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Droplet UHSAS, Operator'S Manual

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Droplet UHSAS Operator'S Manual Download Page 13

Manual, Ultra High Sensitivity Aerosol Spectrometer (UHSAS) 

 

DOC-0210 Rev E-4 

1 3  

© 2017 DROPLET MEASUREMENT TECHNOLOGIES 

2.1.3 

The Mechanical Housing 

The laser and detection optics are built into the optical block, which is a sealed mechanical 

enclosure. See the following figures. 

 

 

 

Figure 4: Light Collection Angles 

 

Figure 3: Side View of Optical Block 

Summary of Contents for UHSAS

Page 1: ...D R O P L E T M E A S U R E M E N T T E C H N O L O G I E S Ultra High Sensitivity Aerosol Spectrometer UHSAS 0 06 1 0 microns Operator Manual DOC 0210 Rev E 4 Software Version 4 1 0 2400 Trade Centre...

Page 2: ...unction 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 us...

Page 3: ...manual may result in hazardous radiation exposure The above certification and identification labels are located on the back panel This label is located on the support structure underneath the instrume...

Page 4: ...DOC 0210 Rev E 4 4 2017 DROPLET MEASUREMENT TECHNOLOGIES Pump Laser Main Laser Wavelength 797 nm 1054 nm Maximum power 1 6 W 50 mW for leakage through mirror 1100 W for recirculating power Maximum ex...

Page 5: ...2 1 3 The Mechanical Housing 13 2 2 Flow System 15 2 3 Analog Electronics 16 2 3 1 Particle Signal Amplification and Tracking 16 2 3 2 Laser Power Monitoring 17 2 4 Digital Electronics System 17 2 4...

Page 6: ...ually Adjusting Flow Knobs 34 7 0 Maintenance 35 7 1 Yearly Maintenance at DMT 35 7 2 Cleaning the Laser Optics 35 8 0 Communications 39 Part II Software 40 9 0 Map Tab 41 10 0 Histogram Tab 44 10 1 A...

Page 7: ...24 Figure 13 100 nm Particle Distribution on an Instrument that Needs Calibration 24 Figure 14 Ambient Air Distribution on a Properly Calibrated Instrument 25 Figure 15 Ambient Air Distribution on an...

Page 8: ...s an airborne instrument Both airborne and ground based versions can be ordered with two additional features bidirectional and particle by particle capabilities The bidirectional feature allows anothe...

Page 9: ...bins 98 if both overflow and underflow are enabled One overflow bin and one underflow bin Flow Range Standard sample flow 1 100 Sccm typically 50 other options available Sheath airflow setting 700 cc...

Page 10: ...T MEASUREMENT TECHNOLOGIES 1 3 Electrical Specifications Power Requirements 100 240 VAC 47 63 Hz 200W Fuse BUSS fuse GMA 2A 1 4 Physical Specifications Size 56 x 43 x 24 cm Weight 31 kg 1 5 Operating...

Page 11: ...w system brings the sample aerosol through the optical interaction region controls and measures the flows 3 Analog electronics system amplifies and processes the particle signals 4 Digital electronics...

Page 12: ...s of Mangin collection optics capable of collecting light over a large solid angle The Mangins image the space at which the sample flow intersects the laser mode The first pair of collection optics th...

Page 13: ...4 1 3 2017 DROPLET MEASUREMENT TECHNOLOGIES 2 1 3 The Mechanical Housing The laser and detection optics are built into the optical block which is a sealed mechanical enclosure See the following figur...

Page 14: ...cattering by particles that pass through the laser The detector is located at 900 to the path of the particle through the laser The laser can be envisioned as shining into the page The mangin mirror p...

Page 15: ...r and a sheath nozzle of 760 m diameter The tip of the sheath jet sits within 1 mm of the edge of the laser mode Sample flow is between 1 and 100 sccm typically 50 sccm The sheath flow is typically 70...

Page 16: ...tages high and low for each of the primary and secondary detection systems Gain stage labeling convention High gain Low gain Primary detector G3 G2 Secondary detector G1 G0 Gain ratios G3 G2 50 G2 G1...

Page 17: ...r 2 4 Digital Electronics System 2 4 1 ADCs and Peak Height Analysis For each of the four gain stages 2 primary 2 secondary there is an associated analog to digital converter ADC The ADCs run a 16 bit...

Page 18: ...set this table at any time to generate a new bin mapping Using the relative gains and the calibration curve and points the instrument automatically converts the bin boundaries to a mapping of voltages...

Page 19: ...ditional programs on the PC including anti virus software may compromise the performance of the system 3 0 Unpacking and Setting up the UHSAS The UHSAS instrument is delivered in a shipping case that...

Page 20: ...ver the sample needle See Figure 9 If the sample tubing needs to be reinstalled use 1 8 3 2 mm outside diameter OD conductive silicon or urethane tubing 3 Connect the keyboard track pad to a USB port...

Page 21: ...ditions are met The keyboard and track pad are connected to the USB port on the front panel of the instrument The zero filter is in place on the inlet The power switch is in the off position The power...

Page 22: ...e factory with a sample flow of 50 sccm so it is a good idea to set the Sample Flow to this value during the following performance check Adjust the flow if necessary either by using the slider control...

Page 23: ...lection of 100 nm particles into the inlet The NIST SRM 1963 100 nm work well These are standard reference particles used during factory calibration 2 The histogram should show a tight distribution wi...

Page 24: ...all bumps in the distribution are normal If you see an uneven distribution of particles around 110 nm and or 215 nm Figure 15 this is usually an indication that calibration is needed The anomalies are...

