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Checklist:

• If you haven't already done it, start up the beam systems in the cell - take me there
• Establish a remote VNC connection with the PC in the cell. - how?
• Start up the DNB conditioning program on Linux - instructions are here
• Take me to the summary.
  

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Overview:

Once the beam capacitor banks are charged the beam is ready to fire. Typically, don't fire the beam until the bank voltage U(C2) is greater than 830 Volts. A good full length shot without faults will cause the voltage to drop to below ~630 V. The beam will usually require a few conditioning shots for a morning startup. If starting for the first time after a cryo pump regeneration, conditioning can be much more involved. Usually the first few shots are fired into the calorimeter target plate, then operation is switched over to firing into the C-Mod chamber or plasma. The beam firing systems are interlocked - "RFX Mode" means that the calorimeter is out and the main gate valve is open, and "Test Mode" means that the calorimeter is in and the main gate valve is closed. The beam won't run unless it is in one of these two operational states.

Beam operation involves three repetitive functions; Moving the calorimeter in or out, enabling or disabling the gate valve to C-Mod, and firing the beam.

• Calorimeter: The calorimeter is controlled via the Java interface. Go to the tab marked "Cryo", and note the calorimeter position indicator on the left side of the chamber illustration. Green indicates that the target is out of the beamline. Red indicates that the target is in the beamline. Black means that the target moving and is somewhere between these two positions. Move the calorimeter by pushing the button "Move Calorimeter". If the calorimeter indicator stays black for more than thirty seconds or so, then there is a problem with the system.
  

• Triggering: The beam can be fired in two ways; internally, by simply pushing the "Start" button on the Java screen or externally, by pushing the "Start" button, and providing an external hardware trigger from the CMod camac within one minute of the button push. Switch between the two modes by switching to the Java interface "Timer" tab and toggling the Internal / External trigger mode. At the top of the screen push the "Internal" button for internal triggering mode, or the "External" button for external triggered mode. Note that the Java "Start" button serves different roles in the two modes. In internal mode, it fires the beam immediately. In external mode, it arms the beam to prepare for an external trigger. Use internal mode for quick operation of the beam, and for troubleshooting. Use external mode whenever you will run the beam from MDSplus using the beam conditioning program to operate the beam and take data. Special Note: The timing of  the first shot after switching to external mode will include a random firing delay of up to 50 ms. Subsequent shots do not exhibit this delay problem.

• Alcator Gate Valve: The gate valve between the beam and CMod is enabled on the PLC vacuum system interface screen. At the top of the screen there is a entry field marked "TMR". (Use the arrow keys to cursor to this location, the 'home' key will move the cursor into the upper screen area). Pushing F4 will change the number to "1" indicating that the gate valve will open on C-Mod shots - If the field indicates a "0", then the gate valve will not open during the CMod shot cycle. An open gate valve is indicated by a vertical white bar through the valve symbol. There must be a permissive from the C-Mod Torvac PLC for the gate valve to open.

Conditioning Shots:

Conditioning shots are fired either into the calorimeter target plate, or into the CMod vacuum chamber.

Internal Trigger Mode:
Trigger a shot by pressing the "Start" button on the Java interface. The calorimeter must be in the beam line. Data from the shot will appear almost immediately on the "HVM ADC" and "Arc ADC" Java screens. Data will not be archived into MDSplus. The gate valve into CMod will not open.

External Trigger Mode:
Once reliable operation of the beam is established, the system should be switched to external triggering mode. Now the beam will receive a hardware based trigger signal from Camac at the time specified in the IDL control screen. The first shot fired after switching into remote trigger mode will be delayed, but all subsequent shots should be correctly timed. For this reason, it is better to fire the first remote shot as a conditioning shot.

As long as the C-Mod shot cycle is in recool and data collection is finished, the conditioning software should be ready to run. Once the capacitor voltage has reached 830 V, start a conditioning shot by pushing the "Pulse DNB" button on the IDL control screen and the "Start" button on the Java screen.

C-Mod Shots:

Plasma shots follow the same procedure as conditioning shots except that the calorimeter must be out of the beam line and the C-Mod gate valve must be enabled. On C-Mod shots, the conditioning software is pre-empted, and the DNB shot cycle will run with C-Mod. The operator should push the "Start" button on the java screen and the beam will fire into C-Mod at the time specified.

Summary:

Conditioning shots:

Into the calorimeter:

1. Disable the C-Mod gate valve on the PLC screen.
2. Move the calorimeter into the beam line using the Java screen.
3. Wait until the capacitor voltage has charged to 830 V, and the conditioning program is ready.
4. Push the "Pulse DNB" button in the IDL control screen and the "Start" button on the Java screen.

Into the CMod chamber:

1. Push the "Pulse DNB" button on the IDL control screen.
2. Push the "Start" button on the Java screen.
   
3. Verify that the main gate valve opens.
4. Verify that the beam voltage drops.
   

Beam into plasma:

1. Enable the C-Mod gate valve on the PLC screen.
2. Move the calorimeter out of the beamline using the Java screen.
3. Wait until the capacitor bank has charged to 830 V.
4. During the C-Mod countdown, push the "Start" button on the Java screen.

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