Jlab Hall C transition from 4 GeV to 11 GeV

H. Mkrtchyan

Yerevan Physics Institute,

ANSL (YerPhI)

2

Outline CEBAF accelerator from 4 GeV energy to 6 GeV, and 12 GeV upgrade Hall C at 4-6 GeV CEBAF YerPhI group contribution in Hall C at 6 GeV era Hall C transition from 6 GeV to 12 GeV 12 GeV energy experiments in Hall C and proposed schedule YerPhI group contribution in Hall C 12 GeV upgrade Hall C current status and YerPhI group activities

3

Important historical dates for CEBAF:

In early 1979 a group of physicists assembled at the University of Virginia for a

conference “Future Possibilities for Electron Accelerators”, to discuss new

approaches to design electron accelerator with ~100% duty factor

This dream had its origins in the 1950s, when Hofstadter and McCarthy

discovered at Stanford’s High Energy Physics Laboratory (used high frequency

electron accelerator Mark III) about the internal structure of nuclei and nucleons.

Its comes clear that future investigations in these areas required higher energies

and better duty factor. This line led to the construction in 1960s of SLAC and

1970s Bates-MIT 400 MeV linac.

In December 1979 NSAC approved proposal for construction of 2 GeV energy

machine by 1985. The beam on target required to be continuous, not pulsed.

The National Bureau of Standards, the University of Illinois, Argonne National

Lab, and MIT-Bates – were established as centers to develop the machine project.

History of how CEBAF was founded

4

In April 1982 NSAC gave highest scientific priority to a high duty factor electron

accelerator of energy 4 GeV, to explore the quark structure of the nucleus.

In April 1983 from the five design first was selected only two, then final one.

(All magnets assumed to be regular “room-temperature” technology. One linac

and several arcs for the beam recirculation.)

To obtain the continuous beam, this conventional accelerator was to work in

combination with a pulse stretcher ring.

History of how CEBAF project was selected

In1985 Grunder led CEBAF as a first director. He proposed build complex with two

linacs and arcs, based on superconducting radiofrequency accelerating technology

5

4 GeV energy CEBAF

By December1993 CEBAF accelerator was ready for commissioning

In summer 1994 first 4 GeV energy electron beam was delivered in Hall C

Experimental program started in 1995

Continuous Electron Beam

1497 MHz operation

Every third pulse to each hall

Simultaneous delivery 3 halls

499 MHz per hall, ~2 ps beam

pulses every 2 ns

Injector Energy 45 MeV

Linac Energy 400 MeV (each)

Beam Energy 0.8-4.0 GeV

Maximum current 200 μA

Beam polarization ~75%

Luminosity up to 1038 cm2/s

Energy spread dE/E ~10-4

Accelerator CEBAF consist of an injector, two superconducting

linac, two sets of arcs and systems of an electron beam extraction

from the accelerator and beam separation between halls.

The injector provide quasi-continuous electron beam with

bunches frequency 499 MHz per each hall and accelerator

frequency is 1.497 MHz.

