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18th ESLS RF WorkshopDaresbury 29-30 September 2004
SUPER-3HC - M.Svandrlik
G.Penco, G.Penco, M.SvandrlikM.Svandrlik
• Operation
• Uptime
• Maintenance
• Performance vs filling
• Conclusions
SUPER-3HC at ELETTRA UpdateSUPER-3HC at ELETTRA Update
28th ESLS RF WorkshopDaresbury 29-30 September 2004
SUPER-3HC - M.Svandrlik
• 3HC is routinely in operation during user’s shifts.
• Lifetime depends on ultimate vacuum conditioning and filling pattern, highest value we can obtain is 27 hrs(320 mA; 2.0 GeV)
• Filling pattern set to 96%
• During refill and energy ramping 3HC set at +94 kHz (from 3rd harmonic) - Transverse Feedbacks ON
• Once beam is at 2.0 Gev 3HC is activated by tuning it at +64 kHz
• Longitudinal Coupled Bunch Instabilities are cured by 3HC, Transverse Instabilities are cured by Feedbacks.
OperationOperation/Uptime/Maintenance/Performance vs Filling/Uptime/Maintenance/Performance vs Filling
38th ESLS RF WorkshopDaresbury 29-30 September 2004
SUPER-3HC - M.Svandrlik
• The increase in Beam Lifetime obtained when 3HC is active, allows us to refill ELETTRA every 36 hrs instead of 24 hrs, as it used to be in the past.
OperationOperation/Uptime/Maintenance/Performance vs Filling/Uptime/Maintenance/Performance vs Filling
3HC tuned:only 3 refills in 5 days operation
How it wasbefore 3HC
48th ESLS RF WorkshopDaresbury 29-30 September 2004
SUPER-3HC - M.Svandrlik
0,0 0,0 0,0
15,8
0,0 0,6 0,00
5
10
15
20
25
30
RUN 85AUG - SEP 03
RUN 86SEP - OCT 03
RUN 87NOV - DEC 03
RUN 88JAN - FEB 04
RUN 89MAR - APR 04
RUN 90APR - MAG 04
RUN 91JUN - JUL 04
Users' downtime caused by 3HC, in hours
• General uptime of the system is good. Since September 2003 only one event caused significant User’s downtime, on Saturday, 31/01/2004.
Operation/Operation/UptimeUptime/Maintenance/Performance vs Filling/Maintenance/Performance vs Filling
58th ESLS RF WorkshopDaresbury 29-30 September 2004
SUPER-3HC - M.Svandrlik
• The event on 31/01/04 was related to a failure of a rough pumping unit of the valve-box insulation vacuum. This was a temporary installation, replaced during the next shutdown with a fail-safe one.
• The uptime statistics does not include systems stops due to electrical power interruptions, mostly caused by thunderstorms in the surroundings. In this case most machine systems are stopped and the restart time of the cryogenic plant is hidden in the general restart of the systems. For this reason the idea of connecting 3HC to a new UPS has not yet been implemented (also financial reasons).
• We still do not have a He recovery system, the experience made so far shows that we can survive without it, not affecting the uptime of the system.
Operation/Operation/UptimeUptime/Maintenance/Performance vs Filling/Maintenance/Performance vs Filling
68th ESLS RF WorkshopDaresbury 29-30 September 2004
SUPER-3HC - M.Svandrlik
• Several important maintenance interventions have been successfully performed in the last 12 months.
• In November 2003 the leaky gate valve between 3HC and the superconducting wiggler was substituted.
Operation/Uptime/Operation/Uptime/MaintenanceMaintenance/Performance vs Filling/Performance vs Filling
This required to break the cavity vacuum. A clean area was therefore created inside the storage ring tunnel. The replacement followed clean room procedures and was done by CEA and Elettra staff.The field performance of the cavity has not been affected by this intervention.
78th ESLS RF WorkshopDaresbury 29-30 September 2004
SUPER-3HC - M.Svandrlik
• In December 2003 the tuning system of cell 1 failed for the 2nd time (1st time in March). In January 2004 the tuning system was replaced with an upgraded version.
• The tuning system is under vacuum, at cold. The gear box was found to be blocked.
• Tests at Saclay showed that the reason could be a heating problem (from the motor).
Operation/Uptime/Operation/Uptime/MaintenanceMaintenance/Performance vs Filling/Performance vs Filling
• Even if the number of cycles after which this shows up is huge, we are limiting the movements of the system.
