Life Cycle of a Nuclear Physics Experiment by Douglas W. Higinbotham
What was that mysterious PAC thing?! ( The Jefferson Lab Program Advisory Committee ) We learn the results of this years PAC at high noon today!
Nuclear Physics Experiments Idea (questions) Proposal (writing & collaboration building) PAC Defense (Typically only 1/3 of proposals pass this point) Jeopardy after several years (i.e. defend again) Funding (no money, no experiment) Construction Readiness Review (for major experiments) Running Analysis (generates Ph.D.’s in nuclear physics) Publication (new questions) Repeat As Needed
Quasi-Elastic Electron Scattering p e' scattering plane pq reaction plane (,q) e pA–1 x “out-of-plane” angle Energy transfer: = e – e’ Four-momentum transfer: Q2 – qq = q2 – 2 Missing momentum: pm = q – p = pA–1
Nuclear Fermi Momenta E. Moniz, I. Sick, R. Whitney, et al., Phys. Rev. Lett. 26 (1971) 445. Fitted with Fermi Gas Model and nice got the shape of Quasi-Elastic peak. NOTE: Missing low omega, high omega, and needs a normalization factor.
Moniz became US Secretary of Energy and is also known for his amazing hair.
A Classic Problem: A(e,e’p) Scattering Rates Independent-Particle Shell-Model is based upon the assumption that each nucleon moves independently in an average potential (mean field) induced by the surrounding nucleons The (e,e'p) data for knockout rate is 60 – 70% of the mean field prediction. SPECTROSCOPIC STRENGTH Target Mass
Possible Answer: Short-Range Correlations 2N-SRC 5o 1.7fermi o = 0.17 GeV/fermi3 Nucleons Nucleon are made up of Quarks, does NOT violate Pauli exclusion principle!
Propose Custom (e,e’pN) Measurement To study nucleon pairs at close proximity and their contributions to the large momentum tail of nucleons in nuclei. A pair with “large” relative momentum between the nucleons and small center of mass momentum Approved by the 2001 Program Advisory Committee
Kinematics and Neutron Detector
Jefferson Lab's Hall A setup for (e,e’p)
Jefferson Lab’s Hall A
Design The New Equipment
BigBite Dipole Magnet
Making BigBite & Neutron Detector JLab buys NIKHEF BigBite Magnet Tel Aviv - Auxiliary Plane Glasgow - Trigger Plane UVa MRI - Scattering Chamber Kent State –Neutron Detectors
New Proton & Neutron Detector
Take Data & Analysis, Analysis, Analysis Three Ph.D. Students Several Years Of Work Use the detectors to “see” passage of particles through matter. Determining Physics Quantities Comparing with Theory
High pm (e,e’p) events have recoiling neutrons. R. Subedi et al., Science 320 (2008) 1476.
Publications Science Article Physical Review Letter Ph.D. Theses Physics Today CERN Courier While explaining your work to others is the last step, in many ways it is the most important!
Modern AV18 and Urbana-X Results R. Wiringa, R. Schiavilla, S. Pieper, and J. Carlson, Phys. Rev. C89 (2014) 024305.
Next Generation SRC Experiment With 3H and 3He E12-14-011: Measurement of the ratio of 3He(e,e’p) to 3H(e,e’p) vs. missing moment. 3He has two protons and 3H has one, so even kids can figure that one out... ( this was one of many tritium target experiments, the first from 2006 )
First Beam On JLab Tritium Target Cell On Friday the 15th of December 2017, Hall A put first beam on a tritium target cell. The face of a graduate student when they finally put beam on their physics target.
The preliminary result from 2018.
Paper is now been submitted for publication
Who Cares?!
Kathy McCormick Cares Homeland Security
Gordon Cates cares MRI Imaging The Lungs
Tancredi Botto Cares Schumburger Oil Exploration
Hampton Proton Therapy Cynthia Keppel Cares Hampton Proton Therapy
James Simons Cares 52th Person on Forbes Billionaires Club 2018 Renaissance Technologies, Renaissance Technologies
James Maxwell Cares Movie Consulting: Ghostbusters
And, of course, Ernest Moniz Cares!