6

Hall C at CEBAF 4-6 GeV

HMS SOS

Nearly identical detector packages

HMS

SOS

7

Number Experiment Grade Approved Days

E-89-008 Inclusive Scattering for Nuclei at x>1 and High Q2 B 8

E-89-009 Investigation of the Spin Dependence of the ΛN Interaction B+ 25

E-89-012 Two-Body Photodisintegration of the Deuteron at Forward Angle A- 10

E-91-003 Charged Pion Electroproduction in D2, 3He and 4He B+ 21

E-91-013 Energy Dependence of Nucleon Propagation in Nuclei B- 24

E-91-016 Electroproduction of Kaons and Light Hypernuclei A- 21

E-93-018 L/T Cross Section Separation in p(e,e’K±)Λ(Σ) for 0.5

8

Number Experiment Grade Approved Days

E-01-004 Charged Pion Form Factor (Extension E93-021) A- 14

E-01-006 Precision Measurements of the nucleon spin structure functions B+ 14

E-01-011 Spectroscopic Study of Lambda Hypernuclei A- 19

E-01-107 Measurement of Pion Transparency in Nuclei A- 14

E-02-017 Status of the ΛS=1 Hadronic Weak Interaction Program B+ 7

E-02-019 Inclusive Scattering from Nuclei at x>1 and high Q2 A 28

E-03-008 Sub-threshold J/Psi Photoproduction B+ 7

E-03-103 Measurement of the Nuclear Dependence of Structure Functions A- 10

E-04-001 Measurement of F2 and R on Nuclear Target in Resonance Region B+ 5

E-04-019 Two Photon Exchange Contribution in ep Elastic Scattering A- 18

E-04-101 Parity Violating Asymmetry in the N to Delta Transition B

E-04-108 Measurement of GEp /GMp to Q2=9 GeV2 via recoil polarization A 40

E-04-115 G0 Backward Angle Measurement A 70

E-05-115 Spectroscopic investigation of the Hypernuclei in the wide mass region A- 20

E-06-008 G0 Experiment: Backward Angle Measurement at Q2=0.23 GeV2 A 34

E-06-009 R=σL∕σT on Deuterium in the Nucleon Resonance Region A- 9

E-07-002 Polarization transfer in Wide Angle Compton Scattering B 3

E-07 003 Spin Asymmetries on the Nucleon Experiment-SANE A 34

E-08-016 The Qweak Experiment: Measurement of the Proton weak charge A 198

Hall C Experiments at CEBAF 4-6 GeV energies

* Experiments in which YerPhI group contribution was essential

9

Hall C results at 6 GeV: Fπ (E93-021 & E01-004)

The Fπ(Q2) extraction requires a model of the 1H(e,e’π+)n and thus is model dependent

The charged pion form factor Fπ(Q2) has been measured for Q2=0.60-2.45 GeV2

dtd

d

dEdd

d

v

Kee

25

2coscos)1(22

2

dt

d

dt

d

dt

d

dt

d

dtd

dTTLTLT

To separate contributions the cross section at low and high

ε as a function of ϕ for fixed values of W, Q2 and t needed

At small –t the σL is dominated by t-channel process and

Form factors play an important role in our understanding the structure of hadrons

The pion is the simplest hadronic system (bound state of quark and anti-quark)

The charged pion form factor Fπ(Q2) is an important quantity that can be used to

advance our knowledge of hadronic structure.

e+p→e’+π++n

),()()(

~222

22

2

tQFtgmt

tQ

NNL

10

Hall C results at 6 GeV: GEn, GMn (E93-038)

e

e’

n

n n ( e, e’ n )

E93-038 measured the ratio GEn/GMn via the recoil neutron’s polarization in the quasielastic

reaction at Q2=0.45, 1.13 & 1.45 GeV2. HneeH 12 ),(

• In polarized electron unpolarized neutron elastic

scattering, one can access to neutron form factors

by measuring transverse (Pt) and longitudinal (Pl)

components of recoil nucleon polarization :

HneeH12

),(

ME

M

e

E

e

ME

etGG

GG

GG

PP

222

2tan)1(2

2tan)1(2

2

222

222

2tan)1(2

2tan

2tan)1()1(2

M

M

e

E

e

M

elG

GG

G

PP

MEltGGPP

• Because of the lack of a free neutron target, the neutron form factors are known with less

precision than are the proton form factors, and measurements have been limited to small Q2.

• Before polarization experiments GEn were extracted from the quasielastic cross

section data and the deuteron elastic structure function A(Q2 ) with very large uncertainties.

• Secondary scattering (polarimeter) needed to define

Pl and Pt components of recoil neutron polarization

In 2000s these were most precise data at Q2>1 GeV2.

11

Hall C results at 6 GeV: Gen (E93-026)

• In this experiment the electric form factor of the neutron was determined from

measurements of the reaction for quasielastic kinematics.

• Polarized electrons were scattered off a polarized ammonia (15ND3) target in which the

deuterium polarization was perpendicular to the momentum transfer.

•To determine Gen the helicity dependent rate asymmetry in electron-neutron scattering was

measured. The scattered electrons were detected in HMS, and the neutrons in neutron detector.