• No problem since January 04• CEA is studying a solution to
move the motor outside the cryomodule.
88th ESLS RF WorkshopDaresbury 29-30 September 2004
SUPER-3HC - M.Svandrlik
• During the January shutdown the cryogenic plant annual maintenance was performed.
• After this maintenance the nominal performance is back to the original, i.e. about 30-35 litres/hour at 13 bar of HP.
• In August 2004 the cryomodule has been warmed-up again in order to replace a coaxial cable which takes out the voltage signal of cell 2.
• In this occasion also the fundamental mode rejection of the dipolar HOM couplers has been improved. In fact on one of them some over-heating effects were observed when tuning the cell.
Operation/Uptime/Operation/Uptime/MaintenanceMaintenance/Performance vs Filling/Performance vs Filling
98th ESLS RF WorkshopDaresbury 29-30 September 2004
SUPER-3HC - M.Svandrlik
Operation/Uptime/Maintenance/Operation/Uptime/Maintenance/Performance vs FillingPerformance vs Filling
• ELETTRA used to operate with a partial filling of the bunch train: typically a 10% empty gap was present.
• As well known, with such a gap the passive third harmonic cavity induces a phase modulation over the bunch train.
• Several STREAK CAMERA experiments were performed for various fillings, measuring the effect on:
– Phase Shift
– Bunch lengthening
– Landau Damping
– Beam Lifetime
• As a result, a new optimum filling was set for operations.
108th ESLS RF WorkshopDaresbury 29-30 September 2004
SUPER-3HC - M.Svandrlik
Phase Shift along the train for different tuning
10
20
30
40
50
60
600 700 800 900 1000 1100 1200 1300 1400 1500Bunch position in the train (ps)
Re
lati
ve
Ph
as
e (
De
g)
1499,070 MHz
1499,060 MHz
1499,050 MHz
1499,025 MHz
1499,020 MHz
1499,015 MHz
Bunch length along the train for different tuning
30
40
50
60
70
80
90
700 900 1100 1300 1500Bunch position in the train (ps)
RM
S B
un
ch
Le
ng
th (
ps
)
1499,070 MHz
1499,060 MHz
1499,050 MHz
1499,025 MHz
1499,020 MHz
1499,015 MHz
Ibeam=315mA, Filling at 80%
Ibeam=315mA, Filling at 80%
80% Filling:80% Filling: Phase Shift/Bunch Length Phase Shift/Bunch Length/Landau/Lifetime/Landau/Lifetime
118th ESLS RF WorkshopDaresbury 29-30 September 2004
SUPER-3HC - M.Svandrlik
Phase Shift along the train for different tuning
10
15
20
25
30
35
40
45
50
0 200 400 600 800
Bunch position in the train (ps)
Rel
ativ
e P
has
e (D
eg)
1499,050 MHz 1499,040 MHz
1499,030 MHz 1499,025 MHz
1499,020 MHz 1499,015 MHz
1499,014 MHzBunch length along the train for different tuning
20
40
60
80
100
120
140
160
180
200
0 200 400 600 800Bunch position in the train (ps)
RM
S B
un
ch
Le
ng
th (
ps
)
1499,050 MHz 1499,040 MHz 1499,030 MHz
1499,025 MHz 1499,020 MHz 1499,015 MHz
1499,014 MHz
Bunch overstretching
Ibeam=315mA, Uniform Filling
Ibeam=315mA, Uniform Filling
100% Filling:100% Filling: Phase Shift/Bunch Length Phase Shift/Bunch Length/Landau/Lifetime/Landau/Lifetime
128th ESLS RF WorkshopDaresbury 29-30 September 2004
SUPER-3HC - M.Svandrlik
f= +92 kHz f= +82 kHz f= +62 kHzf= +72 kHz
The Bunch Profile Averaged on the bunch train in the case of Uniform
Filling is shown below for different tuning positions of 3HC. The “nominal
tuning” of 3HC would be around +75 kHz. Beyond this postion the Bunch
begins to show an overstreched profile. Beam Lifetime increases until the
position of +62 kHz, which is the operating position. A few kHz beyond that,
lifetime starts to decay to a few hours; further the beam is lost.
