How to change ``GATT`` Gas Attenuator to Neon
=============================================

1.
   From the SASE3 Photon Beam Transport ``SA3_MAIN`` main panel, open the SASE3
   Gas Attenuator.

   .. image:: SA3_MAIN.svg
      :width: 50%
      :align: left

#.
   From the SASE3 Gas Attenuator ``G_ATT_03`` main panel, click on ``Pause
   Injection`` (not Stop injection). The ``Process Status`` on top will changed
   to ``PAUSED``.

   Then open the SASE3 Gas Attenuator System Setup ``G_ATT_01`` panel by
   clicking on ``01 - System Settings/Pset= f(Attenuation)``.

   .. image:: G_ATT_03.svg
      :width: 50%
      :align: left

#.
   From the SASE Gas Attenuator System Set-Up ``G_ATT_01`` panel, open the
   Central Gas Injection Module Control panel ``G_ATT_CGI`` panel by clicking on
   ``CGI Module Control Panel``.

   .. image:: G_ATT_01.svg
      :width: 50%
      :align: left


#.
   From the Central Gas Injection Module Control panel ``G_ATT_CGI`` panel,
   open the Extended panel by clicking on ``Extended Panel``.

   .. image:: G_ATT_CGI.svg
      :width: 50%
      :align: left

#.
  In the Extended Panel ``G_ATT - CGI Extended`` one can see the Gas Manifold
  with 5 different incoming gas lines consisting of 2 large gas line, Ar and N2,
  and 3 minican gas line.

  .. image:: G_ATT_CGI_Extended.svg
     :width: 50%
     :align: left


  Labels of the minican gas line are not necessarily
  correct and one needs to know which minican gas line is the Neon gas line.
  The pressure indicates if minican is empty.

   a. Switch ``N2 Mode`` to ``Off``.

   #. Switch ``Ne Mode`` to ``On`` if this is the right minican.

   #. Evacuate the gas manifold by switch on the membrane pump and opening the
      valve at the bottom of the gas manifold.

   #. Pump down the gas manifold for 3 to 5 minutes.

   #. Switch off the membrane pump. It will automatically switch off the valve.

   #. Open the Ne valve.



#.
   From the Central Gas Injection Module Control panel ``G_ATT_CGI`` panel,
   select the adequate shutoff valve according to the orifice size.

   .. image:: G_ATT_CGI.svg
      :width: 50%
      :align: left


   a. Set ``Control Mode`` to be ``1``.

   #. Select the ``Analog S.P. (set)`` to a value between 4.5 to 14 mA. Below
      4.0 mA the shutoff valve should remain closed. The maximum opening is
      obtained for a value of 20 mA.

   #. Regulate the Analog S.P. to get the right Neon absorption in the spectrum.
      Switch to a different shutoff valve orifice size if the value goes outside
      the range of 4.5 to 14mA with the current orifice size.


How to change ``GATT`` Gas Attenuator back to N2 with 2mbar
===========================================================

#.
   From the Central Gas Injection Module Control panel ``G_ATT_CGI`` panel,
   set the ``Analog S.P. (set)`` of the currently used shutoff valve to 0 to
   close it. Then close Shutoff valve.

   .. image:: G_ATT_CGI.svg
      :width: 50%
      :align: left

#.
   From the Extended Panel ``G_ATT - CGI Extended``,  switch the currently used
   minican ``Ne Mode`` to ``Off`` and switch the 'N2 Mode' to 'On'.

   .. image:: G_ATT_CGI_Extended.svg
      :width: 50%
      :align: left

#.
   Use the ``Automatic GAS Exchange`` to ``On`` and click on ``PumpPurgetoN2``.
   This procedure will pump down and purge the gas manifold a few times. The
   procedure takes about 15 min. Wait for the N2 exchange to be finished as
   indicated in the status box below.

#.
   Switch ``Automatic Gas Exchange`` to ``Off``.

#.
   From the SASE3 Gas Attenuator ``G_ATT_03`` main panel, go to 2mbar.

   .. image:: G_ATT_03.svg
      :width: 50%
      :align: left