• If the neutron polarization vector in the scattering plane and perpendicular to the momentum

transfer , then Gen is related to the beam-target asymmetry term by

),( npeed

• The value of Gen was determined by

comparing the acceptance averaged

value of the data to that of MC.

q V

enA

24

2MQ222

2tan)1(2

2tan)1(2

M

e

E

e

MEV

en

GG

GG

A

V

enA

E93-026 value:

GEn = 0.0526 ± 0.0033(stat) ± 0.0026(sys) for Q2=0.5 GeV2

GEn = 0.0454 ± 0.0054(stat) ± 0.0033(sys) for Q2=1.0 GeV2

12

Hall C results at 6 GeV: Gep-III (E04-108) • Jlab’s precise recoil polarization experiments established that

the proton electric form factor GEp falls faster that the magnetic

form factor GMp for momentum transfers Q2>1 GeV2.

• This in disagreement with results obtained from unpolarized

cross section measurements data (Rosenbluth separation)

• The polarization of the recoil proton in the elastic scattering

of longitudinally polarized electrons from unpolarized

protons has longitudinal (Pl) and transverse (Pt) components

with respect of the momentum transfer in the scattering plane.

• The ratio Pl/Pt is proportional to GEp/GMp:

2tan

2

e

p

ee

l

t

pp

M

p

E

p

M

EE

P

P

G

GR

• .In GEp-III, polarized electrons were scattered from 20 cm

liquid hydrogen target and detected in ~2000 channel BigCal.

HMS spectrometer with double FPP polarimeter was used to

detect recoil protons and measure polarization components.

13

View from downstream

Hall C results at 6 GeV: G0 (E00-006 & E04-115)

• The G0 have measured parity-violating asymmetry in elastic

electron-proton and quasi-elastic electron-deuteron scattering

over the range of 0.12 < Q2

14

Hall C results at 6 GeV: Qweak (E08-016)

M

MA

PV

weak

LR

LR

PV

2

The parity-violating weak amplitude can be accessed through the asymmetry APV:

)(22

0QBQQAA

p

WPV

24

2

0

QGA

F

012.0064.0 p

WQ

007.00710.0 p

WQ

Precision test of the Standard Model

(at Q2 ≈0.025 GeV2 small effect)

weakMMM

2~

2

Qweak proposes a 3% measurement of at Q2 ≈0.025 GeV2

• Required ~150 μA beam current, ~80% polarization, 2.5 kWatt power 35 cm long

cryotarget, careful control of backgrounds, Q2, polarization and false asymmetries

• Qweak experiment Aep = -279±35 (stat)±31(syst) ppb (4% of data)

• Standard Model Aep~ -216 ppb (parts per billion)

B(Q2) is hadronic structure (small at Q2 ≈0.025 GeV2)

• Global fit using all data

• Standard Model value

p

WQ

Elastic e + p scattering

15

E00-108: Quark-hadron Duality in Meson Electroproduction

• We have measured semi-inclusive electroproduction of π± from

proton and deuteron target, using 5.479 GeV energy beam.

• We have observed, for the first time, the quark-hadron duality

and low energy factorization in pion electroproduction reactions.

• Several ratios constructed from the data exhibit the features of

factorization in a sequential electron-quark scattering and a

quark-pion fragmentation

XeNe

The Pt dependence of cross section show a

possible flavor dependence of the transverse

momentum dependence of PDFs and FFs.

Extracted ratios on average agree with the QPM

expectations and with the existing high W2 data.

YerPhI group contribution in Hall C at 4-6 GeV

2πq

i

2

iQz,DQx,qσ

16

YerPhI group contribution in Hall C at 4-6 GeV

• Design and construction electromagnetic calorimeters for HMS & SOS magnetic spectrometers. Development their software and calibration code.

• Design and construction threshold Aerogel detector for the HMS.

• PMTs gain monitoring system for the calorimeters and Neutron detector

• Refurbishing HMS hodoscopes, Neutron detector, Lucite Cherenkov

• Participation in installation and data taking in all Hall C experiments

• Leading role in the of-line analysis of Fpi, Mduality, Gen experiments

• Responsibility for the PID system of the HMS and SOS spectrometers

• Leading role in “Meson Duality” proposal and experiment

Two nearly identical calorimeters for HMS & SOS Two type aerogel detectors for HMS

Not full list of YerPhI group contribution in Hall C:

17

CEBAF from 4 GeV energy to 6 and 12 GeV

The 4 GeV CEBAF each linacs has 400 MeV energy provided by 20 cryomodules

(20 MeV / module). Each cryomodule consisted of eight 5-cell and 0.5 m length

cavities with accelerating gradient of ~5 MeV/m (2.5 MeV /cavity).

