1
The SARAF accelerator commissioning
Dan BerkovitsOn behalf of SARAF team
Soreq NRC
Seminar @ FNALFebruary 10, 2011
D. Berkovits Feb 10 2011 @ FNAL2
SARAF – Soreq Applied Research Accelerator Facility• To enlarge the experimental nuclear
science infrastructure and promote research in Israel
• To develop and produce radioisotopes primarily for bio-medical applications
• To modernize the source of neutrons at Soreq and extend neutron based research and applications
D. Berkovits Feb 10 2011 @ FNAL3
SARAF Accelerator ComplexParameter Value Comment
Ion Species Protons/Deuterons M/q ≤ 2
Energy Range 5 – 40 MeV
Current Range 0.04 – 2 mA Upgradeable to 4 mA
Operation 6000 hours/year
Reliability 90%
Maintenance Hands-On Very low beam loss
Phase I - 2009 Phase II - 2016
D. Berkovits Feb 10 2011 @ FNAL4
SARAF Accelerator
PSM – Prototype Superconducting Module
D. Berkovits Feb 10 2011 @ FNAL5
SARAF phase I linac – upstream view
A. Nagler, Linac-2006 C. Piel, EPAC-2008 A. Nagler, Linac-2008 I. Mardor, PAC-2009L. Weissman, Linac 2010
6
Beam lines downstream
the linac
PSM
Beam dump
target
D. Berkovits Feb 10 2011 @ FNAL7
beam
RF power supply2.45 GHz
Plasma chamber
High voltage
extractor
Magnetic solenoid
Vacuum pump 5x10-6 mbar
RF Waveguide& DC-breaker
Focusing solenoid
ECR Ion Source (ECRIS)C. Piel EPAC 2006
F. Kremer ICIS 2007
K. Dunkel PAC 2007
extraction
electrodes20 kV/u
107 mm
gas inlet 1 sccm
RF power 800 W
magnetic coils on ground
cooling water
insulator
D. Berkovits Feb 10 2011 @ FNAL8
LEBT – emittance measurement
wireslitaperture
P. Forck JUAS 2003
5 mA proton beam optics
RFQ entranceECR
C. Piel EPAC 2006
F. Kremer ICIS 2007
K. Dunkel PAC 2007
ECR
magnetic mass
analyzer
FC
aperture
D. Berkovits Feb 10 2011 @ FNAL9
EIS: measured emittance values
ParticlesBeam current
ProtonsX / Y
H2+
X / YDeuterons
X / Y
5.0 mA 0.20 / 0.17 0.34 / 0.36 0.13 / 0.12
2.0 mA 0.13 / 0.13 0.30 / 0.34 0.14 / 0.13
0.04 mA 0.18 / 0.19 0.05 / 0.05
erms_norm._100% [p mm mrad]
Specified value = 0.2 / 0.2 [p mm mrad]
EIS has been in routine operation since 2006
• H2+ planned for mimicking deuterons
• Results due to non-optimized ECR and molecular breakup
D. Berkovits Feb 10 2011 @ FNAL10
SCUBEEx Analysis
0
0.02
0.04
0.06
0.08
0.1
0.12
0 1400 2800 4200 5600 7000Exclusion Ellipse SAP
No
rm. R
MS
Em
it.
-30 -10 10 30-50
-30
-10
10
30
x [mm]
x' [m
rad
]
Elliptical Exclusion
0
0.05
0.1
0.15
0.2
0.25
0.3
0 1400 2800 4200 5600 7000Exclusion Ellipse SAP
No
rm. R
MS
Em
it.
