Data Set Overview : This data set is composed of data produced during the descent to Titan onJanuary 14 2005 from the ACP instrument (Engineering data) and also fromthe GCMS instrument (Science data) which analyses the gaseous products fromACP. Only the channel B data is archived (no data has been recovered by Cassinion channel A). The raw data in binary format is not archived in this data set. It has beenprocessed to calibrated (engineering) data by means of the transferfunctions described in the ACP Software User Manual. This calibrated datais presented hereafter. The ACP engineering data: It includes all the temperatures, pressure, references voltages, DC/DCconverter voltages, mechanisms position sensors, and is sorted in the fourfollowing data files : 1)ACP_OVEN_V1_0.LBL/ACP_OVEN_V1_0.TAB: Oven group parameters which monitor the heating and transfer phaseperformance including (columns title): UTC time, ACP internal samplingtime, oven temperature, oven wall temperature,oven pressure, andelectrovalves V1, V2, VT status. 2)ACP_PUMP_V1_0.LBL/ACP_PUMP_V1_0.TAB: Pump group parameters which monitor the pump performance including (columnstitle): UTC time, ACP internal sampling time, pump temperature, pumpcurrent, pump speed. 3)ACP_TEMP_V1_0.LBL/ACP_TEMP_V1_0.TAB: Temperatures group parameters including (columns title): UTC time, ACPinternal sampling time, temperatures; electronics, base plate, coldjunction, electrovalves VT & V2. 4)ACP_VOLT_V1_0.LBL/ACP_VOLT_V1_0.TAB: Voltages group parameters including (columns title): UTC time, ACP internalsampling time, DC/DC converter voltages (+ 5V , +15V , -15V), calibration &reference voltages (Rcal, RO, TCgnd, Vref1/2/3).  The documentation includes the ACP EAICD, The GCMS EAICD, the ACP on boardsoftware user manual, the ACP & GCMS ESA SP-1177 publications, and the ACP& GCMS Nature publications.  The ACP science data : The GCMS analyses samples from the ACP. The Data Products that arereferencing the ACP are provided to the ACP Science team, and are analyzedby them. The ACP products are sampled at determined times during the descentdirectly by the GCMS Ion source 2 dedicated to ACP (IS 2), and by thecombination of the GC & ion sources 3/4/5 (GC-IS 3/4/5). This dataset contains the calibrated data of the ACP data productsanalysed by the GCMS. The same dataset is archived by the GCMS team. For more information refer to the GCMS DATASET\DATASET.CAT. The GCMS Stage 2 ACP data is converted from raw counts per integrationperiod to counts per second and corrected for the counter overflowcondition where this can be determined to have happened. Stage 3processing corrects this data for pulse pile-up, counter dead-time andother known counting system (error) conditions. These errors can becomesignificant where the count value is large. The files are all of the valid data from MS Ion Source #2 (the ACP data)plus the Ion Sources #3 & 4 data for Sample #3, the ACP injection to the GCColumns attached to Ion Sources #3 & 4. As the Ion Source #5 did not workduring the descent, the IS5 data files are not included. These files are in column aligned comma delimited ASCII TEXT format asrequired by the PSA/PDS for archiving. The overall structure of this dataset is: It contains the data Table files, the Label files associated with the Tablefiles plus the Format files referred to in the Label files.The LBL file gives information on the file.The FMT file gives information on the columns.  The ACP data consists of one GC data product, 6 stage 1 mass scan products,and 6 stage 2 and 6 stage 3 mass scan products. Stage 1 Processed Data: Scripts that call programs convert *.archive to *.dat files; sort data into smaller filesStage 2 Processed Data: Break into smaller files, convert units, add headers and commentsStage 3 Processed Data: Lengthy processing, plotting, comparing to calibration (pre & post encounter)  IS2_Smpl1_Stg2: Ion source 2 (MS) data at 75 eV ionization energy and unitmass resolution for ACP sample #1 in counts per second.IS2_Smpl2_Stg2: Ion source 2 (MS) data at 75 eV ionization energy and unitmass resolution for ACP sample #2 in counts per second.Note - Programmed low IE data is present in this block of data and notmarked between times 10:18:49 - 10:19:01.IS2_Smpl5_Stg2: Ion source 2 (MS) data at 75 eV ionization energy and unitmass resolution for ACP sample #5 in counts per second.Note - Programmed low IE data is present in this block of data and notmarked between times 10:52:48 - 10:52:55. IS2_Stg1: Ion source 2 (ACP) full scans(mass range: 2 - 141) at unit resolution and 25 eV ionization energy.IS2_Stg2: Ion source 2 (ACP) full scans(mass range: 2 - 141) at unit resolution and 25 eV ionization energy. IS2_Smpl1_Stg2: Ion source 2 (MS) data at 25 eV ionization energy and unitmass resolution for ACP sample #1 in counts per second.IS2_Smpl2_Stg2: Ion source 2 (MS) data at 25 eV ionization energy and unitmass resolution for ACP sample #2 in counts per second.IS2_Smpl3_Stg2: Ion source 2 (MS) data at 75 eV ionization energy and unitmass resolution for ACP sample #3 in counts per second.IS2_Smpl4_Stg2: Ion source 2 (MS) data at 75 eV ionization energy and unitmass resolution for ACP sample #4 in counts per second.IS2_Smpl5_Stg2: Ion source 2 (MS) data at 25 eV ionization energy and unitmass resolution for ACP sample #5 in counts per second.IS2_Smpl6_Stg2: Ion source 2 (MS) data at 75 eV ionization energy and unitmass resolution for ACP sample #6 in counts per second. IS3_GC1_Smpl3_Stg2: Ion Source 3 (Column 1) data at 75 eV ionization energy and unit mass resolution for ACP Sample #3 as counts per second. Time relative to the injection has been determined and added to the file.IS4_GC2_Smpl3_Stg2: Ion Source 4 (Column 2) data at 75 eV ionization energy and unit mass resolution for ACP Sample #3 as counts per second. Time relative to the injection has been determined and added to the file. IS3_Smpl3_Stg2: IS3 (GC Column 1) sample 3 mass scans at unit resolutionand 75 eV ionization energy.IS4_Smpl3_Stg2: IS4 (GC Column 2) sample 3 mass scans at unit resolutionand 75 eV ionization energy.  The first results from the ACP data have been published in NATURE2005. There is no specialized software required to view the ACP data products,and no software is provided or archived to do so. Review:  The Huygens data sets were reviewed in two steps: (1) a review of the Experimenter-to-archive-ICD, in 2004. (2) a review of the data sets, in 2006. Procedures and details of this process can be obtained from the ESA archive team:  Olivier Witasse or Joe Zender ESA ESTEC Keplerlaan 1 2200 AG Noordwijk The Netherlands Olivier.Witasse@esa.int or Joe.Zender@esa.int  This data set was reviewed by Nathalie Boudin and Heidi L.K. Manning.

N/A