100% Filling:100% Filling: Phase Shift/Phase Shift/Bunch LengthBunch Length/Landau/Lifetime/Landau/Lifetime
138th ESLS RF WorkshopDaresbury 29-30 September 2004
SUPER-3HC - M.Svandrlik
Phase Shift along the bunch train
0
5
10
15
20
25
30
35
40
45
1499.010 1499.015 1499.020 1499.025 1499.030 1499.035 1499.040 1499.045 1499.050 1499.055 1499.060 1499.065 1499.070
3HC Frequency (MHz)
Deg
Uniform FillingFilling at 98%Filling at 96%Filling at 90%Filling at 80%Filling at 70%
Various Fillings: Phase ShiftVarious Fillings: Phase Shift/Bunch Length/Landau/Lifetime/Bunch Length/Landau/Lifetime
148th ESLS RF WorkshopDaresbury 29-30 September 2004
SUPER-3HC - M.Svandrlik
Bunch length along the train
30
40
50
60
70
80
90
100
110
120
130
140
1499.010 1499.015 1499.020 1499.025 1499.030 1499.035 1499.040 1499.045 1499.050 1499.055 1499.060 1499.065 1499.070
3HC Frequency (MHz)
<> (ps)
Filling at 70%Filling at 80%Filling at 90%Filling at 96%
Filling at 98%Uniform Filling
Various Fillings: Various Fillings: Phase Shift/Phase Shift/Bunch LengthBunch Length/Landau/Lifetime/Landau/Lifetime
158th ESLS RF WorkshopDaresbury 29-30 September 2004
SUPER-3HC - M.Svandrlik
The Landau damping seems to be influenced by the different contribution of the increasing gap width and of the average bunch length, which is reduced as the gap increases.
Various Fillings: Various Fillings: Phase Shift/Bunch Length/Phase Shift/Bunch Length/LandauLandau/Lifetime/Lifetime
Scale isdifferent!
168th ESLS RF WorkshopDaresbury 29-30 September 2004
SUPER-3HC - M.Svandrlik
Uniform Filling90% Filling
f= +112 kHzf= +112 kHz
f= +92 kHzf= +92 kHz
f= +62 kHzf= +62 kHz
Longitudinal UNSTABLE Beam
Longitudinal STABLE Beam
Bunch Length is Uniform
Phase Modulationpresent.
Bunches are longer in the train centre.
Stronger Phase Modulation
Various Fillings: Phase Shift/Bunch Length/LandauVarious Fillings: Phase Shift/Bunch Length/Landau/Lifetime/Lifetime
These strak camera images show the different effect of 3HC on the beam between 90% filling (on the left) and uniform filling (on the right). The Landau damping effect is similar in both cases, the 90% filling shows the expected effect of the phase modulation along th ebunch train.
178th ESLS RF WorkshopDaresbury 29-30 September 2004
SUPER-3HC - M.Svandrlik
The best performance in terms of lifetime is obtained with a fractional filling of 96%. By further increasing the filling, the maximum obtained lifetime is lower, suggesting that the optimum setting for ELETTRA requires a small amount of “empty gap”.The 96% filling is now taken as the new standard filling pattern for User’s Operation Mode (320mA, 2.0GeV). In this condition 3HC is usually tuned from 1499.050 MHz (f=92kHz) to 1499.020MHz (f=62kHz).
Various Fillings: Various Fillings: Phase Shift/Bunch Length/Landau/Phase Shift/Bunch Length/Landau/LifetimeLifetime
188th ESLS RF WorkshopDaresbury 29-30 September 2004
SUPER-3HC - M.Svandrlik
Machine Upgrades and Ultimate Lifetime ValueMachine Upgrades and Ultimate Lifetime Value
During 2003 and 2004 several new vacuum chamber installations were performed. In June 2003 a new Aluminum-NEG coated chamber was installed in section ID10. In pre-3HC conditions the nominal lifetime was recovered at a dynamic pressure of about 10-11 mbar/mA. In the example of the ID10 chamber this took about 70 Ah, i.e. about 2,5 weeks operation.
In fact the ultimate lifetime with 3HC active, i.e. about 27 hours at 2.0 GeV 320 mA, was reached mid of September 2003, that is about 6 weeks of operation after the ID10 installation (there were 2 weeks shutdown in August).
198th ESLS RF WorkshopDaresbury 29-30 September 2004
SUPER-3HC - M.Svandrlik
• 3HC routinely in operation at Elettra• Stable Beam, refill every 36 hours• Operability and Reliability good• Careful maintenance to prevent faults,
recovery time can be long!• Experiments at different fillings confirm
expected effects (phase modulation, bunch lengthening)
• New standard filling set to 96%
ConclusionsConclusions