Transcript MERIT beam spot from optics (update of July 16,2008 talk) I.Efthymiopoulos – CERN, AB Dept. MERIT, VRVS Meeting September 25, 2008

MERIT beam spot from optics
(update of July 16,2008 talk)
I.Efthymiopoulos – CERN, AB Dept.
MERIT, VRVS Meeting
September 25, 2008
MERIT Elements – Layout
QDE.430s (de-focusing) quads
3 elements in series
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QFO.415s (focusing) quads
3 elements in series
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Survey data after the MERIT run – 18.12.2007
Upstream face: -72.3cm
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Beam optics
 Fit parameters: QFO, QDO strengths and locations (within limits)
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Beam envelope (1-sigma) - =0.25 (mm.mrad), Dp=0.1%
 Without dispersion term


s(x) = 1.2mm , s(y) = 1.1 mm
238 J/gr @ 30TP
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 With dispersion term


s(x) = 2.2mm , s(y) = 1.1 mm
130 J/gr @ 30TP
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Reminder – Beam Emittance
 For proton machines, the emittance is measured by measuring the beam
profile in a position of known beam parameters (optics)
 The convention is to use TWO sigma value
Geometrical emittance:
 protons 
s
Normalized emittance:
(2s )2
 *  (  )  ,  

2s
Emittance
(87% of beam)
s 
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P
[GeV/c]
()
14.0
14.92
24.0
25.58
What is measured in the machine:
Including dispersion

p 
     D p


p


P0
M0
2
 2s
 f ( 4s fit t edwidt h,
p
p

p
 w4s 
D

 
p

p 2s
 2 


2

)
2s
2




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Beam Emittance measurement – 14 GeV/c
 Friday 26.10@15:55
Beam intensity:
 h16, 1E13
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Beam Emittance measurement – 14 GeV/c
 Friday 26.10@17:37
Beam intensity:
 2.5E11/bunch
 2 extracted bunches,
 DT=1.7us
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Beam Emittance measurement – 14 GeV/c
 Friday 26.10@18:24
Beam intensity:
 1.3E12/bunch
 2 extracted bunches,
 DT=1.7us
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Beam Emittance measurement – 24 GeV/c
 Friday 02.11@14:55PM
Beam intensity:
 2.5E11/bunch
 16 bunches
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Beam Emittance measurement – 24 GeV/c
 Friday 02.11@16:02PM
Beam intensity:
 16 bunches,
 6E12 protons
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Beam Emittance measurement
 Summary of measured data
 Using the formulas of slide #6

in good agreement with the online calculations
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Emittance extrapolation
Transverse emittance (2s) in TT2
45.000
40.000
MERIT-Eh
MERIT-Ev
Linear (MERIT-Eh)
Linear (MERIT-Ev)
35.000
Eh[2sigma-norm]= 11.23 Intensity[e13] + 1.5998
Eh & Ev [norm]
30.000
R² = 0.6783
25.000
20.000
15.000
Ev[2sigma-norm] = 6.0664 Intensity[e13] + 5.6415
10.000
R² = 0.6321
5.000
0.000
0.0000
0.5000
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1.0000
1.5000
2.0000
2.5000
Beam intensity (1E13)
3.0000
3.5000
4.0000
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Estimated beam spot and density
 Use the extrapolated emittances to estimate the beam spot and
energy density at target
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