1. J.-P. Koutchouk CERN & Uppsala University
20/03/2000
Plans for the assessment of performance for a solenoid hadron collector
J.-P. Koutchouk
CERN & Uppsala University
8/3/2019
Uppsala 2014

2. Outline Former work What technology can offer today
20/03/2000
Outline
Former work
What technology can offer today
Desirable work plan
8/3/2019
Uppsala 2014

3. 20/03/2000
1- Former work
Blue: more recent ref. summarized; black: identified but not yet analyzed
1983: positron sources for LAL (Chehab)
1985: positron sources for SLAC (Bulos et al.)
1999: Angular collection using solenoids (Chehab, Nufact99)
1999: a solenoidal capture system for ν production, (Diwan et al. BNL, PAC99).
1999: Prospective study of muon storage rings at CERN (Autin, Blondel, Ellis, CERN)
2000: Optimum optical systems for future accelerators, (R. Royer CERN)
2002: A scenario for a BNL nu SB experiment (Diwan et al, BNL & Princeton)
2003: A nu horn based on a solenoid lens (McDonald, Princeton)
2006: Solenoid vs horn focus for neutrinos, (R.B. Palmer, BNL)
2006: Comparison of solenoid and horn focusing, (S. Kahn, Muons Inc.)
2008: horn and solenoid options, (M. Yoshida, NuFact08)
8/3/2019
Uppsala 2014

4. Prospective study of muon storage rings at CERN (1)
20/03/2000
Prospective study of muon storage rings at CERN (1)
Edited by B. Autin, A. Blondel & J. Ellis
CERN 99-02, ECFA , 30 April 1999
Step 1: 1-2 GeV proton linac, beam power ~ 20 MW, high-field solenoid for pion and muon collection; prospects for CP violation studies marginal.
“The design and even construction of this line of machines could involve capabilities that are available in different laboratories in Europe. A dedicated collaboration involving EU laboratories is necessary in order to go further, and could become extremely effective”
8/3/2019
Uppsala 2014

5. Prospective study of muon storage rings at CERN (2)
20/03/2000
Prospective study of muon storage rings at CERN (2)
hadron collection by a solenoidal system (p5) :
Quarter wave transformer where the field varies stepwise between 2 solenoids [R. Chehab, positron source, LAL/RT92-17]
Adiabatic device with exponential field decay
20T needed
Section 2.3 solenoids for pion collection, J. Collot and W. Joss
Hybrid magnet: the warm coil protects the cold one.
8/3/2019
Uppsala 2014

6. A scenario for a BNL nu SB experiment (1)
20/03/2000
A scenario for a BNL nu SB experiment (1)
Diwan, Kahn, Palmer, Parsa, Stumer BNL, McDonald, Princeton
Ref: 2002.
Magnetized detector assumed (0.5T)
20T solenoid for capture with field dropping from 20T to 2.5 T in 10 m to provide focusing; sol radius is 15 cm at target; capture up to 450 MeV (similar to Neutrino factory, S. Ozaki et al., nu fact feasibility study II report, Tech.Rep. BNL (2001)
8/3/2019
Uppsala 2014

7. A scenario for a NL nu SB experiment (2)
20/03/2000
A scenario for a NL nu SB experiment (2)
8/3/2019
Uppsala 2014

8. A Nu horn based on a solenoid lens (1)
20/03/2000
A Nu horn based on a solenoid lens (1)
McDonald, Princeton
Ref: Note, 2003
Tutorial on solenoid horns: point to parallel for cumb of pion energies, depends on B field and solenoid length: particles must complete an odd number of half turns before entering the fringe field.
8/3/2019
Uppsala 2014

9. A Nu horn based on a solenoid lens (2)
20/03/2000
A Nu horn based on a solenoid lens (2)
8/3/2019
Uppsala 2014

10. Optimum optical systems for future accelerators
20/03/2000
Optimum optical systems for future accelerators
P. Royer, CERN
Ref: CERN PS seminar, 9th Nov
Study of a system Capture solenoid + matching solenoid for a neutrino factory:
Adiabatic capture with field dropping from 20T to 1 T B0/(1+az)
Matching solenoid (or quads)
Study carried out using a symbolic optics code
8/3/2019
Uppsala 2014

11. Solenoid vs horn focus for Nu’s Preliminary conclusions:
20/03/2000
Solenoid vs horn focus for Nu’s
R.B. Palmer, BNL
Ref: seminar at Princeton, Aug
Adiabatic capture with B=20T down 2T in 2 m and down to .2T over 100 m. solenoid radius 7.5 cm.
Comparison with 5 horn solutions.
Preliminary conclusions:
Solenoid may be superior at low momenta
Solenoid could be improved if larger bore affordable
Horn could be reoptimized at low momenta
8/3/2019
Uppsala 2014

