Scdtl study for erha
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SCDTL study for ERHA. C. Ronsivalle, L. Picardi. TOP-IMPLART (ENEA-ISS-IFO Project in Rome) and EHRA Project (Ruvo di Puglia) do not require radioisotopes production at low energy and foresee for their protontherapy complex a completely linear structure.

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SCDTL study for ERHA

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Scdtl study for erha

SCDTL study for ERHA

C. Ronsivalle, L. Picardi

ADAM meeting Geneve, 09-02-2010


Scdtl study for erha

  • TOP-IMPLART (ENEA-ISS-IFO Project in Rome) and EHRA Project (Ruvo di Puglia) do not require radioisotopes production at low energy and foresee for their protontherapy complex a completely linear structure.

  • In the following the design of a SCDTL structure up to 35 MeV is presented to be used for TOP-IMPLART and EHRA Projects; the first part up to 17.5 MeV is equal to the structure under development in the framework of the ISPAN Project launched by ENEA-ISS-NRT-CECOM (funded for about 500 K€)

ADAM meeting Geneve, 09-02-2010


Ispan irraggiamento sperimentale con protoni per modelli cellulari ed animali project

ISPAN (“Irraggiamento Sperimentale con Protoni per modelli cellulari ed Animali”) Project

SCDTL

  • The Project foresees the realization of a test facility at ENEA-Frascati laboratories by using as injector a PL7 425 MHz linear accelerator

ADAM meeting Geneve, 09-02-2010


Outline

Outline

  • DESIGN CRITERIA OF SCDTL35

  • SCDTL35 LAYOUT AND PARAMETERS FROM DESIGN CODE OPTIMIZATION

  • BEAM DYNAMICS IN SCDTL35:

    - LINAC code results

    - Matching with the 7 MeV injector (PL7)

    - Losses distribution (checked also with TSTEP code)

    - Errors and tolerances study in SCDTL35

    - Start-to-end up to 235 MeV including LIGHT35 (from DeGiovanni data-December 2009 version)

  • CONCLUSIONS

ADAM meeting Geneve, 09-02-2010


Main design criteria and constraints

Main design criteria and constraints

  • INJECTION ENERGY: 7 MeV

  • OUTPUT ENERGY: 35 MeV

  • ONE 10 MW KLYSTRON WITH A POWER CONTINGENCY OF 3 MW (P<7 MW)

  • NUMBER OF MODULES: 4

  • EXTERNAL PMQs WITH A MAXIMUM GRADIENT OF 220 T/m (useful radius for protons =2.9 mm) FROM ASTER

  • MAIN DIFFERENCES RESPECT TO SCDTL DESIGN FOR TOP linac (ENEA Technical Report RT/INN/9717,1997) RELEVANT FOR BEAM DYNAMICS:

    -The old design assumed internal PMQ (Leff=30 mm) with an intertank distance varying in the range 7-35 MeV between 43 and 65 mm too short for allocating external PMQs  (Transverse acceptance1/max, and max  Lperiod)

    - Higher electric field gradient (limited to12 MV/m in the old design) are required to reduce the total length: attention to keep /maxconst. In the allowed range of PMQ gradients and to avoid parametric resonances and longitudinal instability) (phase longitudinal advance l EOT)

ADAM meeting Geneve, 09-02-2010


Scdtl35 layout

SCDTL35 LAYOUT

Modules 1-2

Modules 3-4

ADAM meeting Geneve, 09-02-2010


Scdtl35 electrical parameters

SCDTL35 ELECTRICAL PARAMETERS

* Include flat stems and 20% of coupling losses

Total RF power consumption= 6.57 MW

ADAM meeting Geneve, 09-02-2010


Rf efficiency

RF EFFICIENCY

FLAT stems for an efficient stem cooling

P=1.4 MW

Cylindric stems (diameter=5 mm): no stem cooling

ADAM meeting Geneve, 09-02-2010


Scdtl study for erha

THEORETICAL BEAM DYNAMICS PROPERTIES (from DESIGN data, assuming constant normalized transverse, that means negligible coupling between transverse and longitudinal planes and perfet matched FODO lattice)

  • Transverse acceptance (At=r2/TWISSmax)= 8.7  mm-mrad

  • Longitudinal

    phase stable

    area (foreseen phase

    acceptance58.5°=3|s|)

  • INJECTOR: PL7 OUTPUT BEAM PARAMETERS

Exun Exun Eyun Eyun *DW * El

(100%) (rms) (100%) (rms) (deg) (keV) (deg-MeV)