Page 25: ...is activated go to Histogram tab and press the Record button to stop recording The Record button will change color from a darker grey to the same color grey as the background 2 Put the zero filter on...

Page 26: ...e gain calibration is mostly automated though the results can always be altered if the user needs to make slight adjustments The relative gain calibration works by sampling an ambient air distribution...

Page 27: ...has been hard coded into the instrument by forcing the signals from G3 G2 and G1 to fall on a sixth power curve The final gain stage G0 used for particles from 300 to 1000 nm has a Mie curve appropri...

Page 28: ...meters the calibration curve or the calibration reference points the new parameters are used when the next bin map is generated and committed to the instrument 5 2 Calibration Procedure All calibratio...

Page 29: ...asured on both G3 and G2 will be used to measure the relative gain and offset between these stages When a minimum number of data points has been reached the gain parameters begin to appear in the boxe...

Page 30: ...ability to study these transition regions with high resolution can overemphasize the stitching errors In most cases the semi auto calibration provided should be adequate Stitching errors between the g...

Page 31: ...ize and begin introducing particles to the sample inlet of the UHSAS 6 Go to the Map tab and set up a voltage bin map a Press Volts b Choose a gain stage G3 G2 G1 or G0 appropriate to the particle siz...

Page 32: ...egree of accuracy 3 Configure a size bin map around the particle size used A good choice is a bin map with 99 bins a start value of 0 5 times the nominal size and a stop value of 1 5 times the nominal...

Page 33: ...splayed on the Controls tab These tests and checks should be performed at least once a week to confirm the instrument is functioning properly 6 2 1 To perform a zero count Install the supplied zero co...

Page 34: ...and Laser Temperature is at the correct value Check the Reference level on the Controls tab If the displayed Reference is less than 1 88 V clean the laser optics as described in section 7 0 If cleanin...

Page 35: ...tics may need more frequent cleaning A good indication of whether the laser optics require cleaning is the Reference voltage which is displayed on the Controls tab The initial value for the Reference...

Page 36: ...he tubing at the joint in the exhaust line The exhaust line comes out of the bottom of the large black optical block see Figure 20 Opening the line creates positive pressure in the block and helps kee...

Page 37: ...IES 5 Turn the unit on and start the software program Check the Laser Current reading on the Controls tab It should read zero If it does not depress and release the laser interlock switch again Do not...

Page 38: ...eaning port 7 Using a cotton swab with a one to two drops of spectra photo grade acetone clean the optic Figure 24 A single gentle swipe in one direction across the middle portion of the optic works t...

Page 39: ...they are lower than when the cleaning started the cleaning was unsuccessful 15 Repeat above steps until adequate Scatter and Reference levels have been attained 16 Install the 16 Phillips head mounti...

Page 40: ...t screen that appears upon program start up 2 Map Tab Allows the user to commit the desired bin map to the instrument The bin map determines how the UHSAS categorizes and sizes particles 3 Histogram T...

Page 41: ...controlled through the Map tab The Map tab shows the boundaries of the bin width map that is used for the display The map can be modified in multiple ways depending on user preference This tab sets a...

Page 42: ...rs specified in nm Volts creates a histogram in voltage space mV of the gain stage chosen G3 G2 G1 or G0 Time creates a histogram of transit times s of the gain stage chosen 2 Specify the range minimu...

Page 43: ...underflow bin beneath the smallest particle bin The underflow bin contains all detected particles bigger than the trigger threshold but smaller than the lower limit of the first bin See section 0 for...

Page 44: ...data are broadcast out to the serial port The sample time is set using the slider controls the green control for hours the blue for minutes and the white for seconds or by directly entering numeric va...

Page 45: ...or sec i e rather than units of size if volts or time have been selected as the binning criterion on the Map tab Refer to the bin map tab to identify bins or use the cursor to read the bin boundaries...

Page 46: ...of the window The actual sample flow which may differ from the set flow is listed in the gray box underneath the Sample Flow slider control The actual flow is also indicated by the blue portion of the...

Page 47: ...strument s performance The actual laser current and the set point should be close but not the same An ON OFF button appears beneath the actual current when a password has been entered on the Configura...

Page 48: ...e Configuration tab in Calibration mode Clicking on Revert to Factory Configuration reverts all the parameters to their original default values These parameters are stored in separate configuration fi...

Page 49: ...file on the computer Note that the information being sent to the serial port is identical to that going to the data file The Normalize Histograms to Bin Width switch determines the default normalizat...

Page 50: ...efficients are for the sample flow controllers Temperature Coefficients are for the electronics box temperature reading in K i e the temperature of the ambient air just as it enters the instrument Pre...

Page 51: ...heory behind the calibration process and step by step instructions on calibrating the instrument see Section 5 0 13 1 Calibration Curve Sub tab This tab shows the instrument s calibration curve This c...

Page 52: ...The power law relationship determines the curve for particles smaller than 200 300 nm while the Mie curve determines points for larger particles This theoretical curve is then fitted to empirical data...

Page 53: ...ore precisely it specifies the Mie curve of signal size v versus particle diameter d on the lowest gain channel G0 The diameters specified are absolute in nm and the signal size is specified as a rela...

Page 54: ...processed the number of particles stipulated in the Pts control The Pts control sets the number of particles the UHSAS processes before relative gain calibration is complete The Align button visible...

Page 55: ...to the instrument Sample sccm The flow of the sample air which should be between 1 and 100 sccm The instrument is factory calibrated at 50 sccm so this is a good sample flow setting Ref Volts The lase...

Page 56: ...ormation All 8 30 10 C 1 Revised specifications 1 10 12 10 D Updated screen shots to reflect new software updated data path names All 11 10 10 E Revised acceptable values for Scatter Volts Appendix A...

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