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The Nuclear Detonation Detection System on the GPS satellites

Description: This article begins with a historical perspective of satellite usage in monitoring nuclear detonations. Current capabilities of the 24 GPS satellites in detecting the light, gamma rays, x-rays and neutrons from a nuclear explosion are described. In particular, an optical radiometer developed at Sandia National Laboratories is characterized. Operational information and calibration procedures are emphasized.
Date: July 27, 1993
Creator: Higbie, P. R. & Blocker, N. K.
Partner: UNT Libraries Government Documents Department

The utility of diamond sensors for space flight

Description: Los Alamos National Laboratory has developed diamond sensors with interdigitated electrodes that operate in a photoconducting mode. The specific application for this work was for the Department of Energy`s instruments flown on the Global Positioning System satellites. Sensors have been fabricated and tested for their response to low-energy x-rays. These sensors can be operated to extremely high volumetric radiation doses. We find that the sensors are extremely useful for situations where the surface radiation dose is not excessive, but that this limit is exceeded for the GPS orbit. It is possible that further studies and special detector arrangements or auxiliary heating of the sensor may push this limit to higher values.
Date: March 1996
Creator: Higbie, P. R.; Han, S. S. & Wagner, R. S.
Partner: UNT Libraries Government Documents Department

Calibration of an electron/proton monitor for the earth's radiation belt at 4 R/sub E/

Description: A charged particle dosimeter (the Burst Detector Dosimeter or BDD) was designed and fabricated and will be flown on certain of the Global Positioning Satellite (GPS) series of spacecraft. The BDD will monitor the dose received by the GPS spacecraft from the fluxes of electrons and protons in the Earth's radiation belt. The BDD uses absorbers in front of silicon sensors to determine the energy thresholds for measuring incident particle fluxes; and the magnitude of energy loss in a single sensor distinguishes between ions and electrons over a wide range of energies. Our electron calibrations were performed to determine accurately the energy response function of the dosimeter. The experimentally determined energy and angular responses are used to determine the equivalent energy thresholds and geometric factors for idealized step function responses.
Date: March 1, 1982
Creator: Higbie, P.R.; Belian, R.D.; Argo, H.V. & Baker, D.N.
Partner: UNT Libraries Government Documents Department

Hostile energetic particle radiation environments in earth's outer magnetosphere

Description: Many spacecraft operational problems in Earth's outer magnetosphere appear to be due to intense, transient radiation phenomena. Three types of naturally-occurring, and highly variable, hostile particle radiation environments are encountered at, or near, the geostationary orbit: (1) High-energy protons due to solar flares; (2) Energetic ions and electrons produced by magnetospheric substorms; and (3) very high energy electrons of uncertain origin. Present particle sensor systems provide energetic particle detection and assessment capabilities during these kinds of high-energy radiation events. In this paper, particular emphasis is given to highly relativistic electrons (3 approx. 10 MeV). Electron fluxes and energy spectra are shown which were measured by two high-energy electron sensor systems at 6.6 R/sub E/ from 1979 through 1984. Large, persistent increases in this population were found to be relatively infrequent and sporadic in 1979-81 around solar maximum. During the approach to solar minimum (1981 to present) it is observed that the highly relativistic electrons occur with a regular 27-day periodicity, and are well associated with the re-established solar wind stream structures. Through a superposed epoch analysis technique we show that an energetic electron enhancement typically rises on a 2- to 3-day time scale and decays on 3- to 4-day time scale at essentially all energies above approx.3 MeV. The present analysis suggests that the Jovian magnetosphere is a recurrent source of this significant electron population in the outer terrestrial magnetosphere and that these electrons have a very deleterious influence on spacecraft systems due to deep dielectric charging and low-dose susceptibility effects. 13 refs., 11 figs.
Date: January 1, 1986
Creator: Baker, D.N.; Belian, R.D.; Higbie, P.R.; Klebesadel, R.W. & Blake, J.B.
Partner: UNT Libraries Government Documents Department

