Hall C Opportunities at 12 GeVDave Mack (TJNAF)
for Steve Wood, Hall C Group Leader
Workshop on Hadronic Physics in China and Opportunities with 12 GeV Jlab
August 1, 2009Lanzhou, China
Interactions of Electrons The well understood interactions of point-like electrons, and the high intensity and quality of modern electron beams, make them ideal for studying the charge and magnetization distributions in nuclear matter.
2Hall C at 12 GeV
Because of the different isospin coupling of the γ and Z0, parity violating electron scattering provides an additional window on flavor.
In precision measurements of Standard Model-suppressed observables, the large mass of the Z0 even brings potential new physics at TeV-scales within reach.
Where is Jlab?Jefferson Laboratory is a multi-GeV electron accelerator located in Newport News, Virginia, USA.
3Hall C at 12 GeV
Exploiting the intensity and precision frontiers, with state of the art spectrometers and targets, has made JLab an incredibly productive facility.
Hall C’s 4-6 GeV Base Equipment
4Hall C at 12 GeV
Short Orbit SpectrometerPmax = 1.7 GeV/c
High Momentum SpectrometerPmax = 7.5 GeV/c
world’s highest energy, movable focusing magnetic spectrometer
Since 1995, Hall C has carried out a program of inclusive (e,e’) and coincidence (e,e’h) measurements with the SOS and HMS as base equipment. While the resistive SOS became increasingly obsolete due to increasing beam energy, a rich HMS program with new, user-supplied detectors and targets continued.
e- beam
BYOD Program (Bring Your Own Detector)
5Hall C at 12 GeV
Our hypernuclear and parity programs require such specialized apparatus that that often do not use the base equipment.
G0 spectrometerfor s-quark form factors
• Pion and nucleon elastic form factors at high momentum transfer• Deep inelastic scattering at high Bjorken x • Semi-inclusive scattering at high hadron momenta• Polarized and unpolarized scattering on nuclei
Motivations for Hall C Upgrade
The HMS will remain important in the 12 GeV program, especially for electron detection. What is needed is a new spectrometer better suited for detecting charged hadrons at very high energies:
• Higher momentum capability (11 GeV/c)• Smaller angle capability (5.5 degrees)• Very good particle identification (e, π, k, p)• Accurate and reproducible angle and momentum settings
The SHMS (Super High Momentum Spectrometer) meets these requirements.
6Hall C at 12 GeV
Hall C with SHMS (11 GeV/c)
HMS: QQQD
SHMS: dQQQD
7Hall C at 12 GeV
SOS(removed)
SHMS Small Angle Challenge
HMS10.50
Q1’HB
Q2
targetchamber
SHMS5.50
Horizontal bender
Bender Fit to HMS Q1
SHMS Bender
HMS Q1
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Shield House Fit to Beamline
Shield House
Beamline
Shield House notch
Dipole
Q3
Q2
Q1
Bender
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Giant Scissors? Mating Dinosaurs?Top View Bottom View
SHMS
SHMS
… or just an incredible 3-dimensional jigsaw puzzle for our engineers and designers.
11Hall C at 12 GeV
SHMS All Dressed Up• Key Features:
– 3 quadrupole magnets, 1 dipole magnet
• Provides easily calibrated optics and wide acceptance
• Uses magnets very similar to existing ones
– 1 horizontal bend magnet • Allows forward
acceptance• New design,
developed in collaboration w/MSU
– 6 element detector package • Drift Chambers / Hodoscopes /
Cerenkovs / Calorimeter• All derived from existing HMS/SOS
detector designs
– Rigid Support Structure / Well-Shielded Detector Enclosure
• Reproduces Pointing Accuracy & Reproducibility demonstrated in HMS
12Hall C at 12 GeV
13
Particle ID: Limitations of TOF• TOF over the short ~2.2m
baseline inside the SHMS hut will be of little use for most of the momentum range anticipated for the SHMS.
• Even over a 22.5m distance from the target to the SHMS detector stack, TOF is of limited use.