This goal was surpassed in 2006-2007. The accelerator cavities operate at an

average of ~7.5 MeV/m, and substantially higher energy (6 GeV) were expected.

The achievement of med-2009 to operate CEBAF at 6 GeV (50% higher than the

projected 4 GeV) was crucial for 12 GeV upgrade program.

The12 GeV project includes removing and refurbishing cryomodules to increase

cavity gradient from 5 MeV/m to 12.5 MeV/m (increase energy: 20 50 MeV).

There are 5 empty “zones” at the end of each linac. Installing five cryomodules

with-100 MeV capability in these locations would lead to linacs of 1.1 GeV each,

and 11 GeV beam with 5 passes.

C50 cryomodules each for 50 MeV (refurbished from original 5-cell cavities)

C100 have eight 7-cell cavities and on average provide 100 MeV (length of each

cavity is ~0.7 m with accelerating gradient 17.5 MeV/m, or 12.25 MeV/cavity)

18

CEBAF from 6 GeV 12 GeV

A cryomodule for the 12 GeV upgrade

installed in the CEBAF accelerator tunnel

Reassembly of a reprocessed C50 cavity pair into a one-

quarter-cryomodule (before assembly into helium vessel)

Original CEBAF 5-cele cavity

CEBAF 7-cell upgrade cavity.

19

Accelerator CEBAF upgrade project included:

Upgrade of the Cryomodules to increase the

injector energy from 45 MeV to 123 MeV

New accelerating cryogenic modules C-100

(developed at JLab)

Add 10 new C100 modules (five per each linac)

Add new arc in “West” arcs set to increase

number of pass

New extraction line for hall D

CEBAF Accelerator from 6 GeV to 12 GeV

Timing of the 12 GeV upgrade project:

May 2011 – November 2011: two new cryomodules

C100 were installed for test (one per linac)

June 2012 – October 2013: complete upgrade of

accelerator CEBAF

November 2013 – January 2014: running CEBAF

accelerator with energy 2.2 GeV (one pass)

January-May 2014: run the accelerator with the

beam energy 6.6 GeV (testing the systems & beam

for Hall A)

September 2014 – May 2015: the energy of the

beam up to 9 GeV. Beam delivery to Hall D.

September 2015 – May 2016: 12 GeV beam energy.

The beam delivery to halls B and C.

March 2017: the end of 12 GeV upgrade project.

20

The 12 GeV Groundbreaking ceremony: 14 April 2009

CEBAF from 6 GeV 12 GeV

Jlab director Hugh Montgomery, accelerator

division associated director Andrew Hutton, Jlab

former director Christophe Leeman and director of

operations Arne Freyberger shutting down CEBAF

On 18 May 1212 Jlab shut down its 6 GeV

CEBAF accelerator for 12 GeV upgrade

Jlab director Hugh Montgomery (center), former

directors Herman Grander (right) and Christophe

Leeman (left) at “CEBAF 12 GeV upgrade and

Hall D construction” Groundbreaking ceremony.

21

CEBAF Experimental Halls at 12 GeV

Due to limited funds in Hall A will be upgrade only beam line, Moller and

Compton polarimeters, keeping existing two 4 GeV/c HRS spectrometers

unchanged. In the future, for specialized experiments new SPS (Super Big-

Bite Spectrometer) and equipment for Moller experiment will be created in

Hall A.

Hall B will be equipped with a large acceptance spectrometer CLAS12

consisting of two superconducting magnets: a six-sector torus with

maximum field 2.3 T and a ~1 m long solenoid with a maximum field 5 T..

Some of existing detectors will be used, Will be added silicon-strip vertex

tracker, RICH and preshower. CLAS12 will have 10 times higher luminosity

than the CLAS.

In the Hall C a new spectrometer will be installed (which replaced SOS).

The pair of HMS and SHMS spectrometers allows for high-precision cross

section measurements and L/T separations in valence quark region.

