PDS_VERSION_ID = PDS3
LABEL_REVISION_NOTE = "J. W. Manweiler, Revision 2, 5/4/2005"
RECORD_TYPE = STREAM
OBJECT = DATA_SET
DATA_SET_ID = "CO-E/J/S/SW-MIMI-2-CHEMS-UNCALIB-V1.0"
OBJECT = DATA_SET_INFORMATION
DATA_SET_NAME = "
CASSINI E/J/S/SW MIMI CHEMS SENSOR UNCALIBRATED DATA V1.0"
DATA_SET_COLLECTION_MEMBER_FLG = N
START_TIME = NULL
STOP_TIME = NULL
DATA_SET_RELEASE_DATE = NULL
PRODUCER_FULL_NAME = "Jerry W. Manweiler"
DETAILED_CATALOG_FLAG = N
DATA_OBJECT_TYPE = "SPREADSHEET"
ARCHIVE_STATUS = "IN PEER REVIEW"
DATA_SET_TERSE_DESC = "
This data set contains all of the data collected by the CHEMS sensor
of the MIMI instrument aboard the Cassini spacecraft for the entire
Cassini mission. CHEMS stands for CHarge Energy Mass Spectrometer.
See MANWEILERETAL2005"
ABSTRACT_DESC = "
The Cassini Magnetospheric Imaging Instrument(MIMI) Charge Energy
Mass Spectrometer (CHEMS) uncalibrated data set includes all data
collected from the MIMI Data Processing Unit during the mission.
The original data has been decommutated and decoded by software at
the Applied Physics Laboratory (APL) and has been then further
ordered and filtered by software at Fundamental Technologies, LLC.
The data is provided in an uncalibrated form in conjunction with a
PDS MIMI calibration volume COMIMI_0000 which provides specific
algorithms for the derivation of calibrated data. This data set
includes uncalibrated values for each energy and mass channel for
the CHEMS sensor for all times during the mission including the
Earth flyby, the Jupiter flyby, interplanetary cruise, and the
entire Saturn tour. Data are presented in a set of tables which are
of variable length and use a comma to separate various fields. This
data set is intended to be the most comprehensive and complete data
set included in the Cassini MIMI CHEMS archive. A browse data set
is included with Key Parameter data that is calibrated using the
algorithms provided in the Calibration volume. In addition, a series
of images are provided with the KP browse data that displays the KP
data which can lead the user to the particular times of interest.
This data set should be among the first used by a user of any of the
MIMI CHEMS archive as it will lead one to information required to
search for more detailed or highly specialized features in the
original data."
CITATION_DESC = "Manweiler, J.W., W. Rasmuss, and S. Joy,
CO-E/J/S/SW-MIMI-2-CHEMS-UNCALIB-V1.0, NASA Planetary Data
System, 2005."
DATA_SET_DESC = "
Data Set Overview
=================
The Cassini Magnetospheric Imaging Instrument(MIMI) Charge Energy Mass
Spectrometer (CHEMS) uncalibrated data set includes all data collected
from the MIMI Data Processing Unit during the entire Cassini mission
[MANWEILERETAL2005]. The original data has been decommutated and
decoded by software at the Applied Physics Laboratory (APL) and has
been then further ordered and filtered by software at Fundamental
Technologies, LLC. The data is provided in an uncalibrated form in
conjunction with a PDS MIMI calibration volume COMIMI_0000 which
provides specific algorithms for the derivation of calibrated data.
This data set includes uncalibrated values for each energy channel for
the CHEMS sensor for all times during the mission including the Earth
flyby, the Jupiter flyby, interplanetary cruise, and the entire Saturn
tour. Data are presented in a set of tables which are of variable
length and use a comma to separate various fields. This data set is
intended to be the most comprehensive and complete data set included
in the Cassini MIMI CHEMS archive. A browse data set is included with
Key Parameter data that is calibrated using the algorithms provided in
the Calibration volume. In addition, a series of images are provided
with the KP browse data that displays the KP data which can lead the
user to the particular times of interest. This data set should be
among the first used by a user of any of the MIMI CHEMS archive as it
will lead one to information required to search for more detailed or
highly specialized features in the original data.
Parameters
==========
This data set comprises count rates associated with mass, energy, and charge state
spectrometer measurements for each telescope of the CHEMS detector in
accumulation and science modes. In addition this data set includes
CHEMS PULSE HEIGHT ANALYSIS measurement data for a statistically
select sample of the particle measurements. The standard product ID's
are:
CHEMS Accumulation Rate Data - telescope count rate measurements
CHEMS Science Rate Data - mass per charge, mass and charge count rate
measurements.
