Transcript No Slide Title
STATUS OF THE PROPOSAL FOR A SUPERCONDUCTING PROTON LINAC AT CERN
PLAN 1. Why and how ?
1.1 High intensity beams at CERN 1.2 Organisation 2. Present ideas for an SPL 2.1 Users’requests - Beam specifications 2.2 Outline of the accelerator 2.3 Studies: status and plans 3. Conclusion
R. Garoby 18/11/99 1
SPL at CERN
1. Why and how ?
1.1 High intensity beams at CERN
Planned uses of high intensity proton beams and interesting directions of improvement :
LHC: increased beam brightness at injection
CERN Neutrinos to Gran Sasso (CNGS): higher proton flux*
Anti-proton Decelerator: idem*
Neutrons Time Of Flight (TOF) experiments: idem*
ISOLDE: idem*
Potential uses of high intensity proton beams:
Fixed target Physics with low to medium energy muons and neutrinos “Neutrinos Factory” based on a muon storage ring “Muons Collider”
R. Garoby 18/11/99 2
SPL at CERN
1. Why and how ?
1.2 Organisation
Management Considering the strong interest of the physics community for high intensity proton beams, CERN management has created working groups investigating possible paths of evolution leading ultimately to a neutrino factory. The large inventory of 352 MHz LEP equipment (~ 40 x 1 MW klystrons + 272 cavities giving > 3.2 GeV / turn) is a unique opportunity to be taken into account.
Working groups for accelerators
Neutrino Factory (chairman: H. Haseroth) http://muonstoragerings.cern.ch/Welcome.html/
Linac(s) (chairman: R. Garoby) http://www.cern.ch/CERN/Divisions/PS/SPL_SG/
Synchrotrons (chairman: H. Schonauer)
R. Garoby 18/11/99 3
SPL at CERN
2. Present ideas for an SPL
2.1 Beam specifications Outline of a neutrino factory complex
R. Garoby 18/11/99 4
SPL at CERN
2.1 Beam specifications Proton beam for a neutrino factory
Parameter
Beam kinetic energy Mean beam power Bunch duration (rms) Time interval between bunches Total duration of beam pulse Beam pulse repetition rate
Value
2 GeV 4 MW ~ 1 ns > 100 ns > 300 ns a few s 100 Hz
Source of constraint
Muon production Target power handling capability Uncertainty in pion decay time First bunch rotation after target Second bunch rotation Revolution time in the muon storage ring (single turn injection) Background rejection in the distant experiments Power consumption in the muon accelerator complex R. Garoby 18/11/99 5
SPL at CERN
2.1 Beam specifications Linac beam specification
Particle type Energy (kinetic) Mean Current Duty Cycle (2ms pulse / 10 ms) Beam Power Transverse Emittance (rms norm.) Longitudinal Emittance (total) Bunch Length (total) Bunch Current Beam time structure (within pulse) H 2 10 20 4 0.6
80 24 < 60 Flexible GeV mA % MW m eVs ps !
