# Presentation: 468334

## Hall B Status

- Volker D. Burkert
-   Jefferson Lab

- CLAS Collaboration Meeting
-       June 16, 2005

- Run status
- Publication status
- Pentaquarks – a collaboration priority
- Recent projects
- 2005/2006 run plan
- Detector issues
- 12 GeV Upgrade, prototyping effort
- PAC27/28

## Hall B Status Overview

- 24 major CLAS production runs completed
- e1a/b, g1a/b, g6a, e1c, e2a, g6b, g2a, g1c, g3, e1d, e5, eg1b, g8a, g6c, e1-6,
-       e6, e2b, g7, e1e, e1f/g, eg2, g10, g11**,**** **eg3,** **e1-DVCSa , (+3 non-CLAS experiments: g5, rad-PrimEx)
-  Next scheduled experiment : G8b
- Publications
- 17 technical papers published, 1 submitted
- 43 physics papers published/accepted in refereed journals (7 CLAS related papers)
-   2 submitted
-   3 in collaboration review
- Projects in preparation for new experiments
- -	Polarimeter for linearly polarized photons
- -	BoNus detector (Neutron structure function)
- -	Frozen Spin Target (search for missing N*’s)
- -	Cerenkov counter for one CLAS sector (small Q2 GDH)
- 12 GeV Upgrade – Preparation for CD-1 approval by 9/05
- TOF prototyping (KNU, USC)
- SVT prototyping (JLab, ODU)
- Calorimeter prototyping** **

## Technical Publications

- Drift Chambers
- construction	Mac Mestayer	NIM A323 (1992) 191
- update	Mac Mestayer	NIM A367 (1995) 316
- Region I	Dan Carman	NIM A419 (1998) 315
- Region II 	L.M. Qin		NIM A411 (1998) 265
- Summary 	Dan Carman	NIM A449 (2000)   81
- Cerenkov Counter	Paul Stoler		NIM A465 (2001) 414
- TOF Counters	Elton Smith		NIM 432 (1999) 265
- Start Counters	Simon Taylor	NIM A462 (2001) 484
- Forward Cal.	Cole Smith		NIM A460 (2001) 239
- Large Angle Cal.	Mauro Taiuti	NIM A447 (2000) 431
- Response	Mauro Taiuti	NIM accepted (2004)
- Tagging System
- window	Jim O’Brien	NIM 421 (1999)
- tagger 	Jim O’Brien	NIM 440/2 (2000) 263
- Polarized target	Chris Keith		NIM A501 (2003) 327
- FST coil design	O. Dzyubak	NIM A526 (2004) 132
- CLAS Overview	Bernhard Mecking	NIM A503 (2003) 513
- 2nd Start Counter	Gordon Mutchler	to be submitted to NIM

## Hall B Physics Publications (refereed journals) 

**5**

**10**

**15**

**2000**

**2001**

**2002**

**2003**

**2004**

**year of publication**

**2005**

**2006**

- Submitted

- Collaboration

- Physics groups

## Hall B Publication Overview 

-  43

-             9

-           15

-          19

- Sum

-  10

-            4

-     3

-         3

- 2004

-    4

-             1

-             -

-            3

- 2002

-    5

-             -

-             3

-            2

- 2001

-  12

-             1

-             4

-            7

- 2003

-    2

-             1

-             1

-             -

- 2000

- Sum

- Nuclear processes

- Hard scattering
- & Structure F.

- Spectroscopy & Structure

- Hall B Publication Overview
- Refereed Journals

- 2005

- 2

- 10

- 4

- 4

## Run Group Publications

**E1:**	** **
-  C. Hadjidakis et al., 	Exclusive 0 electroproduction from hydrogen	PLB605, 256 (2005)
-  K. Joo, et al., 	Measurement of LT’ for p(e,e+)n in region 	PRC70, 042201 (2004)
-  K. Joo et al.,	Polarized structure function LT’ in (1232) region 	PRC68, 032201 (2003)
-  D. S. Carman et al., 	First measurement of transferred polarization in p(e,e’K+)PRL90, 131804 (2003)
-  M. Ripani et al., 	Measurement of p(e,e’p) and baryon resonance analysis	PRL91, 022002 (2003)
-  K. Joo et al., 	Q2 dependence of quadrupole strength in (1232) excitation  	PRL88, 122001 (2002)
-  S. Barrow et al.,	Electroproduction of the (1520) hyperon	PRC64, 044601 (2001)
-  M Osipenko et al., 	Kinematically complete measurement of F2 in N* region	PRD67, 092001 (2003)
-  H. Avakian et al., 	Beam spin asymmetry for p(e,e’+)X in DIS region	PRD69, 112004 (2004)
-  S. Stepanyan et al.,	First observation of exclusive DVCS in beam asymmetry	PRL87, 182002 (2001)
-  K. Lukashin et al.,	Exclusive electroproduction of  mesons at 4.2 GeV	PRC63, 065205 (2001)
-  R. Thompson et al.,	The p(e,e’p) reaction at and above the S11(1535) 	PRL86, 1702 (2001)