Effect of finite timing resolution Effect of finite timing resolution (±1.5(±1.5σσ with with σσ=200ps).=200ps).Separation <3Separation <3σσ to the right of to the right of where lines intersect.where lines intersect.
SHMS Particle Identification: +hadrons
Heavy Gas Cerenkov
Rejection Power
Momentum (GeV/c)
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TOF
Aerogels
known experiments
SHMS Detectors
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Noble gas Cerenkov(University of Virginia)
Drift chambers(Hampton University)
Trigger hodoscopes(James Madison University and North Carolina A&T)
Heavy gas Cerenkov(University of Regina)
Lead Glass CalorimeterYerevan/JLab
12-06-101 C Measurement of the Charged Pion Form Factor to High Q2 G. Huber, D. Gaskell
Continuation of successful Fπ
program to dramatically higher Q2
Requires:•small forward angle capability•Kinematic control for L/T separation• resolution to distinguish p(e,e’π+)n events from p(e,e’π +)n+π
Approved 12-GeV Experiment
16Hall C at 12 GeV
Example of an electron-hadron coincidence experiment
12-06-105 CInclusive Scattering from Nuclei at x > 1 in the quasi-elastic and deep-inelastic regimes
D. Day, J. Arrington
Focused on mapping out the distributions of superfast quarks and high momentum nucleons …connected to the short distance structure of nuclei.
Requires:•high momentum•good PID
The black symbols indicated the range with a 6 GeV from E02-019, the red reflect that obtained in the CLAS ratio measurements. The blue symbols and line define the region accessible at 11 GeV. The solid (dashed) blue curve indicates the region where the pro jected statistical uncertainties are 10% (5%) for an x bin of 0.05.
HMS
SHMS
Approved 12-GeV Experiment
17Hall C at 12 GeV
Example of an inclusive electron experiment
Hall C Upgrade CostsConstruction
10.0%
Remainder of 12GeV
Upgrade TEC90.0%
WBS 1.4.3 Hall C Construction FY09 $K Direct1.4.3.1 Magnets 12,249 1.4.3.2 Detectors 649 1.4.3.3 Computing 32 1.4.3.4 Electronics - 1.4.3.5 Beamline 751 1.4.3.6 Infrastructure 5,989
Total 19,670
As part of the entire 12GeV upgrade…
By Subsystem…
Does not include NSF contribution to detectors
Proposing Experiments at 12 GeV Hall CJlab is an open laboratory. By this I mean that, if you have a great idea for one of our end-stations, you can propose it to our Program Advisory Committee (PAC) of mostly outside experts. Your proposal will be judged on the merit of the physics as well as the technical feasibility. An internal co-spokesperson may be helpful but is not required.
A tremendous amount of information can be gain from our website at http://www.jlab.org/
and looking under topics such as “Nuclear Physics”, “Experiment Research”, and “12 GeV Upgrade”.
Proposals now mostly fall into two categories: standard 12 GeV equipment, or major new detectors. Proponents are expected to help build or commission new apparatus.
Of course, funding, manpower (both collaboration and Jlab), and multi-endstation scheduling issues will eventually be looked at carefully.
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Some Contact PersonsThe easiest way to get involved is to join an existing collaboration on an experiment you find interesting. With a nominal “beam on” date of October 1, 2014, most Hall C 12 GeV collaborations are still forming and are eager for new people.
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12 GeV Experiment Some Contact Persons E mail addresses Charged Pion Form Factor and
Scaling in Meson ElectroproductionGarth Huberg (U. Regina),
Dave Gaskell (Jlab), Tanja Horn (Catholic U.)
[email protected], [email protected],
Color Transparency and Hadronization in Nuclei
Dipangkar Dutta (Mississippi), Rolf Ent (Jlab),
Blaine Norum (U. of Virginia)
[email protected]@jlab.org,
Neutron Spin Structure JianPing Chen,Zein Eddine Meziani ,
Brad Sawatzsky
[email protected],[email protected],
J/Psi Production in Nuclei Jim Dunne (Mississippi) Eugene Chudakov (Jlab)
[email protected],[email protected]
Hall C Group Leader Steve Wood [email protected]
Summary
I’ve tried to introduce some of the standard apparatus for Hall C at 12 GeV. More detailed information on the SHMS can be obtained at
http://www.jlab.org/Hall-C/upgrade/index.html
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AcknowledgementsHall C colleagues Howard Fenker and Paul Brindza whose slides formed the basis of my talk.