12. Comparison of solenoid vs horn focus (1)
20/03/2000
Comparison of solenoid vs horn focus (1)
S. Kahn, Muons Inc., USA
Ref: seminar at Princeton, Jul
Adiabatic capture with B=20T down 1.6T in 20 m. solenoid bore radius 7.5 cm.
If only  and not  is desired, then a dipole magnet could be inserted between adjacent solenoids above.
8/3/2019
Uppsala 2014

13. Comparison of Horn and Solenoid Focused Beams (2)
The Figure shows the spectra at 0º at km from the target.
Solenoid Focused Beam.
Two Horned Focused Beam designed for E889.
So-called Perfect Focused beam where every particle leaving the target goes in the forward direction.
The perfect beam is not attainable. It is used to evaluate efficiencies.
A solenoid focused beam selects a lower energy neutrino spectrum than the horn beam.
This may be preferable for CP violation physics
Similar results at 1.5 deg.off axis
S. Kahn -- Comparison of Solenoid and Horn
July 27, 2006

14. Conclusions (for 12 GeV protons/ AGS)
Comparison of solenoid vs horn focus (3)
Conclusions (for 12 GeV protons/ AGS)
Most of this work had been done on and off between 1999 and 2001.
We had appreciated that making long solenoid channels would be an effective way to hold pions until they decayed.
We were concerned about the cost of these long solenoid channels since horns were relatively cheap.
We were not successful keeping the beam focused after we left the solenoid (??).
Horns were reasonably efficient in capturing pions particularly the high part of the spectrum.
There was not much room for enormous gain.
This talk should provide an introduction into Harold Kirk’s talk which discusses more recent work that has been done on this subject.
S. Kahn -- Comparison of Solenoid and Horn
July 27, 2006

15. Horn and solenoid options in Nu factories
20/03/2000
Horn and solenoid options in Nu factories
M. Yoshida, Osaka Univ.
Ref: presentation at NuFact08
Adiabatic capture with B=6T down 1.T in 2.5 m. 50% of pion decay at 5 m . solenoid bore radius 7.5 cm.
8/3/2019
Uppsala 2014

16. My tentative conclusions of the former work analyzed
20/03/2000
My tentative conclusions of the former work analyzed
the solenoid capture has been considered for positron sources and neutrino factories; nothing for SB’s except good words (possibility of separating species with a dipole inside solenoid slices).
In all cases, adiabatic capture by a decaying solenoidal field is considered, assuming NbTi technology and ~15 cm bore.
Tracking seems to show that at 1 km, solenoid capture would be better than horn capture for ESSnuSB energies.
For several 100 km’s however, the quality of point to parallel optics does not seem to be studied hence neither demonstrated.
Concern is expressed for extra cost while no drastic improvement of performance over horns is identified.
Radiation resistance is to be studied.
8/3/2019
Uppsala 2014

17. 2- What technology can offer today
20/03/2000
2- What technology can offer today
Former studies ( done in the LHC time) assume a 20 Tesla superconducting solenoid based on the ATLAS/CMS,… NbTi technology.
Since then, under the impulse of ITER, medical applications, and the LHC upgrade studies, especially by USLARP, …, the difficult Nb3Sn engineering is making rapid progress.
Nb3Sn offers the possibility of higher fields or larger bores, and a somewhat larger temperature margin before quench.
8/3/2019
Uppsala 2014

18. Preliminary feasibility studies of a focusing solenoid for the ESSnuSB, R. Maccaferri, 6-03-2014
16 Tesla, 30 cm bore
R. Maccaferri, CERN, TERA
8/3/2019
Uppsala 2014

19. 16 Tesla, 30 cm bore R. Maccaferri
Field calculation performed for a 2m long model, both without and with magnetic return.
R. Maccaferri
8/3/2019
Uppsala 2014

20. 3- Work Plan (not “resource-loaded”)
20/03/2000
3- Work Plan
(not “resource-loaded”)
Classical solenoidal focusing: Revisit classical solenoidal focusing, including its aberrations. The focusing is a subtle effect of the solenoid edges. Hence it is quite important to master it well when the final aim is to suppress one edge! The potential of solenoids is so far from usual colliders that the knowledge is probably confined to scientists working on sources.
Charge separation: Understand whether, in this classical case, tilting the solenoid or adding a dipole between two solenoid slices produces the charge separation that is wanted.
8/3/2019
Uppsala 2014

21. 20/03/2000
Moving the source inside the solenoid: Investigate the optics when the source is inside the solenoid, both for focusing and charge separation. This is of major impact, as one of the edges will be missing. My understanding is that the system will become monochromatic. Good or bad?
Optimizing the solenoid: What is the real gain of an adiabatic capture vs a standard solenoid? Worth the complexity?
Performance estimate for ESSnuSB: With a provisional layout, using the solenoid devised by R. Maccaferri, track the pions and compare at the detector with the baseline horn, and optimize the layout for maximum yield (within an energy band?)
Cooling and radiation: Investigate the energy deposition and activation of the solenoid coil. Can it be protected by internal shielding liners?
8/3/2019
Uppsala 2014