PDS_VERSION_ID = PDS3
LABEL_REVISION_NOTE = "
2013-01-27, M. Kusterer - initial version;
2013-02-05, M. Kusterer - peer review updates;
2015-12-11, D. Kazden - removed ARCHIVE_STATUS keyword;
2018-07-01, D. Kazden - updated STOP_TIME and DATA_SET_RELEASE_DATE;
2020-03-11, D. Kazden - updated CITATION_DESC;"
RECORD_TYPE = STREAM
OBJECT = DATA_SET
DATA_SET_ID = "CO-S-MIMI-4-CHEMS-CALIB-V1.0"
OBJECT = DATA_SET_INFORMATION
DATA_SET_NAME = "
CASSINI S MIMI CHEMS SENSOR CALIBRATED DATA V1.0"
DATA_SET_COLLECTION_MEMBER_FLG = N
START_TIME = 2004-01-01T00:00
STOP_TIME = 2017-09-17T00:00:00.000
DATA_SET_RELEASE_DATE = 2018-07-01
PRODUCER_FULL_NAME = "Jon Vandegriff"
DETAILED_CATALOG_FLAG = N
DATA_OBJECT_TYPE = "SPREADSHEET"
DATA_SET_TERSE_DESC = "
This data set contains the calibrated Saturn tour data collected by
the CHEMS sensor of the MIMI instrument aboard the Cassini spacecraft
for the Cassini mission. CHEMS stands for CHarge Energy Mass
Spectrometer."
ABSTRACT_DESC = "
The Cassini Magnetospheric Imaging Instrument(MIMI) Charge Energy Mass
Spectrometer (CHEMS) contains a deflection system and an overall field
of view of 159 x 4 deg. that is comprised of three distinct energetic
particle telescopes each having a field of view of 53 x 4. All
telescopes share the same deflection mechanism, but each has its own
start and stop microchannel plate (MCP) and its own solid-state
detector (SSD). Much of the data returned by CHEMS is separated by
telescope. The deflection plate power supply (DPPS) has 32 different
voltages that can be applied across the deflection plates. For any
single DPPS step, the electrostatic analyzer only transmits incoming
ions within a narrow range of energy per charge (a 3% pass band).
The CHEMS calibrated data set includes the Pulse Height Analysis (PHA)
data collected during the Saturn tour. CHEMS PHA provides a list of
individually detected particles, with specific detection parameters
for each event, including TOF, energy deposited in the SSD, and
telescope number.
The energy per charge data for six ion species (H+, He+, H2+, He++,
O++, W+) are presented in two forms. (The W+ water ion group includes
O+, OH+, H20+ and H30+). One form is a set of tables which are of
variable length and use a comma to separate various fields, and the
other is a PDF file containing the energy per charge spectrograms and
are based on CHEMS PHA data.
The original data has been decommutated and decoded by software at the
Applied Physics Laboratory (APL) and calibrated and further processed
by software at the University of Maryland.
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 = "Vandegriff J., Kusterer M.B., Mafi J.,
CO-S-MIMI-4-CHEMS-CALIB-V1.0, CASSINI S MIMI CHEMS SENSOR CALIBRATED
DATA V1.0, NASA Planetary Data System, 2018."
DATA_SET_DESC = "
Data Set Overview
=================
The Cassini Magnetospheric Imaging Instrument(MIMI) Charge Energy Mass
Spectrometer (CHEMS) contains a deflection system and an overall field
of view of 159 x 4 deg. that is comprised of three distinct energetic
particle telescopes each having a field of view of 53 deg. x 4 deg.
All telescopes share the same deflection mechanism, but each has its
own start and stop microchannel plate (MCP) and its own solid-state
detector (SSD). Much of the data returned by CHEMS is separated by
telescope. The deflection plate power supply (DPPS) has 32 different
voltages that can be applied across the deflection plates. For any
single DPPS step, the electrostatic analyzer only transmits incoming
ions within a narrow range of energy per charge (a 3% pass band).
The CHEMS calibrated data set includes the Pulse Height Analysis (PHA)
data collected during the Saturn tour. CHEMS PHA provides a list of
individually detected particles, with specific detection parameters
for each event, including TOF, energy deposited in the SSD, and
telescope number. Telemetry data volume constraints do not allow all
particle events detected by CHEMS to be sent in the MIMI data stream,
so the PHA data need to be carefully normalized, and the procedures
for doing this are described in the section on CHEMS in the MIMI User
Guide [VANDEGRIFFETAL2012].
