
Auxiliary Parameters
Temperature, Pressure
Derived Parameters
•
BC mass distribution as function of particle diameter
•Particle number distribution as a function of particle
size
Maximum Data Acquisition Rate
•25,000 particles/second
•0 – 12,500 particles/cm3at standard flow rate of 120
volumetric cm3/minute
(Concentrations can basically increase until particles
become coincident)
Particle Size Range
•Scattering signal: 200 – 400 nm diameter (this range
encompasses the accumulation mode of most
particles, i.e. range where most mass is found)
•Incandescent signal: depends on particle density, but
70 – 500 nm mass-equivalent diameter assuming a
black carbon density of 1.8 g/cm3
Aerosol Medium
Air, 0 - 40 °C (32 - 104°F)
Lasers
•Nd:YAG Laser: 1064 nm, 3 MW/cm2 intracavity
circulating power
•Pump Laser: 808 nm, 4 W
The pump laser can be controlled through the SP2
software or the touch-screen on the SP2 front panel.
Sample Flow
30 – 180 volumetric cm3/minute (typically 120)

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Flow Control
Electronic flow control with a laminar flow element (LFE)
and a solenoid valve
Pump
Two single-head diaphragm pumps contained in a box
Minimum Black Carbon Detection
Limit
•10 ng/m
3
•0.3 fg/particle
Routine Maintenance
Weekly:
•Refreshing or replacing the desiccant in the drying
cartridge on the purge line
•Conducting PSL size check to monitor laser power
Monthly and around field campaigns:
•Conducting zero check with high-efficiency filtered air
sample
Annually (more frequently for high-BC environments):
•Checking calibration of the laminar flow element on
the sample inlet
Recommended Service
Annual cleaning and calibration at DMT service facility
Front Panel Display
System power switch, 1/8 in. Swagelok® sample inlet, 2
USB 2.0 ports, laser ON/OFF indicator light
Rear Panel Connections
Keyboard port, mouse port, VGA and HDMI monitor
ports, 2 Ethernet ports, 2 RS-232 communications ports,
4 USB 2.0 ports, 4 analog inputs, ¼ in. Swagelok® purge
line, ¼ in. Swagelok® exhaust line, SATA hard drive
connection, exhaust vents, system and pump power
connections.
Computer System
On-board Intel®Core™ i7 CPU
8 GB RAM, 750 GB hard drive for data storage, NI PCI-
6133 DAQ interface card, NI PCI-6259 housekeeping
data card.
User interface via standard keyboard, mouse, and 19”
monitor (included)
Software
•SP2 Executable program written in LabVIEW
•PAPI program written in Igor
Data Storage Capacity
Depends on number of particles; at a concentration of
1,000 #/cm3and a standard flow rate of 120 volumetric
cm3/minute, the SP2 computer has the capacity to store
56 hours of continuous data
Communications Output
Gigabyte Ethernet interfaced through an Intel®
PC82573V PCIe GbE controller

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1.2 Electrical Specifications
Voltage:
SP2: Universal Voltage (100-240 VAC, 50/60 Hz)
Power Consumption:
•300 W for instrument
•
30 W for pump
1.3 Physical Specifications
Weight:
26.1 kg for SP2 alone
3.4 kg for pump
3 kg for monitor
Dimensions:
SP2: 48 cm W x 61 cm L x 26 cm H
Pump: 20 cm W x 25 cm L x 10 cm H
Monitor: 37 cm W x 22 cm L x 39 cm H
Shipping Container:
Durable Atlas Case Corporation ATA Transit Case that
conforms to the Air Transport Association’s Specification
300 Category 1 standards
Other:
Suitable for airborne mounting in the aircraft cabin
1.4 Operating Limits
Temperature:
0 to +40 °C (32 – 104 °F)
Altitude:
0-40,000 ft
Humidity:
0 - 100% (non-condensing)

