1. Target insertion matching and standard cell optics optimization
7th Muon collider meeting
S.M.Liuzzo

2. To achieve this an insertion needs to be accommodated in the lattice:
outline
S. Guiducci suggests to reduce beta and dispersion at the target location.
To achieve this an insertion needs to be accommodated in the lattice:
Gradients not different from other magnets in the lattice
Minimal number of dipoles removed (for space)
keep length constant
Minimal modification of the cell
Easy rematch if cell optics modified
This translated in:
Matching script for cell
Matching script for insertion
l 7th Muon Collider MEETING l 5 April 2017 l S.M.Liuzzo
26/07/2013

3. Half Cell and zoom on region to modify for insertion
l 7th Muon Collider MEETING l 5 April 2017 l S.M.Liuzzo
26/07/2013

4. 1m straight for target Modified cell (ARCT)
Visible quadrupoles have been modified in length and gradient to achieve the matching
1m straight for target
l 7th Muon Collider MEETING l 5 April 2017 l S.M.Liuzzo
26/07/2013

5. Matching
1) Remove 2 dipoles and rescale bending angle of all other dipoles for 2pi 2) Match ARCA cell to initial optics with new bending angles. 3) Match ARCT final quadrupoles to match required beta and dispersion at target. Quadrupole lengths also adjusted to achieve reasonable gradients. Chromaticity corrected, but no local sextupoles at insertion. Tune not fixed.
QD1A: T
QD2A: T
QF1A: T
QF2A: T
QD1E: T
QD2E: T
QF1E: T
QF2E: T
QDT: T
QFT: T
QD1E: T
QD2E: T
QF1E: T
QF2E: T
Br=150
Disclaimer: This is a very first approach (V0.5), the insertion is not at all optimal and there are much better solutions.
l 7th Muon Collider MEETING l 5 April 2017 l S.M.Liuzzo
26/07/2013

6. Positron beam size evolution with target (105 e+)
l 7th Muon Collider MEETING l 5 April 2017 l S.M.Liuzzo
26/07/2013

7. Cell optics optimizations
Objective: increase # e+ surviving after target First action: verify what is the most relevant parameter for optimization Loss pattern after target interaction. e+ survived vs: momentum acceptance at target (optics,sextupoles) momentum acceptance global (optics,sextupoles) angular acceptance at target ?? (optics, sextupoles) physical apertures (magnets gradients) Second action: look at the most relevant of the above parameters and optimize lattice optics knobs, sextupole fields, …
l 7th Muon Collider MEETING l 5 April 2017 l S.M.Liuzzo
26/07/2013

8. Positrons loss location after target interactions
Turn 1
Turn 2
l 7th Muon Collider MEETING l 5 April 2017 l S.M.Liuzzo
26/07/2013

9. Positrons loss location after target interactions
bin = 0.5m
bin = 10m
Turn 1
Turn 2
bin = 200m
l 7th Muon Collider MEETING l 5 April 2017 l S.M.Liuzzo
26/07/2013

10. Increase negative apertures at high dispersion high hor. beta
Increased apertures
Standard apertures
Standard apertures
Increased apertures:
Same particles, lost further in the lattice.
Increase aperture at high loss locations
l 7th Muon Collider MEETING l 5 April 2017 l S.M.Liuzzo
26/07/2013

11. Positron beam size evolution with target (105 e+) with different P.A.
No difference. Particles where already lost on Dynamic Aperture
l 7th Muon Collider MEETING l 5 April 2017 l S.M.Liuzzo
26/07/2013

12. Momentum aperture vs RF voltage
After 1 turn, no visible difference
After 256 turns,
@12MV limited by RF acceptance
#MV x2 RF cavity x 32 cells
l 7th Muon Collider MEETING l 5 April 2017 l S.M.Liuzzo
26/07/2013

13. Survived positrons VS RF voltage
l 7th Muon Collider MEETING l 5 April 2017 l S.M.Liuzzo
26/07/2013

14. momentum aperture at target vs Tune and chromaticity
[%] 3 turns
[%] 3 turns
Starting tune: (.08, .20)
Optimal tune: (.10, .40)
Starting chromaticity: (2,2)
Optimal chromaticity: (9,5)
Q[FD][12] for tune change
S[FD] to keep chromaticity fixed
S[FD] to change chromaticity
l 7th Muon Collider MEETING l 5 April 2017 l S.M.Liuzzo
26/07/2013

15. Positron beam size evolution with target (103 e+) : tune & chromaticity
Only few e+ more
l 7th Muon Collider MEETING l 5 April 2017 l S.M.Liuzzo
26/07/2013

16. Different target materials
l 7th Muon Collider MEETING l 5 April 2017 l S.M.Liuzzo
26/07/2013

17. conclusions
First attempt for a small beta and dispersion insertion: beam sizes increase is reduced if target at this location Studied lost positrons locations: all the particles are lost right after the target and at high dispersion regions. 5cm physical apertures are not a limitation for the beam acceptance. Positron survival plot as a function of RF cavity voltage Initial scan of tune working point (1 unit only) and chromaticity show some improvement. Much more work needs to be done, need parallelization of tracking with target. Different target materials are studied showing liquid He as the less detrimental for the positron beam.
l 7th Muon Collider MEETING l 5 April 2017 l S.M.Liuzzo
26/07/2013