CCSD3ZF0000100000001CCSD3VS00002MRK**001 /* SFDU files: VOLDESC_V02.SFD - updated 3/1/96 by J. F. Cooper, HSTX/SSDOO */ VOL_IDENT: USA_NASA_NSSD_P10L_0001 VOL_CREATION_DATE: 1991-03-15 MEDIUM_DESCRIPTION: 1/2 inch, 9-track, 6250 bpi magnetic tapes TECHNICAL_CONTACT: Dr. Nand Lal Goddard Space Flight Center Code 664 Greenbelt, MD 20771 Electronic Mail: LHEAVX::LAL Electronic Mail: Bitnet, nand@voycrs.gsfc.nasa.gov Telephone: 301-286-5668 PREV_VOLS: None CCSD$$MARKERMRK**001CCSD3SS00002MRK**002 DATA_SET_NAME: PIONEER-10 CRT DATA ARCHIVE DATA_SOURCE: Pioneer-10 Cosmic Ray Telescope SCIENTIFIC_CONTACT: Dr. Frank McDonald Institute for Physical Science and Technology University of Maryland College Park, MD 20742 Electronic Mail: fm27@umail.umd.edu Telephone: 301-405-4861 SPACECRAFT_CHARACTERISTICS: Pioneer-10 was launched on March 3, 1972 and encountered Jupiter on December 4, 1973. After passing Jupiter the spacecraft trajectory is taking it toward the tail of the sun's heliosphere. At the end of 1990 it was about 51 AU from the sun, in the ecliptic plane at about +3 degrees celestial latitude, and 73 degrees (measured eastward from the vernal equinox) celestial longitude. The spacecraft is instrumented with a full suite of magnetic field, plasma and energetic particle and cosmic ray sensors. The spacecraft is spin-stabilized about the axis of the large disk antenna, which is usually kept pointed in the direction of the earth. INVESTIGATION_OBJECTIVES: This instrument is designed to exploit to the fullest practical degree the proposed trajectories of Pioneer F and G. The significance of these measurements will be greatly enhanced by concur-rent measurements with similar particle telescopes on satellites such as IMP or similar series in near-earth orbits. The principle scientific objectives of this experiment are: 1.) To measure the flow patterns of energetic solar and galactic particles separately in the inter-planetary field. To interpret this measurement, simultaneous determination of the energy spectrum, radial gradient, angular distribution, and streaming parameters is required for each nuclear species and over as wide an energy range as is practicable. 2.) To measure the energy spectra, and isotopic composition of galactic and solar cosmic rays from the lowest practical energies up to ~800 MeV/nucleon and (by use of objective 1) to unfold the primary flare and interstellar spectrum. 3.) To measure the time variations of the differential energy spectra of electrons, hydrogen and helium nuclei over the corresponding energy intervals. During flare events, to obtain time histories; during quiet times, to relate gross time variations to those near earth thus deducing a spatial gradient for galactic cosmic rays. 4.) To study the energy spectra, time variations and spatial gradients associated with recurrent and non-flare associated interplanetary proton and helium streams and to define the related solar or inter-planetary acceleration processes. 5.) To provide information on the energetic particle distribution surrounding Jupiter. 6.) To try to determine the extent of the solar cavity, the energetic particle phenomena occurring at this interface and the cosmic ray density in nearby interstellar space. INSTRUMENT_ATTRIBUTES: The Goddard Space Flight Center(GSFC)/ University of New Hampshire Cosmic Ray Telescope(CRT) experiment on Pioneer-10 and -11 consists of two types of solid state detector telescopes, the High Energy Tele-scope (HET) and two Low Energy dE/dx vs. E Telescopes (LET I and II). These are designed to complement each other and to cover a broad range in energy, intensity, and charge spectra. Charged particle spectra and angular distributions are measured over energy intervals as follows: Particle Component Energy Range Galactic cosmic ray protons 4.5 - 800 MeV Solar protons .05- 800 MeV Galactic cosmic ray helium 4.5 - 600 MeV/nucleon Solar helium 1.0 - 600 MeV/nucleon He3/He4, D/H 4.5 - 50 MeV/nucleon Galactic and Solar electrons .05- 5.0 MeV Li,Be,B,C,N,O,F,Ne and their isotopic composition 6 MeV/nuc - 200 MeV/nuc Angular Distribution Studies hydrogen .05- 120 MeV helium 4.5 - 120 MeV/nucleon electrons .05- 5 MeV Geometrical Factors HET 0.220 cm2-ster. LET-I 0.155 cm2-ster. LET-II 0.015 cm2-ster. High Energy Telescope: The HET consists