MAX-lab and Solide State Modulators

plantcitybusinessΠολεοδομικά Έργα

26 Νοε 2013 (πριν από 3 χρόνια και 10 μήνες)

117 εμφανίσεις

MAX
-
lab; Lunds University; Sweden

MAX
-
lab and Solide State Modulators


Dionis Kumbaro



PSI, 18
-
19 Nov. 2008

Solid State Modulator Workshop PSI



MAX
-
lab supports three distinct research areas: Accelerator Physics, research
based on the use of Synchrotron Radiation and Nuclear Physics using energetic
electrons. Time at the facility is shared between groups working within these
three fields.



The accelerators at MAX
-
lab consist of three electron storage rings (MAX I, MAX
II and MAX III) and one electron pre
-
accelerator (MAX injector). All three storage
rings produce synchrotron light used for experiments and measurements in a
wide range of disciplines and technologies. The MAX I ring is also used as an
electrons source for experiments in nuclear physics.


MAX
-
lab accelerators today


Solid State Modulator Workshop PSI

MAX
-
lab accelerators today


Solid State Modulator Workshop PSI


Electrons are emitted at the electron gun by the cathode which is either operated
in the thermal or photo
-
electric effect mode. The thermal mode is used for
storage ring injection while a short pulse laser is used to generate photo
-
electrons used for the FEL experiments



After being pre
-
accelerated by the RF gun to 2 MeV, the electrons are then
further accelerated by two linear accelerators (linacs), each having an energy
gain of 100 MeV. The electron beam can then either be brought upwards to the
MAX I storage ring or recirculated by two 180 degree bending magnet structures
for another acceleration in the linacs up to 400 MeV. These electrons are then
injected into the MAX II or MAX III rings or used for a FEL experiment set up
inside the MAX II ring.


MAX
-
lab injector

Solid State Modulator Workshop PSI

MAX
-
lab injector

Solid State Modulator Workshop PSI

The pre
-
injector used today

Solid State Modulator Workshop PSI




The
3GHz
thermionic

RF
-
gun

system


Old RF
gun

modulator

Solid State Modulator Workshop PSI




Klystron typ TH2056


Beam

voltage

143
kV



Beam

current

123 A


Peak power 6 MW


Averange

power 12 kW


Pulse

duration 5
us



Frequency

2998 M
Hz


New pre
-
injector to injector


The high radiation levels due to low injection efficiency of todays 3GHz
thermionic RF
-
gun system , was the main motivation on designing the new pre
-
injector DC
-
gun.



Today runinig, the injection efficiency particulary during the MAX II injection is
less then 10%.



With new pre
-
injector DC
-
gun, we expect to increase the injection efficiency to
50% and the radiation level shuold be decrease a factor 5.



Bonus on high efficienncy of injection will be decreasing time of filling rings.




The new electron gun, will consist of a 450kV to 500kV DC
-
gun.

Solid State Modulator Workshop PSI

New
pre
-
injector

Solid State Modulator Workshop PSI

Specifications for the new pre
-
injector



Electron energy >400 keV


Pulse length 0
-
250 ns (variable)


Pulse current>60 mA


Normalised emittance <40 mm mrad (as in the former MAX I injection
case)


Bunch energy spread <10% (p
-
p) (not very important)


Max bunch length 20 ps (gives 2 % bunch energy spread, p
-
p).

Solid State Modulator Workshop PSI

MAX
-
lab specifications

Solid State Modulator Workshop PSI

New Solid State Gun Modulator

DC
-
gun modulator

Parameter

Value

E
-
gun Voltage

400 kV

(Max 500kV)

E
-
gun Current

4 A

Pulse length (top)