aperture cut to 5.0 mA
deuterons
6.1 mAopen
aperture
deuterons emittance results
-30 -10 10 30-50
-30
-10
10
30
x [mm]x' [m
rad
]
p mm mrad
B. Bazak JINST 2008
emittance analysis with the SCUBEEx code by M. P. Stockli and R.F. Welton, Rev. Sci. Instr. 75 (2004) 1646
2D plot current scale is enhanced in order to present the tail
D. Berkovits Feb 10 2011 @ FNAL11
LEBT – emittance measurement
wireslitaperture
P. Forck JUAS 2003
5 mA proton beam optics
RFQ entranceECR
C. Piel EPAC 2006
F. Kremer ICIS 2007
K. Dunkel PAC 2007
ECR
magnetic mass
analyzer
FC
aperture
12
Use neutrals for tune LEBTx-x’ y-y’
Idipole=38.65 A
Idipole=38.95 A
Idipole=38.80 A
L. Weissman et al.linac 2010 TUP74
D. Berkovits Feb 10 2011 @ FNAL13
On site 2006
P. Fischer EPAC 2006
In factory 2005
176 MHz Radio Frequency Quadrupole
D. Berkovits Feb 10 2011 @ FNAL14
• Parting from the linear relation indicates onset of dark current due to poor conditioning
• All 4 RFQ pickups showed similar results
RFQ power gain vs. forward power
0
50
100
150
200
250
300
0 50 100 150 200 250 300
FPower (kV)
Pic
kup
V^
2(kW
)
4-Jul
9July
10July
Linear
Forward power (kW)
A. Nagler et al., LINAC08
RFQ voltage squared as a function of RFQ input power
deuterons
protons
For 3 MeV Deuterons:65 kV @ 176 MHz
1.6 Kilpatrick ~ 255 kW CW w/o beam
65 kW/m
Input Power [kW]Duration
[hrs]
190( CW) 12
210( CW) 2
240( CW) 0.5
260( DC = 80% @ 440 Hz)
0.5
2008
15
Non-linearity of voltage response, High x-ray background
Discharge between the back rods and the stems supporting neighboring rods
Discharge between the rods and stems
In spring 2009 the rods were modified locally to reduce the parasitic fields.
This solved the problem of discharge.
I. Mardor, PAC 2009L. Weissman, Linac 2010J. Rodnizki, Linac 2010
D. Berkovits Feb 10 2011 @ FNAL15
Burning of tuning blocks
Contact springs of tuning blocks were burned twice
New design : massive silver plate for better current and thermal conductivity, mechanical contact with stems by a splint system
D. Berkovits Feb 10 2011 @ FNAL16
Melting of plunger electrode
The low-energy plunger electrode has been melted.
It was verified that this was not due to a resonance phenomenon.
New design: plunger was reduced by size ( twice less thermal load), cooling capacity was improved (the plunger and cooling shaft made from one block)
J. Rodnizki et al., Linac 2010, TUP095
D. Berkovits Feb 10 2011 @ FNAL17
Another RFQ hot spots
Further RFQ temperature mapping showed additional problematic regions:
1. the area of the break of tank cooling line especially in the vicinity of the coupler this problem is well understood by simulation, external cooling blocks were installed 2. The region closed to high energy end this is not understood yet and has to be studied
A fan was install in front of the coupler
J. Rodnizki et al., Linac 2010, TUP095
D. Berkovits Feb 10 2011 @ FNAL18
D. Berkovits Feb 10 2011 @ FNAL19 19
MPCT
wire scanners
58 mmTa aperture
Setup for RFQ characterization
4 m
RFQ
ECR
D-plate
Beam dump
D. Berkovits Feb 10 2011 @ FNAL19
D. Berkovits Feb 10 2011 @ FNAL20
Proton energy at RFQ exit by TOFBeam Energy Measurement using TOF
between 2 BPMs sum signals, 145 mm apart,
E = 1.504 ± 0.012 MeV C. Piel PAC 2007
Button pickup for 2 mA pulse and
15 mm bore radius gives a
signal high above noise.
Bunch width measured at
b=0.056 is larger than the predicted value due to the induced charge broadening.
