Introduction

This document is intended to familiarize you with the basics of the content of this archive. It contains comments and general notes on the archival process, data formats used, and part of an example SIMS data sheet. You may access this information directly through the list shown below.

• General notes on the content
• Information on possible data loss or access problems
• Directory layout, filenames and -formats
• An example SIMS data sheet

• 3435 SIMS ion images done in 258 analyses,
• over 200 SEM and optical microscope images,
• 902 photographs of MOS detectors, and
• the complete IDE time- and resolution resolved dataset.

Information on possible data loss or access problems

• Misspelling of filenames may cause hyperlinks to fail. In this case, make a note of the error message. On the CD-ROM, a file with a similar name should be available in the subdirectory/folder that was displayed in the error message and can be found by using the File-Open Local File command.
• Impact features were sometimes numbered according to the sequence they were detected, the SIMS files according to the SIMS analysis sequence. Sometimes it was not possible to associate an image with a SIMS run.
• Some SIMS data files disappeared as the backup process was done on a non-procedural basis.
• Some early EDS analyses may have been available on 8'' floppy disc. The author apologizes for not having time enough at this late stage of the archival process to appropriately take care of these files.
• Some html files may never be accesible through hyperlinks. The design of this archive relies heavily on computer-assisted hyperlink genereation. Pages that were generated manually might have been overseen at some stage of the final archival process. Feel free to contact the author if any problems occur.
• The major problem of this archival process is the fact, that the data acquisition process was only partially done on a computer-assisted basis. Most of the data comes from handwritten notes and from "usually we do this like that" sources, if still available. Future archives should have more mandatory computer support or, at least, appropriate forms to be filled manually.

Standard filenames, pathnames, file extensions and -formats

• All filenames are in the 8+3 letter, period seperated uppercase format used by PC's built from uppercase letters, digits and underscores as required by ISO 9660 for CD-ROMs.
• All SIMS-related filenames base on the original filenames of the analysis. The pattern used was sssTn with sss the three-digit sensor serial number, T an analysis type (like C for crater or discharge, B for Blank or preflight discharge, L for laser blanks, and more). Sometimes the naming convention is slightly inconsistent, however.
• If you want to browse the CD-ROM, I used the following pathname pattern:
  • / contains the main index and some other HTML-files and the database logo
  • /HELP is where this file is located
  • /INFO contains more technical information e.g. on channel plate setting
  • /BIBLIOGR contains references to literature and, sometimes, availability of documents that this databse refers to but does not contain. This is not the complete list of references for all IDE analyses. Refer to the literature for more information on this issue.
  • /IDE contains time- and orientation resolved data prepared by John Oliver and Bill Cooke of ISST and UFL, Gainesville, FL.
  • /SIMS should have been named analyses, since this directory contains SIMS, EDS, SEM, AES and optical analyses together with pre- and postflight. Apologies if this causes confusion. The subdirectories under this path are:
    • /SIMS/A0187_1/ is for analyses on gold samples from A0187-1. /SIMS/A0187_1/G144/G144C1/BRG would be the path for bargraph files taken for crater 1 of sample 144 from A0187-1.
    • /SIMS/MOSnnnn/ holds analyses done on the MOS sensor nnnn from A0201. /SIMS/MOS1195/195C2/PRO is the directory containing depth profile data for crater (.i.e., discharge) 2 on the IDE MOS sensor 1195.

The main archival activity consisted in the conversion of file formats from a SIMS-machine specific format to a format that could hold additional information, entering information from notebooks and verifying and re-verifying this data. A lot of time has been spent on element classification using information from notebooks and preocedures that are not explicitly stored in this database. During the archival activity, the author generated more than 11000 lines of C code, mostly during the first eight weeks of the six-month archival process.

This archive still contains data with rather "raw" character. Results based on this data were, however, published elsewhere before, too. The main purpose of this archive is to provide access to data that might not be further analyzed by the IDE team due to budget constraints. Hopefully, this data will be used before similar experiments are proposed.

All data in the archive came from

• Raw SIMS *.IMG, *.PRO, *.BRG files and raw EDS files, each in proprietary file formats, from fixed and removable harddrives and tapes, or
• were scanned using a HP ScanJet IIc.

If your html client software (e.g. Mosaic) crashes when trying to access a SIMS data page, you may try the one of the following:

• Try to access this database from a computer with more memory (e.g. a workstation). Each SIMS page contains an average of 20 images and roughly 100 hyperlinks.
• Turn off the automatic download of images (to be found under a menu item probably labeled options). You can still look at specific images by clicking on the icon that it is replaced with. Every SIMS page is accompanied by a page with thumbnail ion images which use a lot less memory but provide an excellent overview over the analysis.
• On the Macintosh, increase the memory size for the Mosaic program to a bigger value. The author used a setting of 4000kBytes on a MacIIfx with 8 MBytes RAM and could access all files.
• On a PC, try to activate virtual memory.

• Experiment A0201
• Surface ID 1172 (preflight and postflight images)
• Feature # 10
• LDEF Location: Bay G Row 10
• Coordinates [mm] x 0.0 +- 0.0 y 0.0 +- 0.0
• JSC ID G10E00 6 1172
• Surface Description: MOS Detector, earth end
• Feature Description: ?
• Origin Description:
• Photos available:
  • none
• Analyses performed:
  • SIMS profile
  • SIMS bargraph
  • SIMS images

SIMS Images

Given below are the SIMS images of this feature. A thumbnail image overview is available, too. The analysis was performed on 04-20-1992. The following mass numbers were imaged:
16, 23, 24, 27, 28, 39, 40, 48, 52, 56, 56, 58, 63, 64, 107

This list is generated directly from the SIMS image file. Sometimes, mass numbers that had no counts were skipped by the operator, which is usually noted in the general comments in the previous section. This means that a particular species was not seen.