A new Hall D is designed to conduct experiments on the photon beam and

for the study of new exotic states. Equipment includes a diamond target (for

polarized photon beam production and Gluex detector,

22

Hall C at CEBAF 12 GeV

23

Number Experiment Grade Approved Days Non-standard Equipment

E12 -06-101 P ion Form Factor A 30

E12-06-104 SIDIS R A- 30

E12-06-105 Inclusive at x>1 A- 30

E12-06-107 Color Transparency at 12 GeV B+ 30

E12-06-110 Spin asymmetry A1n, pol. 3He A 30 Polarized He3 target

E12-06-121 Neutron g2 and d2 at high Q2 A- 30 Polarized He3 target

E12-10-002 F2 at large x in res. region B+ 35

E12-10-003 d(e,e’p) at very high momentum B+ 35

E12-10-008 Nucl. dependence of F2, EMC A- 35

E12-11-002 Proton recoil pol. in 4He, 2H, 1H B+ 37

E12-11-009 Neutron FF at Q2 up to 7 GeV2 B+ 37 Magnet + Neutron polarimeter

E12-07-105 Exclusive (e,e’π), L-T separation A- 38

E12-09-002 pi+/pi- and Charge Sym. Viol. A- 38

E12-09-011 L-T in (e,e’K) Excl. at 5-11 GeV B+ 38

E12-09-017 Trans. Moment. in SIDIS pi0 A- 38

E12 -11-007 SRC and EMC (e,e’ backward p) B+ 38 Hall B TOF bars

E12-13-007 SIDIS Pi0 A- 40 Neutral Particle Spectrometer

E12-13-010 DVCS + Exclusive Pi0 A 40 Neutral Particle Spectrometer

E12-14-002 Nuclear Dependence of R B 42 Neutral Particle Spectrometer

E12-14-003 WACS at 8 and 10 GeV A- 42 Neutral Particle Spectrometer

E12-14-005 Wide angle Exclusive pi0 B 42 Neutral Particle Spectrometer

E12-14-006 Helicity correlation in WACS B 42 Neutral Particle Spectrometer

Approved and Conditional 12 GeV Hall C Experiments

Total Days ~800

24 24

Hall C Physics at 12 GeV Energy

25 25

Hall C Timeline

26 26

Early running plans – Year 2016

• Precommissioning detector checkout

~25 PAC days for Commissioning of Hall C

• Proposed Experiments for Commissioning:

• E12-06-107 Search for color transparency at 12 GeV

- only first part, A(e,e’p), relatively “easy” coincidence measurement

• E12-10-002 Precision measurements structure functions at large x

- momentum scan in this experiment will help understand acceptance

• E12-10-108 Nuclear dependence of F2 (EMC Effect)

- Light nuclei part can be combined with F2 run

- point target needed for this experiment will help acceptance studies

- low cross section part of experiment will check capability of equipments

dpF

,

2

27

E12-06-107: The Color Transparency at 12 GeV

• Goal of proposal to measure the A(e,e’p) and the A(e,e’π) cross sections to

extract the proton and pion nuclear transparencies in the nuclear medium

• Nuclear transparency defined as the ratio of the cross section per nucleon

on a bound nucleon in the nucleus to the cross section on a free nucleon.

• The basic idea is that, at high Q2 three quarks of the proton (two of pion)

could form a “color neutral” object of reduced transverse size, and pass the

nuclear medium undisturbed

A(e,e’p) cross-section on 1H and 12C

with 80 μA, of 8.8 & 11.0 GeV beam.

(Q2 = 8,10, 12, 14 & 16.4 GeV2)

• E12-06-017 will perform the proton

transparency measurements on 12C over

the range of Q2 = 8-16 (GeV/c)2

•The π+ transparency measurements will

be performed on 1H, 2H, 12C, and 63Cu,

over the range Q2=5-9.5 (GeV/c) 2

• A signature for the Color Transparency

(CT) would involve a dramatic rise in

the nuclear transparency with rise of Q2

28

• The differential cross section of electron-nucleon scattering can be written as:

, . σM is the Mott cross section for point-like nucleon, )2(2

tan)2

,(1

2)2

,(2

2

QWQWM

Edd

d

)(22

1)(

11MW and )(

2)(

22xF

xxFx

ii

xqi

exFW

E12-10-002: Precision Measurements of the F2

• New Data from Jlab show that Bloom-Gilman

duality holds well down to Q2~1 GeV2. However, a

growing with Q2 discrepancy was observed for at

large x. This in contradiction with the expectation

that duality should work best with increasing Q2.

and W1 and W2 are the nucleon structure functions.