- E1 - Physics Analysis groups:
-  D. Carman, B. Raue	** **L/T for p(e,e’K) from polarization transfer 		PRC, (2005).
-  I. Aznauryan et al.; 	Electroexcitation of , P11, S11, D13 at Q2=0.4, 0.65 GeV2	PRC71, 015201 (2005)**  **
-  V. Burkert et al., 	Single Quark Transition analysis of N* in [70,1-] multiplet	PRC67, 035204 (2003)
-  A. Afanasev et al., 	QED radiative corrections for exclusive pion production	PRD66, 022002 (2003)

## Run Group Publications (cont’d)

-   R. Fatemi et al, 	Proton spin structure function g1(x, Q2) for Q2=0.15-1.6 GeV2  	PRL91, 222002 (2003)
-  J. Yun et al.,	Measurement of inclusive spin S.F.’s of the deuteron 	PRC67, 055204 (2003)
-  A. Biselli et al., 	Polarized beam asymmetry for p(e,ep)0 in (1232) region 	PRC68, 035202 (2003)
-  R. De Vita et al.,	First measurement of double spin asymmetry in p(e,e’+)n	PRL88, 082001 (2002)

**E1-6:**
-  L. Morand et al., 	Deeply vitual and exclusive electroproduction of  mesons 	EPJA (2005)

**E2:**
-  D. Protopopescu et al.,** ****	**ALT’ in electron scattering on He-4 and C-12 	NPA748, 357 (2005)
-  A.V. Stavinsky et al.,	Proton source size measurements in A(e,e’pp)X	PRL93, 192301 (2004)
-  R. A. Niyazov, et al., 	Two-nucleon momentum distribution in 3He(e,e’pp)n	PRL92, 052303 (2004)
-  K. Egiyan et al.,	Observation of nuclear scaling in A(e,e’) at xB > 1	PRC68, 014313 (2003)

- EG1 Physics Analysis groups:
-  M. Osipenko et al.,    	Global Analysis of Proton Structure Function g1 and Moments	PRD 71, 054007 (2005)
-  M. Osipenko et al., 	Higher twist analysis of the proton g1 structure function	PL B 609, 259 (2005)	** **
-  A. Deur et al., 	Experimental determination of the Bjorken Integral at low Q2	PRL 93, 212001 (2004)

**E6:**
-  M. Osipenko et al, 	Deuteron structure function F2 and its moments	PRD submitted (2005)

## Run Group Publications (cont’d)

-  S. Taylor et al., 	 Radiative decays of the o(1385) and (1520) hyperons	PRC, accepted (2005)
-  K. McCormick et al., 	 Tensor polarization of  in high-t photoproduction	PRC69, 032203 (2004)
-  J.W. McNabb et al., 	 Hyperon photoproduction in the nucleon resonance region	PRC69, 042201 (2004)
-  M. Dugger et al., 	 Eta photoproduction on proton for energies 0.75-1.95 GeV	PRL89, 222002 (2002)

**G2:**** **
-   P. Rossi et al, 	Onset of asymptotic scaling in deuteron photodistintegration	PRL94, 012301 (2005)
-  M. Mirazita et al.,  	Complete angular distributions in d(g,p)n from 0.5-3 GeV	PRC70, 014005 (2004)
-  S. Stepanyan et al., 	Observation of S=+1 baryon in D(,K+Kp)n	PRL91, 252001 (2003)

**G3:**** **
-   S. Niccolai, et al., 	 3-body photodisintegration of He-3 for  0.55 - 3 GeV       	PRC 70 064003 (2004)

**G5:**** **
-  C. Cetina et al.,	Photofission of Heavy Nuclei from 0.2 to 3.8 GeV	PRC65, 044622 (2002)
-  C. Cetina et al.,**	**Photofission of Heavy Nuclei at energies up to 4 GeV	PRL84, 5740 (2000)

**G6:**** **
-  J. Price, et al.,** ****	**Photoproduction of cascades from proton targets	 PRC, accepted (2005)
-  V. Koubarovsky et al., 	Observation of baryon with S=+1 in p(, K+K+)n	 PRL92, 032001 (2004)
-  M. Battaglieri et al., 	 Photoproduction of   mesons at large momentum transfer         PRL90, 022002 (2003)
-  M. Battaglieri et al., 	 Photoproduction of 0 on proton at large momentum transfer     PRL87, 172002 (2001)
-  E. Anciant et al., 	 Photoproduction of  at large momentum transfer	 PRL85, 4862 (2000)

## 		Pentaquarks - 

- 	 A Collaboration Priority

- CLAS results contributed substantially to the excitement
- over the pentaquark, and we have the main responsibility to
- clarify the current confusion over the existence.**  **

- The G10 and G11 groups are at the forefront, and have taken
- on this task with great seriousness.