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2.0 Theory of Operation
The Single Particle Soot Photometer (SP2) utilizes the high optical power available intra-cavity from
an Nd:YAG laser. Light-absorbing particles, mainly black or elemental carbon in atmospheric
measurements, absorb energy and are heated to the point of incandescence. The energy emitted in
this incandescence is measured, and a quantitative determination of the black carbon mass of the
particle is made.1This mass measurement is independent of the particle mixing state, and hence
the SP2 is a reliable measure of the black carbon mass concentration. Since the SP2 detects single
particles, the SP2 can also measure the black carbon number concentration.
All particles scatter light, regardless of whether or not they absorb light. A scattering detector is
included in the SP2, which detects single particle scattering at 1064 nm, and the scattering signal
can be used to indicate the black carbon mixing state at the single-particle level. The scattering
detector can also be used to detect non-BC-containing aerosol number and mass concentrations.
The SP2 measures the light scattering and/or incandescence of each particle. The full scattering
and/or incandescence response of each particle is completely digitized for detailed analysis.
Figure 1: Front View of the SP2 Analyzer
1Basic details on the theory of this technique are given by Stephens et al. (2003). Details on the
SP2 and application to atmospheric measurements are given by Schwarz et al. (2006).
Additional work on the theory of the measurements has been published by Moteki and Kondo
(2006).

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Figure 2: Rear View of the SP2 Analyzer Chassis
Rear-panel components:
1
12 VDC pump power connection
8
Monitor ports (VGA on left, HDMI on right)
2
Purge flow
9
RS-232 serial ports
3
Exhaust flow
10
Keyboard port
4
External speakers and microphone
connections
11
Mouse port
5
Ethernet ports
12
Exhaust vents
6
USB 2.0 ports
13
System power connection
7
SATA port (external hard drive)
1
2
3
5
6
4
9
8
10
11
12
12
13
7

