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Simulations: tools and status

Simulations: tools and status. Marco Apollonio, Imperial College - London. G4Beamline : see presentation ORBIT: see presentation Turtle Spreadsheets for BL. Optimising the BeamLine with MINUIT+Turtle. ( e ,P) matrix. Pros & Cons

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Simulations: tools and status

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  1. Simulations:tools and status Marco Apollonio, Imperial College - London MICE CM23 - Beam Line Parallel Session

  2. G4Beamline: see presentation • ORBIT: see presentation • Turtle • Spreadsheets for BL MICE CM23 - Beam Line Parallel Session

  3. Optimising the BeamLine with MINUIT+Turtle MICE CM23 - Beam Line Parallel Session

  4. (e,P) matrix MICE CM23 - Beam Line Parallel Session

  5. Pros & Cons Turtle has been used since ever to design the reference Beam Line: P = 207 MeV/c (d.s. of the diffuser), emi_N=7 mm rad Turtle is a ray-tracing code, well established and capable of dealing with materials along the line. It is not as sexy as G4 based codes and its I/O is pretty cumbersome, also the deck (system) is quite a pain in the neck ... ... however it works, it is fast and we don’t need a very sophisticated code at this stage But we need the flexibility to change initial parameters of the beamline and find the currents for our magnets. So far Optimisation has been done manually: a painstaking (and long) job MICE CM23 - Beam Line Parallel Session

  6. Optimisation via MINUIT is possible albeit not straightforward • As far as I know Turtle source code is not accessible: it comes as a black box, • you change the deck and run it at your convenience • To dribble this problem I have used a main code that uses Turtle (Linux) as an • external function and changes the magnet parameters in the deck as long as the • optimisation goes (via a shell script) • A routine is used to calculate: • 4D normalized emittance, beta, alpha • beta_x, alpha_x, beta_y, alpha_y • muon transmission • These quantities can be used to force the beamline to reach some goal values. In • the early days the goal was increasing Transmission, here it should be possible to • shape the optics of the beam (we don’t do miracles though ... ) MICE CM23 - Beam Line Parallel Session

  7. Beam Line is defined by 3 decks describing 3 elements of MICE BL • Up Stream Beam Line • Transfer • Down Stream Beam Line alpha0 Q1 Q2 Q3Sol Dipole1 Dipole2 OUTPUT u.s. of the diffuser Q4 Q5 Q6 Q7 Q8 Q9 alphaa0 beta b0 INPUT: beamlineu.s. Section MICE CM23 - Beam Line Parallel Session

  8. Up Stream BeamLine Optimisation MICE CM23 - Beam Line Parallel Session

  9. 100000 initial pions Not much to optimise The spirit is a proof of principle MICE CM23 - Beam Line Parallel Session

  10. Bsol=4.2 T Bsol=4.4 T TRANSPORT: Matrix Evolution Original Configuration After Optimisation NOTA BENE: this is the MATRIX for PIONS while optimisation tries to make BETA(mu) flat in the solenoid MICE CM23 - Beam Line Parallel Session

  11. Down Stream BeamLine Optimisation MICE CM23 - Beam Line Parallel Session

  12. Initial emi_N, beta (4D,x,y), alpha(4D,x,y) Some results DS section Q4-5-6-7-8-9 optimised using SIMPLEX algorithm Aim at b0 = 82.7 cm a0 = 0.44 as from diffuser prescriptions Code tries to minimise the function ((b-b0)/0.5)2 + ((a-a0)/0.04)2 Aimed values: beta0, alpha0 Initial quadrupole currents 10000 muons traced, <15 min Initial TR=4.2% Final TR = 3.7% final emi_N, beta (4D,x,y), alpha(4D,x,y) Minimisation seems unable to get a=0.44, it sets at around 0. no matter which precision is required However b reaches the required value MICE CM23 - Beam Line Parallel Session

