|
The beam envelopes computed with TRANSPORT in first (white) and second (red) order are shown in
Fig. 1 (12 kB). A significant growth in
beam size is only showing up in this drawing at the end of the beam line. This is due to the 2 second order
contributions T126 and T346 shown graphically (for dp/p = 1% and x0' = 10 mrad or y0' = 10 mrad)
in Fig. 2 (11 kB). Monte Carlo computations
with the program TURTLE show, that the phase space difference at the patient's location between
2nd and 1st order indicated by the Transport calculations is almost empty. This can be seen from
comparing the 1st order Turtle output shown in Fig. 3 (16 kB)
with the 3rd order Turtle output shown in Fig. 4 (16 kB).
Transport input file producing the 2nd order envelope shown in Fig. 1:
/Gantry of type IBA-GA (@NPTC-MGH)/ 0 15. 11.0 /MEV/ .001 ; 15. 1.0 /MM/ .1 ; 16. 16. 0. /X0/ ; (Initial beam line position) 16. 17. 0. /Y0/ ; 16. 18. 0. /Z0/ ; 16. 19. 0. /THE0/ ; (Initial beamline direction) 16. 20. 0. /PHI0/ ; 13. 12. ; (Output is beamline layout in global coordinates) -17. /SECO/ ; 1. 2.475 10.1 2.475 10.1 0. 1.0 696.0 /BEAM/ ; (Ekin = 230 MeV, dp/p = 1%) 3. 0.5 ; 5. 0.25 -0.6268 38. /Q9/ ; 3. .45 ; 5. 0.25 1.7456 38. /Q8/ ; -10. 1. 1. 15. 0.1 /FIT9/ ; 3. 1.0 ; 5. 0.25 -2.9777 38. /Q7/ ; 3. .45 ; 5. 0.25 2.0222 38. /Q6/ ; -10. 1. 1. 20. 0.1 /FIT2/ ; 3. 0.45 ; 16. 8. 4.4 ; 16. 7. 0.5 ; 16. 5. 37.5 ; 20. -180.0 ; 2. 22.5 ; 4. 0.6 15.195 0. /B2/ ; -10. 3. 3. 25. 0.1 /FIT2/ ; 4. 0.6 15.195 0. /B2/ ; 2. 22.5 ; 20. 180.0 ; 3. 0.45 ; 5. 0.25 3.7665 38. /Q5/ ; -10. 1. 1. 20. 0.1 /FIT2/ ; 3. 0.45 ; 5. 0.25 -2.9749 38. /Q4/ ; -10. 3. 3. 25. .1 /FIT2/ ; 3. 1.0 ; 5. 0.25 6.6298 38. /Q3/ ; 3. 1.0 ; 5. 0.25 -4.4536 38. /Q2/ ; -10. 3. 3. 33. .1 /FIT2/ ; 3. .45 ; 5. 0.25 5.6918 38. /Q1/ ; 3. .45; 16. 8. 4.4 ; 16. 7. 0.5 ; 16. 5. 37.5 ; 2. 35.0 /B/ ; 4. 1.8 15.195 0. /B1/ ; 4. 1.8 15.195 0. /B1/ ; 2. 15.0 /A/ ; 3. -0.062 ; 3. 1.5 ; 3. 1. ; 3. 0.25 ; 3. 0.25 /PAT/ ; 24. 1. 1. 1. ; (put sigmax in reg1) 24. 3. 3. 3. ; (put sigmay in reg3) 24. 2. 2. 4. ; (put sigmax' in reg4) 24. 4. 4. 6. ; (put sigmay' in reg6) 25. 1. 3. 2. 2. ; (put reg1-reg3 in reg2) 25. 4. 6. 2. 5. ; (put reg4-reg6 in reg5) -10. 4. 3. 0 .1 /FIT3/ ; (waist in y) -10. 2. 1. 0. .1 /FIT3/ ; (waist in x) -10. 9. 5. 0. .1 /FIT3/ ; (set reg5 as constraint--->sigmax'-sigmay'=0) -10. 9. 2. 0. .1 /FIT3/ ; (set reg2 as constraint--->sigmax-sigmay=0) -10. -2. 6. 0. .001 /FIT1/ ; -10. -1. 6. 0. .001 /FIT1/ ; 3. 0.25 ; 3. 0.25 ; SENTINEL /Simultaneous fit of all Quads/ -1 5.01 /Q1/ ; 5.01 /Q2/ ; 5.01 /Q3/ ; 5.01 /Q4/ ; 5.01 /Q5/ ; 5.01 /Q6/ ; 5.01 /Q7/ ; 5.01 /Q8/ ; 5.01 /Q9/ ; 10. /FIT1/ ; 10. /FIT3/ ; SENTINEL /*PLOT* Display 2nd order envelope/ -1 5.0 /Q1/ ; 5.0 /Q2/ ; 5.0 /Q3/ ; 5.0 /Q4/ ; 5.0 /Q5/ ; 5.0 /Q6/ ; 5.0 /Q7/ ; 5.0 /Q8/ ; 5.0 /Q9/ ; -10. /FIT1/ ; -10. /FIT3/ ; 17. /SECO/ ; SENTINEL SENTINEL
Turtle input file producing the 3rd order histograms shown in Fig. 4:
/Gantry of type IBA-GA (@NPTC-MGH)/ 100000 15. 11.0 /MEV/ .001 ; 15. 1.0 /MM/ .1 ; 17. 3. /3rd/ ; 13. 10. ; 16. 190. 0. 100. /Meta/ ; (create metafile FOR100.DAT for graphics) 1. 2.475 10.1 2.475 10.1 0. 1.0 696.0 /BEAM/ ; (Ekin = 230 MeV, dp/p = 1%) 3. 0.5 ; 5. 0.25 -0.6268 38. /Q9/ ; 3. .45 ; 5. 0.25 1.7456 38. /Q8/ ; 3. 1.0 ; 5. 0.25 -2.9777 38. /Q7/ ; 3. .45 ; 5. 0.25 2.0222 38. /Q6/ ; 3. 0.45 ; 16. 8. 4.4 ; 16. 7. 0.5 ; 16. 5. 37.5 ; 20. -180.0 ; 2. 22.5 ; 4. 0.6 15.195 0. /B2/ ; 4. 0.6 15.195 0. /B2/ ; 2. 22.5 ; 20. 180.0 ; 3. 0.45 ; 5. 0.25 3.7665 38. /Q5/ ; 3. 0.45 ; 5. 0.25 -2.9749 38. /Q4/ ; 3. 1.0 ; 5. 0.25 6.6298 38. /Q3/ ; 3. 1.0 ; 5. 0.25 -4.4536 38. /Q2/ ; 3. .45 ; 5. 0.25 5.6918 38. /Q1/ ; 3. .45; 16. 8. 4.4 ; 16. 7. 0.5 ; 16. 5. 37.5 ; 2. 35.0 /B/ ; 4. 1.8 15.195 0. /B1/ ; 4. 1.8 15.195 0. /B1/ ; 2. 15.0 /A/ ; 3. -0.062 ; 3. 1.5 ; 3. 1. ; 3. 0.25 ; 3. 0.25 /PAT/ ; 50. 1. -10. 10. 1. ; 51. 1. -10. 10. 1. ; 52. 2. -10. 10. 1. ; 50. 3. -10. 10. 1. ; 51. 3. -10. 10. 1. ; 52. 4. -10. 10. 1. ; SENTINEL SENTINEL
Back to:Medical Gantry Optical Design
Last updated by
Urs Rohrer on 9-Feb-2006