Initial setup for RHIC snakes

Each of the snakes has two power supplies:

the "outer" supply for the 1st and 4th helices, and
the "inner" supply for the 2nd and 3rd helices.

For polarized protons we need to have the snakes on at injection. The snakes run dc, that is, the currents remain constant from injection up to top energy.

Correct settings for snakes bi9-snk7, yi3-snk7, and bo9-snk7

The correct current for the inner (2.3) supplies is

         I_inner = 326.3 A,

and for the outer (1.4) supplies is

         I_outer = 100.0 A.

Correct settings for snake yo9-snk7 with only one supply

The correct current for the outer (1.4) supply is

         I_outer = 300 A.  (Web page value corrected: 27 May, 2003)

On of the inner helices is broken, so the inner supply should not be powered.

Turning on the snakes.

Follow the procedure using the TAPE program as given by Don Bruno

Rough outline of steps for the 1st time before establishing capture

Establish circulating beam at injection in RHIC.
We need a good orbit in the vicinity of the snakes. The orbit should be adjusted by averaging 100 turns or so at injection.
Each snake should be ramped up in steps and the vertical corrector nearest the snake should be adjusted to remove any distortions caused by the snake.
- Note the last 50A for the inner supply cause the most distortion.
Waldo recommends going up to 100 A for both power supplies in the first step, then ramping the inner power supply and correcting with steps to 200, 275, 300, 326.3.
- Note: We must NOT exceed the ramp rates given in Don Bruno's procedure

Turning the snakes back on after we have a good solution

The snakes should be on before trying to inject the beam. Bring them on according to Don's procedure. Pay attention to Don's ramp rates. (We will soon be able to turn them on via Johannes' snake application from last year once he verifies the ramp rates.)

There is a pet page which may be used for controlling all the RHIC snakes and rotators:

        /FECs/Magnets/Summary/Snakes

GPM plots for snakes

for monitoring snake bpms: RHIC/BPM/snake_all.mon
for monitoring rotator bpms: RHIC/BPM/rot_all.mon
for monitoring snake power supplies: RHIC/PowerSupplies/snake-ps.mon
for monitoring rotator power supplies: RHIC/PowerSupplies/rot-ps.mon

Mangled by Waldo MacKay (waldo@bnl.gov)