Friday am 1020 Friday am 1027 Achievement so far Have confirmed the bucking solenoid can be operated at high current without much impact on operation vacuum OK one power supply trip but issues was not reproduced so far ID: 697996
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Slide1
Summary
Three shifts
Sunday (1/2 day) 10-15
Friday am 10-20
Friday am 10-27
Achievement so far:
Have confirmed the bucking solenoid can be operated at high current without much impact on operation (vacuum OK, one power supply trip but issues was not reproduced so far)
Have produced magnetized beam with acceptable magnetization [e.g. of interest for magnetized e-cooling (
Jlab
) and for flat beam generation].
Attempted flat beam
transfomationSlide2
Pushing the B field on photocathode
Slight vacuum activity when bucking solenoid is set to large current
But value has been decreasing over shifts
10-15-17
10-20-17
10-27-17Slide3
Estimate
of
magnetization
Magnetization estimated
from
Spot on X107 cannot bemeasured directly so estimated
from slits separation and spot size at X111X107 CCD addition will be very helpful
Bucked
configuration
Bucking B=280A
Bucking B=250A
Slit images at X111
Bucking current, A
Rotation angle, (
deg
)
<L >,
250A818.3280A1419.8300A1725.3
Bucking current, ARotation angle, (deg)250A818.3280A1419.8300A1725.3
Bucking B=300ASlide4
Scaling of magnetization
Magnetization:
Linear scaling vs applied field
on cathode is
observed
Could not measure the spot
on
cathode (interference with green laser)
-- preliminary --Slide5
X111
X120
First attempt of RTFB
Quadrupole currents calculated with Impact-T +
MagnetOptimizer
Need to match the energy for correct scaling!
Why tilted?
Need to optimizeSlide6
1. M
agnetization
: we need a set of consistent/presentable
data of L vs B (and possibly vs sigma_cath) 80% Ready
2. Flat beam: a
) dynamics in the RFTB, measure beam after each quadrupole to demonstrate decorrelation process, use X111 and X120 to demonstrate flat beam is
produced b) parametric study of emit versus L; probably need to measure the emittance using a quadrupole scan
c) parametric study of emit versus chirp. 30% Ready
3.
C
ompressed
flat beam: for the best flatness (smallest emittance achieved) demonstrate the generation of a compressed bunch. We need to have the Michelson interferometer operational to be able to quote a peak current in addition to the emittance. We could measure the emittance as function of
chirp. 0% ready
Feasible experimental planSlide7
Cathode spot-size measurement (confusion)
S/N very small and UV spot is off the VC
VIRTUAL CATHODE (LIN)
VIRTUAL CATHODE (LOG)
This is NOT UV?
This is NOT UV?
UV spot?Slide8
Next Steps
Take ”presentable” data on angular momentum and scaling vs B and
cathode spot size (if possible)
–
X107 will be very helpful, also need to clear some misunderstanding on the virtual cathode
Test an alternative simple technique to measure the magnetization
Attempt decorrelation to produce flat beams1st attempted at end of 10-27 shift
but did not succeed. Main focus of our next couple of shifts
Once (3) is complete:
Identify beam parameter range of interest (Q, E,
…
) and take dataDemonstrate and characterize compression of flat beam (once X118 available).