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Recents results and future measurements for few body problems in Hall A
I will summarize the latest results in Hall A linked to Few-Body problems and the future measurements planned after the 12 GeV upgrade
Hard photodisintegration of a proton pair
We present a Study of high energy photodisintegration of proton-pairs through the gamma + (3)He -\u3e p + p + n channel. Photon energies, E(gamma), from 0.8 to 4.7 GeV were used in kinematics corresponding to a proton pair with high relative momentum and a neutron nearly at rest. The s(-11) scaling of the cross section, as predicted by the constituent counting rule for two nucleon photodisintegration, was observed for the first time. The onset of the scaling is at a higher energy and the cross section is significantly lower than for deuteron (pn pair) photoclisintegration. For E(gamma) below the scaling region, the scaled cross section was found to present a strong energy-dependent structure not observed in deuteron photodisintegration. (C) 2010 Elsevier B.V. All rights reserved
NaI (Tl) Calorimeter Calibration and Simulation for Coulomb Sum Rule Experiment in Hall-A at Jefferson Lab
A precision measurment of inclusive electron scattering cross sections was
carried out at Jefferson Lab in the quasi-elastic region for He,
C, Fe and Pb targets. Longitudinal () and
transverse () response functions of nucleon were extracted in the
momentum transfer range 0.55 GeV/c1.0 GeV/c. To achieve the
above goal, a NaI (Tl) calorimeter was used to distinguish good electrons from
background including pions and low energy electrons rescattered from walls of
the spectrometer magnets. Due to a large set of kinematics and changes in HV
settings, a number of calibrations were performed for the NaI (Tl) detector.
Corrections for a few blocks of NaI (Tl) with bad or no signal were applied.
The resolution of NaI (Tl) detector after calibration reached at E=1 GeV. The performance of NaI (Tl) detector was
compared with a simulation
Quasi elastic cross sections for the Bi-209(e, e \u27 p)Pb-208 reaction: Jefferson Lab experiment E06007
Quasi elastic cross sections were measured for the first time for both negative and positive missing momenta for the Bi-209(e, e\u27p)Pb-208 reaction leading to the ground state and hole states of Pb-208. Experimental cross sections obtained between -0.3 GeV/c to 0.3 GeV/c agree with theoretical calculations using RDWIA techniques both in shape and magnitude for the ground state. The data for the ground state production of Pb-208 are consistent with a theoretical model assuming a single proton(1.06 +/- 0.10) in the 1h9/2 orbit in Bi-209
Exclusive neutral pion electroproduction in the deeply virtual regime
We present measurements of the ep -\u3e ep pi(0) cross section extracted at two values of four-momentum transfer Q(2) = 1.9 GeV(2) and Q(2) = 2.3 GeV(2) at Jefferson Lab Hall A. The kinematic range allows one to study the evolution of the extracted cross section as a function of Q(2) and W. Results are confronted with Regge-inspired calculations and GPD predictions. An intepretation of our data within the framework of semi-inclusive deep inelastic scattering is also discussed
Improved synthesis of [ 11 C]methylaminobenzovesamicol
An efficient two‐step synthesis of the potential cholinergic neuronal mapping tracer [ 11 C]methylaminobenzovesamicol (MABV) is described. A tert ‐butoxycarbonyl protecting group was used to activate the aniline nitrogen of aminobenzovesamicol toward [ 11 C]methyl iodide methylation under basic conditions. Following labeling, the protecting group was removed by brief acid treatment and the final product was purified by normal phase HPLC. The decay corrected yields of MABV are in the range of 30‐70 %, based on 11 CO 2 , with a specific activity of 0.5‐1.5 Ci/ μmol and synthesis time of less than 45 minutes. This new route makes clinical scale doses of this interesting compound available for human positron emission tomography studies.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90085/1/2580310402_ftp.pd
A high-finesse Fabry-Perot cavity with a frequency-doubled green laser for precision Compton polarimetry at Jefferson Lab
A high-finesse Fabry-Perot cavity with a frequency-doubled continuous wave
green laser (532~nm) has been built and installed in Hall A of Jefferson Lab
for high precision Compton polarimetry. The infrared (1064~nm) beam from a
ytterbium-doped fiber amplifier seeded by a Nd:YAG nonplanar ring oscillator
laser is frequency doubled in a single-pass periodically poled MgO:LiNbO
crystal. The maximum achieved green power at 5 W IR pump power is 1.74 W with a
total conversion efficiency of 34.8\%. The green beam is injected into the
optical resonant cavity and enhanced up to 3.7~kW with a corresponding
enhancement of 3800. The polarization transfer function has been measured in
order to determine the intra-cavity circular laser polarization within a
measurement uncertainty of 0.7\%. The PREx experiment at Jefferson Lab used
this system for the first time and achieved 1.0\% precision in polarization
measurements of an electron beam with energy and current of 1.0~GeV and
50~A.Comment: 20 pages, 22 figures, revised version of arXiv:1601.00251v1,
submitted to NIM
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