sievers - overview of the latest srf projects at the s-dalinac

Overview of the latest SRF projects at the S-DALINAC*

Sven Sievers

TU DarmstadtInstitut für Kernphysik SFB 634

*Supported

by

the

DFG through

SFB 634

04. Oktober 2010 | TU Darmstadt | Institut für Kernphysik | Sven Sievers

Outline

•

Overview

of the

S-DALINAC

•

SRF at the

S-DALINAC

•

Vertical

bath

cryostat

•

Latest

measurements•

Piezo-Actor

•

Oscillating

Superleak

Transducers

•

Test in preparation•

RF power couplers

•

Outlook


Overview of the S-DALINAC

Design values:

Max. energy:

130 MeVEnergy spread:

±10-4

Max. beam

current:

60 µADuty

cycle:

cw


Overview of the S-DALINAC

04. Oktober 2010 | TU Darmstadt | Institut für Kernphysik | Sven Sievers04. Oktober 2010 | TU Darmstadt | Institut für Kernphysik | Sven Sievers

SRF at the S-DALINAC

Material:

Frequency:

Mode:

Temperature:

Niob (RRR=300)

2.9975 GHz

TM010

,π

2 K

Length:

Eacc

:

Q0

:

Pdis

:

1 m

5 MV/m

3·109

4.2 W


Vertical bath cryostat

Diameter:

35 cmDepth:

260 cm

Minimum required

LHe-level: 150 cmMaximum LHe-level:

190 cm

D = 35 cm



Operation characteristics•

Cooldown

300 K → 4 K

~ 1.5 h

•

Fill-up

to maximum

LHe

level

~ 2 h

•

Pump down to 35 mbar

/ 2 K

~ 2.5 h

•

Stand-by

losses

of cryostat

< 1 W

Current limitations•

No pressure

regulation

→ 35 mbar

kept

via cryostat

heating

•

Operation of vertical

cryostat

not

possible

while

linac

is

at 2 K→ Measurements

limited

to shut

downs

of the

S-DALINAC


First measurements: Piezo Actor

Investigation of the

stroke

of a piezo-actor

@ 2 K to replace

magnetostricitive

elements

of fine tuning

system



Existing

tuning

system: Fine tuning

of cavity

with

magnetostrictive

elements


Required

frequency

shift:1000 Hz

Resulting

cavity

deformation:2 µm

Required

stroke

of fine tuner:5 µm




Required

stroke

of fine tuner:

5 µm

Stroke

of piezo-actor

@ 300 K:

90 µmPredicted

stroke

@ 4 K*: 22.5 µm

Measurement

with

simplified

tuner

set-up

Measured

frequency

shift

@ 4 K in LHe:

~ 1100 HzResulting

stroke

of piezo-actor:

~ 5.5 µm

Measured

frequency

shift

@ 2 K in LHe:

~ 950 HzResulting

stroke

of piezo-actor:

~ 4,75 µm

*B. Sahu, G. Chowdhury, S. Ghosh, D. Kanjilal, D. Mathuria, R. Mehta, A. Pandey, P. Patra, A. Rai

and A. Roy: Use

of Piezo

Actuator

to Frequency

and Phase Lock a Superconducting

Quarter

Wave Resonator, Proc. of the

24th Linear Accelerator Conference


First measurements: OSTs

Performance check of the

prototypes

of anOscillating

Superleak

Transducer

(OST)

for

quench

localisation

@ 2 K



OSTs shall be used for thedetection

of quench

positions

of superconducting

cavities

The

quench

causes

a 2nd soundwave

in the

superfluid

LHe

that

can

be

detected

by

the

OSTs

The

location

of the

quench

isdetermined

by

triangulation



R –

Moment of the

heat

pulse1 –

Response of the

1st OST after

~ 2 ms

2 –

Response of the

2nd OST after

~ 4 ms

R

2

1

R 1 2

Test in preparation: RF power couplers

Characterisation

of new

power couplers

for

the

injector

upgrade




Planed injector upgrade

•

Energy increase

in the

injectorsection

from

10 up to 14 MeV

•

Increase

in current

from60 μA to 150 –

250 μA



Actual

power coupler: 500 W Qex = 3·106 - 1·1010


RF power couplers

transition

transition

beam

transfer

Design: TEMF

Fabrication: FZ Julich

M. Kunze, W. F. O. Müller

Actual

power coupler:

500 W Qex = 3·106 - 1·1010

Waveguide

coupler: 2 kW Qex = 5·106


Outlook

•

Construction of Quench-Detection-Array

•

Development

of optical

inspection

setup

•

Further

investigations

of piezo-actors

•

Design of new

equipment

for

the

vertical

bath

cryostat(Bacholer/Master

thesises):

•

Measurement

of Q-value

via decay

time•

Design and construction

of T-Map-System


Thank you for your attention

Institut für Kernphysik, TU Darmstadt

S. Sievers, U. Bonnes, J. Conrad, R. Eichhorn, F. Hug, M. Konrad,T. Kürzeder, N. Pietralla, A. Richter


Closed loop for liquid Helium

sievers - overview of the latest srf projects at the s-dalinac

Technology

sdalinac srf

sdalinac design values

vertical bath cryostatdiameter

maximum lhelevel

maximum lhe level

latest srf projects

losses of cryostat

niob rrr