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2.1 Laser Characteristics
The heart of the SP2 is the Nd:YAG laser. This will be referred to in the following discussion simply
as the YAG laser. Figure 3 gives a schematic diagram of the laser and the main optical components.
The laser cavity consists of a gain medium, the YAG crystal (in the center of Figure 3), and the
output coupler on the right. The particles from the aerosol jet interact with the laser beam at the
center of the cavity. The optical surfaces on both of these components are coated to have a
reflectivity of 99.97% or better at the 1064-nm wavelength of the YAG laser. In a standard laser, the
power that escapes through one of the laser mirrors is used as the laser source; in the SP2
application, the goal is to contain and use the power within the cavity between the mirrors (open-
cavity laser) and utilize it directly. The power in the cavity is approximately 3 Mw per cm2of
circulating laser power.
The YAG laser operates continuously and is not pulsed. The power that is available external to the
cavity, the pump laser, is approximately 50-100 mW. This power is monitored by the YAG power
monitor and is displayed on the data system in relative numbers. The entire laser radiation is
contained, and therefore the system qualifies as a Class 1 laser. The mode aperture on the cavity
side of the gain medium is used to minimize pump light in the cavity and also helps confine the
laser beam to the TEMoo mode. The gain medium is optically pumped with a diode laser at 808 nm
(not shown) and the optical energy is coupled via a fiber. Two mode-match lenses focus the energy
from the fiber onto the gain medium. The laser beam is Gaussian in shape, nominally 230 microns
width at 90% power level.
Output coupler
BK7, n =1.51 at 1064
OD 15 mm, CT 11 mm
S1: 2000mm ROC, HR 1064 nm*
S2: Flat, AR 808 nm
Gain medium
Nd:YAG (1% Nd doped), n =1.82
2.5 < OD < 25 mm, CT 5 mm
S1: Flat, HR 1064 nm* & AR 808nm **
S2: Flat, AR 1064 nm***
Mode match lens
CVI PLCX-10.0-20.6-C 40 mm FL
BK7, n =1.51 at 808 nm
OD 10 mm, CT 2.6 mm
S1: 20.6mm ROC, AR 800 nm
S2: Flat, AR 800 nm
Pump laser multimode fiber
3.3 W at 808 nm
SMA connector
100 um core
Mode match lens
Geltech ASP 0.65NA 2.75 mm FL
Corning CO550, n =1.596 at 808 nm
OD 4 mm, CT 1.9 mm
S1: Flat, BBAR (600-1050nm)
S2: 1.638mm ROC, BBAR
Single mode TEM
00
resonator
Resonator parameter g = 0.85
Estimated inter-cavity intensity ~ 3e6 W/cm2
w
0
= 492 um YAG S1
w
1
= 533 um at output coupler S1
@ center d
13.5%
= 1005 um
@ center d
90%
= 231 um
@ 2/3 length d
13.5%
= 1021 um
@ 2/3 length d
90%
= 234 um
300 mm46 mm
10 mm
1.52 mm
n –index of refraction
w –waist, beam 1/e2 radius
d
13.5%
-beam 1/e2 diameter
d
90%
-beam 90% Intensity diameter
ROC - radius of curvature
S1 –first surface
S2 –second surface
FL –nominal focal length
OD -outer diameter
ID – inside diameter
CT - center thickness
HR – high reflectivity coating
AR –anti-reflective coating
BBAR – broadband AR coating
* HR: coating reflectivity > 99.99% at 1064nm
** AR: coating reflectivity < 1% at 808nm
*** AR: coating reflectivity < 0.01% at 1064nm
mode aperture
ID = 2.4 mm
The following parts must be temp-tuned for optimal performance using Closed Loop T.E. Coolers.
Pump Diode: 5C(+/-15C)
Should be temp tuned so absorption is maximized through the length of the YAG.
Nd:YAG: (15 to 20 C)
Thermal conductivity of Nd:YAG is 14W/m/K at 20 C
To improve thermal conductivity one option is to sandwich the YAG using thin pieces of copper
(1 or 2 mm) with some indium foil.
AVS resonator layout
Figure 3: Schematic Diagram of the YAG Laser in the SP2

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Figure 4 details the YAG laser, the optical configuration for SP2, and the optical detectors. The YAG
laser is central to the system, with the four detectors being seen as in the plane of the page. The
aerosol jet is perpendicular to the plane of the page and sends the particles across the laser beam.
Figure 4: SP2 Optical Diagram
2.2 Optical Detectors
Four optical detectors are used. One detector is optically filtered to pass only the 1064 nm
radiation. This will measure the scattering signal from all particles, both those that scatter light
only, and those that absorb light and both scatter and incandesce. This detector is identified as
Channel 0 in the data. Two photomultiplier tube (PMT) detectors measure the incandescence signal
in the visible region. These channels are optically filtered to pass broadband light, nominally from
400-650 nm and narrow-band light, nominally from 610-650 nm. These are identified as channels 1
and 2 in the data, respectively. The ratio of the signals from these two detectors allows the color
temperature of the incandescing particles to be calculated, providing assurance that the particle
measured is elemental carbon. A fourth detector allows measurement of the leading edge of the
scattering signal. This can be used to analyze the amount of coating or mixing state of the
incandescing particle. Details on this analysis are given by Gao et al. (2007). This is Channel 3 in the
data.

