Advanced RF-KO excitation methods for high quality spills Slow - - PowerPoint PPT Presentation

▶
advanced rf ko excitation methods for high quality spills
SMART_READER_LITE
LIVE PREVIEW

Advanced RF-KO excitation methods for high quality spills Slow - - PowerPoint PPT Presentation

Oct 28, 2023 160 likes •599 views

Advanced RF-KO excitation methods for high quality spills Slow Extraction Workshop 2019, Fermilab, July 22nd-24th 2019 Fiona Faber Heidelberg Ion-Beam Therapy Center Overview HIT-Facility Accelerator RF-KO Examined

slide-1
SLIDE 1

Slow Extraction Workshop 2019, Fermilab, July 22nd-24th 2019 Fiona Faber Heidelberg Ion-Beam Therapy Center

Advanced RF-KO excitation methods for high quality spills

slide-2
SLIDE 2
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 2

Overview

  • HIT-Facility
  • Accelerator
  • RF-KO
  • Examined excitation methods
  • Simulated micro spill structure
  • Extraction process
  • Experimental results
slide-3
SLIDE 3
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 3

Heidelberg Ion-Beam Therapy Center

Cancer therapy using p and C-ions Particle energy defining depth in matter

Irradiating tumor slice by slice Slow extraction used for scanning the tumor 668 patients in 2018

slide-4
SLIDE 4
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 4

HIT-Facility

Synchrotron, (48 - 430 MeV/u) 3 Ion sources Linac (7 MeV/u) 3 treatment rooms Gantry Beam dump High energy beam transport Experimental area Treatment: p (~1010 particles/spill), C (~108 particles/spill) Experiments: p, He, C, O

slide-5
SLIDE 5
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 5

Extraction method

RF-KO

  • Excitation of 3rd order resonance
  • Triangular stable phase space area is formed (separatrix)
  • Optical elements constant during extraction
  • Increase of transversal emittance with RF-signal
  • The signal of the excitation function defines the quality of the spill
  • K. Noda et al., Nucl. Instr. and Meth. A 374 (1996)
slide-6
SLIDE 6
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 6

Extraction method

RF-KO

  • Excitation of 3rd order resonance
  • Triangular stable phase space area is formed (separatrix)
  • Optical elements constant during extraction
  • Increase of transversal emittance with RF-signal
  • The signal of the excitation function defines the quality of the spill
  • K. Noda et al., Nucl. Instr. and Meth. A 374 (1996)
slide-7
SLIDE 7
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 7

Extraction method

RF-KO

  • Excitation of 3rd order resonance
  • Triangular stable phase space area is formed (separatrix)
  • Optical elements constant during extraction
  • Increase of transversal emittance with RF-signal
  • The signal of the excitation function defines the quality of the spill
slide-8
SLIDE 8
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 8
  • Intensity feedback loop

enables controlled mean extraction rates (PID)

  • Higher average intensity
  • > faster irradiation

Intensity feedback loop

Exciter Ionization chambers

  • C. Schoemers et al., Nucl. Instr. Meth. A vol. 795

(2015), pp. 92 - 99.

  • Less machine tuning
  • Fast variation of extraction rates
slide-9
SLIDE 9
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 9

Motivation

To prevent peaks exceeding the measurement limit the mean intensity is reduced

  • > increasing the treatment time

Increasing spill quality:

  • Higher mean intensity
  • > decreasing treatment time
  • Higher comfort for patients
  • Increasing number of patients

Spill with intensity control and AM

C: 1.55 · 108 extracted particles E: 430.1 MeV/u Resolution: 50 ms/bin

slide-10
SLIDE 10
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 10

Frequency modulation methods used at HIMAC

1995 2002

  • K. Noda et al., Nucl. Instr. and Meth. A 374

(1996) 269-277

Time Scale: 200 ms/div

  • K. Noda et al., Nucl. Instr. and Meth. A 492

(2002) 253 - 263

Time Scale: 2 ms/div | 500 ms/div

slide-11
SLIDE 11
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 11

Simulation

  • Combining MADX for tracking

& Python for analysis

  • Only synchrotron lattice
  • Space charge and positioning

inaccuracies neglected

  • Start distribution:

Gaussian particle distribution after acceleration

  • Extracted defined by passing

electrostatic septum Exciter Electrost. septum

  • Magn. septum
slide-12
SLIDE 12
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 12

Exemplary excitation signal

Pseudo random binary phase shift keying (PRBPSK)

Excitation methods

Excitation spectrum

slide-13
SLIDE 13
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 13

Simulated micro spill structure for PRBPSK

slide-14
SLIDE 14
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 14

Frequency modulation

Single frequency modulation (FM)

Excitation methods

Exemplary excitation signal

Idea by K. Noda et al., Nucl. Instr. and Meth. A 492 (2002), pp. 253 - 263

slide-15
SLIDE 15
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 15

Single frequency modulation (FM)

Excitation spectrum

Excitation methods

Exemplary excitation signal

Idea by K. Noda et al., Nucl. Instr. and Meth. A 492 (2002), pp. 253 - 263

slide-16
SLIDE 16
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 16

Simulated micro spill structure for single FM

Frequency modulation Spill

slide-17
SLIDE 17
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 17

Simulated micro spill structure for single FM

Frequency modulation Spill PRBPSK Single FM

slide-18
SLIDE 18
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 18

Dual frequency modulation (FM)