D. Berkovits Feb 10 2011 @ FNAL21
Approximated rms eZ extracted from protons bunch width measurements
0
15
30
45
60
75
90
55 60 65 70 75
power RFQ [kW]
ez )RFQ( [pi deg keV]1s at FFC1 [deg]1s at FFC2 [deg]s_f at RFQ [deg]s_E at RFQ [keV]
Specified rms eZ = 120 p deg keV Value for simulations = 74 p deg keV
C. Piel EPAC 2008
D. Berkovits Feb 10 2011 @ FNAL22
Protons current downstream RFQ vs. RFQ forward power for 3 mA injection
MPCT current
sum of 4 BPM current signals
0.0
0.5
1.0
1.5
2.0
2.5
45 50 55 60 65 70 75
RFQ power (PS forward) [kW]
Be
am c
urr
ent
D-Plate_MPCT [mA]
A_MBPM1 [V_p]
A_MBPM2 [V_p]
4D-WB simulation [mA]
J. Rodnizki et al. EPAC 2008
Uni
ts a
re in
the
lege
nd
70% transs.
Specified transmission=90%
D. Berkovits Feb 10 2011 @ FNAL23
Deuterons beam (through a detuned PSM)
60% transs.
DF=10-4
Specified transmission=90%
24
After improving field homogeneity observe much smaller RFQ power effects
RFQ steering effects
0
10
20
30
40
50
60
70
80
90
100
50 52.5 55 57.5 60 62.5 65 67.5 70 72.5
RF power (kW)
Tra
ns
mis
sio
n (
%)
Apr-2010 Nov-2009
Profile X
-2
-1
0
1
2
3
4
5
6
7
-12.5 -10 -7.5 -5 -2.5 0 2.5 5 7.5 10 12.5
Position (mm)
Cu
rre
nt
(au
. Un
.)
61 kW
56 kW
53 kW
Profile X
-1
0
1
2
3
4
5
-12.5 -10 -7.5 -5 -2.5 0 2.5 5 7.5 10 12.5
Position (mm)
Cu
rre
nt
(au
. un
.)
62 kW
56 kW
54 kW
Nov 2009
Apr 2010
D. Berkovits Feb 10 2011 @ FNAL
D. Berkovits Feb 10 2011 @ FNAL25
Prototype SC Module (PSM)General Design:• Houses 6 HWR and 3
superconducting solenoids• Accelerates protons and
deuterons from 1.5 MeV/u on• Very compact design in
longitudinal direction• Cavity vacuum and insulation
vacuum separated
M. Peiniger, LINAC 2004
M. Pekeler, SRF 2003
M. Pekeler, LINAC 2006
2500 mm
D. Berkovits Feb 10 2011 @ FNAL26
HWR – Basic parameters• f = 176 MHz & bandwidth ~ 130 Hz
• height ~ 85 cm high
• Optimized for b=0.09 @ first 12 cavities (2
modules)
b=0.15 @ 32 cavities (4 modules)
• Bulk Nb single wall 3 mm (in SS vessel)
• Epeak, max = 25 MV/m & Epeak / Eacc ~ 2.9
• Q0 ~ 109 @ 4.45 K
• Designed cryogenic Load < 10 W (@Emax)
• Measured response to pressure = 57 Hz/mbar
D. Berkovits Feb 10 2011 @ FNAL27
HWR measured fields and dissipated power
C. Piel et al. EPAC 2008
A. Perry et al. SRF 2009
At Accel (single cavity) At Soreq (inside PSM)
Target values 60 W @ 4.5 K for 25 MV/m
dynamic loss
Closed loop operation
with a voltage controlled oscillator
(VCO)
Cavity # VerticalTest
Before Processing
After He Processing
25 MV/m
20 MV/m
25 MV/m
20 MV/m
25 MV/m
1 7.3 1.9 7 2.2 5.5
2 7.3 3.0 6.3 4.8 8.7
3 6.3 12.3 16.8 7.0 14.8
4 6.3 11.1 --- 3.9 10.6
5 5.5 5.4 15.1 3.3 8.8
6 7.3 9.6 --- 5.4 10.7
total 40 43.3 --- 26.6 59.1
28 D. Berkovits Feb 10 2011 @ FNAL
PSM Helium distribution system
beam
D. Berkovits Feb 10 2011 @ FNAL29
Setup with Diagnostic plate (D-Plate) for PSM beam commissioning
L. Weissman DIPAC 2009
SARAF Phase I
ECRLEBT
RFQ
PSM
D-plateBeam dumps
D. Berkovits Feb 10 2011 @ FNAL30
Beam operation through the PSM• First proton beam was delivered through the PSM in
November 2008
• Accelerator parameters were set according to beam dynamics simulations )using TRACK - ANL(
• In August 2009 beam was accelerated using all cavities
DF I )mA( E )MeV(
1×10-4 * 2 4.0 protons
CW 1.4 3.2
1×10-4 * 0.5 4.5 deuterons* 100 msec pulse, 1 Hz
I. Mardor et al., SRF 2009
Microphonics measurements* HWRs are extremely sensitive to He pressure fluctuations (60 Hz/mbar)
Detuning signal is dominated by the Helium drift
Detuning sometimes exceeds +/-200 Hz (~ +/-2 BW).
