Download 5. Power supplies requirements

CTF3
Technical Specifications
Modulator for a 50 MW – 12 GHz Klystron
G.McMonagle AB-RF
CONTENTS
1.
2.
3.
4.
5.
Introduction....................................................................................................................................... 3
General description .......................................................................................................................... 3
Characteristics of the klystron .......................................................................................................... 4
Oil tank ............................................................................................................................................. 4
Power supplies requirements ........................................................................................................... 5
5.1
High voltage pulsed power supply ........................................................................................... 5
5.2
Filament power supply ............................................................................................................. 5
5.3
Ion pump power supplies ......................................................................................................... 6
6. Fast protective network .................................................................................................................... 6
7. Cooling ............................................................................................................................................. 6
8. Electrical network ............................................................................................................................. 6
9. X-ray shielding, HV protection.......................................................................................................... 7
10.
Local control, status and interlocking ........................................................................................... 7
10.1 Status ....................................................................................................................................... 7
10.2 Measurements.......................................................................................................................... 7
10.3 Interlocks .................................................................................................................................. 8
11.
Remote control ............................................................................................................................. 8
12.
Mechanical specifications for the installation ............................................................................... 9
13.
Transport .................................................................................................................................... 10
14.
Acceptance tests ........................................................................................................................ 10
15.
Guarantee of operation .............................................................................................................. 10
16.
Maintenance ............................................................................................................................... 10
17.
Management .............................................................................................................................. 10
18.
Deliverable documents ............................................................................................................... 10
19.
Schedule .................................................................................................................................... 11
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1. Introduction
CLIC, an acronym for “Compact Linear Collider”, is a study of a linear electron / positron collider for
the 1 to 5 TeV energy range. A conceptual feature of CLIC is the two beam scheme, where a lower
energy, high current drive beam runs in parallel to the high energy beam. The drive beam produces
the RF power required to accelerate the main beam. CLIC is recognized as a potential project after the
Large Hadron Collider (LHC)
The CLIC Test Facility CTF has already in the past served as a test bench for CLIC technology. In its
3rd stage, CTF3, it can be considered as a CLIC module, designed to demonstrate the RF power
generation scheme.
In addition to the CTF3 facility a stand alone test stand is required for 12GHz high gradient testing is
required .
This document describes the technical specifications of a high voltage modulator. The modulator will
provide power for the 50 MW – 12 GHz klystron for the test stand.
2. General description
The modulator is composed of:
- a permanent magnet focussed klystron Toshiba or SLAC model (provided by CERN).
- a high voltage pulsed power supply (negative polarity)
- a filament heater power supply
- an ion pump power supply
- a hydraulic network
- a X-ray shielding
- a control-command system
- racks containing the materiel
The supply include the design and manufacture of the elements, the integration of the klystron(s)
provided by CERN, the control – command and interlocks system, the testing and measurements, the
delivery and the on-site installation.
The modulator will be installed at CERN in Geneva.
The general layout of the modulator is presented in Figure 1.
Figure 1 : General layout of the modulator
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3. Characteristics of the klystron
The klystron will be supplied by CERN. The reference is Toshiba or SLAC. The klystron will be
manipulated and installed by CERN.
The general characteristics of the klystron can be found in Table 1.
Parameters
Specifications
units
RF Frequency
12 (11.4)
GHz
Peak RF power
RF gain
50
MW
dB
Efficiency
RF pulse length
Observations

1
%
µs
100
Hz

Duty cycle
Klystron voltage
470 (Toshiba)
%
kV
Nominal voltage: kV
Klystron current
Inverse klystron voltage
250 (Toshiba)
max
A
kV
Nominal current: A
Heater voltage
max
V
Nominal value between and V
Heater current
Heater start up surge current
max
max
A
A
Nominal value between and A,
15 min
max
mn
kW
max
max
kW
kW
Pulse repetition rate
Preheating period
Average collector power
Average output power
Average body and window power
Peak RF drive power
Output circuit VSWR
A x kV x3.5 µs x 100 Hz
50 MW x 1.0 µs x100 Hz
W
1.5 max
Pref < 1.8 MW, 4% of reflected power
Table 1: Characteristics of Toshiba or SLAC klystron
4. Oil tank
The high voltage oil tank supports the klystron and it will contain the gun and all elements at high
voltage (pulse transformer). The tank will be provided by the supplier.
The oil properties are given in Table 2:
Parameters
Dielectric strength
Oil temperature
Specifications
Observations
16 kV/mm min.
40 kV min for a 2.5 mm gap
50 °C max.
Table 2: Insulating oil specifications
The tank must be equipped with an expansion tank (transparent container) to control the oil level. A
cooling system can be included to keep the oil temperature under 50 °C. The tank must be tight to
avoid any entry of humidity. The modulator must include an additional tank in case of leakage from the
main tank.
The tank will have to be designed in such a way that it is easy and fast to manipulate and change the
klystron.
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5. Power supplies requirements
5.1
High voltage pulsed power supply
The power supply must deliver a maximum high voltage pulse of 500kV during 3.5µs (at 75% pulse
width) with a pulse repetition rate of 100 Hz.
The power supply polarity is negative.
The specifications are given in Table 3.
Parameters
Specifications
Units
Observations
Peak voltage
500
kV