Frequency modulation

Excitation methods

Exemplary excitation signal

Idea by K. Noda et al., Nucl. Instr. and Meth. A 492 (2002), pp. 253 - 263

slide-19
SLIDE 19
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 19

Dual frequency modulation (FM)

Excitation spectrum

Excitation methods

Exemplary excitation signal

Idea by K. Noda et al., Nucl. Instr. and Meth. A 492 (2002), pp. 253 - 263

slide-20
SLIDE 20
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 20

Simulated micro spill structure for dual FM

Frequency modulation Spill

slide-21
SLIDE 21
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 21

Simulated micro spill structure for dual FM

Frequency modulation Spill PRBPSK Dual FM

slide-22
SLIDE 22
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 22

Excitation process

slide-23
SLIDE 23
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 23

Excitation process

Washed out spill -> high quality Caused by exciting the diffusion region* Direct excitation + synchrotron motion (Chromaticity ≠ 0 & bunched)

*Idea by K. Noda et al., Nucl. Instr. and

  • Meth. A 492 (2002), pp. 253 - 263
slide-24
SLIDE 24
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 24

Excitation process

Caused by exciting the extraction region* Driven oscilation effect

*Idea by K. Noda et al., Nucl. Instr. and

  • Meth. A 492 (2002), pp. 253 - 263
slide-25
SLIDE 25
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 25

Excitation process

Simulation of isolated driven oscillation

  • f betatron amplitudes of particles

3 particles starting at 100%, 50% and 5%

  • f the initial emittance while excited by

the single FM

slide-26
SLIDE 26
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 26

Excitation process

Simulation of isolated driven oscillation

  • f betatron amplitudes of particles

3 particles starting at 100%, 50% and 5%

  • f the initial emittance while excited by

the single FM Kick at cycle restart depending on phase

slide-27
SLIDE 27
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 27

Frequency modulation

Extended frequency modulation (FM)

Excitation methods

Exemplary excitation signal

slide-28
SLIDE 28
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 28

Excitation spectrum

Extended frequency modulation (FM)

Excitation methods

Exemplary excitation signal

slide-29
SLIDE 29
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 29

Simulated micro spill structure for extended FM

Frequency modulation Spill

slide-30
SLIDE 30
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 30

Simulated micro spill structure for extended FM

Frequency modulation Spill PRBPSK Extended FM

slide-31
SLIDE 31
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 31

Experiment

  • Particle: Carbon
  • Energy: 430.1 MeV/u
  • Particles: 4 · 108 per spill
  • Resolution: 50 ms/bin
  • Bunched: fsync = 500 Hz
  • Chromaticity: -0.79
slide-32
SLIDE 32
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 32

Measured macro spills confirming simulations

PRBPSK Single FM 1Hz Dual FM 1Hz Extended FM 1Hz (Constant exciter amplitude)

slide-33
SLIDE 33
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 33

Experimental results

Optimized by parameter scans:

  • Lower frequency limit
  • Higher frequency limit
  • Sweep rate
  • Frequency limits of additional FM

Extended FM Sweep rate: 1800 Hz PRBPSK (Intensity control + AM)

slide-34
SLIDE 34
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 34

Experimental results

Max-to-Mean ratio: Calculation of 200 bins ≙ 10 ms 1.55 · 108 particles extracted in total Extended FM Sweep rate: 1800 Hz PRBPSK

<MM> = 2.18 <MM> = 1.47

(Intensity control + AM)

slide-35
SLIDE 35
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 35

Experimental results

Zoom PRBPSK Zoom Extended FM Sweep rate: 1800 Hz Extended FM Sweep rate: 1800 Hz PRBPSK (Intensity control + AM)

slide-36
SLIDE 36
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 36

Extraction rate distribution of PRBPSK and extended FM

slide-37
SLIDE 37
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 37

Extraction rate distribution of PRBPSK and extended FM

Reduction of spill ripple by 45% !

slide-38
SLIDE 38
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 38

Excitation spectrum

Extended FM Sweep rate: 1 Hz

slide-39
SLIDE 39
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 39

Excitation spectrum

Extended FM Sweep rate: 1800 Hz

slide-40
SLIDE 40
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 40

Extraction rate drops due to increasing gaps in excitation spectrum 1.55 · 108 particles extracted in total Instead of 4 · 108

Excitation spectrum

Extended FM Sweep rate: 1800 Hz

slide-41
SLIDE 41
  • F. Faber Slow Extraction Workshop 2019 - Fermilab, 22nd-24th July 2019 41

Conclusion

  • The extended FM increases the spill quality by decreasing the spill ripple

around 45%

  • Extraction rate drops -> more exciter power necessary
  • Extended FM will be implemented at HIT
  • Total treatment time could be reduced by 18%
slide-42
SLIDE 42

Thank You for Your Attention

  • O. Boine-Frankenheim, S. Sorge
  • J. Adamy
  • R. Cee, F. Faber, E. Feldmeier,
  • Th. Haberer, M. Galonska, A. Peters,
  • S. Riegler, C. Schömers
  • C. Krantz, U. Scheeler