Transcript LDRD 2: Bunched Beam Cooling Demo

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
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
A DC e-Cooler at IMP, China
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
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
Additional Information
cathode
control
anode
Circumference
m
161
MeV/u
7.0
µs
4.4
• What is the realistic distribution function?
• How to input this into the simulation code?
• How to determine the density profile (weak
focusing)
Revolution frequency
KHz
227
Pulse
Number of ions
109
1
m
3.4
Electron current
mA
100
DC cooling time
s
~0.5
----
------
RMS
1î 10-3
12C+6
Ion type
Kinetic energy
Revolution time
Cooling section length
Emittance
Energy spread
Repetition rate
KHz
227
Time between pulses
μs
4.4
Pulse length range
μs
0.4 – 4.0
Raise/full time
μs
-------
Peak current
mA
~10