The energy per charge data for six ion species (H+, He+, H2+, He++,
O++, W+) are presented in two forms. One form is a set of tables
which are of variable length and use a comma to separate various
fields, and the other is a PDF file containing the energy per charge
spectrograms and are based on CHEMS PHA data. (The W+ water ion group
includes O+, OH+, H20+ and H30+)
The original data has been decommutated and decoded by software at
the Applied Physics Laboratory (APL) and further processed by software
at the University of Maryland. The data is provided in an calibrated
form in conjunction with a PDS MIMI calibration volume COMIMI_0000
which provides specific algorithms for the derivation of calibrated
data.
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 energy per charge intensities for six ion
species (H+, He+, H2+, He++, O++, W+) for each telescope and the
sum of all the telescopes of the CHEMS detector. (The W+ water ion
group includes O+, OH+, H20+ and H30+). The data consists of 60 minute
averages and cover 20 days per file. Each file includes the
intensities for each of the 32 energy per charge steps.
The product ID's consist of a prefix followed by a date range.
The prfixes are:
CPHAFLX0_T1_HP The energy per charge data for H+ for telescope 1
CPHAFLX0_T2_HP The energy per charge data for H+ for telescope 2
CPHAFLX0_T3_HP The energy per charge data for H+ for telescope 3
CPHAFLX0_TA_HP The energy per charge data for H+ for all telescopes
CPHAFLX0_T1_H2P The energy per charge data for H2+ for telescope 1
CPHAFLX0_T2_H2P The energy per charge data for H2+ for telescope 2
CPHAFLX0_T3_H2P The energy per charge data for H2+ for telescope 3
CPHAFLX0_TA_H2P The energy per charge data for H2+ for all telescopes
CPHAFLX0_T1_HEPP The energy per charge data for He++ for telescope 1
CPHAFLX0_T2_HEPP The energy per charge data for He++ for telescope 2
CPHAFLX0_T3_HEPP The energy per charge data for He++ for telescope 3
CPHAFLX0_TA_HEPP The energy per charge data for He++ for all telescopes
CPHAFLX0_T1_HEP The energy per charge data for He+ for telescope 1
CPHAFLX0_T2_HEP The energy per charge data for He+ for telescope 2
CPHAFLX0_T3_HEP The energy per charge data for He+ for telescope 3
CPHAFLX0_TA_HEP The energy per charge data for He+ for all telescopes
CPHAFLX0_T1_OPP The energy per charge data for O++ for telescope 1
CPHAFLX0_T2_OPP The energy per charge data for O++ for telescope 2
CPHAFLX0_T3_OPP The energy per charge data for O++ for telescope 3
CPHAFLX0_TA_OPP The energy per charge data for O++ for all telescopes
CPHAFLX0_T1_WP The energy per charge data for W+ for telescope 1
CPHAFLX0_T2_WP The energy per charge data for W+ for telescope 2
CPHAFLX0_T3_WP The energy per charge data for W+ for telescope 3
CPHAFLX0_TA_WP The energy per charge data for W+ for all telescopes
The standard data product ID's are gropuped by species and are:
CHEMS_PHAFLUXAV_HP
CHEMS_PHAFLUXAV_H2P
CHEMS_PHAFLUXAV_HEPP
CHEMS_PHAFLUXAV_HEP
CHEMS_PHAFLUXAV_OPP
CHEMS_PHAFLUXAV_WP
Each of these logically incorporates four types of products -- one for
each of the three telescopes and one for all telescopes.
In addition, this data set includes energy per charge spectrograms for
the same six species. Each PDF includes the spectrograms for each of
the three telescopes and their sum.
The standard data product ID's are:
MIMI_CHEMS_SPGM_HP The energy per charge spectrograms for H+
MIMI_CHEMS_SPGM_H2P The energy per charge spectrograms for H2+
MIMI_CHEMS_SPGM_HEPP The energy per charge spectrograms for He++
MIMI_CHEMS_SPGM_HEP The energy per charge spectrograms for He+
MIMI_CHEMS_SPGM_OPP The energy per charge spectrograms for O++
MIMI_CHEMS_SPGM_WP The energy per charge spectrograms for W+.
