1. Multiple Partial Siberian Snakes
in the AGS
Junpei Takano

2. RHIC Solenoidal snake for imperfection res. but produce coupling res.
Absolute Polarimeter (H jet)
RHIC pC Polarimeters
Superconducting
Siberian Snakes
BRAHMS & PP2PP (p)
RHIC
Superconducting
Siberian Snakes
PHENIX (p)
STAR (p)
Spin Rotators
Solenoidal snake
for imperfection res.
but produce coupling res.
Achieved P=40% in 2003
LINAC
BOOSTER
Pol. Proton Source
500 mA, 300 ms
AGS
Warm snake
for imperfection res.
Reduced coupling res.
Achieved P=50% in 2004
and P=55% in 2005
Cold snake
for imperfection res. and intrinsic res.
Achieved P=65% in 2006 with Warm snake

3. Injection
Extraction
Snake strength has energy dependence

4. Double snake scheme Merit 1: large spin tune gap
to RHIC
from Booster
AGS
120°
A20:CSNK
E20:WSNK
← Spin tune Eq. for “single” snake
↓ Spin tune Eq. for “double” snake
: CSNK strength
Merit 1: large spin tune gap
Merit 2: small spin mismatch
: WSNK strength

5. Spin tune around first intrinsic resonance with 2 snakes
12k±νy (νy = 8.9)
Large spin tune gap
= 3m
WSNK=8.4%
CSNK=15%
Injection energy

6.
inj
ext
inj
CSNK
WSNK
Spin mismatch

7. Without Warm Snake (Cold Snake only) With 8% Warm Snake (Double snake)
vert
comp
Pol. at
injection
1.000
80.00 5
0.997
79.75 10
0.988
79.02 15
0.972
77.79 20
0.951
76.09 25
0.924
73.91 30
0.891
71.28
Cold
snake%
vert
comp
Pol at
injection
0.992
79.37 5
0.999
79.91 10
79.96 15
0.994
79.52 20
0.982
78.58 25
0.965
77.17 30
0.941
75.27
Snake strength at “injection” energy

8. If the SSNK is relocated from I10 to I20....
Spin tune gap will be larger.
SSNK
I20←I10
to RHIC
from Booster
AGS
A20:CSNK
E20:WSNK (
: CSNK strength
: WSNK strength
: SSNK strength )

9. Spin tune around first intrinsic resonance with 3snakes
Large spin tune gap
CSNK=16%
WSNK=8%
SSNK= 10%

10. Spin mismatch with 3snakes
CSNK=15%, WSNK=8%, SSNK=-7%
inj
ext
inj
CSNK
WSNK
SSNK
No spin mismatch

11. Red: 10%CSNK+6%WSNK
Blue: 6%CSNK+6%WSNK
Result in RUN6

12. Summary
The triple snake scheme was simulated.
・Larger spin tune gap
・No spin mismatch
6%CSNK+6%WSNK was operated.
Achieved same level polarization
to 10%CSNK +6%WSNK
If the 6%+6% machine is optimized,
the polarization might be improved.

13. Extra slides

14. 4. Double partial snakes scheme
CSNK = 24%
Injection energy
Spin mismatch
Vertical component at L20 = 0.930

15. CSNK = 10%, WSNK = 6%, SSNK = 4%
Extraction energy
No spin mismatch

16. Operation of SSNK for triple snake scheme
10%
extraction 4%
ramp up
SSNK strength % 0%
-7.6%
injection
The current at injection is negative for no spin mismatch.
Then the sign should be turned to positive
to open the spin tune gap larger,
but the bipolar PS is needed in this case.