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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
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