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## PowerPoint Slideshow about ' Beam line Optics' - agalia

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Q1

Q2

Q3

Q4

Q5

Q6

Q7

Q8

Q9

Dipole1

Dipole2

DK solenoid

m

p

sx = 2.55 mm

sy = 1.4 mm

sx’= 0.33 rad

sy’= 0.1 rad

ex = 0.8415 mm rad

ey = 0.1400 mm rad

June 1st 2009

MICE CM24 - RAL

3

3

tuning for all (e,P)

Also known as ...

the MATRIX

search for Q4-5-6 & Q7-8-9 currents to match optics at the

u.s. face of the diffuser fine tuning

for every chosen e [3,6,10] mm rad (norm.)

at every defined P = [140,200,240] (MeV/c)

GA+Turtle Optimiser

m

INPUT: beamline US section >>>>>>>>>

Q1

Q2

Q3

Q4

Q5

Q6

Q7

Q8

Q9

Dipole1

Dipole2

DK solenoid

p

OUTPUT: Twiss parameters

@ diffuser US face (+TOF1)

- GA procedure
- Define 6-genes genotypes: Q4-5-6-7-8-9 currents
- Express it as a phenotype: the Twiss parameters at some Z’s
- Evaluate phenotype’s fitness
- Mate genotypes and produce new individuals
- Choose the best & repeat for several cycles

MICE CM24 - RAL

5

- Pro’s and con’s of the method
- running is fast (2.5 h for initial 70K muons after DKsolenoid)
- preparing it a bit cumbersome (TTL…)
- 3 decks (US / MID / DS)
- I think of a change:
- generate p m (G4BL) and record m after DKsolenoid
- use THIS output as input for GA+TTL optimisation
- NB In principle the GA algorithm should be able to run G4BL directly
- It calls a script via a system call
- possibility of tuning the solenoid
- CAVEAT :
- need to insert the spectrometer solenoid in the simulation (fringe field)
- could take some time to have a working version

June 1st 2009

MICE CM24 - RAL

8

8

- are we ready?
- STEP I (shutdown 17 Aug/1 Sept) 2Sept – 25 Oct
- depends on what we want to reach
- - beam optics for a beam of 214 MeV/c before diffuser IS ready
- - it can be easily scaled for other momenta
- - a check of beam size at TOF1/ECAL should be sufficient to
- assess it
- - requires more work IF we need tuning (e.g. beta too big and
- we need to re-define it)
- STEP II (shutdown 17 Aug/1 Sept) 2Sept – 25 Oct
- a bit more laborious
- as before, optics exists for e=6,10 and P=214 MeV/c
- HOWEVER, this has been tuned for a tracker solenoid present (fringe field)
- re-defining it could require some work. We should try using it ‘just so’
- also, matrix has to be completed (hasn’t it to?)
- this requires values for B at 140/240 [ B(140)=140/200 * B(200), while
- B(240)=B(200) ]

June 1st 2009

MICE CM24 - RAL

9

9

Q8

Q9

Q7

Q8

Q9

Q7

Q8

Q9

are we ready?

b

STEP II.1

sXY

(a) well defined problem

know b in solenoid

know b at US-diffuser

b-line tuned

(e=6,10 mm rad, P=214 MeV/c)

STEP II.0

(b) NOT well defined problem

b in solenoid ?

b-line NOT tuned

SUGGESTION:

use case (a) tuning

STEP I

as case (b) but

beam smaller at TOF2/KL

due to less drift

SUGGESTION:

use case (a) tuning

June 1st 2009

MICE CM24 - RAL

10

10

1) beamline momentum tuning

m

Q1

Q2

Q3

Q4

Q5

Q6

Q7

Q8

Q9

Dipole1

Dipole2

DK solenoid

p

fix D2

fix D1

Pp=444 MeV/c

Pm=255 MeV/c

Pm=214 MeV/c

Pm=208 MeV/c

June 1st 2009

MICE CM24 - RAL

11

11

- a level-0 optics for any P can be obtained by momentum rescling
- then a Q4-5-6-7-8-9 tuning is required to match the line

June 1st 2009

MICE CM24 - RAL

12

12

3 6 10 rescling

recalculated e=6mm rad, P=207

new tuning e=10 mm rad, P=207

investigate case e=3 mm rad P=207

(does not converge)

PLAN: fix P=140/240 and cover the remaining empty elements

140

200

240

???

June 1st 2009

MICE CM24 - RAL

13

13

- TPT/TTL used so far to define the optics rescling
- TPT: matrix transport through material
- description decks a bit cumbersome
- what if we need to re-define?
- can we use something more?
- flexible
- understandable
- capable of matching

- MADX?

Optics

OPTIM

June 1st 2009

MICE CM24 - RAL

14

14

Optics rescling

G4BL @ Q1DS

ex= 0.074 mm rad

ey= 0.047 mm rad

I ‘d like to cross check with Mark’s

calculations on the same set of particles

Why emittance grows here?

June 1st 2009

MICE CM24 - RAL

15

15

Summary rescling

- a central optics exists for (p,m) beamline with Pm~200 MeV/c
- ande=6 mm rad
- level-0 optics for Pm=140/240 can be generated by momentum
- rescaling
- a fine tuning of Q[4-9] can be done to match the optics to
- US-diffuser values [STEPII.1]
- - optics for STEPII.0/STEPI can be the one for STEPII.1
- so far DKsol is kept fixed (not tuned)
- could be inserted in tuning if TTL G4BL (but requires work)
- codes other than TPT (MADX) could be used to improve optics
- US of DKsol (ditto)

June 1st 2009

MICE CM24 - RAL

16

16

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