Plans for Polarized Beams Plans for Polarized Beams at VEPP-2000 and U-70at VEPP-2000 and U-70
Yu.Shatunov
BINP, Novosibirsk
PS INS IN20062006
OUTLINE2 in 1
● VEPP-2M → VEPP-2000 Collider ● Physical program ● Round beams ● VEPP-2000 status ● Radiative polarization (transverse and longitudinal) ● Summary #1
● U-70 – 40 years in operation ● Spin resonances ● Proposal for polarized proton accel. ● Siberian snakes ● Spin tracking ● Summary #2
Radiative PolarizationRadiative Polarization at VEPP-2000 at VEPP-2000
A.Otboev, I.Koop, Yu.Shatunov
BINP, Novosibirsk
PS INS IN20062006
ILU3 MeVLinac
B-3M200 MeVsynchro-betatron
BEPe,e
booster
–+
900 MeV
e,e–+
VEPP-2M
SND
180–700 MeV
RF cavity
SCwiggler
CMD-2
ee– +convertor
e+
e–
ILU3 MeVLinac
B-3M200 MeVsynchro-betatron
BEPe,e
booster
–+
900 MeV SND
CMD -2
ee– +convertor
2 m2 m
Layout of the VEPP(-2M)-2000 collider complex
♦ E 1 GeV (per beam)♦ L 1×1032 cm-2 sec-1 (1×1 bunch)
VEPP-2M (1974-2000)
VEPP-2000
1. Precise measurement of the quantity R=(e+e-- > hadrons)/ (e+e-->+--)2. Study of hadronic channels: e+e-- > 2h, 3h, 4h …, h= ,K,,… 3. Study of ‘excited’ vector mesons: ’, ’’, ’, ’,..4. CVC tests: comparison of e+e-- > hadr. (T=1) cross section with -decay spectra5.Study of nucleon-antinucleon production – nucleon electromagnetic formfactors, search for NNbar resonances, ..6. Hadron production in ‘radiative return’ (ISR) processes7. Two photon physics8. Test of the QED high order processes 2->4,59. Study of round colliding beam concept 10 Radiative polarization (incliding longitudinal)
VEPP-2000 physical program
Increasing the luminosity
Number of bunches Bunch-by-bunch luminosity
22
2 *1x y x y
e y x
fL
r
Geometric factorBeam-beam limit enhancement !
Round Beams:2 2
2 *
2
e
fL
r
Strong-Strong Beam-Beam Simulation
Concept of Concept of RRoundound Colliding Colliding BBeamseams
yxz xpypM Conservation of the z-component of angular momentum
Motion in central field with additional integral of motion shrinks the transverse oscillations to 1D ! (Solar system: >109 turns)
Round cross-section of beams at IPMachine optics has rotational symmetry
Requirements:
4×4 transfer matrix
AB
BAT
CMD-3
SNDe
Pulse quad
Cartoon lay-out of VEPP-2000
Practical Realization of Round Beams: Options for VEPP-2000
l
zsol dsHdsH0 2
1
First “mile stones” of VEPP-2000 (14.05.2001)
100 0 100 200 300 400 500 600 700 800 90010
5
0
5
10
15
S,mm
B,T
Solenoid 13.0 T
VEPP-2000 (15.09.06)
First injection (RF “off”)
15.09.06
Radiative polarization
max ;
1973 DKS 3
0 ;B b n d
31 5 2 2
0 05 3 2 11
18 9 18p q B n V d
Bb
B
1964 ST8
;5 3ST
235 3
164clP P
E
1970 ACO and VEPP-2
13
3 25 20ST
RB hour
B T E GeVq
nd
spin-orbit coupling vector
VEPP-2000: ST = 0.2 (hour) at E=1 GeV
Radiative polarization
IBS polarimeter 2 210 1 0.12N I
.
Energy calibration ~10-6
sec
2dHzf
14155.3 0.1d kHzf
509.325 0.002 MeVE
d kHzf
VEPP-2M
Radiative polarization at VEPP-2000
0
1
0
00
q
q
Siberian snake1
2
Longitudinal polarizationE = 1 GeV ST = 12 min
Siberian snake: longitudinal polarization
+ + - +
1
2 e e e e
Spin transparency?