Los Alamos synchronous orbit data set

Description: Energetic electron (30-15000 keV) and proton 145 keV to 150 MeV) measurements made by Los Alamos National Laboratory sensors at geostationary orbit (6.6 R/sub E/) are summarized. The instrumentation employed and the satellite positions are described. The spacecraft have been variously located, but in their present configuration the Los Alamos satellites designated 1976-059, 1977-007, and 1979-053 are located, respectively, at approx. 70/sup 0/W, approx. 70/sup 0/E, and approx. 135/sup 0/W longitude. Several examples of the high temporal and full three-dimensional spatial measurement capabilities of these instruments are illustrated by examples from the published literature. Discussion is also given for the Los Alamos Synoptic Data Set (SDS) which gives a broad overview of the Los Alamos geostationary orbit measurements. The SDS data are plotted in terms of daily average spectra, 3-hour local time averages, and in a variety of statistical formats. The data summarize conditions from mid-1976 through 1978 (S/C 1976-059) and from early 1977 through 1978 (S/C 1977-007). The SDS compilations presented correspond to measurements at 35/sup 0/W, 70/sup 0/W, and 135/sup 0/W geographic longitude and thus are indicative of conditions at 9/sup 0/, 11/sup 0/, and 4.8/sup 0/ geomagnetic latitude, respectively. The bulk of the SDS report presents data plots which are organized according to Carrington solar rotations and, as such, the data are readily comparable to solar rotation-dependent interplanetary conditions. Potential applications of the Synoptic Data Set (available to all interested users in June 1981) are discussed.
Date: January 1, 1981
Creator: Baker, D.N.; Higbie, P.R.; Belian, R.D.; Hones, E.W. & Klebesadel, R.W.
Partner: UNT Libraries Government Documents Department

BDD: a dosimeter for the Global Positioning System

Description: This report describes the design and operation of the BDD, a four-channel spectrometer carried by some satellites of the Global Positioning System to collect data about magnetically trapped particle fluxes. The methods of data collection and analysis are also discussed.
Date: October 1, 1980
Creator: Argo, H.V.; Baker, D.N.; Belian, R.D.; Cope, L.K. & Higbie, P.R.
Partner: UNT Libraries Government Documents Department

Pitch angle distributions of > 30 keV electrons at geostationary altitudes. [Spherical harmonics, spatial distribution, probability]

Description: The satellites 1976-059A and 1977-007A each carry energetic particle detectors which measure fluxes of electrons in the 30 to 300 keV energy range. Five separate sensors mounted at 30, 60, 90, 120, and 150/sup 0/ to the spacecraft spin axis provide two hundred samples of the three dimensional distribution function for every ten second spacecraft rotation. Spherical harmonic functions up to the fourth order were fit to the observed pitch angle distributions. The second and fourth order coefficients obtained for these fits were averaged for each hour of local time. The probability distributions for the averaged harmonic coefficients were calculated and are presented as a function of local time. Possible relations of these distributions to interplanetary conditions are discussed. Using the present analysis techniques, the intensity of electrons at the noon meridian is derived as a function of pitch angle and radial distance and is given by j(..cap alpha..,r) = 2.03 x 10/sup 8/ (0.49 sin/sup 4/./sup 78/..cap alpha.. + 0.51 sin/sup 0/./sup 27/..cap alpha..) e/sup -r/1.60/ el/cm/sup 2/ sec sr. 11 references.
Date: January 1, 1978
Creator: Higbie, P.R.; Baker, D.N.; Hones, E.W. Jr. & Belian, R.D.
Partner: UNT Libraries Government Documents Department

Prediction of high-energy (> 0. 3 MeV) substorm-related magnetospheric particles. [Probability]

