h- low energy emittance measurements to optimize injections into an rfq christoph gabor
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H- Low Energy Emittance measurements to Optimize Injections into an RFQ Christoph Gabor ASTeC (south) , Rutherford Appleton Laboratory. The Front End Test Stand Collaboration. Mike Perkins John Back Ajit Kurup Ciprian Plostinar Mike Clarke-Gayther Phil Wise Javier Bermejo Julio Lucas - PowerPoint PPT PresentationTRANSCRIPT
[email protected]/ Spain, Ditanet Diagnostics Conf., 2011 slide 1
H- Low Energy Emittance measurements to Optimize
Injections into an RFQ
Christoph GaborASTeC(south),
Rutherford Appleton Laboratory
[email protected]/ Spain, Ditanet Diagnostics Conf., 2011 slide 2
Companies:Tekniker, Jema, Elyt
Diversified TechnologyToshiba
Further collaboration:CERN
IHEP, ChinaFermilab
IAP, Frankfurt University
Dan FairclothSimon JollyScott Lawrie
David LeeAlan Letchford
Jürgen PozimskiPeter Savage
Christoph GaborMark Whitehead
Trevor WoodsGary BoormanAlessio Bosco
Mike PerkinsJohn BackAjit Kurup
Ciprian PlostinarMike Clarke-Gayther
Phil WiseJavier Bermejo
Julio LucasJesus Alonso
Rafael EnparantzaGrahame BlairZunbeltz IzaolaIbon Bustinduy
The Front End Test Stand Collaboration
[email protected]/ Spain, Ditanet Diagnostics Conf., 2011 slide 3
Outline of the talk
Details of the Low Energy Beam Transport (LEBT), diagnostics hardware, i.e. emittance scanner
Front End Test Stand FETS at RALOverview of the project
Experimental results anddiscussion of measurements
(PD) Diagnostic & Support
Beamstop
IonSource
(PD) Emittance Measurement
3 Solenoids90
sect
or
ma
gn
et LEBT RFQ324 MHz3 MeV
MEBTDiagnosticQuads,
Buncher,Chopper
Fron
t slit
of t
he IS
IS
emitt
ance
sca
nner
, wat
er-
cool
ed, p
ower
dep
ositi
on
up to
600
W p
ossi
ble
[email protected]/ Spain, Ditanet Diagnostics Conf., 2011 slide 4
The main components of the beamline are.....
65 keV, 60 mA, 2 ms, 50 Hz, H– Ion Source
3 Solenoid Magnetic LEBT
324 MHz, 3 MeV, 4 Vane RFQ
MEBT and Beam Chopper
Beam Diagnostics and Beam DumpThe LEBT transforms the
the divergent into a convergent beam tomatch the acceptanceof the RFQ.
In high power applications typical problems are high space charge forces and (large) divergence angles.
[email protected]/ Spain, Ditanet Diagnostics Conf., 2011 slide 5
Beam travels through sector magnet, post acceleration and solenoid LEBT.
Isolating Column
1×10-4 mBar
6×10-5 mBar
Beam shutter
Slit-slit scanners
5×10-6 mBar
Retractable Faraday Cup
2000 Ls-1 Turbo Pump
Pepper pot or profile scintillator
head
Camera7×10-6 mBar
Solenoid 3
Toroid3
Solenoid 2
Solenoid 1
Toroid 1
Toroid 2
4 × 800 Ls-1 & 1 x 400 Ls-1 Turbo Pumps
Differential pumping and laser
profile vessel
400 Ls-1 turbo pump
Diagnostics vessel
Toroid 4
[email protected]/ Spain, Ditanet Diagnostics Conf., 2011 slide 6
Laser
Diagnostics Vessel
3 Solenoid LEBT
Ion Source
[email protected]/ Spain, Ditanet Diagnostics Conf., 2011
Design now complete for the 4m long, 3MeV, 324MHz 4—vane RFQ
horizontal, vertical
x, yx’, y’
+/- 2mm+/- 100mrad
rms
0.25 mmmrad 0.840.032 mm/mrad
Sections made of 2 major and 2 minor vanes
3D o-ring
[email protected]/ Spain, Ditanet Diagnostics Conf., 2011 slide 8
Two independent slit—slit scanner are installed in a multipurpose diagnostics vessel.
0.25 x 60 mm position
sampling slit
0.08 x 60 mm slit and
Faraday cup
500 V Electron Suppressor
Scan in one plane with resolution used for this work ~13min1mrad, 0.25mm: Mechanical resolution is enhanced by oversampling (Lucy—Richardson Deconvolution)For data processing, bias, threshold and SCUBeX can be applied.