100 110 120 130 140 150 160 170 180 190 200-100
-80
-60
-40
-20
0
20
40
60
80
100
Time[Sec]
Fre
quen
cy D
etun
ing
[Hz]
Frequency Detuning
* Performed in collaboration with J.Delayen and K. Davis )JLab(
D. Berkovits Feb 10 2011 @ FNAL31
Cavity Tune*
Piezoelectric actuator provides fine tuning of the resonance frequency
Range reduction of the piezoelectric elementsWere subsequently replaced
Stepper motor is used for coarse tuning.Stepper motor movement induces instabilities and is therefore disabled during RF operation
* Performed in collaboration with J.Delayen and K. Davis )JLab(
600 700 800 900 1000 1100 1200 1300 1400700
750
800
850
900
950
1000
1050
1100
Piezo Amplifier applied voltage[scaled]
Fre
quen
cy d
etun
ing[
Hz]
Tuner Response Curve
1st cycle2nd cycle
Response of the fine tuner is highly non-linear
D. Berkovits Feb 10 2011 @ FNAL32
D. Berkovits Feb 10 2011 @ FNAL33
phase probe 1
phase probe 2
x/y wire scanners
Faraday cup
FFC 1
FFC 2
MPCT
x/y slit scanners
beam halomonitor
1.18 m
doublet
VAT beam dump BPM1
BPM2
D-Plate for commissioning
L. Weissman DIPAC 2009
D. Berkovits Feb 10 2011 @ FNAL34
-7 1 8-12
-6
0
7
X [mm]
X' [m
rad
]
Scanned area
Transversal emittance• Protons at 2.2 MeV• e~0.15 p mm mrad
rms norm. out of an area excluded the satellite peak
beam
-
-
-
-
- -
X' [m
rad]
X [mm]
1.019999977-1.029500008
0.999999978-1.019999977
0.979999978-0.999999978
0.959999979-0.979999978
0.939999979-0.959999979
0.919999979-0.939999979
0.89999998-0.919999979
0.87999998-0.89999998
0.859999981-0.87999998
0.839999981-0.859999981
0.819999982-0.839999981
0.799999982-0.819999982
0.779999983-0.799999982
0.759999983-0.779999983
0.739999983-0.759999983
0.719999984-0.739999983
0.699999984-0.719999984
0.679999985-0.699999984
0.659999985-0.679999985
0.639999986-0.659999985
Colors chosen to enhance background
D. Berkovits Feb 10 2011 @ FNAL35
BeamSi det 45°
Si det 100°
Au foil
LiF crystals
target ladder
target ladderdrive
targetload-lock
mini FC
I. Mardor et al, LINAC 2006 L. Weissman et al, DIPAC 2009
300 mg/cm2 gold foilglued on graphite frame
Beam energy at the Halo Monitor
Energy measurements are possible because FFC and beam dynamics simulation show that the energy distribution on the beam side is similar to the core
D. Berkovits Feb 10 2011 @ FNAL36
Proton beam energy measurement using Rutherford scattering (RS)
Typical spectrum without cavity voltages )RFQ only(. Background )removed foil( was subtracted.
