RHESSI GLOSSARY
Attenuator | Two sets of aluminum disks that can be moved in front of the detectors to lower the count rate during large flares. Attenuator state 0=both attenuators out; 1=thin in, thick out; 2=thick in, thin out; 3=both in. Also referred to as shutters. |
Decimation | Method of reducing volume of data to save space in the SSR. Decimation level n means n out of (n+1) events below a specified decimation energy are deleted. Front and back segments are decimated separately. |
Detector Event | The recording of a photon in the detector. It has the attributes: time, a2d index, and channel. |
DRM | Detector Response Matrix for RHESSI spectral deconvolution. Also referred to as SRM (Spectral Response Matrix). |
Eventlist | A list of detector events. The event list contains the background. |
Filedb | Database file containing a cross-reference between time intervals and the file names containing that interval. Used for Level-0, obs summary, and other RHESSI file types. Distributed with SSW in the hessi dbase directory. |
FITS | Flexible Image Transport System. Standard format for storing scientific data sets consisting of multi-dimensional arrays. RHESSI uses FITS format for the Level-0 and Observing Summary files, as well as spectrum, image, and other output files. |
GeD | Germanium Detectors. RHESSI has 9 segmented GeDs, one behind each RMC. |
Grid | Planar array of equally-spaced, X-ray-opaque slats separated by transparent slits. Grid pitches range from 34 µm to 2.75 mm in steps of the square root of 3. |
IDPU | Instrument Data Processing Unit |
Level-0 | Raw telemetry data files. ~15 files per day. Contain packed data and can only be interpreted with the SSW RHESSI software. |
MOC | Mission Operations Center at SSL, Berkeley |
Observing Summary | Daily files containing pre-binned data (from the Level-0 files) for quick access. |
OSPEX | An object-oriented spectral analysis package. RHESSI spectra and imagecube, MESSENGER, SOXS, and XSM data input are implemented as of October 2008. |
PLOTMAN | Interactive plot package for images, spectra, time plots and spectrograms. |
PMTRAS | PhotoMultiplier Tube Roll Aspect System |
QLP | Quick Look Product |
RAS | Roll Angle System |
RHESSI | Reuven Ramaty High Energy Solar Spectroscopic Imager launched in February 2002. |
RMC | Rotating Modulation Collimator - a pair of widely separated grids mounted on a rotating spacecraft. RHESSI has nine RMCs in front of a spectrometer with nine GeDs. |
SAS | Solar Aspect System |
SHOW_SYNOP | A data integration tool allowing selection and display of observations from numerous instruments. |
SSR | Solid State Recorder on board RHESSI. Data are recorded on the SSR and dumped to ground-based computer during passes over ground stations. |
Subcollimator | A pair of identical pitch co-aligned grids separated by ~1.5m |
TMS | Twist Monitoring System - used to align the grid pair in the X-ray collimator |
Tohban | On-duty scientist monitoring daily spacecraft operations from the science perspective. |
CHIANTI | Package consisting of an atomic database and IDL routines for analyzing the spectra from astrophysical plasmas. |
CLI | Command Line Interface |
CoSec | Collaborative Sun Earth Connector - an effort underway at the Lockheed Martin Solar and Astrophysics Lab to enable the integration and coordination of data analysis tasks across disparate data sources |
DEM | Differential Emission Measure |
EGSO | European Grid of Solar Observations |
ETHZ | Eidgenössische Technische Hochschule (Zentrum) in Zurich, Switzerland |
FAQ | Frequently Asked Questions |
FHNW | Fachhochschule Nordwestschweiz, University of Applied Sciences Northwestern Switzerland |
GB | Gigabytes |
GDL | GNU Data Language. A freeware open-source alternative to IDL under development. (http://gnudatalanguage.sourceforge.net) |
GIF | Graphics Interchange Format. One of several standard graphics formats. |
GOES | Geostationary Operational Environment Satellite. Series of satellites in operation since ~1974 providing continuous measurements of the Sun in two channels, 1.0-8.0 and 0.5-4.0 Å. |
GSFC | Goddard Space Flight Center in Greenbelt, Maryland, USA |
GUI | Graphical User Interface |
HEDC | HESSI European Data Center |
I4DS | Institute of 4D Technologies in Windisch, Switzerland |
IDL | Interactive Data Language. Proprietary software purchased from ITT (www.itt.com). Almost all the RHESSI data analysis software is written in IDL. |
IHY | International Heliophysical Year - 2007 & 2008 |
JAVA | An object-oriented platform-independent programming language |
Jython | An implementation of the Python programming language written in Java |
MB | Megabytes |
NSSDC | National Space Science Data Center. NSSDC provides deep archiving for RHESSI data archive, as well as access to other data sets. |
PINTofALE | Package for Interactive Analysis of Line Emission - Markov Chain Monte Carlo differential emission measure analysis package (Kashyap & Drake, 2000) |
PNG | Portable Network Graphics. One of several standard graphics formats. |
QLP | Quick Look Product |
RHESSI | Reuven Ramaty High Energy Solar Spectroscopic Imager launched in February 2002. |
SAA | South Atlantic Anomaly |
SDAC | Solar Data Analysis Center at GSFC. Hosts SSW software, data repository for SOHO, TRACE and other solar missions, and science support staff. |
SEP | Solar Energetic Particles Event |
SHOW_SYNOP | A data integration tool allowing selection and display of observations from numerous instruments. |
SPASE | Space Physics Archive Search and Extract. Standard protocol under development for searching and retrieving data from VxOs. |
SSL | Space Sciences Lab at the University of California, Berkeley |
SSW | Solar SoftWare. A collection of general and instrument-specific IDL routines for solar data analysis. The SSW archive is hosted at the SDAC, and is freely available for download and automatic updates to local computers. RHESSI software is distributed through SSW. |
TB | Terabytes |
TGF | Terrestrial Gamm-ray Flashes |
UTPLOT | An collection of IDL routines that provide instrument-independent display utility for time-series data. |
VCn | Virtual Channel n |
VSO | Virtual Solar Observatory |
VxO | Generic term for any Heliophysics virtual observatory, including the EGSO, the VHO, the VIO, the VSO, the VSPO, and the VSTO |
WCS | World Coordinate System - standards for defining the relationship between pixel coordinates in an image and sky coordinates. |
Last Modified: 14 February, 2011 by Kim Tolbert