Design, modeling, optimization, and experimental tests of a particle beam width probe for the aerodyne aerosol mass spectrometer

被引:159
作者
Huffman, JA
Jayne, JT
Drewnick, F
Aiken, AC
Onasch, T
Worsnop, DR
Jimenez, JL [1 ]
机构
[1] Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA
[2] Univ Colorado, CIRES, Boulder, CO 80309 USA
[3] Aerodyne Res Inc, Billerica, MA 01821 USA
[4] Max Planck Inst Chem, D-55128 Mainz, Germany
关键词
D O I
10.1080/02786820500423782
中图分类号
TQ [化学工业];
学科分类号
0817 ;
摘要
Aerodynamic lens inlets have revolutionized aerosol mass spectrometry by allowing the introduction of a very narrow particle beam into a vacuum chamber for subsequent analysis. The realtime measurement of particle beam width after an aerodynamic lens is of interest for two reasons: (1) it allows a correction to be made to the measured particle concentration if the beam is so broad, due to poor focusing by non-spherical particles, that some particles miss the detection system; and (2) under constant lens pressure it can provide a surrogate particle non-sphericity measurement. For these reasons, a beam width probe (BWP) has been designed and implemented for the Aerodyne Aerosol Mass Spectrometer (AMS), although this approach is also applicable to other instruments that use aerodynamic lens inlets. The probe implemented here consists of a thin vertical wire that can be precisely positioned to partially block the particle beam at fixed horizontal locations in order to map out the width of the particle beam. A computer model was developed to optimize the BWP and interpret its experimental data. Model assumptions were found to be reasonably accurate for all laboratory- generated particle types to which the model was compared. Comparisons of particle beam width data from a number of publications are also shown here. Particle losses due to beam broadening are found to be minor for the AMS for both laboratory and ambient particles. The model was then used to optimize the choice of the BWP dimensions, and to guide its use during continuous operation. A wire diameter approximately 1.55 times larger than the beam width to be measured provides near optimal sensitivity toward both collection efficiency and surrogate non-sphericity information. Wire diameters of 0.62 mm and 0.44 mm ( for the AMS " long" and " short" chambers, respectively) provide reasonable sensitivity over the expected range of particle beam widths, for both spherical and non- spherical particles. Three other alternative BWP geometries were also modeled and discussed.
引用
收藏
页码:1143 / 1163
页数:21
相关论文
共 42 条
[1]   Characterization of urban and rural organic particulate in the lower Fraser valley using two aerodyne aerosol mass spectrometers [J].
Alfarra, MR ;
Coe, H ;
Allan, JD ;
Bower, KN ;
Boudries, H ;
Canagaratna, MR ;
Jimenez, JL ;
Jayne, JT ;
Garforth, AA ;
Li, SM ;
Worsnop, DR .
ATMOSPHERIC ENVIRONMENT, 2004, 38 (34) :5745-5758
[2]   A generalised method for the extraction of chemically resolved mass spectra from aerodyne aerosol mass spectrometer data [J].
Allan, JD ;
Delia, AE ;
Coe, H ;
Bower, KN ;
Alfarra, MR ;
Jimenez, JL ;
Middlebrook, AM ;
Drewnick, F ;
Onasch, TB ;
Canagaratna, MR ;
Jayne, JT ;
Worsnop, DR .
JOURNAL OF AEROSOL SCIENCE, 2004, 35 (07) :909-922
[3]   A method for single particle mass spectrometry of ice nuclei [J].
Cziczo, DJ ;
DeMott, PJ ;
Brock, C ;
Hudson, PK ;
Jesse, B ;
Kreidenweis, SM ;
Prenni, AJ ;
Schreiner, J ;
Thomson, DS ;
Murphy, DM .
AEROSOL SCIENCE AND TECHNOLOGY, 2003, 37 (05) :460-470
[4]   Particle morphology and density characterization by combined mobility and aerodynamic diameter measurements. Part 1: Theory [J].
DeCarlo, PF ;
Slowik, JG ;
Worsnop, DR ;
Davidovits, P ;
Jimenez, JL .
AEROSOL SCIENCE AND TECHNOLOGY, 2004, 38 (12) :1185-1205
[5]  
DELIA AE, 2004, THESIS U COLORADO BO
[6]   Intercomparison and evaluation of four semi-continuous PM2.5 sulfate instruments [J].
Drewnick, F ;
Schwab, JJ ;
Hogrefe, O ;
Peters, S ;
Husain, L ;
Diamond, D ;
Weber, R ;
Demerjian, KL .
ATMOSPHERIC ENVIRONMENT, 2003, 37 (24) :3335-3350
[7]   A new time-of-flight aerosol mass spectrometer (TOF-AMS) - Instrument description and first field deployment [J].
Drewnick, F ;
Hings, SS ;
DeCarlo, P ;
Jayne, JT ;
Gonin, M ;
Fuhrer, K ;
Weimer, S ;
Jimenez, JL ;
Demerjian, KL ;
Borrmann, S ;
Worsnop, DR .
AEROSOL SCIENCE AND TECHNOLOGY, 2005, 39 (07) :637-658
[8]   Real-time analysis of individual atmospheric aerosol particles: Design and performance of a portable ATOFMS [J].
Gard, E ;
Mayer, JE ;
Morrical, BD ;
Dienes, T ;
Fergenson, DP ;
Prather, KA .
ANALYTICAL CHEMISTRY, 1997, 69 (20) :4083-4091
[9]   Thermal plasma deposition of nanophase hard coatings [J].
Heberlein, J ;
Postel, O ;
Girshick, S ;
McMurry, P ;
Gerberich, W ;
Iordanoglou, D ;
Di Fonzo, F ;
Neumann, D ;
Gidwani, A ;
Fan, M ;
Tymiak, N .
SURFACE & COATINGS TECHNOLOGY, 2001, 142 :265-271
[10]   Semicontinuous PM2.5 sulfate and nitrate measurements at an urban and a rural location in New York:: PMTACS-NY summer 2001 and 2002 campaigns [J].
Hogrefe, O ;
Schwab, JJ ;
Drewnick, F ;
Lala, GG ;
Peters, S ;
Demerjian, KL ;
Rhoads, K ;
Felton, HD ;
Rattigan, OV ;
Husain, L ;
Dutkiewicz, VA .
JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION, 2004, 54 (09) :1040-1060