g2p HRS Optics

with Septum Min Huang

Duke University, TUNL

On Behalf of the E08-027 g2p collaboration

Hall A Analysis Workshop, 12/12/12

Hall A Analysis Workshop, Dec 2012 Min Huang

E08-027 g2

p & the LT Spin PolarizabilitySpokespeople

Alexandre Camsonne (JLab)

Jian-Ping Chen (JLab)Don Crabb (UVA)Karl Slifer (UNH)

Post DocsKalyan AlladaJames MaxwellVince SulkoskyJixie Zhang

Graduate StudentsToby BadmanMelissa CummingsChao GuMin Huang Jie LiuPengjia ZhuRyan Zielinski

Hall A Analysis Workshop, Dec 2012 Min Huang

OutlineGeneral HRS Optics

Intro of g2p Optics Goals and designTarget and SeptaData taken

Status of Optics data calibration

HRS Optics with SeptumTarget plane info Focal plane info (VDC tracking)Multi-dimensional polynomialsFirst order approximation

Target Septum

VDC

Sieve slitHall A Analysis Workshop, Dec 2012 Min

Huang

Q1

Q2

Dipole

Q3

0 0

0 0

0 0

0 0

0

| ( | ) ( | )

( | ) ( | ) ( | )

( | ) ( | )

( | ) ( | )fp

xx x x x x

xy

y y y y

y

Top View

Target planeFocal

plane

Hall A Analysis Workshop, Dec 2012 Min Huang

g2p OpticsWhat is a good first order matrix for g2p?

(x|θ0) very small point to point HRS focusing

g2p goal: syst. uncertainty of cross section 5%Optics goal

Syst. uncertainty of θ: 0.5% Contribution to cross section uncertainty: 2%Requires good uncertainty of angle (horizontal)

reconstructionMomentum uncertainty not sensitive, but not hard to

achieve 10-4 level

Hall A Analysis Workshop, Dec 2012 Min Huang

g2p OpticsFirst order matrix

Matrix elements can be adjusted by tuning quarupole fields

Optics designTuned Quadrupole fields in SNAKE to satisfy the goalsNew I vs P0 setting of HRS Quads for g2p experimentOnline database from SNAKE model

0

0 0

0

0 0

0 0

| ( | )

( | ) ( | ) ( | )

( | ) ( | )

( | ) ( |

( |

)

)

fptg

xx x x x

xy

y y y y

y

x

Target planeFocal

plane

Thanks to John Lerose for his help!

Hall A Analysis Workshop, Dec 2012 Min Huang

g2p Optics --Target Configuration

Target Insert

Target Nose (Al)

Carbon Foil

4.2 cm

Beam

….

LHe Shield (Al)

….

NH3CH2Carbon

NH3

Dummy

Carbon

2.9 cm

Designed symmetric left and right septum

Each septum has top and bottom 3 pairs of coils

48-48-16 1st good septum

g2p Optics --Septa

Courtesy Jixie Zhang

Beam goes into the pipe

Turns:48

48

16

Hall A Analysis Workshop, Dec 2012 Min Huang

Right septum caught on fire twice

Right septum field changed a lot, while left one field also got impacted

Optics data on each situations

g2p Optics --Septa

Only right top coils changed

1) Good 2) Bad 3) Very Bad

48-48-16 40-32-16 40-00-16 Talk by Melissa Cummings in Hall A Collaboration Meeting

Hall A Analysis Workshop, Dec 2012 Min Huang

g2p Optics DataDelta scan with sieve in, C foil: databasePointing, C foil in LHe or CH2 foil: central scattering

angleFast & slow rasters, C foil: acceptanceBeam position scan, C foil: small angle ~6°, short

production target ~3cm

6°

12.5°

Top View

Standard g2p

Beam Horizontal Scan

Target

Sieve slit

Hall A Analysis Workshop, Dec 2012 Min Huang

11 total sets of data at 6°Beam energy: 2.254GeV, 1.706 GeV, 1.158 GeV Target field: 0, 2.5T, 5T3 different septa situations

2 sets of 0 target field data: base for target field on situationsBeam energy 2.254 GeVRight septum: 48-48-16 (1), 40-00-16 (3)

g2p Optics Data

Hall A Analysis Workshop, Dec 2012 Min Huang

LHRS Before Calibration (1st septum)-3%

-2%

0%

2% 3%

With database from SNAKE model

Hall A Analysis Workshop, Dec 2012 Min Huang

Calibration Steps1. Tg_y vs. Tg_ph vetex cut for the whole run

Hall A Analysis Workshop, Dec 2012 Min Huang

Calibration Steps2. Cut on each hole3. Cut carbon elastic for each hole

C12 elastic

Contamination, like Al elastic

C12 1st excited

Hall A Analysis Workshop, Dec 2012 Min Huang

LHRS Angle (1st septum)

-3%

-2%

0%

2% 3%

Hall A Analysis Workshop, Dec 2012 Min Huang

LHRS Matrix Dp calibration

Before

AfterFull Acceptance Scan

Hall A Analysis Workshop, Dec 2012 Min Huang

RHRS Angle (1st septum)-3.5%

-1%

0%

2% 3.5%

Hall A Analysis Workshop, Dec 2012 Min Huang

RHRS Momentum (1st septum)Full Acceptance Scan

Hall A Analysis Workshop, Dec 2012 Min Huang

LHRS Angle (3rd septum)Before All delta

scan combined

Courtesy Chao Gu

After

Hall A Analysis Workshop, Dec 2012 Min Huang

LHRS Momentum (3rd septum)

Courtesy Chao Gu

-3% -1%

0%

1% 3%

Full Acceptance Scan

Hall A Analysis Workshop, Dec 2012 Min Huang

Performance SummaryBeam energy 2.254 GeV, no target field, 1st & 3rd septum,

carbon foil

Reference: beam energy 845 MeV, angle 16°, no septum standard HRS, carbon foil (Hall A NIM)

Resolution (RMS) LHRS (1st )

RHRS (1st )

LHRS (3rd )

In-plane Angle [mrad] 0.9 0.9 0.7

Out-of-plane Angle [mrad]

1.5 1.6 1.4

Momentum [(p-p0)/p0] 1.3x10-4 2.0x10-4 1.8x10-4

Resolution (RMS)

In-plane Angle [mrad] 0.8

Out-of-plane Angle [mrad]

2.5

Momentum [(p-p0)/p0] 1.1x10-4

* FWHM=2.3548*RMS

Hall A Analysis Workshop, Dec 2012 Min Huang

What to doTarget y calibration for each settingPointing: improve the accuracy of central angleRHRS 3rd septum 40-00-16 settingWrap up 0 target field results with better accuracy &

resolution

Continue on target field ON situations

Talk by Jixie Zhang on HRSMC simulation

Hall A Analysis Workshop, Dec 2012 Min Huang

Thanks!I would like to thank the following people for their

guidance and helpful discussions!John LeroseJian-ping ChenNilanga LiyanageJixie Zhang, Vince Sulkosky, Chao GuJin Huang, Xin Qian, Yi Qiang, Kiad Saenboonruang, Huan

Yao, Zhihong Ye