0
100
200
300
400
500
600
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Energy (keV)
Pulser peakresolution 6.6 keV1.5 MeV peak
used for calibration
Possibly doubly scattered particles
Au foil: 0.3 mg/cm2
Foil rotated by 45°Si detector at 45°
D. Berkovits Feb 10 2011 @ FNAL37
Proton beam energy measurement using Rutherford scattering
0
100
200
300
400
500
600
1400 1420 1440 1460 1480 1500 1520 1540 1560 1580 1600
Energy (keV)
Gaussian fit: FWHM = 18 keV
The low energy tail is most probably enhanced due to rise time of RFQ voltage pulse )Si detector not gated(. This is supported by beam dynamics simulations.
Width includes:• Detector resolution )<12 keV(• Scattering in Au foil• Beam energy width )slide 19(
D. Berkovits Feb 10 2011 @ FNAL38
Calibrating HWR#4
2
2.05
2.1
2.15
2.2
2.25
2.3
0.25 0.3 0.35 0.4 0.45 0.5 0.55
Applied Voltage [MV]
Ene
rgy
[MeV
]
E/u simulated
E/u ToF
E/u Si
Protons 2 mARFQ 56 kW
Phase )deg(
Vacc )kV(
HWR
-95 177 1
0 100 2
20 470 3
-30 4
D. Berkovits Feb 10 2011 @ FNAL39
0
20
40
60
80
100
120
-150 -100 -50 0 50 100
RS
Spec
trum
Std
[keV
]
HWR6 Phase[deg]
0 2000 40000
10
20
Energy[keV]
Cou
nts
0 2000 40000
50
100
Energy[keV]C
ount
s
0 2000 40000
10
20
Energy[keV]
Cou
nts
0 2000 40000
50
100
Energy[keV]
Cou
ntsPhasing of cavity HWR#6
Protons 2 mA
A. Perry et al. SRF 2009
SARAF today
EIS
LEBT RFQPSM
MEBTPhase I - 2010
D-plate
Beam line - 2010 targets
Beam dumps
Situation in beginning of 2011:
The turn-key concept did not work. At present work is done mostly by the local team.
The local team and its expertise grew significantly Phase I is not commissioned yet to full specs (CW deuterons), but accelerator is operational
The concept of Phase II is being developed in collaboration with accelerator laboratories
D. Berkovits Feb 10 2011 @ FNAL40
Beam lines downstream
the linacfor in vacuum target studies
PSM
Beam dump
target
H. Hirshfeld et al. NIM A 2006E. Lavie et al. INS23 2006
I. Silverman et al., NIM B261 2007M. Hass et al., J. Phys. G 2008
T. Hirsh et al., PoS 2009G. Feinberg et. al., Nucl. Phys. A 2009Halfon et. al., Appl Radiat Isot. 2009
M. Paul et al. US patent WO/2009/007976S. Vaintraub et al. INS25 2010
PSM
D-plate
VAT-BDTungsten Metal -BD
Experience with the Tungsten Beam dump
The beam dump 250 micron Tungsten sheet fused to a water cooled cooper plate. Up to 20 kW, no activation is expected.Visual inspection reveal strong blistering effects.