------------------------------------------------------------------------------

6.6 (100%) 1.1 7.2(100%) 1.2 59° 93.3 5.411

4.4 (90%) 4.8(90%) (at 2998 MHz) (at 2998MHz)

* Half width

ADAM meeting Geneve, 09-02-2010


Scdtl study for erha

BEAM DYNAMICS: LINAC CODE RESULTS FOR AN IDEAL MATCHING BETWEEN PL7 AND SCDTL35 (distance from injector=0)

M1 M2 M3 M4

ADAM meeting Geneve, 09-02-2010


Scdtl study for erha

  • Input coordinates

  • Accepted coordinates in the three phase space planes

  • SCDTL35 output beam: transmission=46.3%

ADAM meeting Geneve, 09-02-2010


Beam quality in these conditions emittance

BEAM QUALITY IN THESE CONDITIONS: EMITTANCE

RMS unnormalized emittance

at 35 MeV:

0.7  mm-mrad

RMS normalized emittance

at 35 MeV:

0.2 mm-mrad

ADAM meeting Geneve, 09-02-2010


Effect of injector bunch lenghtening on scdtl transmission

EFFECT OF INJECTOR BUNCH LENGHTENING ON SCDTL TRANSMISSION

Bunch lenghtening due to velocity spread in a drift following the injector

transmission vs distance between injector output and center of the first PMQ on SCDTL: (matched beam on transverse planes)

PL7 425 MHz

PL7 428 MHz

ADAM meeting Geneve, 09-02-2010


Scdtl study for erha

MATCHING PL7 at 425 MHz – SCDTL35 (3 EMQs in a LEBT 1 m long before the PMQ at the SCDTL entrance)compatible with the current Frascati installation and ISPAN scheme

Total length (up to the middle of the PMQ at the entrance of SCDTL)=1131.74 mm



X-envelope

- + - +

Y-envelope

-----------------295--- ------------><-------150-------<--70-------150-------70---------150---------------231.74------------><15

ADAM meeting Geneve, 09-02-2010


Scdtl study for erha

MATCHING PL7 AT 428 MHZ-SCDTL (3 PMQs in the a very short LEBT before the PMQ at the SCDTL entrance) to be discussed with ACCSYS

Total length (up to the middle of the PMQ at the entrance of SCDTL)=293.33 mm



X-envelope

- + - +

<--16 -><----30-----<----------------80--------------------------30-----<----------------80----------------------------30---<12.33><15

ADAM meeting Geneve, 09-02-2010

Y-envelope


Linac code output in these conditions

LINAC code output in these conditions

  • Accepted PL7 output coordinates in the three phase space planes

  • SCDTL35 output: beam transmission=33.7%

ADAM meeting Geneve, 09-02-2010


Tstep code losses distribution in scdtl tanks and average energy of lost particles

TSTEP code: LOSSES DISTRIBUTION IN SCDTL TANKS AND AVERAGE ENERGY OF LOST PARTICLES

ADAM meeting Geneve, 09-02-2010


Tstep code losses distribution in terms of power

TSTEP code: LOSSES DISTRIBUTION IN TERMS OF POWER

Plot normalization: injected current from PL7=1 A

ADAM meeting Geneve, 09-02-2010


Errors and tolerances study

ERRORS AND TOLERANCES STUDY

ADAM meeting Geneve, 09-02-2010


Errors and tolerances pmqs

ERRORS AND TOLERANCES: PMQs

Nruns=50, Random errors (uniformly distributed in  |error|)

Effect on transmission:

markers position on the points corresponding to a factor=0.9 on transmission for a loss with probability of 90% - Rot. angle=2°, gradient=4%, displacement=50m

ADAM meeting Geneve, 09-02-2010


Errors and tolerances tanks

ERRORS AND TOLERANCES: TANKS

Nruns=50, Random errors (uniformly distributed in  |error|)

Effect on transmission:

markers position on the points corresponding to a factor=0.9 on transmission for a loss with probability of 90% - Field amp. error=2%, tank displacement=150 m

entire tank is displaced independently in x,y

each end of tank is independently displaced (tilt)

ADAM meeting Geneve, 09-02-2010


Errors and tolerances phase shifts

ERRORS AND TOLERANCES: PHASE SHIFTS

Nruns=50, Random errors (uniformly distributed in  |error|)

Effect on transmission:

markers position on the points corresponding to a factor=0.9 on transmission for a loss with probability of 90% -

error in distance between tanks=150 m,

error in the length of the cells=50 m

ADAM meeting Geneve, 09-02-2010


Errors and tolerances total np 100k nruns 300

ERRORS AND TOLERANCES (Total Np=100K, nruns=300)

