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).