  13. ********************************************** * * * Function minimization by SUBROUTINE HFITV * * Variable-metric method * * ID = 0 CHOPT = 0 * * * ********************************************** Convergence when estimated distance to minimum (EDM) .LT. 0.10E+01 FCN= 143.4691 FROM MIGRAD STATUS=CONVERGED 453 CALLS 454 TOTAL EDM= 0.12E-05 STRATEGY=1 ERROR MATRIX UNCERTAINTY= 2.9% EXT PARAMETER STEP FIRST NO. NAME VALUE ERROR SIZE DERIVATIVE 1 P1 68.371 2.4827 -0.32050E-01 -0.21101E-03 2 P2 -0.86933 0.94910E-01 -0.39128E-03 -0.10718E-01 3 P3 4.6328 1.6825 0.48669E-02 -0.15841E-03 4 P4 3.4303 0.71097E-01 0.31790E-03 -0.14099E-01 5 P5 60.499 1.2328 0.74829E-02 0.10867E-02 6 P6 -0.15806 0.27740E-01 -0.61581E-04 -0.30442E-02 CHISQUARE = 0.1435E+01 NPFIT = 106 68.3 -0.86 4.63 3.43 60.49 -0.15 0.975016 2.07481 4.22428 1 ********************************************** * * * Function minimization by SUBROUTINE HFITV * * Variable-metric method * * ID = 0 CHOPT = 0 * * * ********************************************** Convergence when estimated distance to minimum (EDM) .LT. 0.10E+01 FCN= 78.47191 FROM MIGRAD STATUS=CONVERGED 252 CALLS 253 TOTAL EDM= 0.23E-04 STRATEGY=1 ERROR MATRIX UNCERTAINTY= 2.9% EXT PARAMETER STEP FIRST NO. NAME VALUE ERROR SIZE DERIVATIVE 1 P1 125.27 4.4452 0.67998E-01 0.87830E-04 2 P2 0.96546E-01 0.91543E-01 -0.15508E-02 0.70039E-02 3 P3 0.81872 0.88086 -0.22246E-02 -0.74252E-03 4 P4 3.3471 0.68870E-01 -0.13344E-02 -0.10475 5 P5 -32.680 0.59870 0.15268E-02 -0.68178E-02 6 P6 0.37815 0.21789E-01 0.38693E-03 0.77574E-01 CHISQUARE = 0.1019E+01 NPFIT = 83 125.2 0.09 0.81 3.34 32.67 0.37 0.857006 1.09118 2.22163 y’ x’ x (cm) MICE CM23 - Beam Line Parallel Session y (cm)

  14. 215 MeV/c x (cm) P (GeV/c) at the end of the line [u.s. of the diffuser] MICE CM23 - Beam Line Parallel Session y(cm)

  15. NO CUTS DP/P<10% (P=215 MeV/c) MICE CM23 - Beam Line Parallel Session

  16. Beamline with Kevin’s parameters with MINUIT optimisation http://www.isis.rl.ac.uk/accelerator/MICE/Task%20Notes%20and%20Specifications/beamline%20-%20optics/some_reference_data.htm MICE CM23 - Beam Line Parallel Session

  17. Where do we go from here? • the idea is that this system can be used to optimise the missing beam lines • driving parameters are the BETA,ALPHA u.s. of the diffuser • (for different e and P) • force the BL to reach those values and also try to maximize transmission MICE CM23 - Beam Line Parallel Session

  18. Spreadsheets for BL selection http://mice.iit.edu/bl/Documentation/index_doc.html MICE CM23 - Beam Line Parallel Session

  19. magnet rescaling table dE/dX table (specific for material) calculates the local momentum according to a material budget table MICE CM23 - Beam Line Parallel Session

  20. Summary • All conventional magnets up and running • Solenoid down • reduced rate • need to increase pion production • target studies & improvement • tool to define beamlines by rescaling currents currently used • tool (TTL + MINUIT) under test to optimise future configurations MICE CM23 - Beam Line Parallel Session

  21. the END MICE CM23 - Beam Line Parallel Session

  22. extra slides [on initial Beam Emittance] The following two figures show the second order TRANSPORT beam profiles, corresponding to the above beam line optics (7.1π, 200MeV/c case). The initial pion source from the target occupied half widths of 0.255 cm and 0.1 cm in x and y (respectively) and 33.0 mrad and 14 mrad in x’ and ,y’, with a mean momentum of 444.71 MeV/c and uniform Δp/p =± 2.5%. The full width pion beam profile is shown in Figure 7.4‑4. ex=0.085 mm rad ey=0.014 mm rad e4D~0.023 mm rad Q1 Q2 y’=23mrad x’=34mrad 101.5 mm 2573 mm 3000 mm 4400 mm MICE CM23 - Beam Line Parallel Session

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