G. E. Dodge

Experimental determination of the evolution of the Bjorken integral at low Q**2

We extract the Bjorken integral Gamma1(p-n) in the range 0.17 < Q2 < 1.10 GeV2 from inclusive scattering of polarized electrons by polarized protons, deuterons, and 3He, for the region in which the integral is dominated by nucleon resonances. These data bridge the domains of the hadronic and partonic descriptions of the nucleon. In combination with earlier measurements at higher Q2, we extract the nonsinglet twist-4 matrix element f2.

The CLAS drift chamber system

Abstract Experimental Hall B at Jefferson Laboratory houses the CEBAF Large Acceptance Spectrometer, the magnetic field of which is produced by a superconducting toroid. The six coils of this toroid divide the detector azimuthally into six sectors, each of which contains three large multi-layer drift chambers for tracking charged particles produced from a fixed target on the toroidal axis. Within the 18 drift chambers are a total of 35,148 individually instrumented hexagonal drift cells. The novel geometry of these chambers provides for good tracking resolution and efficiency, along with large acceptance. The design and construction challenges posed by these large-scale detectors are described, and detailed results are presented from in-beam measurements.

A polarized target for the CLAS detector

Abstract We describe the design, construction, and performance of a polarized solid target for use in electron scattering experiments with the CEBAF Large Acceptance Spectrometer. Protons and deuterons are continuously polarized by microwave-induced spin–flip transitions at 1 K and 5 T . The target operated successfully during two cycles in 1998 and 2000, providing proton and deuteron polarizations as high as 96% and 46%, respectively. The unique features of the target which permit its use inside a 4π spectrometer are stressed. Comparison is made between the target polarization measured by the traditional method of NMR and by electron elastic scattering.

Experimental study of isovector spin sum rules

We present the Bjorken integral extracted from Jefferson Lab experiment EG1b for

High momentum transfer RT,L inclusive response functions for 3,4He.

0.05l{Q}^{2}l2.92\text{ }\text{ }{\mathrm{GeV}}^{2}

Electroproduction of neutral pions on the proton

. The integral is fit to extract the twist-4 element

Differential cross sections for pion charge exchange on the proton at 27.5 MeV

{f}_{2}^{p\ensuremath{-}n}

The 4He(e, e′p) cross section at large missing energy

which appears to be relatively large and negative. Systematic studies of this higher twist analysis establish its legitimacy at

Prototype studies and design considerations for the CLAS Region 2 drift chambers

{Q}^{2}

A Recoil Detector for electron scattering experiments with internal targets

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