0.25 0,3
Transverse radiative polarization
00
q
q
+ - - +
High accuracy absolute energy calibration
~10-5 ν 0=
3 -
νz
ν 0= ν
z -1
+ -e e p p
00
q
q
Transverse radiative polarization
+ - + -
Beam polarization in the booster BEP;
g-2 comparison at 220 MeV with accuracy ≈ 10-13
ν 0= ν
z
ν 0= 4
- ν
z
Summary #1
• Project VEPP-2000 is near to completion
• Commissioning started in the summer 2006
• First beam is in the VEPP-2000 on 15.09.06
• Machine study
• First luminosity – at the end of 2006
• Games with luminosity and polarized beams
Proposal to polarized proton acceleration
at U-70
A.Otboev*, I.Koop*, A.Romanov*, P.Shatunov*, Yu.Shatunov*,
S.Nurushev**, S.Ivanov,** A.Vasiliev**
* BINP, Novosibirsk; ** IHEP, Protvino
PS INS IN20062006
Synchrotron U-70
+
+
-
E = 70 GeV
P = 12
Spin rotator
Spin resonances
Imperfection Resonances::
Zo ≈ 1 mm
Synchrotron U-70
S = -(99% S0 )
δS = 99% S0
0 ;x z sa k p q l
Intrinsic resonances:
0 0; 10z zk P k 0
0 10
k P
k
z = 9.85
= 9.7x 10z норм
мм мрад
0a
ν 0= 6
0 -
ν z
ν 0= 6
0 +
νz
0 k P
Partial Siberian snakes
intrinsic
intrinsic
28 0.3kw
27.5 28.0 28.5
28.5
28.0
27.5
0
Imperfection resonances:
2kw
0 ;k
2 secHz
ВЭПП-2М (1975)
0 1
wk
= (wk/νs) >>1
w28
z
xy
0 cos( )zh h
2 2kw
0kw h= (wk/νz)>>1
0q hp
ck
2k
In laboratory frame after one period spin rotates around 0m z m z
by angle φ = 2π(νs -1)
p1
λ λ λ λp1
-p1p2 -p2
1) No outside orbit distortions due to mirror symmetry2) Moderate orbit deviations inside3) Spin rotation by any angle4) Low focusing
1 2 0 30; 1 ;pk
W W W k
Rotating frame
2 3m Ap e e
with frequency2 21S A p
1( );A a Spin precession around
Ap ≈ 0.5 by h = 5T; λ = 3m
(ap= 1.79284735);
2e
-1
-Ap m
1e 3e
sin ;xB h kz cos ;yB h kz 0zB
x
y2λ
0
0.031
x z( )
y z( )
10 z
x
2λ
y
Helical dipole magnets (1994)
0 0sinp p
y kz y z yk
0 01 cosp
x kz x z zk
Bx(z) and By(z) on the snake axis
Helix 3.4 m
correctorcorrector
( 75 )cm
Partial snake for U-70
BxBzBy
Proton’s trajectory in the snake
x
E=25 ГэВ
Helix 3.4 m
correctorcorrector
( 75 )cm
Spin rotation in the snake
φy ≈ 1.14
0.20
0.15
0.10
0.05
Snake strength: |ws| =φ/2π
40
30
25
10
(%) |wS|
●
●
●
●
●
●
●
●
●
●●
●
У-70
1
2
3
Partial snakes at U-70
1 2 3+ +
1 2 3- +
00
00
; even4
1; odd
4 2
m
m
Lattice functions
γ
; kw
0
ν; |wk|
0
0
0
ν; |wk|
Vertical polarization with snakes
0
Spin tracking(30 particles)
betatron tune 9.70 10z mm mrad
10z mm mrad
{ } 5 / 6z
Snake resonance ?
Spin tracking(30 particles)
betatron tune 9.83
10z mm mrad
Spin tracking(30 particles)
betatron tune 9.86
10z mm mrad
Spin tracking(30 particles)
betatron tune 9.94
Спиновый ротатор● Spin rotation to horizontal plane with arbitrary angle relatively to momentum ● Beam position on targets is fixed
● No additional focusing
sin ;xB h kz cos ;yB h kz 0zB | |
kR
k
0
| |
q hp
c k
+ + -p1
p2 p2p3
H
H
V
+ - -p1
p2 p2p3
+ - +p1
p2 p2p3
3 3 1 1 2 2p R p R p R A
B
С
V
V
V+ + -
p1p1p2 p2
-
+ - -p1
-p2p2 p2
-
+ - +p1
p2-p1 p2
+
A
B
С
Spin rotator
0
| |
q hp
c k helicity
3 3 1 1 2 2 0.15;p R p R p R 3 3 1 1 2 2 0.15;p R p R p R
3 3 1 1 2 2 0.15;p R p R p R
Second Case
-0.6 -0.4 -0.2 0.2 0.4 0.6p1
-0.6
-0.4
-0.2
0.2
0.4
0.6
j , grad
-0.6 -0.4 -0.2 0.2 0.4 0.6p1
25
50
75
100
125
150
175
j , grad
B
p1
p1
p2 (град)
Pi =1 by h = 19.66 Тм
P1=+0.45P2=+0.31;
P2= - 0.54;
3 3 1 1 2 2 0.15;p R p R p R
3 3 1 1 2 2 0.12;p R p R p R P1= - 0.42
Spin rotator (option 1)
+ - +p1
p2 p2p3
First Case
-0.4 -0.2 0.2 0.4p1
-0.6
-0.4
-0.2
0.2
0.4
0.6
j , grad
-0.4 -0.2 0.2 0.4p1
25
50
75
100
125
150
175
j , grad
A
p1
p2 (град)
p1
Pi =1 by h = 19.66 Тм
P1=+0.22P2=+0.35
P2= - 0.36 P1= - 0.20
Spin rotator (option 2)
+ + -p1
p1p2 p2
-
Summary #2
Polarized proton acceleration in U-70 is possible with three partial snakes (36% )
Spin tracking (SPINK) confirms the idea:
(νz ≈ νx ≈ 9.9 )
Save beam emittance ( εz = 10-15 mm mrad)
To develop helical 4 full twists magnets (λ = 0.75 м ; L=3.4 m; B = 4.5 Т)
Spin rotator 4 full twist magnets (λ = 2.5 м ; B = 4 T).