The NEAR X-ray Spectrometer detectors are three gas proportional counters collimated to 5 degrees field of view to determine X-ray line emissions from the asteroid. Balanced filters on two detectors (Al on one and Mg on the other) are used to separate Mg, Al, and Si lines and the Fe, S, Ti, and Ca lines can be resolved. The detectors have a 25 square cm active aperture area and a 25 micrometer beryllium window with a beryllium liner and window support. The detector energy range is 1 to 10 keV with rise-time discrimination to reduce background contamination. The energy resolution is better than 1 keV FWHM at 5.95 keV.

The NEAR XRS is part of the X-Ray/Gamma-Ray Spectrometer (XGRS) suite on the NEAR mission.  It is 
 an X-ray resonance fluorescence spectrometer that detects the characteristic X-ray line emissions 
 excited by solar X-rays from major elements in the asteroid's surface. It covers X-rays in the 
 energy range from 1 to 10 keV using three gas proportional counters.  The balanced, differential 
 filter technique is used to separate the closely spaced Mg, Al, and Si lines lying below 2 keV. The 
 gas proportional counters directly resolve higher energy line emissions from Ca and Fe. A mechanical     
 collimator gives the XRS a 5 deg FOV, with which it will map the chemical composition of the asteroid 
 at spatial resolutions as great as 2 km in the low orbits. It also includes a separate solar monitor 
 system to measure continuously the incident spectrum of solar X-rays, using both a gas proportional 
 counter and a high-spectral-resolution silicon X-ray detector. The XRS performs in-flight calibration 
 using a calibration rod with Fe-55 sources that can be rotated into or out of the detector FOV.

XRAY SPECTROMETER for NEAR

GAMMA RAY SPECTROMETER for NEAR

MAGNETOMETER for NEAR

MULTI-SPECTRAL IMAGER for NEAR

NEAR INFRARED SPECTROMETER for NEAR

NEAR LASER RANGEFINDER for NEAR

RADIO SCIENCE SUBSYSTEM for NEAR

NEAR

NEAR EARTH ASTEROID RENDEZVOUS

253 Mathilde

433 Eros

C/1996 B2 (Hyakutake)

Moon

NAIF ID 399

Earth

The bundle contains all the mission wide information needed to use and understand the scientific data products produced by the NEAR mission.

NEAR Mission Information Bundle

The NEAR X-Ray Spectrometer (XRS) is part of the X-Ray/Gamma-Ray Spectrometer (XGRS) instrument package on the NEAR spacecraft. This bundle contains all of the raw and calibrated XRS instrument data from the NEAR mission, plus derived results.

NEAR X-Ray Spectrometer (XRS) Data Bundle

The NEAR X-Ray Spectrometer (XRS) is part of the X-Ray/Gamma-Ray Spectrometer (XGRS) instrument package on the NEAR spacecraft.  This bundle contains all of the raw and calibrated XRS instrument data from the NEAR mission, plus derived results.

This data bundle was migrated from PDS3 to PDS4 in 2025 by PDS SBN. This bundle contains all the data and documentation in the PDS3 NEAR XRS archived data sets with data set IDs starting with "NEAR-A-XRS-".

Data Processing Level	Data set ID	Mission phase	Browse	Download
Raw data (level 1b):
	NEAR-A-XRS-2-EDR-CRUISE2-V1.0	Cruise 2	432 Mb	87 M
	NEAR-A-XRS-2-EDR-EARTH-V1.0	Earth Flyby	254 Mb	33 Mb
	NEAR-A-XRS-2-EDR-CRUISE3-V1.0	Cruise 3	400 Mb	77 Mb
	NEAR-A-XRS-2-EDR-CRUISE4-V1.0	Cruise 4	409 Mb	81 Mb
	NEAR-A-XRS-2-EDR-EROS/ORBIT-V1.0	Eros Orbit	1.5 Gb	404 Mb
Calibrated data (levels 2 and 3):
	NEAR-A-XRS-3-EDR-EROS/ORBIT-V1.0	Eros Orbit	2.0 Gb	596 Mb

NEAR X-Ray Spectrometer (XRS)

Description

Identifier (LID)

Version

Data

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