250 ns

Flat top flatness

<
±
0.05%

Pulse Repetition Frequency

10 Hz

E
-
gun pulse at 507kV

Solid State Modulator Workshop PSI

New Solid State Gun Modulator

Solid State Modulator Workshop PSI


500kV gun modulator

Solid State Gun Modulator




Technical specifications pulse output


Peakpower to electrongun 500kW


Averagepower to electrongun 33W


Voltagerange 0
-
400kV


Currentrange 1
-
10 Hz


Pulselength(FWHM) 3
-
5
μ
s


Top flatness <
±
0.05% during 300 ns


Rate of rise 200
-
500kV/
μ
s


Amplitudestability <
±
0.1


Trigger delayjitter <
±
3


Internaldummy load


Filament max voltage 15V


Filament max current 10A

Solid State Modulator Workshop PSI


Curvs from Modulator 500kV


Load

Voltage

Pulse

Length


FWHM = 5,8us

Solid State Modulator Workshop PSI

Solid State Gun Modulator





Pulse

flat
top

≈250ns


at pulse width
5,8us

Solid State Modulator Workshop PSI

Solid State Gun Modulator




Amplitude stability <
±
0.1%


Solid State Modulator Workshop PSI

Solid State Gun Modulator

New High
Voltage

DC
-
Gun

Solid State Modulator Workshop PSI




The 3 GHz
buncher

cavity


Choper


Deflector


Solenoid


CT


Gun



New High
Voltage

DC
-
Gun

Solid State Modulator Workshop PSI

Cathod

of the new
DC
-
Gun

Solid State Modulator Workshop PSI

MAX
-
lab accelerators tomorrow (MAX IV)

3 GeV ring

0.24 nmrad

1
-
1.5 GeV ring

Upgraded MAX II

0.7 GeV ring

MAX III

3 GeV linac

Injection + Short Pulse Facility






Solid State Modulator Workshop PSI

Here will be place MAX IV

Solid State Modulator Workshop PSI

Budget
breakdown

on
years

Solid State Modulator Workshop PSI

Injector

place

under the rings

Solid State Modulator Workshop PSI

The MAX IV injector

L1A
L1B
L2A
L2B
L3A
L3B
L4A
L4B
L7A
L7B
L8A
L8B
L17B
The MAX IV injector

layout v 0.11
-
081009
BC1
200 MeV
10 m
BC2
600 MeV
10+ m
MAX III
extraction
700 MeV
MAX II
extraction
1.5 GeV
MAX IV
extraction
3 GeV
9 GHz cavity
Chopper
Thermionic
RF gun
Photo cathode
RF gun
Kicker &
septum
Kicker &
septum
Kicker &
septum
Laser
heater
SPF & FEL
RF deflector
RF deflector
Diagnostics
Diagnostics
L17A
Solid State Modulator Workshop PSI

MAX IV
3GeV
Linac

Specifications

Linac





Injector

SPF (Short Pulse Facility)

End Energy (GeV)


3


3+

Charge/pulse (nC)


10


1

Bunch length (ps)


1


0.1
-
1

Bunches/RF pulse


10


1

Rep Rate (Hz)


0
-
10


0
-
200

Emittance (mm mrad)

10


10

Energy spread


10
-
3


10
-
3


Linac

injector will have 17 stations, 200
MeV

each.

Variable pulse length: 1us to 5us

Repetition rate: 0 to 200Hz







Solid State Modulator Workshop PSI

Storage
Rings








MAX II


MAX III

MAX IV

Electron energy (GeV)

1

1.5


0.7


3


Circ current (mA)


500

300


500


500

Circumference (m)


90

90


36


527

Nr of long straights


10

10


8


20

Length (m)



3.14

3.14


2.45


5

Nr of short straights


-

-


-


40

Length (m)



-

-


-


1.5

Hor emittance (nm rad)

5

10


14


0.24

Hor RMS beam size


230

350


360


45

Vert RMS beam size

10

10


40


2.6





MAX IV
Storage

Rings
Specifications

Solid State Modulator Workshop PSI

MAX IV ring

Solid State Modulator Workshop PSI



.