of a multi-element array of solid state detectors. Two of these elements are single lithium drift detectors, 300 mm2 area and 2.5 mm thick. The third element is a stacked arrangement of five 850 mm2, 2.5 mm thick lithium drift detectors. For particles which come to rest within this stack (20 - 50 MeV/ nucleon) three measurements are made - energy loss (dE/dx), total energy, and range. For particles which penetrate completely through the stack of solid state detectors three separate dE/dx measurements are made. This multiparameter analysis reduces the back-ground level of spurious events to a negligible level. Charge resolution for penetrating particles is possible up to about 200 MeV/nucleon. It is estimated that the absolute uncertainty in the helium flux is about 12% at 400 MeV and about 7% at energies below 200 MeV. Low Energy Telescope I. This detector was designed to measure low-energy solar flare particles in the interplanetary space and trapped particles in the Jovian magnetosphere. Its small geometry factor (1.5E-02 cm**2.sr) allows measurement of fluxes as high as 5.0E+05/(cm**2.s.sr). The LET I is a double dE/dx vs. E solid state detector. Two thin (100 microns thickness and 100mm2 area) surface barrier detectors serve to define the geometry and to provide a double dE/dx measurement. A thick (2.5mm thickness and 300mm2 area) lithium drift detector provides a total energy measurement. LET I covers the energy range 3 to 22 MeV/nucleon with charge resolution from Z=1 to 8. Angular distributions are available for this data. Low Energy Telescope II. Two solid state detectors, one thin (50 microns thick and 50mm2 area) and one thick (2.5mm thick and 50mm2 area) are used individually and in coincidence as total absorption spectrometers. A third detector operating in an anticoincidence mode insures that only stopping particles are analyzed. The thin detector responds to protons between 50 keV and 3 MeV and electrons between 50 and 150 keV. The thick detector is sensitive to protons between 3 and 20 MeV and electrons between 150 keV and 1 MeV, and in these latter energy intervals an unambiguous separation of protons and electrons is possible. For more information, refer to the document: DATA PROCESSING AND PROGRAMMERS GUIDE FOR THE PIONEER-10 AND -11 COSMIC RAY EXPERIMENTS, VOL. 2 CSC/TM-81/6203, March 1982 and the document: D.E.Stillwell, R.M.Joyce, B.J.Teegarden, J.H.Trainor, G.Streeter, and J.Bernstein, "The Pioneer-10/-11 and Helios A/B Cosmic Ray Instruments", ISEE Transactions on Nuclear Science, Vol. NS-22, February 1975, pp. 570-573 DATA_SET_PARAMETERS: 6 hour averages of the following fluxes, plus statistical errors units of particles/(cm**2.sec.ster.MeV/nuc) as follows: Date and time of start of averaging interval, TIME; 3.45 - 5.15 MeV proton flux, PROTONFLUX1; 30.55 - 56.47 MeV proton flux, PROTONFLUX2; 120.7 - 227.3 MeV proton flux, PROTONFLUX3; 3.44 - 4.97 MeV/nucleon helium flux, HELIUMFLUX1; 10.03 - 21.7 MeV/nucleon helium flux, HELIUMFLUX2; 30.67 - 56.7 MeV/nucleon helium flux, HELIUMFLUX3; 112.7 - 413 MeV/nucleon helium flux, HELIUMFLUX4; 2 - 6 Mev electron flux, ELECTRONFLUX; 6 hour averages of the following fluxes, plus statistical errors units of particles/sec as follows: HET telescope data: * Counting rate (20-56 MeV/n z >= 1 and 2-8 MeV e), R1; * Counting rate (>180 MeV z = 1 and >8 MeV e), R2A; * Counting rate (z >= 2 particles of stopping range < 1.5 cm Si), R2B; * Counting rate (56-180 MeV z = 1 and >56 MeV/n z = 2), R3A; Counting Rate (particles that lose > .22 MeV in the B detector), R9A; Counting Rate (particles that lose > 1.0 MeV in the CI detector), R9B; Counting Rate (particles that lose > 1.1 MeV in the CII detector), R9C; Counting Rate (particles that lose > .23 MeV in the CIII detector), R9D; LET-I telescope data: Counting Rate (particles that lose > .13 MeV in the DI detector), R10A; DI1 Counting rate (.66 - 33 MeV z = 1; >.39 MeV/n z = 2), R10B; DI2 Counting rate (.72 - 20 MeV z = 1; >.42 MeV/n z = 2), R10C; DI3 Counting rate (.84 - 14.2 MeV z = 1; >.46 MeV/n z = 2), R10D; DI4 Counting rate (1.1 - 8.1 MeV z = 1; >.53 MeV/n z = 2), R10E; DI5 Counting rate (1.6 - 5.1 MeV z = 1; >.63 MeV/n z = 2), R10F; DI6 Counting rate (2.29 - 3.8 MeV z = 1; >.75 MeV/n z = 2), R10G; DI7 Counting rate (>.99 MeV/n z = 