Creating a Spectrum File Using the HESSI GUI

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===Setting Energy Bins===
===Setting Energy Bins===
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The next choice is  
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Next we must choose the energy bins for our spectrum. In the Spectra GUI there are two options associated with selecting energy bins. We can select energy bins based on binning codes. Selecting a binning code automatically defines the energy bins used to create the spectrum file by a predetermined schema. The show binning codes button displays a listing of all available schema. The Define Bins Manually... button allows the user to set energy bins to any scheme they choose. The following GUI appears when the button is selected:
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[[Image:Energy_intervals.jpg|center|thumb|600px|The Select Energy Intervals GUI allows the user to specify energy bins for creating a RHESSI spectrum file.]]
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There are several options for available for selecting energy bins. The top two panels allow the user to edit a list of intervals by doing things such as deleting a current interval or adding a new interval to a preexisting list, defining the intervals graphically, or reading them from a text file. In most cases the easiest way to define intervals is using the bottom panel, Define Intervals Manually.
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For instance a set of energy bins from 3keV to 300keV  with different size bins for different energy ranges can be defined as follows:
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*Selecting energy bins of width 1/3keV for the range 3keV to 15keV
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**In the Energy Range(keV) boxes enter 3.0 in the low box and 15.0 in the high box
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**Under Create Multiple(max=10000) bands: select 'Divide this Energy Range into bands of width D'
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**Next to D(keV) below this enter .33333
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**To the left of this choose 'Replace List'. A list of energy bands going from 3.0keV to 15keV in 1/3keV bins should appear in the list in the middle of the GUI
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*Selecting energy bins of width 1keV from 15.0keV to 100keV
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**In the Energy Range(keV) boxes enter 15.0 in the low box and 100.0 in the high box
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**Under Create Multiple(max=10000) bands: select 'Divide this Energy Range into bands of width D'
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**Next to D(keV) below this enter 1.0
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**To the left of this choose 'Add to list'. The list of energy bands should now contain 1/3kev bands from 3.0keV to 15kev plus 1keV bands from 15keV to 100keV.
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*Selecting energy bins of width 5kev from 100keV from 300keV
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**In the Energy Range(keV) boxes enter 100.0 in the low box and 300.0 in the high box
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**Under Create Multiple(max=10000) bands: select 'Divide this Energy Range into bands of width D'
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**Next to D(keV) below this enter 5.0
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**To the left of this choose 'Add to list'. The list of energy bands should now contain 1/3kev bands from 3.0keV to 15kev, 1keV bands from 15keV to 100keV, and 5kev bands from 100keV to 300keV
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*Select 'Accept' at the bottom left of the GUI. The energy bins are now set as defined and we are back at the 'Spectra' GUI

Revision as of 19:44, 6 August 2009

Contents

Creating A Spectrum File with the HESSI GUI

Introduction

Under Construction. See Ospex - The Basics for an older version of the HESSI GUI Documentation. If you have already created a spectrum file go to OSPEX Documentation for a simple tutorial on fitting an interval.

Creating a Count Rate Spectrum File

Start the HESSI GUI at the sswidl command line by typing: 

     hessi

The HESSI GUI start screen will appear. Select the 'File' drop down menu. The GUI should now appear as below.

The Hessi GUI start screen with File drop down menu

From the file drop down menu choose the 'Select Observation Time Interval...' option. The 'Observation Time Interval Selection' GUI will pop up.