tight
Peak current
360
A
Pulse length (flat top)
1.0 min
µs
tight
Klystron
setting
area
Pulse repetition rate
100 max
Hz
tight
Inverse voltage
75 max
kV
Pulse voltage ripple
%
±0.5 max
Pulse to pulse stability
%
±0.1 max
Rise time 10 – 90 %
1 max
µs
Fall time 90 – 10 %
2 max
µs
Pulse width at 75 %
3.5 max
µs
Table 3: Specifications of the high voltage pulsed power supply
Particular attention must be made to minimize the pulse voltage ripple and to provide the best pulse to
pulse stability.
These two parameters will be optimized for the nominal operating value of the klystron.
The voltage rise times and fall times for the high voltage pulse must be fast enough to obtain
maximum width state while attaining the 1.0 µs flat top. In any case, the pulse width at 75 % must not
be more than 3.5 µs.
The voltage must be tuneable between 50 and 100 % of the maximum voltage.
5.2
Filament power supply
This power supply is at high voltage potential.
The power supply can be either a DC or an AC supply. If a DC supply is used, the positive pole must
be connected to filament / cathode connection and the negative pole to filament connection.
The filament power supply specifications are given in Table 4:
Parameters
Heater voltage
Heater current
Heater start up
surge current
Preheating period
Specifications
? max
? max
Units
V
A
? max
A
Observations
Nominal value between ? and ? V
Nominal value between ? and ? A
15 min
mn
Table 4: Filament power supply specifications
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5.3
Ion pump power supplies
The ion pump power supply is voltage regulated.
A maximum security threshold for the current must be included. This threshold must be tuneable from
0 to 0.1 mA.
The specifications are given in Table 5:
Parameters
Number of power supply
Ion pump voltage
Ion pump current
Ion pump dissipation
power
Specifications
1
5
0.1 max
Unit
kV
mA
50 max
W
Observations
Between 3 and 5.5 kV
Table 5: Ion pump power supply specifications
6. Fast protective network
The modulator needs a crow bar or other related protective network in case of a klystron fault
(electrical arc).
When a discharge occurs, the energy dissipation in the klystron must be limited to 10 joule.
7. Cooling
The modulator includes the hydraulic network for the klystron and the electromagnet cooling. The
hydraulic specifications are given in Table 6:
Parameters
Specifications
Unit
Observations
Water inlet temperature
? max
°C