Improve diagnostics tools: temperature mapping radiation mapping (gamma, neutrons) better vacuum control including RGA segmented collimator on-line visual inspection
D. Berkovits Feb 10 2011 @ FNAL42
D. Berkovits Feb 10 2011 @ FNAL43
SARAF Phase II simulations with error analysis
Simulations shown in next slide:• 4 mA deuterons at RFQ
entrance. • Last macro-particle=1
nA
Errors are double than in: J. Rodnizki et al. LINAC 2006, M. Pekeler HPSL 2005
B. Bazak et al., Submitted for Publication
J. Rodnizki et al., HB2008
D. Berkovits Feb 10 2011 @ FNAL44
Deuteron beam envelope radius at SARAF SC Linac
RFQ exit3.4 mA deuterons
32k/193k particles in core/tailLast macro-particle = 1 nA
General Particle Tracer 2.80 2006, Pulsar Physics S.B. van der Geer, M.J. de Loos http://www.pulsar.nl/
rmax
rRMS
nominal
200 realizations 70 realizations
Bore
Solenoids 19
B. Bazak et al., Submitted for Publication
J. Rodnizki et al., HB2008
Tail emphasis simulations
D. Berkovits Feb 10 2011 @ FNAL45
Beam loss criterion
SPIRAL2 [4], IFMIF [6]
* Beam loss criterion which will yield the specified dose rate along SARAF SC linac
[1] J. Alonso, "Beam loss working group report", The 7th ICFA mini-workshop on high intensity high brightness hadron beams, Lake Como, Wisconsin, September 1999.
[2] R. A. Hardekopf, "Beam loss and activation at LANSCE and SNS", The 7th ICFA mini-workshop on high intensity high brightness hadron beams, Lake Como,Wisconsin, September 1999.
[4] T. Junquera et. al., “Status of the construction of the SPIRAL2 accelerator at GANIL”, Proc. Of LINAC08, Victoria, BC, Canada, 2008.
[5] M. Sugimoto and H. Takeuchi, “low activation material applicable to the IFMIF accelerator”, Journal of Nuclear Material, 329-333 )2004( 198-201.
[6] P. A. P. Nghiem et. al., “Parameter design and beam dynamics simulations for the IFMIF-EVEDA accelerators”, Proc. Of LINAC08, Victoria, BC, Canada, 2008.
IFMIF [5]
Unconstrained "hands-on“ [1,2] for SARAF SARAF old
0 5 10 15 20 25 3010
-2
10-1
100
101
102
103
Position along SARAF SC linac )m(
Allo
w lo
sses
for
han
ds o
n m
aint
enan
ce )
nA/m
(
Calculated losses10 mrem/h
2 mrem/h
1 W/m
1 nA/m50/20/5 nA/m
*
*
Halfon et al., 2009
RFQ exit
HEBT
46
People involvedSARAF team (including students, advisers and partially affiliated personal ) : A. Nagler (until 2008), I. Mardor, D. Berkovits,A. Abramson , A. Arenshtam, Y. Askenazi, B. Bazak (until 2009), Y. Ben-Aliz, Y. Buzaglo, O. Dudovich, Y. Eisen, I. Eliyahu, G. Finberg, I. Fishman, I. Gertz, A. Grin, S. Halfon, D. Har-Even D. Hirshman, T. Hirsh, A. Kreisel, D. Kijel, G. Lempert, A. Perry, R. Raizman (until 2010), E. Reinfeld, J. Rodnizki, A. Shor, I. Silverman, B. Vainas, L. Weissman,Y. Yanay (until 2009).