CHEMS Pulse Height Analysis Data - Statistically sampled set of
discrete particle measurements.
The data is organized in time by the spin of the spacecraft. When the
spacecraft is in staring mode then the MIMI DPU automatically creates
a virtual spin that divides the time collection periods into 16
sectors, 16 subsectors, and 16 microsectors and maintains a simple
organizational structure for characterizing the collection of the time
into time segments. When the spacecraft is spinning at a minimally
defined spin rate (adopted by the MIMI DPU) then the MIMI data is
automatically segregated into 16 sectors, 16 subsectors, and 16
microsectors. When the spacecraft is spinning and the LEMMS
instrument is rotating the LEMMS rotation period is synchronized to the
spacecraft spin period so that there are 16 sectors in a spin, 16
subsectors in a sector and 16 microsectors in a subsector. The CHEMS
and INCA instrument collection times are then also keyed to these
values.
Processing
==========
Data in this data set were processed by the use of a number of
software programs which assemble segmented mini-packets in the raw
telemetry packets into complete sets, de-compress the data that were
compressed by one of a number of compression algorithms by the MIMI
flight software onboard and organize the channel data into
appropriate time segments.
Data
====
The MIMI CHEMS uncalibrated data set includes three ASCII CSV tables
(each associated with a Standard Product ID of CHEMS Rate data as a
function of time collected from the MIMI CHEMS Detectors and collated
into data sets. Each table contains variable length records for which
the fields are comma delimited.
CHEMS Accumulation Rate Data
----------------------------
Fields include:
a purpose identifier where science data records are identified
with purpose = sci
starting and ending ephemeris times
Spin, sector, subsector (and for CHEMS Fine Rate (FRT) data
microsector)
SCLOCK and spin period that are used to derive the starting
ephemeris time
Notes regarding the SCLOCK value:
1. Only the SCLOCK major segment value is provided - MIMI
currently does not have access to the fine SCLOCK value
hence SCLOCK resolution is limited to +- 1/2 SCLOCK count
2. The SCLOCK is only available from telemetry at the
beginning of each spin. All other published SCLOCKS are
derived from the spin starting SCLOCK, the spin numbers
(for the current and next available spins), and the spin
period.
3. SCLOCK values are assumed to drive the value of the
ephemeris times and not vice-versa. All effort is made to
validate the published ephemeris times but since updates to
the Cassini SCLOCK kernel in SPICE can occur the values of
ephemeris time are only as accurate as the currently
published Cassini SCLOCK SPICE kernel.
Spacecraft staring mode where staring = 0 when spinning and 1
otherwise
CHEMS Accumulation rate data organized as:
DPPS Step - the controlling parameter that identifies the
current Spectrometer energy level
Start, Stop, and Sum of the number of triggering events for each
telescope
Energy count of the number of triggering events for each
telescope and a summation
Double coincidence counts for each telescope and a summation
triple coincidence counts for each telescope and a summation
UFSR counts (Universal Front SEDA Rate - Secondary Electron
Detector Assembly)
URSR counts (Universal Rear SEDA Rates)
CHEMS Science Rate Data
-----------------------
Fields include:
a purpose identifier where science data records are identified
with purpose = sci
starting and ending ephemeris times
Spin, sector, subsector
SCLOCK and spin period that are used to derive the starting
ephemeris time
Notes regarding the SCLOCK value:
1. Only the SCLOCK major segment value is provided - MIMI
currently does not have access to the fine SCLOCK value
hence SCLOCK resolution is limited to +- 1/2 SCLOCK count
2. The SCLOCK is only available from telemetry at the
beginning of each spin. All other published SCLOCKS are
derived from the spin starting SCLOCK, the spin numbers
(for the current and next available spins), and the spin
period.
3. SCLOCK values are assumed to drive the value of the
ephemeris times and not vice-versa. All effort is made to
validate the published ephemeris times but since updates to
the Cassini SCLOCK kernel in SPICE can occur the values of
ephemeris time are only as accurate as the currently
published Cassini SCLOCK SPICE kernel.