Processing
==========
Data in this data set were processed by the use of a number of
software programs which calibrate, perform the 1 hour averages on the
data, and create the spectrograms.
In the original CHEMS data, accumulation interval for basic and
species rate counters is one DPPS step, which lasts for one subsector,
where 16 subsectors make a sector, and 16 sectors make one spin.
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. Note that for CHEMS, there is a 150 millisecond dead time
per DPPS step, and this must be subtracted from the subsector duration.
Converting a species count rate in units of counts/sec into a
differential intensity in units of counts/(sec*ster*cm2*keV) requires
knowledge of the geometry factor of the instrument, the energy width
of the channel, the detection efficiency for ions of that species, and
the energy width of the channel expressed as an energy per charge. The
procedures for calibrating CHEMS data are described in the section on
CHEMS in the MIMI User Guide [VANDEGRIFFETAL2012].
Data
====
The MIMI CHEMS calibrated data set includes the 24 ASCII CSV tables
(each associated with a Standard Product ID of CHEMS energy per charge
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 Energy Per Charge ASCII data
----------------------------------
Fields include:
Start and Stop minutes of hour long average
Year, and midpoint of the hour-long average interval expressed as a
fractional day of year.
Radial_distance which is the position of Cassini at midpoint of the
interval in Saturn radii
Latitude of Cassini at midpoint of measurement in Saturn equatorial
frame
Local_time of Cassini at the midpoint of the measurement given in
hours and in the Saturn equitorial frame.
Particle intensity and the uncertainty in particle intensity for
each of the 32 energy bands. Units are counts/sec/ster/cm^2/keV.
This data set comprises energy per charge intensities in separate
files for six ion species (H+, He+, H2+, He++, O++, W+) and for each
telescope and the sum of all the telescopes of the CHEMS detector. The
data consists of 60 minute averages and cover 20 days per file. Each
file includes the intensities for each of the 32 energy per charge
steps.
CHEMS Energy Per Charge Spectrograms
------------------------------------
This data set comprises six ion species plots in PDF files. There are
4 horizontal panels in the plot. The top panel contains
the average intensity from all three CHEMS telescopes combined (full
4 degrees x 159 degrees FOV). Each panel below is for an
individual telescope (4 degrees x 53 degrees FOV) (1, 2, and 3
respectively).
Pixels are 15 percent in
energy per charge by 60 minutes and are based on
CHEMS PHA data. The bottom axis is time covering a 20 day
interval. The y-axis is energy per charge (keV/e). The
color represents the differential intensity for this species, and
the units are particles per (cm^2 sec sr keV/e). No background has
been subtracted.
Ancillary Data
==============
Coordinate System
=================
The data in this data set are measurements of counts/sec/ster/cm^2/keV
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 access on the MIMI web site, to an analysis package currently
being used by the MIMI team to browse, plot and analyze MIMI data that
reads data directly from the PDS and makes available to anyone the
same analysis and visualization capabilities currently used by the
MIMI team. The main benifit of the tools is that they provide an
intuitive way to browse and analyze the data without having to worry
about calibration details or file access and file reading details.
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.
Large Data Gaps:
1. Post SOI 2004-187 - 2004-193 - Spacecraft Safing
shut off
2. Tour 2005-006 - 2005-015 -
3. Tour 2007-254 - 2007-258 - Spacecraft Safing
shut off
3. Tour 2007-279 - 2007-291 - Spacecraft Flight
S/W testing shut off
3. Extended Mission 2009-071 - 2009-076 - Spacecraft Thruster
branch swap, deactivated S48
background sequence.
3. Extended-Extended Mission 2010-306 - 2010-319 - Spacecraft Safing
shut off
3. Extended-Extended Mission 2012-293 - 2012-303 - Spacecraft Propellant
Gauging Test shut off.
On 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 INCA detector as of the writing of this catalog."
END_OBJECT = DATA_SET_INFORMATION
OBJECT = DATA_SET_MISSION
MISSION_NAME = "CASSINI-HUYGENS"
END_OBJECT = DATA_SET_MISSION
OBJECT = DATA_SET_TARGET
TARGET_NAME = "SATURN"
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 = "VANDEGRIFFETAL2012"
END_OBJECT = DATA_SET_REFERENCE_INFORMATION
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
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