1. Yuhong Zhang MEIC Collaboration Meeting March 30 & 31, 2015
JLab LDRD: A Pilot Study for An Experimental Demonstration of Cooling By A Bunched Electron Beam
Yuhong Zhang
MEIC Collaboration Meeting
March 30 & 31, 2015

2. A DC e-Cooler at IMP, China
Experimental Demonstration of Cooling of Ions by a Bunched Electron Beam
All electron cooling were performed using a DC electron beam
For medium and high energy bunched proton/ion beams, cooling electron beams will be bunched ones and accelerated in RF linacs
It is general believed ion beams can be cooled by a bunched electron beam, but this has never been demonstrated before, nor its physics has been systematically studied
JLab, IMP (China) and BINP (Russia) proposed to experimentally demonstrate this technology at one of the IMP e-coolers
Idea: replacing the thermionic gun power supplier by a RF source (commercially available) and use it to modulate the grid voltage, thus the bunch length
Experimental results
Help physics understanding
Guide the machine design
Be used for code benchmarking
A DC e-Cooler at IMP, China

3. The JLab Role in the Cooling Demo Collaboration & Deliverables of This Proposal
Finalize the joint proposal for submission to Chinese funding agency and IMP program advisory committee (JLab, IMP and JINR)
Identify and bench test RF power sources (IMP)
Construct a high voltage platform as a test stend for the experiment (IMP)
Run the grid-voltage modulated thermionic gun and take measurements of cooling electron beam (IMP, JINR and JLab)
Perform cooling simulations using the measured beam parameters (JLab and IMP)
Create an experiment test plan (JLab, IMP and JINR)
Conduct experiment (JLab, IMP and JINR)
Supported by LDRD

4. Additional Information
Circumference m 16 1
Ion type 12 C +6
Kinetic
energy
MeV /u
7.0
Revolution time s
4.4
Revolution frequency
KHz
227
Number
of ions 10 9
Cooling
section length
3.4
Electron
current mA 00 DC
cooling time
~0.5
Emittance
----
------
Energy
spread
RMS î - 3
What is the realistic distribution function?
How to input this into the simulation code?
How to determine the density profile (weak focusing)