<?xml version="1.0" encoding="UTF-8"?>
<geometry>

<!-- Definition of Cells -->
  <cell id="1">
    <universe>0</universe>
    <region>-1 2 -3 4 -5 6</region>
    <material>1</material>
  </cell>

<!-- Defition of Surfaces -->
  <surface id="1">
    <type>x-plane</type>
    <coeffs>10</coeffs>
    <boundary> vacuum </boundary>
  </surface>
  <surface id="2">
    <type>x-plane</type>
    <coeffs>-10</coeffs>
    <boundary> vacuum </boundary>
  </surface>
  <surface id="3">
    <type>y-plane</type>
    <coeffs>1</coeffs>
    <boundary>reflective</boundary>
  </surface>
  <surface id="4">
    <type>y-plane</type>
    <coeffs>-1</coeffs>
    <boundary>reflective</boundary>
  </surface>
  <surface id="5">
    <type>z-plane</type>
    <coeffs>1</coeffs>
    <boundary>reflective</boundary>
  </surface>
  <surface id="6">
    <type>z-plane</type>
    <coeffs>-1</coeffs>
    <boundary>reflective</boundary>
  </surface>

</geometry>