• When the energy is high enough the structure functions can be expressed as a

functions of the only Bjorken x:

• In 70s Bloom & Gilman observed that the inclusive structure functions at low

energy follows a global scaling curve which describes high-energy data.

The ratio of integrals of F2 resonance data

and the QCD fits remains constant in Q2

Goal of proposal: extend proton and deuteron F2

structure function data to x~0.99 and Q2 ~17 GeV2

by measuring H(e,e’) and D(e,e’) cross sections in

the resonance region and beyond.

pF

2

29

E12-10-008: Nuclear dependence of F2 (EMC effect)

• In 80s the EMC found significant deviation between the

structure functions of heavy (Fe) and light (D) nuclei.

• Since then, the x and nuclear dependence (A-dependence)

of structure functions has been extensively studied, but the

origin of the EMC effect still is not understood.

Goal of proposal to perform inclusive

electron scattering measurements from

several light to medium nuclei over

range of 0.1 < x < 1 up to Q2 ≈15 GeV2.

• Experiments have looked for evidence of modification

the nucleon structure functions (form factors) in medium.

•Assuming that the shape of the EMC effect is universal,

and only the magnitude varies with target nucleus, one

can compare light nuclei by taking the x-dependence of

the ratio in the linear region, 0.35

30

Early running plan: Years 2017-2018

31

E12-09-017: Transverse Momentum Dependence of Semi-

Inclusive Pion and Kaon Production

• Not much is known about the orbital motion of partons • Significant net orbital angular momentum of valence quarks

implies significant transverse momentum of quarks

Goal: Map the pT dependence of π+ and π-

production off proton and deuteron targets to

study the kT dependence of u and d quarks

Final transverse momentum of the detected

pion Pt arises from convolution of the struck

quark transverse momentum kt with the

transverse momentum generated during the

fragmentation pt. Pt = pt + z kt +O(kt2/Q2)

Pt dependence very similar for both targets.

Deuterium slopes systematically smaller?

Assuming the width of the quarks (μu, μd) and

width of the fragmentation functions (μ+ μ-)

are Gaussian, and that the convolution of these

distributions combines quadratically, the total

width for each combination can be given by:

D+(z)

1)

2μ

2d

μ2

(zd

b and 1

)2

μ2u

μ2

(zu

b

Spokespersons R. Ent, P. Bosted, H. Mkrtchyan

32

E12-06-104: Measurement of the R = σL/σT in SIDIS

Goal: perform measurements on LH2 and LD2:

i) R as a function of z at x=0.20 & Q2 =2.0GeV2;

ii) map RH versus z at x = 0.40 and Q2 = 4.0 GeV2;

iii) map RH versus of PT at x=0.3 and Q2=3.0GeV2

Pt dependence very similar for both targets.

Deuterium slopes systematically smaller?

▪ In the asymptotic limit, in the quark-parton model the electro-produced pions are the fragmentation products of the spin-1/2 partons, and the ratio R = σL/σT disappears like 1/Q

2, like in the inclusive DIS. ▪The handbag diagram model (developed for the pion electroproduction), factorize these processes into a hard-scattering process and a soft process, and anticipate a behavior R = σL/σT ~ Q

2 at constant x, in the asymptotic limit. ▪At low energies and at large PT RSIDIS must anneal to RDIS for consistency.

Spokespersons R. Ent, P. Bosted, H. Mkrtchyan

33

E12-13-007: Measurement of Semi-Inclusive 0 Production as Validation of Factorization

Spokespersons: R. Ent, T. Horn, H. Mkrtchyan & V. Tadevosyan

• Essential ingredient of basic (e,e’) cross section measurements to lay a solid foundation for the SIDIS program at a 12-GeV JLab.

JLab Theory Group Report (Prokudin & Radyushkin):

• No diffractive r contributions • Smaller radiative tail - no pole contributions • Less resonance region contributions - for example, compare with ep e-D++ • Proportional to average fragmentation function - easier to disentangle quark and fragmentation functions

Why need for (e,e’0) beyond (e,e’+/-)?