The organizers of this workshop for their invitation and the countless headaches they must have undergone.
The workshop support staff for making it all work.
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Extras
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Exp. # Hall Title Spokespersons Status
12-06-101 CMeasurement of the Charged Pion Form Factor to High Q^2 G. Huber, D. Gaskell A
12-06-104 CMeasurement of the Ratio R = sigma_L/sigma_T in Semi-Inclusive DIS R. Ent, P. Bosted, H. Mkrtchyan A
12-06-105 C
Inclusive Scattering from Nuclei at x > 1 in the quasi-elastic and deep-inelastic regimes D. Day, J. Arrington A
12-06-121 C
A Path to “Color Polarizabilities” in the Neutron: A Precision Measurement of the Neutron g_2 and d_2 at High Q^2 in Hall C
B. Sawatzky, T. Averett, W. Korsch, Z.E. Meziani A
12-07-105 CScaling Study of the L-T Separated Pion Electroproduction Cross-Section at 11 GeV T. Horn, G. Huber A
12-06-107 CThe Search for Color Transparency at 12 GeV D. Dutta, R. Ent CA
12-06-110 C
Measurement of the Neutron Spin Asymmetry A1n in the Valence Quark Region Using an 11 GeV Beam in Hall C
X. Zheng, J.P. Chen, G. Cates, Z.E. Meziani CA
12-07-101 CHadronization in Nuclei by Deep Inelastic Electron Scattering B.E. Norum, J.P. Chen, H. Lu, K. Wang CA
12-07-102 C
Precision Measurement of the Parity-Violating Asymmetry in DIS off Deuterium Using baseline 12-GeV Equipment in Hall C P. Reimer, X. Zheng, K. Paschke CA
12-07-106 CThe A-Dependence of J/Psi Photoproduction near Threshold E. Chudakov, P. Bosted, J. Dunne CA
Hall-C 12-GeV Experiments
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SHMS PID Requirements : negative polarity
Experiment p (GeV/c)
Req’d e-:π- Disc.
Spec’d NG Cerenkov
Spec’d Calorimeter
Total Expected
E12-06-101 (Fpi-3) 2.2 - 8.1 4.5•103:1
50:1
(HMS Cerenkov gives up to 300:1
now)
>200:1
(1000:1 above 6 GeV/c)
>104:1
E12-06-104 (σL/σT) 5.4 - 5.8 103:1
E12-07-103 (pion factorization) (d)
2.4 - 8.5 103:1
E12-06-105 (x>1) 4.8 -10.6 5•103:1
E12-06-110 (c) 2.2 - 6.8 103:1
E12-06-121 (g2n, d2
n) 6.3 - 7.5 >102:1
• PID requirements at negative polarity are dominated by the x>1 experiment
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SHMS Experiment Resolution Requirements
Experiment p (GeV/c)
Δp/p (%) Δθ (rad) Δφ (rad)
Pion Form Factor(12-06-101)
2.2-8.1 2x10-3 1.5x10-3 1.5x10-3
Transition Form Factors* 1.0-8.5 1x10-3 1.0x10-3 1.0x10-3
* Not yet submitted to PAC
Δp/p (%) Δθ (radians)Δφ (radians)
Spec’d ResolutionSpec’d Resolution & MCS
2x Spec’d Resolution & MCS
-10% +22%
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SHMS Elements
Dipole18.4 Degree BendMax Field: 4.76 T
EFL: 2.85 m
Q2 Q3Max Gradient:
14.4 T/mEFL: 1.61 m
Q1Max Gradient:
10.63 T/mEFL: 1.86m
Bender3 Degree Bend
Max Field: 3.11 TEFL: 0.75 m
27Hall C at 12 GeV
The SHMS Detector SystemNoble Gas Cerenkov: e/π (or π /K) separation at high momenta
2.5 m long gas radiator at atmospheric pressure•Argon: π threshold ~ 6 GeV/c•Adding Neon: threshold may be varied up to 12 GeV/c•Para-Terphynyl PMT window over-coating •Performance 20 photoelectrons
(worst case: pure Neon)
At low momenta: remove mirrors, insert coupling so that the tankbecomes part of the vacuum system – reduces MCS
University of Virginia
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The SHMS Detector SystemNoble Gas Cerenkov
4 spherical mirrors, 45cm x 45 cm
Ray-trace simulation of optics.