2; z = 1), R10H; DI8 * Counting rate (3.2 - 21 MeV/n z >= 1), R11A; * Counting rate (3.2 - 21 MeV/n z >= 2), R11B; Counting rate (5.6 - 21 MeV/n z >= 1), R12A; Counting rate (5.6 - 21 MeV/n z >= 2), R12B; LET-II telescope data: Counting rate (.20 - 2.15 MeV z = 1; z >= 2), R15A; Counting rate (.74 - 2.15 MeV z = 1; .22 - 2.05 MeV/n z = 2), R15B; Counting rate (1.24 - 2.15 MeV z = 1; .34 - 2.05 MeV/n z = 2), R15C; Counting rate (.69 - 2.05 MeV/n z = 2) R15D; Counting rate (3.2 - 20.6 MeV z = 1; z = 2), R16A; Counting rate (5.7 - 20.6 MeV z = 1; z = 2), R16B; Counting rate (14.9 - 20.6 MeV z = 1; z = 2), R16C; Counting rate (6.6 - 20.6 MeV/n z = 2) R16D; * indicates PHA conditions [If a counting rate has more than one particle specified, the rate includes contribution from all particle species in the list.] DATA_SET_QUALITY: Narrative Summary of Pioneer 10 and 11 In-Flight Performance and the Development of Experiment Anomalies given by Dr. F.B. McDonald The initial data from Pioneer 10 and 11 following their launch on March 2,1972 and April 6, 1973 indicated that all three cosmic ray telescopes and their associated electronics in each of the CRT experiments were functioning in a normal fashion and there was no evidence of a malfunction in any part of the system. In fact, the charge, mass and energy resolution and the very low background levels in the 3 parameter analysis were significantly better than our pre-launch expectations. This excellent performance made possible the discovery of anomalous oxygen and nitrogen in the low energy portion of the galactic cosmic ray spectra, Jovian electrons in interplanetary space and the detailed study of the charge composition of the August 1972 solar cosmic ray events. The excellent energy resolution proved to be a necessity when the measured cosmic ray gradients were found to be almost an order of magnitude smaller than predicted by the theories of cosmic ray modulation existing at that time. Furthermore, these particle gradients are decreasing with increasing heliocentric distance. The long-term gain stability of both the HET and LET telescopes on P10/11 has been remarkable with no observable shift in the end-points of the stopping particle distribution. During the 19.8 years since the launch of P-10 there developed 4 electronic anomalies of which only one has impaired the quality of the cosmic ray data. On P-11 there was one detector problem which extended over significant periods of time (months to years) and which was followed by a return to normal operation. The nature of these anomalies and their impact on the quality of the data and the data analysis programs are discussed in the following sections. Pioneer 10 Three of the four P-10 anomalies occurred during or immediately following the December, 1973 Jovian encounter period. The CRT experiment is mounted outside the main body of the spacecraft in order to measure bi-directional H and He in the 100-500 MeV/n range. The exterior walls of the experiment were 500 microns of AL to meet the stringent weight requirements. As a result, J.H. Trainor has estimated that the CRT experiment received a total radiation dose in excess of 500,000 RAD during the period the spacecraft was inside the Jovian magnetosphere. Despite the fact that a great deal of effort has been made to use radiation hardened components this extreme dose led to 3 electronic failures: (A) A failure in the HET PHA scaler that resulted in the addition of 256 counts to the digitized A (or CIII) pulse height. This problem was readily solved by changing the H and He flux programs to include the possibility of a double-valued, or alternate, response. The effects of long-term annealing has restored the register so it has been functioning in a nominal fashion since the late 70's. (B) The rate transfer register developed a 'slipping-bit' problem that produced excessively high rates. This malfunction was solved by writing a computer program that recognized the large deviation from the nominal rate values and made the proper adjustment in the 'errant bit' . This problem has also been significantly reduced by annealing. (C) There was a failure in the LET I E channel electronics that effectively eliminated this pulse height measurement. The analysis was redefined to a 2 parameter stopping particle