SQUID2 Files

NOTES ACCOMPANYING THE JUNE 2015 RELEASE OF SQUID2.50.11.02.03


INTRODUCTION

Users new to SQUID2 should read SQUID2.50_OVERVIEW.txt before reading this
document.


RELEASE NOTES

This June 2015 release of the 03 February 2011 version of Squid2.50
(Squid2.50.11.02.03) contains a bug fix. 

The bug, affecting many (and perhaps all) previous versions of Squid2, involves
incorrect duplication of the collector deadtime correction during processing of
a PD or XML file, if any such file has been processed earlier in the same Excel
2003 session. In this situation, isotopic ratios calculated by Squid2.50 contain
inaccuracies which are generally very minor in typical U-Pb applications, but
scale with the count-rates of the constituent ionic species. As a result, the
bug affects repeatability of data processing: even when the user-defined set of
preferences and parameters remains unchanged throughout, the isotopic ratios
calculated by Squid2.50 differ very slightly depending on whether the data-
reduction is the first performed since Excel 2003 was started (in which case the
collector deadtime correction is correctly applied once) or not (in which case
the collector deadtime correction is incorrectly applied twice).

The files forming part of this release contain detailed documentation of the
bug, including (1) diagnosis of the problem via collector deadtime calculation
from first principles, (2) a test to see whether any given version of Squid2 is
affected by the bug, (3) instructions for download and installation of a
repaired XLA file, in which the bug has been fixed, and (4) an evaluation of the
effect of the bug, using a typical U-Pb dataset collected by Geoscience
Australia. In addition to the repaired XLA, this release also contains a default
squiduser folder intended for users new to Squid2.50 (users of pre-existing
Squid2.50 versions are encouraged to retain their existing squiduser folders and
their contents), as well as the Squid2.50 User Manual, and the GNU Public
License terms and conditions for copying, conveying and modification of the
Squid2.50 software.


DOWNLOAD CONTENTS

The Squid2.50.11.02.03_June 2015 release comprises the components defined and
summarised below:

- SQUID2.50_OVERVIEW.txt
- SQUID2.50_JUNE2015_README.txt
- LICENSE_and_COPYING.txt
- SQ2_DoubleDeadtime_June2015\
    - SQ2_DoubleDeadtime_June2015.pdf
    - Appendix1_DoubleDeadtimeCalculation.xls
    - Appendix2_SinglevDoubleDeadtime_Compared.xls
- CURED_Squid2.50.11.02.03_June2015\
    - Squid2.50.11.02.03.xla
    - Squid2.50_User_Manual.pdf
    - squiduser\
        - SquidPreferences.xls
        - SquidTask_Z1 = 9pk (fixed slope 2).GA.xls
        - SquidTask_Z2 = 9pk RSES (floating slope).GA.xls
        - SquidTask_Z3 = 10pk (fixed slope 2).GA.xls
        - SquidTask_Z4 = 10pk (floating slope).GA.xls
        - TaskCatalog.xls

SQUID2.50_OVERVIEW.txt = An overview of Squid2.50 intended primarily for new 
users, containing information relating to licensing, software and hardware
requirements, and dependencies that require attention during readying the
software for use.

SQUID2.50_JUNE2015_README.txt = Information about this release of Squid2.50,
including a summary of (1) the issue requiring the bug fix,(2) the files used to
define, demonstrate and repair the bug, and (3) instructions for installation of
a repaired XLA file.

LICENSE_and_COPYING.txt = The GNU Public License terms and conditions for
copying, conveying and modification of this software.

The directory SQ2_DoubleDeadtime_June2015 contains 3 files:

SQ2_DoubleDeadtime_June2015.pdf = A document describing the bug, a test to see
whether the bug affects any given version of Squid2 (including those versions
predating Squid2.50), detailed instructions for replacing a defective Squid2 XLA
with a repaired XLA in which the bug has been fixed, and an example assessment
of the effect of the bug, using results obtained from a typical U-Pb dataset
obtained by Geoscience Australia.

Appendix1_DoubleDeadtimeCalculation.xls = A spreadsheet demonstrating manual
calculation of the collector deadtime correction from first principles, and
demonstrating the derivation of erroneous Squid2.50 output attributable to the
bug. Note that this spreadsheet requires Isoplot3 in order to be fully
functional, and a single-page PDF of the worksheet has been included as Appendix
1 in SQ2_DoubleDeadtime_June2015.pdf for users without Isoplot3.

Appendix2_SinglevDoubleDeadtime_Compared.xls = A multi-tab spreadsheet
containing a summary of key parameters calculated from a typical U-Pb dataset
collected by Geoscience Australia, showcasing the effect of the bug. This
spreadsheet may require Isoplot3 in order to be fully functional, and a 3-page
PDF of the worksheet has been included as Appendix 2 in
SQ2_DoubleDeadtime_June2015.pdf for users without Isoplot3.

The directory CURED_Squid2.50.11.02.03_June2015 contains 2 files and a
subdirectory:

Squid2.50.11.02.03.xla =  The Microsoft Excel 2003 add-in Squid2.50.11.02.03,
with the bug fix applied.

Squid2.50_User_Manual.pdf = A comprehensive user guide covering the software and
hardware requirements of Squid2.50 and in-depth instructions on how to use
Squid2.50.

squiduser = a folder containing 6 Excel 2003 workbooks (*.xls files), comprising
4 SquidTasks, 1 SquidPreferences and 1 TaskCatalog) that are used in the
processing of raw PD and XML files, and are offered as a starting point for
users new to Squid2.50. Users of pre-existing Squid2.50 versions are encouraged
to retain their existing squiduser folders and their contents.