34 Slide from Hugh Montgomery.

Hall A meeting, December 2014

35

SHMS Structure Assembly Underway

April 2014

August 2013

March 2014

February 2014 January 2014

October 2013

36

SHMS Structure Assembly Underway

April 2014

Detector hut

January 2015

Detector hut

1st Quadrupole 2nd Quadrupole

Q1 and Q3

View from Q1 to Q3

37

SHMS Detectors Status

Drift Chambers: HU

Scintillation Hodoscopes: JMU

Noble Gas Cherenkov: UVA Heavy Gas Cherenkov: UR

Quartz Hodoscopes: NCAC&T

Calorimeter: YerPhI Aerogel Cherenkov: CUA & YerPhI

S1X: 13 paddles @ 8 x 100 x 0.5 cm3

S1Y: 13 paddles @ 8 x 100 x 0.5 cm3

S2X: 14 paddles @ 10 x110 x 0.5 cm3

Two identical modules of six planes

each, 5mm drift distance, Ar+CO2 gas

2.3 m long Ar/Ne radiator

at atmospheric pressure

Diameter 1.6 m, length 0.6 m, C4F8O

gas, variable pressure, with n-1< 0.001

Assembly most of the detectors completed,

cosmic studies well underway. Installation

in the SHMS hut: end 2014 & spring 2015.

Aerogel with n=1.03, 1.02, 1.015 and

1.01. Effective area ~100 x 110 cm2

Preshower: 28 TF-1 type Pb0Glass

blocks, Shower: 224 F-101 type Pb-

Glass blocks. Effective area ~1.2 m2

S2Y: 21 Quartz bars, each about 1 m

long, width 5.5 cm , thickness ~2.5 cm.

38

CEBAF Accelerator status

• 12 GeV energy Beam line elements to the halls installations are completed.

• All radiofrequency and cryogenic module installation has been completed.

• All supplies for arcs magnetic elements are installed onsite and various stages of

checkout have been completed.

• 2.2 GeV/pass tune beam was transported to Hall A, B and D. This energy is a new

record for one pass and is the machine performance needed to eventually deliver 12

GeV beam to Hall D and 11 GeV beam to Halls A, B and C.

• This demonstrates the Performance Parameters needed for the 12 GeV CEBAF

Upgrade project.

• On December 2014 the accelerator was able to deliver 7 GeV energy CW beam to

the Hall A for DVCS experiment. Work is progressing to provide continuous wave

beam to Hall A/B/C/D for commissioning.

• Work in the Hall D Tagger area continues.

39

YerPhI contribution in 12 GeV upgrade: Calorimeter SHMS Calorimeter (Preshower+Shower)

Assembling and installation of the SHMS calorimeter: completed on 12 December 2014

40

YerPhI contribution in 12 GeV upgrade: Aerogel SHMS Aerogel detector

Type of

Particle

Pth in

n=1.030

Pth in

n=1.015

Pth in

n=1.010

Pth in

n=1.006

μ 0.428 0.608 0.746 0.963

π 0.565 0.803 0.984 1.272

K 2.000 2.840 3.482 4.500

P 3.802 5.397 6.618 8.552

41

YerPhI group activities in Hall C At 6 GeV energy era:

Design and construction lead-glass electromagnetic calorimeters for SOS and HMS

spectrometers. In1994, they were recognized as the first operational detectors at Jlab.

Design and construction threshold aerogel Cherenkov detector for HMS which

played key role in a series of +/-, K+/- production experiments since 2003.

Participation in installation, data taking and analysis in more than ~50 experiments

Proposed and carried out first semi-inclusive charged pion electroproduction

experiment E-00-108, “Duality in Meson Electroproduction”.

At 12 GeV energy era:

Design and construction electromagnetic calorimeter for SHMS spectrometer

Design and construction aerogel detectors for SHMS (in collaboration with CUA)

Proposed (in collaboration with Jlab & CUA) experiments

- E12-06-104, “Measurement of the Ratio R=σL/σT in Semi-Inclusive DIS”

- E12-09-017, “Transverse Momentum Dependence of Semi-Inclusive π-production”

- E12-13-007, “Measurement of Semi-Inclusive π0 Production“. Required

construction of the Neutral Particle Spectrometer (NPS).

YerPhI group will played leading role in development and construction of NPS.