Analytical Conditions:

Missing values are marked using a question mark. Although sometimes an educated guess could have been made to assume a value, the author decided against it as this seemed not suitable for an archive. Hint: Look for analyses performed chronologically before or after the analyses you may want to guess the value for as it is relatively safe to assume that procedures did not change significantly during subsequent analyses.

Contrast diaphragm had alwas a constant value of 3 and image pixel size was 256 by 256 16-Bit for all analyses. Note that you have to correct the aspect ratio of the images if you want to have undistorted images. Convert the image to a 256 by 212 pixel image for geometrically correct images.

Primary beam:

• Gas and polarity: O+
• Primary Acceleration Voltage: 15 kV
• Secondary Acceleration Voltage: +4.5 kV
• Primary beam current: 250 nA
• Raster size: 250 (range 250, pot setting 10)

Secondary beam:

• Polarity: +
• Transfer Optics Setting: 150 micrometers
• Energy slit setting: ?
• Energy slit translation: ?
• Entrance slit setting: 1.000
• Exit slit setting: 1.000
• Contrast Diaphragm: 3 (150 micrometers)
• Field Aperture: 2 (750 micrometers)
• Imaged Area: 60
• Image Pixel Size: 256 x 256 (aspect ratio correction: multiply y by 0.83)
• Channel plate ID: 2

Image 7, Ca (Mass 40)

1. Image 7, Ca (Mass 40)
2. Image 10, Mass 56 (Fe)
3. Image 13, Mass 63 (unidentified)
4. Image 14

The ion image is available as a TIFF image by clicking on the image. Notes:

• The TIFF image is a 8 bit representation of 16 bit data. Data loss (in the TIFF image) occurs if the max count rate was greater than 255. See the signal intensity value below.
• All images use the same color palette or color lookup table with 255 colors (the 256th is used for white) to maximize the display contrast as most computer display cards allow only 256 colors. That means that a red pixel in e.g. an Al image carries a different value than a read pixel of e.g. an Au image.
• The images are not corrected for ion yields, channel plate gain settings
• The images are shift-corrected if the CCD array was moved during an anlysis if this was possible
• The original 16 bit values may be obtained by directly accessing the IDE data file. See the description of the two donload buttons below.
• If image size information was available, the two white scale bars represent 50 micrometers.
• If you click on the image and are confronted with a viewer window filled with characters instead of getting access to the TIFF file, you may try two things:
  • Activate the load to disk function of your HTML viewer (as Mosaic). You will then be able to save the TIFF file for later processing with your software.
  • Provide the correct extension or suffix mapping in your version of your software. On the Macintosh, use Options Preferences Helper Applications to map TIFF to a viewer of your choice, on the PC edit the MOSAIC.INI file and

signal intensity scale: 0 -> 189; scale bars are 50 micrometers

The table below a ion image lists all relevant mass interferences for this particular mass. The instrument was operated at a mass resolution of at least 3000, which is the reason why interfering species which need resolutions less than 3000 are not individually listed in this table. For "uncommon" masses this table is not given.

--------------------------------------------------------------------------------
			% isotopic	Resolution
Element Interferents	abundance	  (m/Dm)	Comments
--------------------------------------------------------------------------------
40Ca	40K		  0.012 	 +28,000	not resolvable, very low
							abundance.
	39KH		 93.1		  +4470 	not resolvable, used
							44Ca (SiO resolvable
							interference) or non-
							coinci-dence with K dis-
							tribution
      *28SiC,*24MgO,27Al13C,		   <2993	resolved
       12C2O,12C3H4
--------------------------------------------------------------------------------
NOTE: An asterisk (*) means that these species were in fact observed on Hi-Res
      Mass Spectra of a particular mass on the Standard.

Image Conditions

These parameters directly affect image intensities.

• Number of frames taken: 500
• Channel Plate Gain setting: 2.4
• Channel Plate ID: 2
• total count rate: 231226
• max count: 189
• species classification positive
• sensitivity factor for material implanted in Si matrix: 38.5000

The SIMS/IDE data file contains most of the data relevant for a particular impact, standard or clean surface together with the 16 bit SIMS analyses. A IDE data file editor is available for PC's. A very crude C source code file is available, by clicking on the icon below to the right, to read the IDE data files accesible by the icon on the left. Individuals interested in the quantitative analysis of the SIMS runs should use the IDE SIMS data file editor instead.

Mass Ratio Plot

Sometimes, a mass abundance plot is shown for a selected "boxed" area. This is done to aid in semiquantitative impactor classification. The underlying data file can be accessed by clicking on the plot. The description below appears on every SIMS data sheet that comes with such a plot. Information on the origin classification procedure and SIMS procedure is available, too. Please note that the text "0.185abundance" below should read "0.185% abundance". A bug (or a feature) in the C software used to generate the html files made the % disappear. The image displayed below shows the area (71,57 to 162,175) and the image (number 5, mass 28) that was used to compute mass ratios.

Only identifiable masses with the same channel plate gain value and ID may be displayed. The plot shows data points with Relative Sensitivity Factors for both material implanted in a silicon matrix and material implanted in a lunar analog glass matrix applied to them. When comparing the values of the data file available for this feature with the data of another feature, all instrument and image acquisition parameters must be the same to make any quantitative comparison of these two features. The values in the data file are shift-corrected pixel counts summed over the entire area inside the box and divided by the box area. 48Ti signals are corrected for 48Ca (0.185abundance, not resolvable). Please refer to the element classification information for the interpretation of this plot.

---

retrieve SIMS data fileget C source code

---

IDE database home page Back to surfaces page

---

Klaus G. Paul, 6-17-1994