--obsolete-- Energy Change for 23Na5+ to DRAGON

By Marco Marchetto, Sep. 7, 2007 (edited by R. Tanaja)

DRAGON may request small energy steps for the 23Na run. Here is the procedure:

- Turn off the HEBT 35MHz buncher.

- Turn off the last DTL Buncher (which is) on (eg. the experiment starts with 681keV/u, so in this case the buncher is DTL Buncher 3).

- Fiddle save the HEBT optics 1 page, then change HEBT:Q6, Q7, and Q8 to the Prague optics. (see the ISAC I Open Office spreadsheet).

- Get the field  of the Prague Magnet for the requested energy from Open Office.

- Set the energy with the last DTL tank on (in the above example, DTL tank 3): Set the amplitude first, then, just in case, check the phase in order to have the maximum acceleration for the set amplitude and a symmetric beam profile (remember that when the beam moves towards the left side of the Prague harp, it is accelerating, meaning higher energy).

- Set the DTL Buncher you previously turned off (Buncher 3, in the previous example): First, the phase for no acceleration (remember that there are two phases that give no acceleration - the correct one is when the beam moves in the direction of the phase slider). Then set the amplitude, in order to minimize the energy spread (the amplitude shouldn't change too much if the energy step is small).

- Restore the HEBT optics page 1 with the fiddle.

- Rescale the optics downstream of the DTL up to DRAGON for the new energy.

- Send the beam to DRAGON and wait: They have to check the energy and centre the beam on DRA:XSLITC, closed down to 1mm.

- Once they finished you have to set the HEBT Buncher 35MHz.

- Turn on the Buncher with the amplitude around 400.

- Bring the amplitude down to 180.

- Set the buncher phase in order to have the beam centred again on DRA:XSLITC/ You should find two phases which  centre the beam. Choose the one that gives maximum current on DRA:FCCH cup.

- Deliver beam to DRAGON.