TERA Foundation
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Transcript of TERA Foundation
TERA Foundation
U. Amaldi, A. Degiovanni
Silvia Verdú Andrés
November 23, 2011CLIC RF structure development meeting
Expected Performances of TERA High-Gradient Accelerating Structures
Motivation
The hadrontherapy community demands a compact, reliable accelerator with the appropriate beam performances for tumour treatment with ions.
Motivation
The hadrontherapy community demands a compact, reliable accelerator with the appropriate beam performances for tumour treatment with ions.
The linac length could be reduced if high accelerating gradients (~ 35 MV/m) were achieved for an acceptable value of breakdowns (BDR ~ 10-6 bpp/m), as breakdows compromise the machine reliability.
CABOTO is a copper standing-wave Side-Coupled Linac operating at 5.7 GHz.
Motivation
The hadrontherapy community demands a compact, reliable accelerator with the appropriate beam performances for tumour treatment with ions.
The linac length could be reduced if high accelerating gradients (~ 35 MV/m) were achieved for an acceptable value of breakdowns (BDR ~ 10-6 bpp/m), as breakdows compromise the machine reliability.
Which are the expected high gradient performances for such a machine?
CABOTO is a copper standing-wave Side-Coupled Linac operating at 5.7 GHz.
Experimental evidence
- TERA 3 GHz single-cell cavity……………………………………………….… tests ongoing
- TERA 5.7 GHz single-cell cavity……………………………………….……… tuning
- Frascati@KEK 5.7 GHz structure…..........................……………… tested!
- Several structures at 12 and 30 GHz………………………………..……. scaling laws but applicability?
TERA 3 GHzFrascati@KEK 5.7 GHz
constBDRtS pulsec 515
*scaled to BDR = 10-6bpp/m; tp=200 ns
The Frascati@KEK structure is a 5.7 GHz travelling-wave (TW) structure made in copper. It has been designed to accelerate relativistic electrons (Es/E0 ~ 2).
The structure was tested with a 0.2 ms-long RF pulse.
Structure characteristics
The Frascati@KEK structure is a 5.7 GHz travelling-wave (TW) structure made in copper. It has been designed to accelerate relativistic electrons (Es/E0 ~ 2).
The structure was tested with a 0.2 ms-long RF pulse.
Structure characteristics
CABOTO is a standing-wave (SW) structure made in copper. It has been designed to accelerate non-relativistic hadrons. Therefore, accelerating cells present «noses» in order to improve acceleration but then Es/E0 ~ 4—5.
Typical RF pulse for therapy application would be 2 ms-long. « nose »
Assumptions
The Frascati@KEK structure is a 5.7 GHz travelling-wave (TW) structure made in copper. It has been designed to accelerate relativistic electrons (Es/E0 ~ 2).
The structure was tested with a 0.2 ms-long RF pulse.
Structure characteristics
CABOTO is a standing-wave (SW) structure made in copper. It has been designed to accelerate non-relativistic hadrons. Therefore, accelerating cells present «noses» in order to improve acceleration but then Es/E0 ~ 4—5.
Typical RF pulse for therapy application would be 2 ms-long.
- Applicability of results of TW to SW.- Validity of modified Poynting vector and associated scaling laws. - Validity of pulse length scaling laws.
« nose »
Scaling and expected performances
constBDRtS pulsec 515
*scaled to BDR = 10-6bpp/m; tp=200 ns
Frascati@KEK 5.7 GHz
Scaling and expected performances
constBDRtS pulsec 515
*scaled to BDR = 10-6bpp/m; tp=200 ns
Frascati@KEK 5.7 GHz
Scaling and expected performances
constBDRtS pulsec 515
*scaled to BDR = 10-6bpp/m; tp=200 ns
Frascati@KEK 5.7 GHz
Attention: Z, Sc/E0 and Rbore affect E0, linac length and power requirement!
Conclusionso Maximum achievable average axial field for the TERA C-band structures is around 40
MV/m.(assumptions:– TW and SW are comparable– Modified Poynting vector and associated scaling laws validity– Pulse length scaling laws validity)
o High power tests of the C-band TERA prototypes are useful to:1) Check the validity of the scaling laws.
2) Increase the statistics of RF high power measurements at 5.7 GHz.
[TERA] Drive the choice of the most suited cell geometry for the CABOTO-C design.
o High-power test of the TERA 3 GHz single-cell cavity gains in importance:1) Comparison of structures in S, C and X-bands.
2) Validation of modified Poynting vector.
Conclusionso Maximum achievable average axial field for the TERA C-band structures is around 40
MV/m.(assumptions:– TW and SW are comparable– Modified Poynting vector and associated scaling laws validity– Pulse length scaling laws validity)
o High power tests of the C-band TERA prototypes are useful to:1) Check the validity of the scaling laws.
2) Increase the statistics of RF high power measurements at 5.7 GHz.
[TERA] Drive the choice of the most suited cell geometry for the CABOTO-C design.
o High-power test of the TERA 3 GHz single-cell cavity gains in importance:1) Comparison of structures in S, C and X-bands.
2) Validation of modified Poynting vector.
Conclusionso Maximum achievable average axial field for the TERA C-band structures is around 40
MV/m.(assumptions:– TW and SW are comparable– Modified Poynting vector and associated scaling laws validity– Pulse length scaling laws validity)
o High power tests of the C-band TERA prototypes are useful to:1) Check the validity of the scaling laws.
2) Increase the statistics of RF high power measurements at 5.7 GHz.
[TERA] Drive the choice of the most suited cell geometry for the CABOTO-C design.
o High-power test of the TERA 3 GHz single-cell cavity gains in importance:1) Comparison of structures in S, C and X-bands.
2) Validation of modified Poynting vector.
Thanks for your attention