(for more information see M.P. Stockli et al., AIP Conf. Proc. 639, pp135 2002)
[email protected]/ Spain, Ditanet Diagnostics Conf., 2011 slide 9
17keV 20keV 35keV 40keV 60keV
17keV 20keV 35keV 40keV 60keV
ho
rizo
nta
lv
ert
ica
l
v/ h006 1-0075_2 01108 09
0
10
20
30
40
50
60
1 2 3 4
Toroid No. 1...4Bea
mC
urre
nt/m
A17keV 20keV
30keV 40keV
50keV 60keV
35 45 55 65
unnormalized emittance100% emittance
based on SCUBeX algor ithm
Beam energy /keV20
40
60
80
100
120
15 25
rms,
SC
UB
eX e
mitt
an
ce /
m
mm
rad
possible exaggeration due to truncated beam
Solenoids were set to same field,
equivalent to 70A.
verticalhorizontal
B [T] ~1.4*10-3*I
[I / Ampere]
Variation of the beam energy with constant extraction voltage of 17kV.
[email protected]/ Spain, Ditanet Diagnostics Conf., 2011 slide 10
Constant beam energy of 65keV at different solenoid settings and beam currents up to 60mA.
S =137A, S =0A, S =0A
1
2 3
S =137A, S =0A, S =100A
1
2 3
S =137A, S =100A, S =100A
1
2 3
S =137A, S =100A, S =150A
1
2 3
S =137A, S =123A, S =216A
1
2 3
vert
ica
lh
ori
zon
tal
147...156_20110817
y = -30.....+60mm
y =
-8
0..
...+
80
mra
d
x = -60.....+30mm
100%,norm (SCUBeX)=0.502 mm mrad
100%,norm(SCUBeX)=0.594 mmmrad
100%,norm (SCUBeX)=0.446 mm mrad
100%,norm(SCUBeX)=0.546 mm mrad
100%,norm(SCUBeX)=0.604 mm mrad
100%,norm(SCUBeX)=0.459 mmmrad
100%,norm(SCUBeX)=0.765 mm mrad
100%,norm(SCUBeX)=0.560 mm mrad
100%,norm(SCUBeX)=0.564 mm mrad
100%,norm (SCUBeX)=0.438 mm mrad
[email protected]/ Spain, Ditanet Diagnostics Conf., 2011 slide 11
Fractional rms—emittance versus different post acceleration gap lengths & extraction system.
Green: PA=13mm (v)Red: PA=6mm (v)Blue: PA=13mm (v)Solenoids off:Black: PA=13mm (V)dash: PA=13mm (h)
Definition of fractional rms-emittance
• Calculate sum of 100 of all pixel-intensities • Sort intensities from top by their contents• Sum them up until the fraction p% from 100
is reached• Use the pixels included in this sum for the rms—emittance.
0.01
0.10
1.00
10.0
100
0 0.2 0.4 0.6 0.8
Inte
ns
ity
10
0-%
norm / m m m rad
horizontal, all off, PA=13m m
focussing,PA=13m m
focussing,PA=6m m ve
rtic
al
0.01
0.10
1.00
10.0
100
0 0.1 0.2 0.3 0.4 0.5 0.6
Inte
ns
ity
10
0-%
norm / m m m rad
vertical em ittances
extr
act
jaw
1.1m
m w
ide
extract jaw2.1m m wide
S1=115A, S2=0A, S3=70A
40keV40keV
[email protected]/ Spain, Ditanet Diagnostics Conf., 2011 slide 12
Summary and Outlook.
Horizontal 0.49 πmm.mRad (rms norm.)
Vertical 0.29
πmm.mRad (rms norm.)
The most urgent problem to solve is the misaligned beam in both transverse planes.Displacement depends heavily on solenoid/ PA settings and is not easily to correct with implemented steerer magnets.
[email protected]/ Spain, Ditanet Diagnostics Conf., 2011 slide 13
Thank you for your attention
Questions, Comments?
[email protected]/ Spain, Ditanet Diagnostics Conf., 2011 slide 14
Sector magnet, post acceleration and LEBT with dimensions in long./ radial direction.
[email protected]/ Spain, Ditanet Diagnostics Conf., 2011 slide 15
The PA influences the beam with its lens effect, measured with a scintillator at z~1st solenoid.
The effective focusing depends on current and chosen beam energy, assuming that the gap is constant. It is difficult to estimate the best compromise for both transverse planes.