Date post: | 31-Dec-2015 |
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NON-DESTRUCTIVE SINGLE PASS MONITOR OF
LONGITUDINAL CHARGE DISTRIBUTION
P.V.Logatchov, P.A.Bak, E.A.Gousev, A.A.Starostenko, N.S.Dikansky,
M.V.Korabelnikov, S.V.Shiyankov, BINP, Novosibirsk, Russia
Contact e-mail: [email protected]
Z
Y
X
0
Linear
scattering
22 )(
)()(2)(
zx
dzznzxrx e
z
22 )(
)(2)(
zx
dzznrx e
y
dzznNe )(
dllqI
cx
B
A
<<1.
for
1. >>1,
2. max y
Single pass beam monitor is sutable tool for:
1. Longitudinal charge distribution2. Beam trains transverse distribution3. Wake-fields observation after the bunch
The longitudinal distribution of charge density in an bunch:
-10 ..- 60 kV, 5mks
Faraday cup
0..- 800 V, 30 ns
+6.2 kV, 60 ns1.2 GeV bunch
Testing beamCathode MCP Luminophore
CCD
Synchronization system
Videograbber
Electron gunmodulator
MCPmodulator
Luminophoremodulator
LensCorrector
Electron gun
Scheme of LCDM
The bunch parameters range for better then 10% time resolution of this method:
• bunch peak current: 10 A - 250 A
• bunch length: 20 ps - 2000 ps
• gamma factor: > 30
• offset parameres: < 1/6 of bunch length
Single bunch regime
Single bunch regime: offset parameter goes downSingle bunch regime: offset parameter goes down
11
33
22
44
Collision with the single bunch
Single bunch regime: offset parameter goes down
Multi bunch regime: offset parameter goes down1-4: offset parameter > 05 : offset parameter 06-8: offset parameter < 0
88765
4321
Pictures with wakes
Collision with single bunchTwo bunches
Wakes start to appear
330 ps
Wake fields 10 ns after bunch
Wake fields150 ns after bunch
The bunch with starting wakes
330 psDifferent vert. probe beam position
• Observation of the wake fields corresponded to the frequency of 8714 MHz