42

YerPhI group members in Hall C

1. Tsolak Amatuni

2. Ashot Gasparian

3. Ruben Badalyan

4. Grigor Kazaryan

5. Vardan Tadevosyan

6. Samvel Stepanyan

7. Hamlet Mkrtchyan

8. Razmik Asaturyan

9. Arthur Mkrtchyan

10. Arshak Asaturyan

11. Simon Zhamkochyan

Thanks for Your Attention !

43

44 Slide from Hugh Montgomery.

Hall A meeting, December 2014

45 Slide from Hugh Montgomery.

Hall A meeting, December 2014

46

Aerogel Detector in the SHMS

The Aerogel detector is situated between heavy gas (C4F8O) Čerenkov detector and S2

Hodoscopes of the SHMS detector stack

A dedicated kaon PID detector

With dimensions 113x103x28 cm3, covers SHMS acceptance

2 detectors possible

Consists of a diffusion box with 14 PMTs (plus optional 6 on top) and 4 replaceable

trays with Aerogel of different indexes: 1.03, 1.02, 1.015, 1.011

Detector Hut Aerogel Detector

47

The NPS is envisioned as a facility in Hall C, utilizing the well-understood HMS

and the infrastructure of the new SHMS, to allow for precision (coincidence) cross

section measurements of neutral particles (,0).

NPS cantilevered off SHMS platform NPS on SHMS platform

Detector Detector

Magnet

Magnet

NPS angle range: 25 – 60 degrees NPS angle range: 5.5 – 30 degrees

The Neutral-Particle Spectrometer (NPS)

Currently 5 experiments are approved by the JLab PAC (three with A-

rating), which require the availability of the NPS

Ideas exist for new scientific directions, e.g., using a polarized

(transverse) target and LD2

The NPS design is flexible and could also be used in Hall A

48 new and currently at development stage, IR curing (λ>900 nm)

NPS Prototype Design

• Components of the NPS prototype

• NPS prototype is being constructed to optimize technical aspects of the calorimeter before finalizing the design of the NPS

o Crystal matrix: 3×3 PbWO4 (SICCAS, 2014), each 2.×2.×20. cm3 in a copper frame

o Light Monitoring System based on Blue Light source >450 nm (matrix of LEDs)

o Curing of the crystals will test two approaches:

standard, based on a blue light source (λ~460 nm)

49

E12-09-002:Precise Measurement of π+ ∕ π- Ratios in SIDIS

• In parton distribution functions, it is routinely assumed that charge symmetry is valid.

• Charge symmetry implies the invariance of up and

down quarks in proton and neutrons, i.e.

up(x, Q2) = dn(x, Q2)

dp(x, Q2) = un(x, Q2)

• Charge symmetry in the valence quark distribution

has never been tested with precision. The most

precise estimations (by NMC) gives the upper limit

of 9% for charge symmetry violation effects.

Goal: To measure precision ratios of charged pion electroproduction

in SIDIS from Deuterium. Data will be used to test the validity of the

charge symmetry (CS) in the valence quark distributions.

At large x, neglecting the sea quark contribution: The upper and lower limit of CSV contribution

(Calculations based on MRST

parameterization)

),(

),(),(

zxY

zxYzxR

y

)()(2

zDxqeYiii

)(3

)(4)(

vvdu

udxCR

)()()(

)()()(

xdxuxu

xuxdxd

np

np

Experiment will measure the ratio of the π+ and π-

yields on deuterium for different x & z:

where

x-dependence of R at fixed z

is a sensitive probe of CSV

where

50

E12-09-011:Studies of the L-T Separated Kaon Electroproduction

• The p{e,e’K+ )Λ and p(e,e’K+)Σ reactions are important tool in our study of hadron structure.

• Separated p{e,e’K+)Λ, Σ0 cross sections allow

investigations of the transition from hadronic to par

tonic degrees of freedom in exclusive processes.

• Practically no any data above the resonance region.

The Q2 dependence of p{e,e’K+)Λ, Σ0 cross

section is the main interests of proposal.

dtd

d

dEdd

d

v

Kee

25

2coscos)1(22

2

dt

d

dt

d

dt

d

dt

d

dtd

dTTLTLT

• The existing data have large uncertainties, they suggest significant contribution of σT at Q

2~2 GeV2.

• The Reggie model suggest strong Q2 and W dependence of the σL/σT.