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2.3 Control Board Inputs
The SP2 control board inside the chassis has three inputs for sampling external voltages and
recording the data in the housekeeping file. These inputs are J13, J14, and J15, corresponding to
Aux Input 0, Aux Input 1, and Aux Input 2, respectively. Pin 1 of the connector is the signal input
and pin 2 is the return. These inputs have buffer amplifiers so that low-level signals can be
connected to the inputs.
3.0 Unpacking and Setup
3.1 Unpacking
The SP2 will be shipped in two cartons. One is a case specially designed to fit and protect the
analyzer chassis. This case should be saved and used to return the analyzer to DMT if service is
needed. The other carton will contain the sample pump, keyboard, monitor, cables and other
accessories. Check both cartons for damage immediately upon receipt, and notify the carrier and
DMT if damage is noted. After unpacking, remove the cover from the analyzer chassis to look for
components shaken loose in transit.
3.2 Set Up
To set up the SP2, follow the instructions below. Note: Users who have the SP2 with an Auto
Sampler and Nebulizer should consult DOC-0318, the Set-up and Operation Manual for the SP2 with
Auto Sampler for this procedure.
1.) Using Poly tubing with ¼” Swageloks (included), connect the exhaust port on the SP2 to the
exhaust in-flow port on the SP2 pump.
Figure 5: Connecting SP2 and SP2 Pump Exhaust Valves

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2.) If you want to connect a Drierite cartridge to the system, follow the steps below. (Both the
Drierite and Nafion dryer are used to dry sheath and purge flow air in humid conditions.)
a. Connect the Poly tubes exiting the SP2 purge port to the Drierite cartridge (Figure 6).
Figure 6: Connecting SP2 Purge Valve to Drierite Cartridge
b. Connect the Drierite cartridge to the out-flow purge port on the SP2 pump (Figure 7). The out-
flow purge port is on the left side of the pump.
Figure 7: Connecting SP2 Pump Purge Port to Drierite Cartridge
c. Plug in the power supplies for the SP2 and SP2 pump. The set-up is now complete; you do
not need to follow the steps below.

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3. If you want to connect the SP2 directly to the pump without a Drierite cartridge, connect the SP2
purge valve to the SP2 Pump purge port. See Figure 8.
Figure 8: Connecting the SP2 Purge Valve to the SP2 Pump Purge Port
4. Plug in the SP2 pump power connector to the back of the SP2 instrument.
5. Plug in the SP2 power supply. See warning below.
Warning: If not properly grounded, the instrument can cause an electrical shock.
Use a three-conductor cord and a plug appropriate for the location in which the
instrument will be used. Connect the plug to a properly grounded receptacle.
3.3 Turning On the System
To turn on the SP2, follow the instructions below. Note: Users who have the SP2 with an Auto
Sampler and Nebulizer should consult DOC-0318, the Set-up and Operation Manual for the SP2 with
Auto Sampler for this procedure.
1.) Turn on the SP2 Computer using the Computer switch on the SP2.
2.) Turn on the SP2 using the System Power switch on the SP2.2
2The SYSTEM POWER switch controls the power to the SP2 analyzer electronics, and is the
master switch for the SAMPLE PUMP power. If SYSTEM POWER is off, the PUMP cannot be
powered. The COMPUTER switch is independent of the other two switches, and turns only the
computer on and off.

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3.) Start the SP2 software by double-clicking on the SP2 icon on desktop.
4.) In the software, go to Config tab and Program sub-tab.
5.) Check to ensure Config File Being Viewed is set to the correct config file. See Figure 9 for
the location of this parameter. The name of the config file may vary depending on your
instrument. If the correct file is loaded, skip to step 10.
Figure 9: Verifying the Config File on the Config Tab
6.) If a different file is listed, press the Load a File button (Figure 10). Navigate to the directory
C:\DMT\SP2 Support. Select the correct file and click on OK.

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Figure 10: Loading a New Configuration File
7.) Click on the Control tab in the SP2 software. Move the Sample Pump Power Switch to ON
(Figure 11). You should hear the pump motor switch on.

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Figure 11: Sample Pump Power Switch
8.) Go to the SP2 tab on software. Wait until the flow has stabilized. Sample Flow LFE should
be approximately 120 vccm (Figure 12).
Figure 12: Sample Flow Stabilizing

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9.) Click on the Control tab in the SP2 software (Figure 13). Move the Laser Power Switch to
ON.
Figure 13: Turning on the Laser from the Control Tab