Proton Polarimetry at the U-70 Facility Sandibek Nurushev Institute for High Energy Physics,...

Proton Polarimetry at the U-70 Facility

Sandibek Nurushev

Institute for High Energy Physics, Protvino, Russia

International Seminar on High Energy Spin Physics Sept. 27- Oct. 1 2005, Dubna

Sandibek Nurushev, 1 Oct. Dubna, SPIN 20052

Proton Polarimetry at Protvino U-70 Facility

Items: • Definitions of some terminologies:• The desirable precisions in the beam polarization • Classification of Polarimeters • The general scheme of the U70 facility• Polarimeters: - At very low energies (10-100 KeV, PIBS) - At low energies (0.1-30 MeV, RFQ Linac Ural-30) - At intermediate energies ( 30 MeV-1.5 GeV, Booster) - At higher energies (1.5-70 GeV, U70) - At the extracted beam line (70 GeV) - At the experiment (70 GeV, local polarimeter)• Conclusions



Polarimetry presents a part of the polarization technology completely devoted to the research and development of the tools for measuring the polarization (vector, tensor, etc.) of targets and beams.

Left-right or raw asymmetry

Analyzing power is a raw asymmetry normalized to the polarization

Factor of Merit M=I·P2

Polarimeter is a tool, designed on the base of the process with the known analyzing power, for the measurement of the beam (target) polarization.

RL

RL

NN

NN

PAN /



Polarizer is a process producing the polarized particles. Example: 3He(d,p)4He

Analyzer is a process identifying the polarization of the incident particles.

• The desirable precisions in the beam polarization measurements:1. Single spin asymmetry

D(P)=[(ANd)2·L·]-1,

Where d stands for the dilution factor, L presents the integrated luminosity, is the useful cross section.

2. Double-spin asymmetry:D(P)=[(ALLd)2·L·]-1/2.

Precision in PB is defined by the following factors: a) PIBS, b) statistics and c)

systematics.

Classification of polarimeters: a)absolute, b) relative, c) of the general use or local, d) constructive or distrucrive, e) fast or slow and f) contimuos or periodic.

)3(

222

N

N

B

B

A

A

P

P


U70

U1.5

U-70

U-1.5

I.B.S.P.I.B.S.

URAL30

Fig.1 presents the following accelerator elements :

1. Ion Source

2. Polarized Ion Beam Source (PIBS)

3. RFQ Linac Ural-30

4. Booster U-1.5

5. Beam transport from U1.5 to U-70

6. U-70 accelerator

7. Beam extraction and transport line

8. General and Local polarimeters


2 1

3

4

6

78



P I BS



Parameters

p H-↑ p D↑

Current, mA 6 3.8 50

P, % 80-90 85-90

N, mmmrad 1.7 1.7

T, s 100 100

, Hz {rep. rate) 1-10 1-10D, atoms/cm2s 21017 21017

PIBS parameters:


Linac Ural - 30

%,p

p

Number of resonators

Length, m

Injection-Extraction energy, MeV

Radiofrequency, MHz

Current pulse amplitude, designed, mA

At start

Operating

Current pulse duration, µs

Transverse emittance (@95%), ·mm·mrad

Momentum spread (at 40 mA),

-----------------------------------------------

RFQ focusing is applied to the front and end sections of Linac

5

25.26

0.1-30

148.5

100

70-80

30-50-70

1-10

40

0.3



Polarimeter for Linac: p↑+ = p + (W.G. Weitkamp and W. Haeberli, Nucl. Phys. 83 (1966) 46-54).


Booster-1.5

Injection energy, MeV

Number of injection turns

Maximum enregy, designed, MeV

For injection in U70, GeV

For application research

Orbit length, m

Magnetic field, T

Radius of curvature, m

Structure periodicity

Orbit expansion coefficient

Critical energy (kinetic), GeV

Superperiod structure, separate functions

Pulse packet regime: pulse repetition rate

(32=3+29)

