[Nuclear] undergrad poster at DNP meeting

[Jerry Gilfoyle]

Dear NPWGers,

I have some undergraduates working for me this summer on some CLAS12
related projects who want to present posters at the Conference Experience
for Undergraduates (CEU) held at the fall, DNP meeting. The CEU due date is
August 1. Drafts of their abstracts are below for your comments. Let me
know what you think.

Jerry Gilfoyle

---

Dual Target Design for CLAS12 $^1$ OMAIR ALAM, GERARD GILOYLE,
University of Richmond, STEVE CHRISTO, Jefferson Lab –  An experiment
to measure the neutron magnetic form factor ($G^M_n$) is planned for
the new CLAS12 detector in Hall B at Jefferson Lab. This form factor
will be extracted from the ratio of the quasielastic electron-neutron
to electron-proton scattering off a liquid deuterium ($LD_2$) target.
A collinear liquid hydrogen ($LH_2$) target will be used to measure
efficiencies at the same time as production data is collected from the
$LD_2$ target. To test target designs we have simulated CLAS12 and the
target geometry. Electron-nucleon events are produced first with the
QUasiElastic Event Generator (QUEEG) which models the internal motion
of the nucleons in deuterium.$^2$ The results are used as input to the
CLAS12 Monte Caro code gemc; a Geant4-based program that simulates the
particle’s interactions with each component of CLAS12 including the
target material. The dual target geometry has been added to gemc
including support structures and cryogenic transport systems. A Perl
script was written to define the target materials and geometries. The
output of the script is a set of database entries read by gemc at
runtime. An initial study of the impact of this dual-target structure
revealed limited effects on the electron momentum and angular
resolutions.

1 Work supported by the University of Richmond and the US Department
of Energy.



Study of the Neutron Detection Efficiency for the CLAS12 Detector$^1$
KEEGAN SHERMAN, GERARD GILFOYLE, University of Richmond -
One of the central physics goals of Jefferson Lab is to understand how
quarks and gluons form nuclei. The 12 GeV upgrade is nearing completion
and a new detector, CLAS12, is being built in Hall B. One of the approved
experiments will measure the magnetic form factor of the neutron. To make
this measurement, we will extract the ratio of electron-neutron (e-n) to
electron-proton (e-p) scattering events from deuterium in quasi-elastic
kine-
matics. A major source of systematic uncertainty is the neutron detection
efficiency (NDE) of CLAS12. To better understand the NDE we used the
Monte Carlo code gemc to simulate quasi-elastic e-n events like those ex-
pected in the experiment. We then analyzed the simulated e-n events by
using the measured, scattered electron information to predict the neutron’s
path. The neutron is detected in CLAS12’s electromagnetic calorimeter (EC).
If the predicted neutron path intersected the fiducial volume of the EC, we
searched for a hit near that point. The NDE is the ratio of the number of
neutrons found in the EC to the number of neutrons predicted to hit the EC.
The analysis was done using the newly released CLAS12 reconstruction tools.
We observe a rapid rise in the NDE at low neutron momentum and a plateau
above 60%.

1 Work supported by the University of Richmond and the US Department
of Energy.



Cryotarget Control Software for Liquid Deuterium^1 DAVID BRAKMAN, GERARD
GILFOYLE, University of Richmond; CHRIS CUEVAS, STEVE CHRISTO, Jefferson
Lab - One of the experiments in Hall B at Jefferson Lab will measure the
neutron elastic magnetic form factor with a 12 GeV electron beam striking
a liquid deuterium target (LD2) and measuring the resulting debris in the
CEBAF Large Acceptance Spectrometer (CLAS12). A program was created that
acts as a control system for the LD2 target. It will monitor the
deuterium target and send data to the main control system and the shift
workers monitoring the experiment in real time. The data include
measurements of pressure, temperature, and liquid level. The system will
also control setpoints for temperature, heater power, and other parameters
as well as download calibration curves. The program was written in LabVIEW,
a graphical programming language noted for readily interfacing with lab
equipment. This project has completed two stages so far. Simulated data
was generated within LabVIEW and passed to subroutines that send, log, and
display data. In the second stage, the PC was connected to a data
acquisition (DAQ) board, and test signals were read and analyzed to
simulate the target sensors.

1 Work supported by the University of Richmond and the US Department
of Energy.


-- 
Dr. Gerard P. Gilfoyle
Physics Department
University of Richmond, VA 23173  USA
e-mail: ggilfoyl at richmond.edu
phone:  804-289-8255
fax:    804-484-1542
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