Inverting raw data

szdist can handle a few file formats. It default format is called "lamp2013". The rest of this page will cover this one. It is recommended to generate such files with your SMPS/DMPS system. If you can't, or if you have legacy data, then the szconv utility should be complemented to read your custom format and produce files that szdist can read.

"lamp2013" raw file format

Download the raw data test file. It is a DMPS file, but it could be a SMPS file as well.

The file looks like the sample bellow. Note that the header contains the geometrical properties of the DMA. These are used by the inversion program, as well as the sheath flow rate and number of size bins, to determine the first and last particle diameters of each scan. The diameters are logathmically distributed. As a consequence, it is not necessary to save the full diameter list since it is easy to Build_the_list_of_diameters.

This file contains only real raw data : no concentrations but counts, no particle diameters but voltages.

# <<<
# Raw file content : DMPS CPC
# Format version : 1
# DMA R1 (m) : 0.009375
# DMA R2 (m) : 0.0195
# DMA len (m) : 0.4404
# Eq len (m) : 10.1
# start (UTC) ,,,,,,Vbeg   ,Vend   ,Nv    ,Tv    ,Tc    ,RHin  ,Tin   ,Pin   ,Qin   ,Tex   ,Pex   ,RHsh  ,Qsh   ,Qae   ,RES   ,Counts
# yr,mo,dy,hr,mn,sc,V      ,V      ,ul    ,ms    ,ms    ,%     ,degC  ,mbar  ,l/min ,degC  ,mbar  ,%     ,l/min ,l/min ,RES   ,ul
# >>>
2019,05,22,10,03,29,    9.9, 8997.9,    26, 12000,  2000,  35.4,  30.9, 964.4,  1.00,  29.7, 962.9,  41.5,   5.0, 1.004, -99.9,12,23,41,79,117,185,330,542,699,930,1071,1212,1243,1320,1523,1599,1496,1305,1049,731,449,356,179,86,45,19
2019,05,22,10,09,22,    9.9, 8999.4,    26, 12000,  2000,  35.2,  31.1, 964.5,  1.01,  29.7, 962.9,  41.5,   5.0, 1.006, -99.9,9,22,43,58,117,212,347,419,710,910,1084,1181,1242,1316,1447,1452,1466,1285,1027,725,497,282,138,87,34,12
2019,05,22,10,15,15,    9.9, 8999.8,    26, 12000,  2000,  34.8,  31.2, 964.4,  1.01,  29.7, 962.8,  41.5,   5.0, 1.009, -99.9,2,9,14,51,77,157,243,384,611,760,930,1015,1099,1268,1456,1494,1446,1232,974,651,503,264,142,64,34,9

Where :

  • Vbeg : 1st voltage of the scan.
  • Vend : last voltage of the scan.
  • Nv : number of voltage steps.
  • Tv : duration of a voltage step.
  • Tc : duration of the counting period. Tc <= Tv.
  • RHin : %RH at the inlet of the instrument.
  • Tin : temperature at the inlet of the instrument.
  • Pin : pressure at the inlet of the instrument.
  • Qin : volume flow rate at the inlet of the instrument (DMA polydisperse aerosol flow), measured by the PFM (pressure flow meter)
  • Tex : temperature in the excess flow of the DMA.
  • Pex : Pressure in the excess flow of the DMA.
  • RHsh : %RH in the sheath flow of the DMA.
  • Qsh : sheath flow rate of the DMA.
  • Qae : aerosol flow rate, used to calculate the concentration.
  • RES / Tgrad : in the CPC file, reserved for future use ; in the mCCNC file, temperature gradient.
  • Counts : particle counts, accumulated during Tc. There must be Nv columns.

Invoking szdist

When you diplay the help message (szdist -h), you'll notice that some options are between brackets. It means that they are optional. All other options are mandatory.


$ szdist -i tsi3010_sn2257_20180314.ini -t lamp2013 -o tsi3010_sn2257_20180314.csv -l 10 -c1 -z xray