<?xml version="1.0" encoding="UTF-8"?>
<!-- For help on the notation used to specify an Instrument Definition File 
     see http://www.mantidproject.org/IDF -->
<instrument xmlns="http://www.mantidproject.org/IDF/1.0" 
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xsi:schemaLocation="http://www.mantidproject.org/IDF/1.0 http://schema.mantidproject.org/IDF/1.0/IDFSchema.xsd"
 name="GPD" valid-from   ="1900-01-31 23:59:01"
		       last-modified="2013-06-27 00:00:00">
  <defaults>
    <length unit="meter"/>
    <angle unit="degree"/>
    <reference-frame>
      <!-- The z-axis is set parallel to and in the direction of the beam. the 
           y-axis points up and the coordinate system is right handed. -->
      <along-beam axis="z"/>
      <pointing-up axis="y"/>
      <handedness val="right"/>
    </reference-frame>
  </defaults>

  
  <!-- BRIEF DESCRIPTION OF THE PSI GPD INSTRUMENT: 
  
      Data provided by Stephen Cottrell - dimensions of pixels are incorrect!
  -->
  
  <parameter name="Default grouping file" type="string">
    <value val="Grouping/GPD_Detector_Grouping_LF_2.xml"/>
  </parameter>     
  
  <!-- LIST OF PHYSICAL COMPONENTS (which the instrument consists of) -->
  
  <!-- dummy components added for visualisation purposes. 
       To easy spot what geometry the instrument is in -->
       
  <!-- source and sample-position components -->

  <component type="source">
    <location z="-10.0" />
  </component>
  
  <type name="source" is="Source" />
  
  <component type="some-sample-holder">
    <location />
  </component>
  
  <type name="some-sample-holder" is="SamplePos" />
 
  <!-- detector components --> 
  
  <component type="FBdetector"  idlist="all">
       <location />  
  </component>  

  <type name="FBdetector" >
     <component type="front" >
       <location />
     </component>
     <component type="back" >
       <location />     
     </component>    
  </type>

  <type name="front" >
     <component type="pixel">
        <location z="-0.1" name="front" />
     </component>
  </type>
  
  <type name="back" >
     <component type="pixel">
        <location z="0.1" name="back" />
     </component>
  </type>
     
  <type name="pixel" is="detector">  
    <!-- It is implicitely assumed here that the front y-z plane (looking down
         the x-axis) is the surface that see the neutron beam.
         This surface is 36mm along y and 30mm along z and the dept along x is 5mm.  -->
    <cuboid id="inner-shape">
      <left-front-bottom-point x="0.0" y="-0.04" z="-0.04"  />
      <left-front-top-point  x="0.0" y="0.04" z="-0.02"  />
      <left-back-bottom-point  x="0.010" y="-0.04" z="-0.02"  />
      <right-front-bottom-point  x="0.0" y="-0.04" z="0.02"  />
    </cuboid>
    <algebra val="inner-shape" />     
  </type>
      
  <!-- DETECTOR ID LISTS -->
  
  <idlist idname="all">
    <id start="1" end="2"/>            
  </idlist>


  
</instrument>