1.
Try
to minimize C
q

(Theoretical Minimum Emittance
)


But: Doesn’t work, the ring gets unstable



2. Increase the number of magnets.


But: The ring will get a 2 km or so circumference.
(PETRA, PEP)




So: We make the componenets small but keep a
large number of magnets


Recepi for designing a low emittance ring:




As you know:





2
1


Brilliance
3
2
)
(
magnets
q
N
Energy
C


MAX IV ring magnet mounting

Light magnets




Concrete

=> Low magnet
weight, rigid mounting
favours high
eigenfrequencies

Solid State Modulator Workshop PSI

Injector

tunnel

Solid State Modulator Workshop PSI

RF and modulator system

Linac “2n
-
1”

Linac “2n”

Modulator “n”

Klystron “n”

ή
kly
=
45%

0.7
μs

P
RFpeak
=35MW

ή
mod
=80%

4,5
μs

P
modpeak
=77.8MW

4,5
μs

4,5
μs

SLED “n”

Driver “n”

G

180º


Solid State Modulator Workshop PSI

MAX IV
injector



tot
linac
RFtot
tot
L
Z
P
U

RFkly
SLED
SLED
P
G
P
2

2
SLED
WGBL
RFlinac
P
P


2
2
RFkly
SLED
WGBL
RFlinac
P
G
P


linac
linac
linac
RFlinac
linac
L
L
Z
P
E

linac
tot
tot
E
U
L

linac
linac
RFlinac
linac
tot
tot
L
Z
P
L
U
L

linac
tot
Lin
L
L
N

linac
tot
Kly
L
L
N


2
linac
linac
RFlinac
tot
Kly
L
Z
P
U
N


2
linac
linac
RFkly
SLED
WGBL
tot
Kly
L
Z
P
G
U
N
2
2



Input parameter
description:

Id:

Unit:

Value:

Total Acceleration voltage

U
tot

GV

3

Linac

impedance

Z
linac

MΩ/m

55

Length of Linac

L
linac

m

5.2

Gain of SLED cavity

G
SLED

1.8

Efficiency


Waveguide,

Beam Loading

0.5

WGBL

Solid State Modulator Workshop PSI

Solide

State Modulator

Solid State Modulator Workshop PSI

Klystron alternatives

Input

parameter

Id

Unit

Alt. 1

Alt. 2

Alt. 3

Type of klystron

Type

TH2100D

TH2132A

TH2155

Klystron RF peak power

Prfkly

MW

35

45

47.5

RF frequency

Frf

MHz

2998.5

2998.5

2998.5

SLED RF peak power

Psled

MW

113.4

145.8

194.4

LINAC section RF power

Prflinac

MW

28.35

36.45

48.6

LINAC total RF power

Prftot

MW

945

1071

1237

Acceleration gradient

Elinac

MeV/m

17.

19.6

22.7

Solid State Modulator Workshop PSI

TH2100D Klystron
specifications

Parameter

Id

Unit

Min

Typ

Max

Notes

RF
peak

power output

Prfkly

MW

26

35

38,4

RF
peak

power input

Prfdrive

W

100

135

250

RF

averange

power

Prfkly

kW

38

RF
pulse

length

1

4,5

5

Perveance

μ
灥牶

ㄮ1

2

㈮2

䭬祳瑲漠
条gn



㔱⸹

㔴⸱

㔴⸵

Efficiency

(
RFout/Rfin
)

%

43.3

45

46.6

Filament

voltage

Ukfil

V

20

29

30

Filament

current

Ikfil

20

25.2

28

Pfil

= 1kW

Solid State Modulator Workshop PSI

Parameter

Id

Unit

Typ.

Max

Notes

Pulse

Voltage

to Klystron

Ukly

kV

274

280

Pulse

Current

to Klystron

Ikly

A

284

290

Peak power to Klystron

Pkly

MW

77.8

Averange

Power to Klystron

Pavkly

kW

116.6

Flat
-
Top

Pulse

Width

tkly

μ
s

㐬4

S

T畮u扬攠灵p獥s睩摴d

䙵c氠
坩摴t

偵汳l

䵡M業畭i䙗䡍c



㰷⸵

Power efficiency (Power Out/Power in)

%

80

Power factor

0.9

Pulse Repetition Rate

PRF

Pulse Flatness (peak
-
to
-
peak)

%

<0.1

<0.5

Pulse
-
Pulse Regulation

%

<0.01

<0.1

Pulse rice time

μ
s



Pulse current fall time

μ
s



Modulator
specifications

Solid State Modulator Workshop PSI