- Thanks to the excellent leadership, the highly motivated
- postdocs and graduate students, and the splendid calibration
- effort, the analyses are now in their final phases, just a year or
- even less after the experiments took data.

- The CLAS pentaquark publication committee has taken on the
- responsibility with great seriousness and responded in a
- timely manner.

## Pentaquarks -  A Collaboration Priority,

- You are doing a great service not only to the collaboration
- but to the entire nuclear and particle physics communities,
- independent of what you are finding !

- cont’d

## Cross Section Extraction

** ****Different final states are measured**
**  ****simultaneously in the CLAS detector**
** ****Cross section for known reactions **
**  ****have been extracted to test the **
**  ****accuracy of the analysis procedure**

**Cross Section Extraction**

**WORLD data**

******p********p**********

******p********p******

** ****CLAS g11**
**   ****preliminary**
** ****SAPHIR**

******p********K****+******

** ****1% of statistics**

**E************GeV)**

******(********b)**

**E************GeV)**

******(********b)**

** ****CLAS g11**
**   ****preliminary**
** ****SAPHIR**

** ****CLAS g11**
**   ****preliminary**
** ****world data**

## G11 - Preliminary Results

- APS talk @ Tampa,
- R. De Vita

## CLAS/DVCS

- Superconducting solenoid

- Inner calorimeter
-       (PbWO4)

***CLAS/DVCS***

- 424 crystals, 16 mm long,
- pointing geometry, ~ 1 degree/crystal,
- APD readout

*Photon detection in IC and EC*
*          **(view from target)*

**Notes:**
Intro

## Hall B - DVCS Solenoid and Inner Calorimeter

- Hall B - DVCS Solenoid and Inner Calorimeter

**Solenoid cryostat**

**Calorimeter**

## Slide 15

## 2-cluster calibration events in IEC

- E1-DVCS

## p(e,e’p reconstruction in CLAS

- p(e,e’p reconstruction in CLAS

- E1-DVCS

## E1 - DVCS Experiment – First round

- Approved total beam time:			60 PAC days
- Proposal integrated luminosity:		100 fb-1
- Accumulated luminosity:			  36 fb-1
- Beam polarization:
- 	- Proposed			75%
- 	- Achieved 			76-80%
**	****  ***(the higher number is due to use of super lattice cathode**)*
- Maximum Luminosity:
- 	Goal: 	  Luminosity on H2	2x1034cm-2s-1
- 	Achieved: Luminosity on H2 	1.7x1034cm-2s-1
- 		  Luminosity total:		2.5x1034cm-2s-1
**	**[*2.5cm lH**2** + 0.0116 cm Al +50 cm air]*
**	****Luminosity total (H****2**** equiv.):****	****2.2x10****34****cm****-2****s****-1**** !**

## Hall B - BoNuS Experiment - CLAS

-  Measurement of “free” neutron
- structure through detection of
- spectator proton in Radial TPC.

## Slide 20

## BoNuS Target cell and Single Event Display

- Kapton straw of 4mm o
- filled with 7 atm H2, D2 gas.

##   Reduce interactions in air downstream of target ( 3-4 times 

-   Reduce interactions in air downstream of target ( 3-4 times
-    more material than in production target !)

## Hall B Run Plan

- Run 		 PAC	PAC	Target	Energy	Electron	Comment
- group		 time	rating		(GeV)	polar.
- BoNuS & SVT	(7) 	A-	D2	4.5	-	SC Solenoid
- g8b 		29	A**-**	H2	4.5	-	Goniometer, polarimeter
- e8-BoNuS	25	A**-**	D2 gas	4 & 6	-	Radial TPC
- Tentative
- eg4 (GDH)	20	A	NH3	1.2-4.0	High	New Cerenkov
- Unscheduled
- g12		35	A	H2	>5.75	-
- e1-DVCS(b) 	35	A	H2	>5.75	High	Solenoid, IC
- g9-Frost 		87	A**-**	Butanol	various	High	Frozen spin target
- eg2b		11	B+	nuclear	> 5	-
- TPE experiment	  5	A-	H2	>5.75	-	Major change in set up
-  (unscheduled)	249 (168)