Description: Measurements both at 6.6 R/sub E/ and in the plasma sheet (greater than or equal to 18 R/sub E/) show that high energy substorm-accelerated particles occur preferentially when the solar wind speed (V/sub sw/) is high. Virtually no > 0.3 MeV protons, for example, are observed in association with substorms that occur when V/sub sw/ is < 400 km/sec. On the other hand, the probability of observing high energy protons is very large, both at geostationary orbit and in the plasma sheet, when V/sub sw/ is > 700 km/sec. These results suggest that realtime monitoring of interplanetary conditions could allow simple, effective prediction of high energy magnetospheric particle disturbances. 7 references.
Date: January 1, 1979
Creator: Baker, D.N.; Belian, R.D.; Higbie, P.R. & Hones, E.W. Jr.
Partner: UNT Libraries Government Documents Department

Burst Detector X-Ray IIR

Description: The Burst Detector X-Ray (BDX) instrument for the Block IIR series of Global Positioning System satellites is described. The BDX instrument can locate and characterize exoatmospheric nuclear detonations by using four sensors consisting of sets of filters over silicon diodes to detect x rays of various energies from the burst. On the BDX-IIR, a fifth sensor with a response spanning those of the other sensors confirms coincidences among the four main channels. The mechanical and electronic features of the BDX-IIR and its sensors are described. The calibrations and the system tests used in flight are presented. The commands for the BDX-IIR are given. The messages sent from the BDX-IIR are described in detail.
Date: February 1998
Creator: Higbie, P. R.; Spencer, K. M.; Guyker, F.; Vigil, R. P. & Reedy, R. C.
Partner: UNT Libraries Government Documents Department

Los Alamos energetic particle sensor systems at geostationary orbit

Description: The Los Alamos National Laboratory has provided energetic particle sensors for a variety of spacecraft at the geostationary orbit (36,000 km altitude). The sensor system called the Charged Particle Analyzer (CPA) consists of four separate subsystems. The LoE and HiE subsystems measure electrons in the energy ranges 30 to 300 keV and 200 to 2000 keV, respectively. The LoP and HiP subsystems measure ions in the ranges 100 to 600 keV and 0.40 to 150 MeV, respectively. A separate sensor system called the spectrometer for energetic electrons (SEE) measures very high-energy electrons (2 to 15 MeV) using advanced scintillator design. In this paper we describe the relationship of operational anomalies and spacecraft upsets to the directly measured energetic particle environments at 6.6 R/sub E/. We also compare and contrast the CPA and SEE instrument design characteristics with the next generation of Los Alamos instruments to be flown at geostationary altitudes.
Date: January 1, 1985
Creator: Baker, D.N.; Aiello, W.; Asbridge, J.R.; Belian, R.D.; Higbie, P.R.; Klebesadel, R.W. et al.
Partner: UNT Libraries Government Documents Department

Los Alamos geostationary orbit synoptic data set: a compilation of energetic particle data

Description: Energetic electron (30 to 2000 keV) and proton (145 keV to 150 MeV) measurements made by Los Alamos National Laboratory sensors at geostationary orbit 6.6 R/sub E/ are summarized. The data are plotted in terms of daily average spectra, 3-h local time averages, and in a variety of statistical formats. The data summarize conditions from mid-1976 through 1978 (S/C 1976-059) and from early 1977 through 1978 (S/C 1977-007). The compilations correspond to measurements at 35/sup 0/W, 70/sup 0/W, and 135/sup 0/W geographic longitude and, thus, are indicative of conditions at 9/sup 0/, 11/sup 0/, and 4.8/sup 0/ geomagnetic latitude, respectively. Most of this report is comprised of data plots that are organized according to Carrington solar rotations so that the data can be easily compared to solar rotation-dependent interplanetary data. As shown in prior studies, variations in solar wind conditions modulate particle intensity within the terrestrial magnetosphere. The effects of these variations are demonstrated and discussed. Potential uses of the Synoptic Data Set by the scientific and applications-oriented communities are also discussed.
Date: August 1, 1981
Creator: Baker, D.N.; Higbie, P.R.; Belian, R.D.; Aiello, W.P.; Hones, E.W. Jr.; Tech, E.R. et al.
Partner: UNT Libraries Government Documents Department