Pop up GUI to set time over which to create the spectrum file

We can set the start and end times we would like to use by simply entering times in this widget or selecting 'Start' and entering times in the popup menu, then doing this again for the end time. Once we have selected our times we can plot the observing summary for the flare. In this example we have selected the flare on 21Apr2002 starting at 00:20:00 and continuing until 01:40:00. We can plot the observing summary in the main window by selecting the 'Plot Observing Summary Data' button. The observing summary should appear as below:

The observing Summary for the 21Apr2002 flare

This is the standard time history for the flare of interest on 21 April 2002. Note that it is the summed counting rate of all the front and rear detector segments in counts s-1 detector-1. The detailed markings in this plot are described in detail in Kim Tolbert's write up on RHESSI Quicklook Light Curves. The various changes in count rate with time in the different energy ranges are described in Brian Dennis' write up on Artifacts in RHESSI Light Curves. This count rate plot gives us very important information on the impulsive phase of the flare of interest. We see, for example, that RHESSI came out of nighttime at about 00:33 UT as indicated by the vertical blue dashed line but more accurately, by the rapid increase in the 3 - 6 and 6 - 12 keV count rates. This indicates that a flare was already going on at this time. Images show that it was at a different location than the flare of interest that began at about 00:39 UT. (Note that right clicking on the plot gives you the time at the cursor.) The horizontal purple line at the top of the plot labeled A0 indicates that all attenuators were out of the detector fields of view at this time. The counting rate at all energies up to 25 keV rose very rapidly until at about 00:48 UT the thin attenuators moved into the detector fields of view (as indicated by the purple line dropping to the A1 level); the rates below 25 keV dropped precipitously at this time. Thereafter, every 4 minutes, the thin attenuators were removed for 1-minute intervals to test the low energy rate from the flare. At about 01:30 UT, the thick attenuators were added to the thin attenuators in the detector fields of view (the A3 state as indicated on the purple line) and the rates up to 50 keV dropped precipitously. Finally, at abut 01:33 UT, RHESSI went into night and the rates again fell to their non-solar background levels. Note that the rates up to 300 keV continued to climb as RHESSI entered the South Atlantic Anomaly (SAA) as indicated by the orange line marked with an "S" at the top of the plot. No data is recorded during passages through the most intense parts of the SAA to preserve space in the on-board memory.

Once we have identified the flare for which we would like to create a spectrum file select the Set Obs Time and Close button at the lower left corner of the Observation Time Interval Selection GUI. To create the spectrum files access to the RHESSI data is necessary. In order to access the data, make sure you are online, then from the IDL command line type the following: 

IDL>search_network, /enable

When trying to create your spectrum file IDL will now try to automatically download all necessary data from an available RHESSI archive. The files are copied to a local directory specified by the user during setup of X-ray package in ssw.

To begin creating a spectrum file under the File drop down menu select Retrieve/Process Data ->, from the menu that appears to the side of this select Spectrum.... The following GUI should appear:

Spectra GUI for creating RHESSI Spectrum files.

Using this GUI we can set the the parameters for our spectrum file.

The time set in the the Observation Time Interval GUI is already transferred to the Spectra GUI. We are allowed to specify a different time or select a Spectrum Time Interval directly below, which is different (though contained by the observation time interval).

Setting Energy Bins

Next we must choose the energy bins for our spectrum. In the Spectra GUI there are two options associated with selecting energy bins. We can select energy bins based on binning codes. Selecting a binning code automatically defines the energy bins used to create the spectrum file by a predetermined schema. The show binning codes button displays a listing of all available schema. The Define Bins Manually... button allows the user to set energy bins to any scheme they choose. The following GUI appears when the button is selected:

The Select Energy Intervals GUI allows the user to specify energy bins for creating a RHESSI spectrum file.

There are several options for available for selecting energy bins. The top two panels allow the user to edit a list of intervals by doing things such as deleting a current interval or adding a new interval to a preexisting list, defining the intervals graphically, or reading them from a text file. In most cases the easiest way to define intervals is using the bottom panel, Define Intervals Manually.

For instance a set of energy bins from 3keV to 300keV with different size bins for different energy ranges can be defined as follows:





[STILL UNDER CONSTRUCTION]

Retrieved from "https://sprg.ssl.berkeley.edu/~tohban/wiki/index.php/Creating_a_Spectrum_File_Using_the_HESSI_GUI"
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