## Hall B 2005-2007 Schedule 

-  Date	Experiment	days	Energy (GeV)	Rating	Polarization?
- ------------------------------------------------------------------------------------------------------------------------
- 06/20 - 09/02/05	g8b 	29	4.5 		A-	-
- 11/	  - 12/10/05	e8-BoNuS	25	4, 5.4	 A-	-
- Plan for reduced accelerator/Hall operation assuming 60-70 days of PAC running
- 2006
- 		eg4-GDH 	20	1.1–3.2 		A	High
- 		g12 	35	5.76		A	-
- 2007
- 		e1-DVCS(b)	35	6	 A	High
- 		g9a-Frost 	35	1.5 – 3.2		A-	circ/ linear
- 2008
- 		g9b-Frost	52	1.5 – 3.2	 A-	circ/linear
- 		TPE 	  5	>5.75	 A-	-
- 		eg2c	10	4-6	 B+	-

## Drift Chamber Issues

-  In early phase of E1-DVCS significant problems with
- beam stability resulting in frequent trips of DC HV due
- to high dark currents in some areas of region 2 and
- region 3.
-  Beam Offset Monitor in Fast Shut Down
-  Increase gas flow through chambers
-  Reduce humidity around chambers

-  Region 1 has two large dead areas** **that impact track
- reconstruction efficiency in two sectors.
-  To fix problem we may have to remove
-   chambers during next long machine down time.

## 12 GeV Upgrade

-  DOE Science Review: April 11-13,  2005 – no report yet, but high praise
- 	received from panel and DOE reviewers
-  Director’s Project Review (internal) May 6-8, 2005
-  Independent Project Review:  July 12-14, 2005
- 		(25 reviewers + DOE observers)
-  CD-1  approval  September 2005 (Goal)

- Sequence of events:

**Major Goal: CD-1 in FY2005**

- Personnel:
- 	Will Brooks 	=> Associate Project Manager for Physics
- 	Latifa Elouadrhiri	=> Senior Team Leader for Hall B Upgrade

## CLAS12 

- Re-using the Hall B infrastructure

## CLAS12 -  Prototyping Effort

- Component	Interested		Status
- 		Institutions
- ----------------------------------------------------------------------------------------------------------------------------
- SVT 		JLab, ODU,	Testing of stave, signal readout,
- 		Fermilab,...	parasitic beam test, ongoing
- ----------------------------------------------------------------------------------------------------------------------------
- Central TOF 	KNU, JLab		CLAS note 2005 xxx, 2004-15, 2004-39 (NIM paper)
- 				Evaluating scintillators, light guides, PMTs
- Forward TOF	USC, . .		Project R&D funds requested for FY06/07
- Central EC		JLab, NSU,..	Prototype built and tested with cosmics,
- (not currently in 			~ 60 photoelectrons/MeV in SciFi
- Project scope)
- SC Solenoid	Saclay, ITEP	Design evaluation
- SC Torus		ITEP		Design evaluation
- HT Cerenkov	RPI, ITEP, ...	Project R&D funds requested for FY07/08
- Drift chambers	??		Project R&D funds requested for FY07/08
- Pre-shower EC	Yerevan, ....	Project R&D funds requested for FY07/08

## Slide 29

## KNU: Prototyping of CD TOF

- KNU: Prototyping of** **CD TOF
- CLAS notes: 2005 – xxx, 2004-016, 2004-039 (NIM submitted)

- 50cm scintillator with
- 1m long light guides

- Resolution with short LGs: PMT~ 60ps

**Scintillator**
**3cm thick**

## CLAS12 – Silicon Vertex Tracker 

- forward track reconstruction
-  large angle tracking
- - high rate operation near target

- Silicon micro strip:

***CLAS12 – ******Silicon Vertex Tracker ***

- 45,000 channels

- A 3000 strip SVT “stave” mounted
- on Saclay solenoid during test

## CLAS12 – CD Calorimeter

***CLAS12 – ******CD Calorimeter***

*Fiber readout*

* **Polar angle *

*fibers*

*Axial fibers*

*PMTs*

*Tungsten-SciFi  *

## Tungsten-powder/SciFi calorimeter

**~60 p.e./1.5MeV in SciFi**

- 5,500 SciFi
- 0.75 mm
- diameter

- Average material
- density
- 9 g/cm3

**Radiation length = 1 cm**

## CLAS as a neutral particle detector?

- p

- Coverage for  detection
- from 3o - 1350

- FEC

- IEC

- CD EC

- 3o-135o

## PAC27/28

-  Frozen spin target experiments: PAC27 emphasized that the FST program needs organizational structure with coordination, distribution of responsibilities, detailed plan for data runs to optimize output, analysis plans, possible inclusion of other collaborators. Data runs cannot be scheduled without detailed plans.
-  PAC28: Hall B backlog is currently below the nominal 3 years (assuming 100 days/year). We plan on Hall operation until 2010. We need well developed, high class physics proposals that truly enhance the JLab physics program.
-  New instrumentation should also be useful for 12 GeV upgrade (e.g. transverse polarized target, low Q2 tagger, vertex tracker, calorimeter, ...) . This is especially important if the expected budget cuts will be realized in the coming years.