RI&Varian /(former ACCEL): H. Vogel, C. Piel, K, Dunkel, P. Von Stain, M. Pekeler, F. Kremer, D. Trompetter, many mechanical and electrical engineers and technicians
NTG/ Frankfurt Univ: A. Bechtold, Ph. Fischer, A. Schempp, J. Hauser
Cryoelectra : B. Aminov, N. Pupeter, …
D. Berkovits Feb 10 2011 @ FNAL47
END
D. Berkovits Feb 10 2011 @ FNAL48
MEBT: Overview
Main components:
• Three quadrupols (31 T/m) with steering magnets
• Two diagnostic chamber • Two x/y wire scanners• Three pumps and one gauge• Two 4-button BPMs
• Position• Phase• Current
D. Berkovits Feb 10 2011 @ FNAL49
MEBT
RFQD-plate
pumpspump
wire scanner 1
wire scanner 2
BPM1BPM2
beam
650 mm
D. Berkovits Feb 10 2011 @ FNAL50
phase probe 1
phase probe 2
x/y wire scanners
Faraday cup
FFC 1
FFC 2
MPCT
x/y slit scanners
beam halomonitor
1.18 m
doublet
VAT beam dump BPM1
BPM2
D-Plate for commissioning
L. Weissman DIPAC 2009
D. Berkovits Feb 10 2011 @ FNAL51
RFQ RF conditioning
Input Power [kW] Duration [hrs]
190( CW) 12
210( CW) 2
240( CW) 0.5
260( DC = 80% @ 440 Hz) 0.5
Melted tuning plate after extraction
beam
Melted area
I. Mardor et al., PAC 2009
I. Mardor et al., SRF 2009
60 mm
D. Berkovits Feb 10 2011 @ FNAL52
RFQ: Protons bunch profile measurements
Measurement results are backed up by simulations
)TRACK(
Rodnizki et al. EPAC 2008
C. Piel PAC 2007
Wire scan profiles
FFC time profiles
-4 -2 0 2 40
0.2
0.4
0.6
0.8
1
position )cm(
coun
ts
meanm 0.00 cm
FWHMs 0.40 cm
FWHMm 0.46 cm
-4 -2 0 2 4position )cm(
meanm 0.00 cm
FWHMs 3.70 cm
FWHMm 3.57 cm
0.0
0.2
0.4
0.6
0.8
1.0
1.2
0 100 200 300
proton relative phase )deg(
curre
nt )a
rb.(
gauss fit
simulated
0 100 200 300
proton relative phase )deg(
gauss fit
gauss fitmeasurement
32.5 kV 63.5 kW
FFC1 FFC1
32.0 kV
61.5 kW
MEBT Entrance
D-Plate
Simulation Measured
D. Berkovits Feb 10 2011 @ FNAL53
RFQ Conditioning – status• Several hundred conditioning hours for two years• Conditioning schemes
– Set maximum power and increase duty cycle– Set CW duty cycle and increase power
• Special actions to improve conditioning rate:– Rounding of sharp edges of rods bottom part– Cleaning of rods– Installation of circuit for fast recovery after sparks– Baking at 75°C for a week in vacuum and for a day with
flowing nitrogen– Add a 3rd pump to the two existing TMPs
Reach field for deuterons and hold CW for minutes
D. Berkovits Feb 10 2011 @ FNAL54
RFQ field flatnessFollowing the modification of electrodes the frequency correction procedure (moving and removing of tuning plates) changed the field flatness along the 39 RF cells .
This may lead to a transmission reduction and consequently to emittance reduction
LEBT D-plate transmission = 40%Typical LEBT norm. rms emittance ~ 0.2 p mm mrad D-plate=0.15 p mm mrad + satellite
D. Berkovits Feb 10 2011 @ FNAL55
Phasing of resonator HWR#1
1350
1400
1450
1500
1550
1600
1650
-260 -230 -200 -170 -140 -110 -80 -50 -20 10
Phase HWR1 (deg)
En
erg
y (M
eV)
TOF
RBS
Simulations
0
2
4
6
8
10
12
14
16
18
-260 -230 -200 -170 -140 -110 -80 -50 -20 10
Phase HWR 1 (deg)
sig
ma
(k
eV
)
simulations
RBS
Energy spectra were monitored as a function of phase of an individual HWR while the rest downstream HWRs are detuned. As a result the synchronous phase and resonator voltage can be calibrated. The beam energy obtained from RS is compared with TOF results and TRACK simulation. L.Weissman et al. DIPAC 2009
The RS measurements provide information on the beam energy spread and low-energy background. The experimental results are compared with TRACK simulation. The intrinsic energy resolution and effects of scattering on the gold foil were not taken in account in the simulation of the beam energy spread.
D. Berkovits Feb 10 2011 @ FNAL56
Calibrating cavity #6
2.6
2.7
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3
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-60 -30 0 30 60 90 120 150 180 210
Ene
rgy[
MeV
]
Phase HWR6 (deg)
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3.8
100 200 300 400 500 600 700 800 900 1000
En
erg
y )M
eV
(
HWR )kV(