Polarimetry Design Updates

IPBI 6 April 05 Ken Moffeit

Polarimetry Design Updates

- Dispersion in upstream chicane - 20mrad extraction line

0.75 mrad beam stay clearlocation of Synchrotron Radiation Stripe DetectorComments about ShieldingNumber of Cells for Cerenkov DetectorBetter R22 etc

- 2mrad extraction line R22 issuesEnergy and Polarimeter Chicanes

- aligning the Compton IPComments about surveying and tolerance for direction at Compton IPs.

IPBI Meeting6 April 05

Ken Moffeit


Upstream Polarimeter with Dispersion = 5 mm

BPC1s = 711.595 m

BPC2730.695 m K Moffeit 31 Apr 05

UpstreamPolarimeter Chicane

10 cm

10 meters

CerenkovDetector

Compton IP250 GeVx = 5 mm

3 cm

Plan View

Angle = 0.24272 mrad

BPC3738.095 m

BPC4760.195 m

250 GeVAngle = 0.24272 mrad



4.5 cm


Dispersion 5mm > 20mm2 is 16 times larger

R(20mm) = R(5mm)/4R3 (20mm)= R3 (5mm)/32Emittance(20mm) = 45 Emit (5mm)

Slide from Ray Arnold

Upstream Polarimeter Emittance Growth versus Dispersion


Emittance Growth versus Dispersion

Hor

izon

tal E

mitt

ance

Gro

wth

Chicane Dispersion (mm)

Mark Woodley

0

10%

20%

30%

0 10 20

For eta=20mm & 500 GeV beam: Short bend has pole-tip field of 5.4 kG;

Long bend is half of that.

Magnets ok for higher dispersion.


Upstream Polarimeter with dispersion = 10 mm

BPC1s = 711.595 m



10 cm

10 meters

CerenkovDetector

Compton IP250 GeV

x = 10 mm

6.14 cm

Plan View


BPC3738.095 m

BPC4738.095 m




7.9 cm

3.5 cm


Space for Laser Beam Insertion/exit

Only 1.4 meters between the inner dipoles is unacceptable. Peter Schuler needs a nominal 8 meters of space (or 14 meter between magnet centers) for the laser beam insertion/exit.This is to accomodate a crossing angle of 10 mrad, and keep the optics away from any synchrotron radiation. These conditions accomodate a vertical beam crossing, but retain a minimal magnet gap height of only 20 mm for all dipoles.


10 mm dispersion and 8m for laser input

BPC1s = 711.595 m



10 cm

10 meters

CerenkovDetector

Compton IP250 GeV

x = 10 mm

6.14 cm

Plan View


BPC3~745 m

BPC4~767 m




7.9 cm

3.5 cm

8meters


20 mrad Extraction Line

Eight Cerenkov Cells 1 cm wide Six cover the region between 36 GeV (12 cm from beam line) 25.1 GeV (17.8 cm)And 2 outside the kinematic limit

Location of Synchrotron Detector

Cerenkov Detector Shielding issues:Cells closest to beam pipe will see Synchrotron Radiation (below 10 MeV?)

250 GeV

25 GeV

45.59 GeV

K Moffeit 4 Apr 05

2 mradenergystripe

2 mradenergystripeBVX1

z=59.69 m

3 mradenergystripe

3 mradenergystripe

Shielding

Energy Chicane

Polarimeter Chicane

10 cm

10 meters

SynchrotronStripe Detector

SynchrotronStripe Detector

CerenkovDetector

Wiggler

Low Field

25.1 GeV

BVX2z=61.99 m

BLEXz=64.29 m

BLEXz=66.89 m

WEX1z=65.59 m

0.75mrad

BVX3z=68.19 m

BVX4z=70.49 m

BVX5z=72.79 m

BVX6z=75.09 m

BLEXz=77.39 m

BLEXz=79.99 m

WEX1z=78.69 m

BVX7z=81.29 m

BPM BPM

BVX8z=83.59 m

BVX9z=100.59 m

BVY1z=120.59 m

BVY2z=132.59 m

BVY3z=152.59 m

Compton IP

17.8cm

QFX4z=156.59 m

0.75mrad

35.7 GeV 12.0cm

Synchrotron StripeDetector z=143.69 m


LCWS Mar 05 Yuri Nosochkov

Original Optics Improved R22 Optics

bad

Good


Yuri Nosochkov (5 April 05)

Most Recent Optics LCWS Improved R22 Optics

GoodNot Good > Lose 1cm at Cerenkov Det1st Cell starts at 13 cm instead of 12 cm2 mrad synchrotrotron swipe barely gets out of 0.75 mrad beam stay clear


2mrad extraction line R22 issues Energy and Polarimeter Chicanes

K Moffeit 12 Mar 05

Polarimeter ChicanePlan View

10 m

10 cm

BHEX3Az=180.06 mx=106.20 cm

BHEX3Bz=182.36 mx=107.57 cm

BHEX3Cz=184.66 mx=108.56 cm

BHEX4Bz=198.96 mx=111.81 cm

BHEX4Az=196.67 mx=111.12 cm

BHEX4Cz=201.26 mx=112.88 cm

BHEX4Dz=203.56 mx=114.35 cm

BHEX4Ez=205.86 mx=116.22 cm

Compton IPAngle 8.850 mrad

Angle 7.138 mrad

Angle 5.425 mrad

Angle 3.712 mradAngle 2.0 mrad

Angle 3.621 mrad

Angle 5.242 mrad

Angle 6.863 mrad

Angle 2.0 mradat IR

Focusz=191.66 mx=110.12 cm

25 GeV

CerenkovDetector

Optics ImprovementR22 ~ 1.3 nowNeed R22 ~ 0.5

Expand 2 mrad section to include Energy chicane Polarimeter chicane


Aligning the Compton IP

Precision surveying should be good to <50 micro radians

Can precision gyroscopes be used to achieve better accuracy?Perhaps <25 micro radians

Polarimetry Design Updates

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