Spacecraft staring mode where staring = 0 when spinning and 1
otherwise
CHEMS Science rate data organized as:
DPPS Step - the controlling parameter that identifies the
current Spectrometer energy level
Counts associated with Ranges 0-6 for each telescope plus the
sum over telescopes
He+, He++ doubles and triples count rates
O+ doubles and triples count rate per telescope plus the sum
over telescopes
CNO (mass 4 and higher) triples count rate
Counts of energy, tof, and mass (mass/q) under and overflow
conditions
CHEMS Pulse Height Analysis Data
--------------------------------
Fields include:
a purpose identifier where science data records are identified
with purpose = sci
starting and ending ephemeris times
Spin, sector, subsector
SCLOCK and spin period that are used to derive the starting
ephemeris time
Notes regarding the SCLOCK value:
1. Only the SCLOCK major segment value is provided - MIMI
currently does not have access to the fine SCLOCK value
hence SCLOCK resolution is limited to +- 1/2 SCLOCK count
2. The SCLOCK is only available from telemetry at the
beginning of each spin. All other published SCLOCKS are
derived from the spin starting SCLOCK, the spin numbers
(for the current and next available spins), and the spin
period.
3. SCLOCK values are assumed to drive the value of the
ephemeris times and not vice-versa. All effort is made to
validate the published ephemeris times but since updates to
the Cassini SCLOCK kernel in SPICE can occur the values of
ephemeris time are only as accurate as the currently
published Cassini SCLOCK SPICE kernel.
Spacecraft staring mode where staring = 0 when spinning and 1
otherwise
Index in sector number - auto generated number to guarantee
uniqueness within a sector
CHEMS Pulse Height Analysis data organized as:
DPPS Step - the controlling parameter that identifies the
current Spectrometer energy/charge level
Energy - calibrated measure of the energy deposited into the SSD
TOF - calibrated measure of the time of flight for the particle
SSD - identifies which solid state detector was triggered
Start microchannel plate - identifies which microchannel plate
was used in particle identification
Range - identifies which PHA range was identified by the CHEMS
DPU for this particle
Ancillary Data
==============
Included with the CHEMS data set volumes are ancillary data files
representing the MIMI Key Parameter (KP) data. The MIMI KP data is a
calibrated subset of the important channels for each of the MIMI
detectors. The subset of channels have been identified to most
reasonably show characteristic energetic particle events during the
mission. The KP data is calculated at an arbitrarily defined 60
second cadence which is different than the approximate collection
times for the instruments as identified below for standard operations:
(It must be realized that the collection times vary based upon the
telemetry rate but nothing more than a factor of 2, 4, or 8.)
Instrument Product Type Approx Collection Time (s)
------------------------------------------------------------
LEMMS Accumulation 5 (each subsector)
LEMMS Fine Rate 0.6 (each microsector)
LEMMS PHA 5 (each subsector)
CHEMS Accumulation 4
CHEMS Science 5 (each subsector)
CHEMS PHA 80 (each sector)
INCA Accumulation 7.5
INCA IMAGES 180 (2 sectors)
INCA PHA 22
Data points for each record of the KP data are first Median Quartile
Filtered then averaged (except in the case where the median is zero)
for each sector. The sectored data is then interpolated into the 60
second data cadence of the KP data file. The KP data is then
converted into a flux in units of 1/(cm^2*sr*sec*KeV) or for the case
of CHEMS 1/(cm^2*sr*sec*keV/e)
Browse plots for each of the KP data files are produced. There are 7
different browse plots available.
Inst Wild Card File Name Plotted KP data
---------------------------------------------------------------------
LEMMS LEMMS_KP_ELEC_(yyyydoy)_(ver#).JPG KP LEMMS Electron flux
LEMMS LEMMS_KP_ION_(yyyydoy)_(ver#).JPG KP LEMMS Ion flux
CHEMS CHEMS_KP_HEP_(yyyydoy)_(ver#).JPG KP CHEMS Helium Plus
flux per charge
CHEMS CHEMS_KP_HEPP_(yyyydoy)_(ver#).JPG KP CHEMS Helium Plus
Plus flux per charge
CHEMS CHEMS_KP_HP_(yyyydoy)_(ver#).JPG KP CHEMS Hydrogen Plus
flux per charge
CHEMS CHEMS_KP_OP_(yyyydoy)_(ver#).JPG KP CHEMS Oxygen Plus
per charge
INCA INCA_KP_(yyyydoy)_(ver#).JPG Hydrogen TOF flux
Usage Note
----------
The KP browse data and associated browse plots are to be used as an
initial characterization of the particle environment and are NOT to
be used for publications. The data is not at publication quality
and is provided as is.
Coordinate System
=================
The data in this data set are measurements of count rates based upon
the orientation of the CHEMS instrument (CHEMS Center look direction).