analysis which provides excellent information on anomalous He (3.3- 21.8 MeV/n) and oxygen (6.6 - 40 MeV/n) . The data for these components is of excellent quality. The H data contains significant background contamination. This background can probably be removed by the use of appropriate background corrections. These will be implemented for the forthcoming ~1993-1999 cycle 22 solar minimum period. (D) There was a significant degradation of the gain of the LET II in the early 80's. However, this telescope with its geometric factor of .015 cm2-s was designed for magnetospheric studies and even with normal operation it is not useful in the outer heliosphere. Much of the low energy range is covered by the LET I 8-channel analyzer with a geometric factor that is 100 times greater than that of the LET II. In summary, as of January 1992 the P-10 CRT experiment is essentially fully functional for its program of studies of the outer heliosphere. Pioneer-11 The radiation dosage received by the P-11 CRT experiment at Jupiter was much less due to the greater inclination of the fly-by trajectory. However, prior to that time, beginning in July 1974 the HET B detector became noisy and the B single rate increased from a nominal 20 counts per second to greater than 40,000 counts per second. This B-rate is involved in all coincidence modes of the HET system. High B rates produce an increase in the AB double coincidence rate and a decrease in the B, CI & CII , CIII triple rate. Above 1000 counts/s there is significant deterioration in the data quality and no satisfactory algorithms have been developed. The P-11 HET system returned to normal operation in mid January 1988. There were extended intervals in 1972- 78 when the rate was at the background level. This problem appears to be radiation induced. The onset is coincident with a moderate level solar cosmic ray event; and the problem was made more severe by the large spring 78 solar particle increases and the Saturn encounter. The return to normal operation in 1988 came after a prolonged period of very reduced low energy particle fluxes and of cooling to very low detector temperature due to the necessity of power sharing between various P-11 experiments. The LET I operation has been completely nominal over the entire span of data. DATA_PROCESSING_OVERVIEW: Four generic types of data are sent back by the cosmic ray telescopes: rates data, pulse height data, internal calibration data and engineering housekeeping data. All are preserved in the reduction steps described below. Time-ordered datasets containing RATES and PHA data are created from the experimenter data records. The time resolution in these datasets varies depending on the spacecraft data mode. Full time resolution is preserved. These datasets can be considered to be level 0 data. The data are de- compressed and reorganized while preserving the time order. A time-ordered dataset containing fifteen minute data blocks is then created from the RATES and PHA datasets. Each block contains summarized counts and accumulation times for RATES. In addition, the PHA data is sorted and orgainized by event types. Time tags of individual particles are lost in this process. This database is called the FLUX Database. Using the instrument response matrices and the FLUX database, rates and particle fluxes averaged over multiples of fifteen minutes can be derived. The desired count rates and fluxes are computed on demand, and the NSSDC data is produced in this manner. We have submitted encounter data at 15 minute resolution and the rest of the data at 6 hour time resolution. The interplanetary dataset submitted to NSSDC is periodically updated, and the new submission supercedes the previous data. FLUX database volumes for Pioneer-10 and Pioneer-11 are approximately 2 Gbytes each. All permanent databases reside on magnetic tape volumes in the library at the NCCS IBM 3081. This data set is not intended to be used as an encounter data set. LIT_REFERENCES: DATA PROCESSING AND PROGRAMMERS GUIDE FOR THE PIONEER-10 AND -11 COSMIC RAY EXPERIMENTS, VOL. 2, CSC/TM-81/6203, March 1982 .......TO BE ADDED CCSD$$MARKERMRK**002CCSD3KS00002MRK**003 VOL_TIME_COVERAGE: 1972-03-06 to 1994-12-31 LABEL=ATTACHED; REFERENCE=FORMAT.SFD; LABEL=NSSD3IF0011700000001; REFERENCE=CRT_P10_*.DAT /* EOF */