Water pressure at klystron
?max
bar
Absolute pressure
collector inlet
Water pressure at klystron
? max
bar
Absolute pressure
body and window inlet
Collector water flow
? min
dm3/mn
Body / window water flow
? min
dm3/mn
Table 6: Hydraulic specifications of the klystron-electromagnet
A hydraulic network will be available for the supplier. This network is equipped with flow meters and
temperature probes. The supplier will only have to do the connections between the network and the
elements.
All the metallic parts of the connectors must be in copper or stainless steel.
8. Electrical network
The electrical network is 380 V ± 10 %, 50 Hz 3-phase line with neutral at ground.
The supplier must define what electrical connectivity is required for the modulator.
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9.
X-ray shielding, HV protection
The modulator will include a shielding to protect users from X-ray radiations.
The maximum acceptable dose is 3 µSv / hr from any part of the system. The shielding must be
designed to achieve this goal.
The users must be protected from any risks of high voltage electrocution.
10. Local control, status and interlocking
The control system to be provided must be based on a Siemens SIMATIC Programmable Logic
Controller (PLC) S7-300.
The slow changing signals are directly managed by the PLC. Faster signals must have electronics to
monitor from pulse to pulse and the interlock information will be sent to the PLC.
Local supervision and control commands will be made by a SIEMENS Touch Panel.
Personal security interlocks must be treated by hard-wired interlocks.
10.1 Status
The modulator system can be found in one of the four control status:
OFF, HEATER, STANDBY, PULSING
OFF status: the water cooling and the ion pump are on. The high voltage tank temperature is checked
and the filament power supply is off.
HEATER status: the klystron filament power is on. A delay of 15 minutes must be respected. The ion
pump current and voltage are checked.
STANDBY status: When this status is on, the premagnetisation of the pulse transformer is activated at
this level.
The following interlocks are also on:
- Klystron water temperature input and output
- RF network vacuum or SF6 pressure, RF network water flow
- Klystron high voltage pulse (interlock levels given by “pulse surveyor” cards)
- RF pulses (interlock levels on incidents and reflected powers, given by “pulse surveyor”
cards)
The high voltage and RF pulses interlocks are dynamics interlocks. It means that the waveform is
controlled for every pulse. For example, on the CERN modulator, the system is switched off if we
detect more than 3 pulses faults in 2000 pulses. Should the PLC not be fast enough to react to a pulse
to pulse monitoring, electronic modules supplying the signals to the PLC need to ne included
PULSING status: the high voltage pulses are applied on the klystron.
10.2 Measurements
The following measurements will be available in local or remote:
- Klystron cathode voltage and current
- Klystron filament voltage and current
- Electromagnet currents
- Ion pump voltage and current
- Inlet and outlet body water temperature
- Oil temperature.
This list is not exhaustive and additional measurement can be included depending on the chosen
technology of the modulator.
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10.3 Interlocks
All the interlock levels must be available in local or remote. The complete list of the interlocks must be
provided by the supplier.
11. Remote control
The PLC will have an Ethernet module to communicate with the CERN network.
The PLC will include a specific library which is developed and supplied by CERN.
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12. Mechanical specifications for the installation
The modulator system will be installed in the CLic EXperiment Gallery (CLEX-G).
The maximum acceptable dimensions are given in Figure 2:
Modulator
H = 2.6
m
L = 5.9 m (zone A)
L = 9.2 m (zone B)
w = 2.7m (zone A)
w = 4.5m (zone B)
Figure 2: Mechanical dimensions for a mounted modulator system
The maximum charge of the building is about 500 kg/m².
There is no crane in the building. Every pieces of the system must be transported with a chariot.
Transportation from the outside to CLEX-G:
The building is at the second floor (ground floor + one floor). Every piece must be transferred via an
elevator which is 2.4 m height. The passageway from the elevator to CLEX-G crosses the LIL gallery.
The element to transport must be 1.1 m maximum width and 1.5 m maximum length (seeError!
Reference source not found.: Top view of the LIL and CLEX gallery
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Changing a klystron:
It is very important that the klystron can be changed easily and quickly. On the CERN modulator, the
assembling composed of the oil tank, the klystron and the X-ray shielding can be independently
moved. It has to be transported to a place where a crane is available (2500 kg, 4 m maximum height
under crane). To go to this place, the assembly must go through the same passageway as described
above (see figure 4)
13. Transport
The supplier is responsible for the packing, the transport to CERN
14. Acceptance tests
Acceptance will be given by CERN after all tests specified have been successfully completed and all
the documentation has been supplied.
CERN will agree on a date with the supplier to do the acceptance at least 15 days before.
An Acceptance Test Data Sheet will be signed after the test by CERN and the supplier.
The Acceptance Test will involve the transfer of property of the supply.
15. Guarantee of operation
This guarantee covers repairs (pieces, displacement and manpower) during the 24 months as from the
on-site acceptance test.
16. Maintenance
The supplier must ensure the maintenance of the material after the guarantee period if request by
CERN
17. Management
The supplier will indicate only one contact person for technical management.
The supplier will provide a schedule for manufacturing, making reference to T 0 of the signature of the
contract. The design, the procurements, the manufacture, the delivery and installation at CERN will be
explicitly mentioned on the schedule.
A report will be written by the supplier and co-signed after every meetings with the updates of the
schedule.
18. Deliverable documents
The supplier will deliver the following documentation at least the last day of the delivery (in French or
English language):
- The electrical and mechanical drawings of the modulator
- The software of the PLC
- The Acceptance Test Data Sheet and the Acceptance Test Procedure
- An operating and maintenance manual of the modulator
- An operating and maintenance manuals of commercial components if it exists
10/11
-
a list of reference for components of replacement and, if possible, European sales offices
packing and unpacking manuals
any other useful documents
19. Schedule
The supplier will respect the following schedule:
 T0 + 12 months: design, procurements and manufacture
 T0 + 14.5 months: delivery, on-site installation and acceptance tests
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