Packet frequency, Hz

Intensity, p/bunch

30

1 – 4

1.35

1,32

0.2 (1) 1.32

99.16

0.139 – 1.20

5.73

12

0.07235

2.55

oMoFoDoFoM

16.6

0.1

2-9·1011



Accelerating garmonics

Radiofrequency, MHz

Acceler. voltage (9 sections ), KV

Acceleration time, ms

Duration of magnetic cycle,ms

Working point (Qx, Qy), standart

High intensity

Bunch duration @1.32 GeV, ns

Momentum spread @ 1.32 GeV, %

Transverse emittance @ 1.32

Horizontal, ·mm·mrad

Vertical, ·mm·mrad

Beam pipe aperture hor·vert, cm2

1

0.75 – 2.70

0.6-60

30

60

(3.85 – 3.80)

(3.92 – 3.75)

80 – 100

0.3

20-25

10-15

14·6.1


Booster-1.5 (cont)


Polarimeter for Booster U-1.5


Injection energy, GeV

Max. energy, designed, GeV

Operating energy, GeV

Circumference, m

Magnetic field, T

Radius of curvature, m

Structure periodicity

Orbit expansion coefficient

Critical energy (kinetic), GeV

Superperiod structure, combined functions

Cycle repetition rate, s

Intensity, p/cycle

Accelerating harmonics

Number of bunches

Vacuum, Tor

1.32

76

50 – 60 – 70

1483.699

0.0355 – 1.2022

194.125

12

0.011120

7.96

FoDoFoD’oFoD’oF’oDoFoDo

9.8-10

1.7·1013

30

1-29

4·10-7-10-6

Synchrotron U70



Radiofrequency, MHz

Accel. Volt. (40 stations), MeV

Ramping time, s

Working point (Qx, Qy):

Standard (I<1·1013p/cycle)

High intensity

bunch duration @ 70 GeV, ns

Momentum spread @ 70 GeV, %

Transverse emittance @ 70 GeV:

Horizontal, ·mm·mrad

Vertical, ·mm·mrad

beam pipe aperture, hxv, cm2

5.518-6062

0.2-0.3

2.8

(9.88, 9.82)

(9.92, 9.85)

35-40

0.08-0.1

1.4

1.1

20x10


Synchrotron U70 (cont)

Operating conditions:

Acc. Cycle(sec)=flat (2.2)+ramp(2.8)+flat(2)+down(2.8)-standard. Extr. Plato 2-3-4 s for 70-60-50 GeV correspondingly. Operaion is foreseen for crossing the critical energy.



Operating conditions:• Acc. Cycle(sec)=flat

(2.2)+ramp(2.8)+flat(2)+down(2.8)-standard. Extr. Plato 2-3-4 s for 70-60-50 GeV correspondingly. Operation is foreseen for crossing the critical energy.


AGS CNI Polarimeter

Measuring the recoil carbons from

Carbon identification by kinematics cut (banana cut)

60cm

Ultra thin Carbon ribbon Target

(5 cm long, 3.5g/cm2 ,600m)

beamview

Si strip detectors(TOF, EC)

CpCp

RL

RLLR

N

LRB NN

NN

AP

,

0.015AN originates from

anomalous magnetic moment of p


Relative polarimeters at U70 GeV

Two external polarimeters:

A. Using the internal targets: a) p↑+A→+ + X, b) p↑+A→- + X

B. Extraction of the small portion of the internal polarized proton beam by bent crystal and measure the asymmetry in inclusive pion productions. Goal: selection of the local polarimeter for the experimental set-up.

References: 1. Yu.B. Bushnin et al., Phys. Lett., 29 B (1969) 48. 2. Yu.P. Gorin et al., Sov. J. Nucl. Phys. 14 (1971) 004. 3. N.I. Bojko et al., IHEP Preprint 70-79, Serpukhov, 1970.

Assuming AN(-)= AN(+)=0.1, I(pp/s)=1011 one could measure beam polarization with a precision of 5% during 3hrs (-) and 0.5hrs (+) .


Summary

• U701. Two Absolute CNI polarimeters (elastic pp and pC on the

internal targets)2. One Relative pion inclusive polarimeter (internal targets)3. Extraction of the portion of the circulated polarized beam

by the bent crystall and polarimetry on this beam• U1.51. Relative polarimeters on elastic pp or pC - scatterings• Linac Ural-301. Relative polarimeter based on the elastic p scattering• PIBS1. Polarimeter based on the Lamb-shift effect.

Proton Polarimetry at the U-70 Facility Sandibek Nurushev Institute for High Energy Physics,...

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