Using the High Pressure Equipment
in the µE1 area at the PSI

In the area µE1, before any action in the Studio A:

	Close the relief valve  behind the round hole in the "wood box" (turning clockwise=closing). Open He bottle  (if you don't find a bottle: go shopping, the Rohmateriallager (WMSA) offers a 50 liter He 4.6 bottle for approx. sfr 270.-; don't forget to apply a tight binding approximation between bottle and wall).
Caution: Use max. 80 bar as input for the HP pump, there should be a reduction valve installed! Disregarding this damages the first stage of the pump. For any HP operation, the area (bunker door) has to be locked, even for tests without the beam. Sometimes you have to convince the people in the control room of that.

Situation:

• The green and the red (or orange) light is ON.

A1: Close the valves C and D (push green buttons, light=closed).   A2: Switch ON the membrane compressor  (push green button, light=on).   A3: Open the valve E  (perhaps already open, the normal state when you start from ambient pressure).   A4: Pressure should increase slowly (1.5 kbar after 3-5 min).

This procedure is suitable for pressures up to 1.5 kbar. Finally

A5: Close the valve E  when desired pressure is reached.   A6: Switch OFF the membrane compressor  (push red button),  you hear the noise of releasing "some" pressure; don't panic it seems to normal.

For higher pressure you have to use the additional intensifier, the second stage of the pumping unit, so after A4 continue with:

A5b: Set the regulator to 0  (turning anticlockwise completely).  If the pressure exceeds 600 bar,  switch ON the intensifier (push green button, light=on).  You can use the intensifier already with a pressure of about 300 bar. Since the cylinder of the intensifier is moved down by this pressure it takes longer if the pressure is lower.

A6b: Slightly open the regulator,  i.e. set regulator to 0.5...2.0. Warning: Go only far beyond 2.5 with the regulator if the pressure, after several moves of the cylinder (orange light=cylinder going down, red light=cylinder going up=pumping), does not increase anymore. Increase the value of the regulator only in steps of 0.5 and keep your eyes on the pressure display!

A7b: Close the valve E  when the desired pressure is reached.   A8b: Set the regulator to 0.  Switch OFF the intensifier (push red button).   A9b: Switch OFF the membrane compressor  (push red button).

• Cell under high pressure,
• valves C, D and E are closed.      Mind the order!

B1: Open the valves C and D  (push red buttons), wait 10 sec.   B2: Close the valves C and D  (push greenbuttons).   B3: Open the valve E. Wait 10 sec.  Pressure should go down 200-800 bar.   B4: Close the valve E.  If the pressure is higher than approx. 1 kbar then goto point B1 else   B5: Open the valves C and D  (push red buttons).  Open the valve E.  The pressure should be in the range of the bottle pressure, i.e. 80 to 150 bar.

Now you can safely open the area door.
If you are going to disconnect your pressure cell from the pumping unit first of all close the bottle and open the relief valve!

• Cell under pressure.
• Valves C, D and E are closed.
• Membrane compressor and intensifier are switched OFF.

C1: Open the valve E.  Pressure goes down approx. 200-800 bar.   C2: Switch ON the membrane compressor  (push green button). If you want to reach a pressure below 1.5 kbar goto point A3.   C3: If you want reach a pressure above 1.5 kbar additionally switch on the intensifier. Continue with point A5b.

• Always be sure what you are doing.
  Trial and error is not the right stragety for dealing with the HP equipment.

• If someone enters the µE1 area during a high pressure experiment, the complete pressure will be released immediately due to safety regulations. This might damage your sample (expensive single crystals are good canditates).

• We strongly recommend not to use home-made extension to increase the power of the pumps.

• While using the intensifier and regulator the eyes should kept on the pressure display. 20 seconds are enough to pump 12 kbar into your pressure cell which you carefully constructed for 8 kbar!

• Before any mechanical manipulation (e.g. fixing screws, removing the pressure cell, etc.) close the He bottle and open the relief valve in the µE1 area!

The high pressure equipment is owned and maintained by the µSR group in München Address: Technische Universität München, Department E15, D -- 85748 Garching, Fax: 0049-89-3207 780.

Last change: 21-08-1998, Alexander Röck.