Particle flux effects are then determined by transforming from a
spacecraft centered coordinate system, properly rotated to account for
the appropriate CHEMS telescope direction, into whatever external
coordinate (reference system) is most appropriate.
Software
========
There is no sample software provided as of the writing of this catalog
file although the calibration volume does provide algorithms for
conversion of count rates into flux. In general the CHEMS Science
data can be converted into a measurement of flux per species with
these algorithms and the CHEMS PHA and Accumulation Rates data are
used for determining the health and wellness of the CHEMS detectors.
Media/Format
============
These data are supplied to the Planetary Data System via electronic
means and are then broken into segments based upon the media currently
prescribed by PDS."
CONFIDENCE_LEVEL_NOTE = "
Confidence Level Overview
=========================
This data set contains all calibrated data for the CHEMS Detector as
part of the Cassini MIMI instrument for the interval described above.
Every effort has been made to ensure that all data returned to APL
from the spacecraft is included and that the calibrated browse data
products are accurate.
As of this writing there are no known issues associated with the CHEMS
detector that would limit the usability or reliability of the data.
Review
======
The MIMI CHEMS data will be reviewed internally by the Cassini MIMI
team prior to release to the PDS. The data set will also be peer
reviewed by the PDS.
Data Coverage and Quality
=========================
All data in the stated interval are included, to the best of our
knowledge and attempts to determine completeness. In general, the
instrument was operated only briefly during early tour for the
following intervals:
1. Antenna deployment 1997-10-25T00:00 - 1997-10-26T05:30
2. Venus 1 flyby 1998-04-26T12:54 - 1998-05-08T19:21
3. Instrument Checkout 1998-12-30T09:10 - 1999-01-19T05:40
4. Venus 2 flyby 1999-06-24T09:08 - 1999-06-24T21:20
5. Earth flyby 1999-08-13T17:39 - 1999-09-14T22:20
Only data for interval 5 is provided to PDS due to technical issues in
processing.
Beginning in February of 2000 the instrument was operated more-or-less
continuously with small daily runs of approximately 8 hours.
Intermittent data collection occurred during 2002 and 2003 with
multiple day gaps in the data
Large Data Gaps:
1. Cruise 2000-066 - 2000-155
2. Cruise 2000-210 - 2000-246
3. Cruise 2000-311 - 2000-320
4. Cruise 2000-322 - 2000-333
5. Post Jupiter Cruise 2003-018 - 2003-104
6. Post SOI 2004-187 - 2004-193 - Spacecraft safing
shut off
Those days for which the instrument did not collect data either due to
the instrument being off or due to communication issues, the data set
will not contain any files.
Limitations
===========
As noted above there are no know issues associated with the data from
the CHEMS detector as of the writing of this catalog.
The KP browse data and associated browse plots are to be used as an
initial characterization of the particle environment and are NOT to be
used for publications. The data is not at publication quality and is
provided as is."
END_OBJECT = DATA_SET_INFORMATION
OBJECT = DATA_SET_MISSION
MISSION_NAME = "
CASSINI-HUYGENS MISSION TO SATURN AND TITAN"
END_OBJECT = DATA_SET_MISSION
OBJECT = DATA_SET_TARGET
TARGET_NAME = "SATURN"
END_OBJECT = DATA_SET_TARGET
OBJECT = DATA_SET_TARGET
TARGET_NAME = "EARTH"
END_OBJECT = DATA_SET_TARGET
OBJECT = DATA_SET_TARGET
TARGET_NAME = "SOLAR WIND"
END_OBJECT = DATA_SET_TARGET
OBJECT = DATA_SET_TARGET
TARGET_NAME = "JUPITER"
END_OBJECT = DATA_SET_TARGET
OBJECT = DATA_SET_HOST
INSTRUMENT_HOST_ID = CO
INSTRUMENT_ID = MIMI
END_OBJECT = DATA_SET_HOST
OBJECT = DATA_SET_REFERENCE_INFORMATION
REFERENCE_KEY_ID = "KRIMIGISETAL2004"
END_OBJECT = DATA_SET_REFERENCE_INFORMATION
OBJECT = DATA_SET_REFERENCE_INFORMATION
REFERENCE_KEY_ID = "MANWEILERETAL2005"
END_OBJECT = DATA_SET_REFERENCE_INFORMATION
OBJECT = DATA_SET_REFERENCE_INFORMATION
REFERENCE_KEY_ID = "KUSTERER&BURKE2003"
END_OBJECT = DATA_SET_REFERENCE_INFORMATION
END_OBJECT = DATA_SET
END
|