Reference Design (HMS Cerenkov)
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The SHMS Detector SystemTrigger Hodoscopes
S1-XFront View
905 mm
900 mm
Mechanical Design is a re-scaling of existing HMS/SOS design
0.5cm paddle overlap – all paddles
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The SHMS Detector SystemTrigger Hodoscopes - design drawings from JMU group.
31Hall C at 12 GeV
The SHMS Detector SystemOptimizing Heavy Gas Cerenkov
-- University of Regina Group
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The SHMS Detector System
Yerevan Group’s working drawings for the Calorimetry
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The SHMS Detector SystemCalorimeter: e/π separation
Side Elevation Front Elevation
Plan view
Yerevan Physics InstitutePreshower: Re-use SOSShower: Gift from HERMES (NIKHEF, Vr.Univ. Amsterdam, Frascati, Yerevan, DESY)
•Lead-Glass Block / PMT / Base Assemblies from HERMES•Low-Exposure modules from HERMES selected•Now On-Hand at JLab•Tests-to-Date indicate the modules are perfectly suitable for SHMS
•Glass Transparency•PMT Gain•Stability
34Hall C at 12 GeV
The SHMS Detector SystemTrigger Hodoscopes: basic trigger; efficiency determination.•3 Planes Scintillator Paddles + 1 Plane Quartz Bars
S1X: 12 bars 8cm x 110 cm x 5mmS1Y: 14 bars 8cm x 90cm x 5mmS2X: 14 bars 8cm x 105cm x 5mm
S2Y: 10 quartz bars: 11cm 115cm x 2.5 cm
0.5 cm overlap / 2 PMTs on each bar
35Hall C at 12 GeV
The SHMS Detector SystemHeavy Gas Cerenkov: π/K separation for momenta > 3.4 GeV
Gas choice now C4F8O (instead of C4F10)•Widely used in semiconductor industry•Many commercial suppliers•Much less expensive than C4F10
•Extensively studied by BTeV•Stable, non-toxic, non-explosive, non-reactive•Does not destroy ozone
51.05
91.33
117 °
113 °
95 cm
155 cm110 cm
0.020" Ti Window
5" FlatPMT
Side Elevation Line Drawing
University of Regina
SLD ECRID Gas System
36Hall C at 12 GeV
12-07-105 CScaling Study of the L-T Separated Pion Electroproduction Cross-Section at 11 GeV
T. Horn, G. Huber
A
•Contributions: •Heavy Gas Cerenkov effort•SHMS Optics Design & Calculations•HB Magnet Heating R&D
GOALS:•Measurement of the Q2 dependence of the L and T cross sections for exclusive ep -> e’π+ n above the resonance region at fixed values of x and –t.
•Does σL tend towards predicted Q-6 scaling?
ep e’ π+ n
SHMSHMS
Needs:•π+/K+ separation over 2.4-8.5 GeV/c•L/T separations require rigid attachment to pivot and frequent angle/momentum changes, as well as well-understood spectrometer acceptance.
Approved Hall-C 12-GeV Experiments
37Hall C at 12 GeV
SHMS Design Parameters
SHMS
Target
Bender Q1 Q2 Q3 Dipole Detectors
Electronics RoomCryo
Transfer Line
Power Supplies
Shield House
39Hall C at 12 GeV