PMQs: Rot. angle=2°, gradient=4%, x-y displacement=50m

TANKS AND CELLS ERRORS: Field amp. error=2%,

tank displacement=150 m

error in distance between tanks=150m,

error in the length of the cells=50 m

Prob=90% of transmission/max. transmission>50%

Prob=90% of Exn<0.28 mm-mrad,

Eyn<0.29  mm-mrad

ADAM meeting Geneve, 09-02-2010


Scdtl study for erha

THE LOW ENERGY SCDTL PART 7-17.5 MEV IS MORE CRITICAL RESPECT TO TOLERANCES (that can be relaxed in the last two modules)

7-35 MeV

17.5-35 MeV

tolerance on tank field amplitude error from 2% to 6%

tolerance on PMQ displacement from 50 m

to 100 m

7-35 MeV

17.5-35 MeV

ADAM meeting Geneve, 09-02-2010


Start to end 7 235 mev

START-TO-END(7-235 MeV)

ADAM meeting Geneve, 09-02-2010


Start to end scdtl35 light35 retrieved from degiovanni design data december 2009

START-TO-END: SCDTL35+LIGHT35(retrieved from DeGiovanni DESIGN data-December 2009)

  • SCDTL35 beam portion that is transmitted up to 235 MeV in LIGHT35

The total capture drops from 33.7 % at SCDTL output to

20 % at LIGHT35 output.

ADAM meeting Geneve, 09-02-2010


Scdtl study for erha

START-TO-END: possible revision of LIGHT35 to optimize the matching between the two structures and reduce losses at high energy

REASONS OF THE CAPTURE REDUCTION IN LIGHT35

parameter SCDTL35 LIGHT35

(TERA DESIGN)

s -18° -13°

Number of cells/tank 6 (i.e 6 ) 18 (i.e 9 )

Intertank distance at 35 MeV 3.5 4.5

With some modifications in the part at fixed energy (35-100 MeV) it is possible (as it will be shown in the next slides) to increase the longitudinal and transverse acceptance of LIGHT35, so improving the matching between the two structures and avoiding losses at high energy without getting a longer structure (inter-tank distance in the last two modules from 2.5  to 1.5 )

ADAM meeting Geneve, 09-02-2010


Scdtl study for erha

LIGHT35 ORIGINAL

LIGHT35 MODIFIED (three more tanks, but no greater final length)

ADAM meeting Geneve, 09-02-2010


New start to end from 7 to 235 mev

NEW START TO END FROM 7 to 235 MeV

  • PL7 at 428 MHz

  • LEBT 29 cm long

  • SCDTL35

  • LIGHT35 (modified)

LAYOUT:

30%

20%

SCDTL35

LIGHT35

ADAM meeting Geneve, 09-02-2010


New start to end from 7 to 235 mev1

NEW START TO END FROM 7 to 235 MeV

  • Accepted SCDTL35 output coordinates by LIGHT35

  • LIGHT35 output beam: transmission from the injector=30%

ADAM meeting Geneve, 09-02-2010


Start to end 7 235 mev emittance

START TO END 7 - 235 MeV: EMITTANCE

Final un-normalized

RMS emittance:

0.25  mm-mrad

Final normalized

RMS emittance:

0.2  mm-mrad

ADAM meeting Geneve, 09-02-2010


Conclusions

CONCLUSIONS

  • A SCDTL structure up to 35 MeV with a length <5.4 m to be used as the first part of ERHA linac has been designed: a prototype of the first two modules up to 17.5 MeV is under realization in the framework of ISPAN Project

  • the transverse emittance of the PL7 output beam is inside the transverse acceptance of SCDTL. The losses are due to longitudinal mismatching due to the jump of RF frequencies

  • the longitudinal capture can be improved passing from 425 MHz to 428 MHz for the PL7 linac (to be discussed in the next contacts with ACCSYS)

  • A proper revision of the LIGHT35 structure design allows to optimize the matching between the low and high energy parts of the linac, bringing the total transmission (in absence of errors) to 30% (near to the typical values of captures in medical electron linacs) and reducing losses at high energy

  • The total length from the injector output from 7 to 235 MeV is  20 m

ADAM meeting Geneve, 09-02-2010


Addendum scdtl35 drawings

ADDENDUM: SCDTL35 drawings

ADAM meeting Geneve, 09-02-2010


Addendum scdtl35 drawings1

ADDENDUM: SCDTL35 drawings

ADAM meeting Geneve, 09-02-2010


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