mA R. Garoby 18/11/99 6
SPL at CERN
2.1 Beam specifications Filling scheme for the Accumulator of a Neutrino Factory 284 ns 82.3 ns 30 bunches 12
per turn 30
12
590 bunches 2 ms 10 ms no beam 6 ns (on target) BUNCH ROTATION RF (h=12) 284 ns 12 bunches 3.4
s 10 ms PROTON ACCUMULATOR
T
REV = 3.407
s (1200 periods @ 352.2 MHz) BUNCH COMPRESSOR
T
REV = 3.407
s (1200 periods @ 352.2 MHz) H DRIFT SPACE + DEBUNCHER Charge exchange injection 590 turns T= 2 GeV
l b
= 1 ns
I DC
= 10 mA (during the pulse)
I Bunch
= 33 mA 0.6
10 9 protons/bunch
l b
= 24 ps
* H,V
=0.6
m r.m.s
Fast ejection KICKER 10 ms 3.3
s Fast injection (1 turn) Fast ejection TARGET H+ 12 bunches 1.04
10 13 protons/bunch
l b
~ 6 ns (on target)
R. Garoby 18/11/99 7
SPL at CERN
2.1 Beam specifications Macro-bunch compression in the longitudinal phase plane T BCOMP ~ T B
p/p ACC
p/p COMP
p/p LINAC
Energy ( p/p) Time
During Accumulation After bunch rotation Application (???):
p/p max at ejection = 2 %
T = 53 MeV T BCOMP = 6 ns
l ~ 0.3 eVs + assuming SPL @ 100 Hz filling 12 bunches (1.04
10 13 p/b)
Longitudinal density ~ 4
10 13 p/eVs
R. Garoby 18/11/99 8
SPL at CERN
2. Present ideas for an SPL
2.2 Outline of the Accelerator Preliminary SPL layout
50
keV
7
MeV
100
MeV 1 GeV 2 GeV 12m 2 MeV 100m 20MeV
50
MeV 300m
240
MeV
400
MeV 320m
H-
Source Low Energy section
LEP-II dump
Drift Tube Linac Superconducting low-
Superconducting
1 Bending, collimation and stretching
R. Garoby 18/11/99 9
SPL at CERN
2.2 Outline of the Accelerator Basic Sections Parameters
Section RFQ1 RFQ2 DTL SC SC SC SC - LEP II TOTAL Out. Energy [MeV] 2
7 100 235 360
1010 2000 Frequency [MHz]
352.2
352.2
352.2
352.2
352.2
352.2
352.2
No.
Cavities 1 1 29 40 24 48 104 303 RF Power [MW] 0.5
0.5
5.8
1.4
1.2
6.5
9.9
25.8
No.
Klystrons 1 1 6 5 3 12 13 41 Length [m] 2.5
4 99 89 60 148 320 ~723 R. Garoby 18/11/99 10
SPL at CERN
2.2 Outline of the Accelerator RF and Superconducting cavities Parameters
Section design Gradient beta N. of [MeV/m] cells/cavity Cryostat length Input Energy Output Energy [m] [MeV] [MeV] N.of
N.of
N.of
cavities cryostats klystrons RF Power Length [MW] [m] TOTAL 1 2 3 4 0.48
0.66
0.8
1 5 5 9 6.7
4 4 5 4 7.88
8.97
11.29
11.29
100 235 360 1012 235 360 1012 2000 40 24 48 104 272 10 6 12 26 68 5 3 12 13 33 1.4
1.2
6.5
9.9
19 88.8
59.8
147.5
319.5
615.6
NOTES: distance between cryostats (for focusing doublets) is 1 m all along the linac 8 cavities/klystron sections 1,2,4 4 cavities/klystron section 3 (beta 0.8) gradient in section 4 adjusted for maximum klystron power <800 kW RF power per klystron: minimum 220 kW maximum 780 kW RF power per cavity: minimum 25 kW maximum 145 kW R. Garoby 18/11/99 11
SPL at CERN
2.2 Outline of the Accelerator Sketch of a possible layout
R. Garoby 18/11/99 12
SPL at CERN
2. Present ideas for an SPL
2.3 Studies: status and plans
ITEM
H- source (100 mA pulsed) Chopper RFQ(s) DTL SC – reduced SC – LEP 2
Servo-systems for pulsed operation of SC cavities Debunching
MAIN THEME 20 % duty cycle & low emittances Rise time ~ 1 ns 20 % duty cycle & emittances preservation 20 % duty cycle & emittances preservation Maximum gradient Maximum gradient Microphonics
Beam dynamics Cryogenics Services (electricity, cooling water etc.) Radio-protection Lay-out & civil engineering Coordination with users – Refinement of specs.
Minimise energy spread & maximize bunch length Optics design, particle tracking Halo and distributed losses STATUS Collecting information Pending Active Active Active Active Study started in stage 1. To be continued… Pending Study started in stage 1. To be continued… Pending Pending Recommendations available Pending Active R. Garoby 18/11/99 13
SPL at CERN
2.3 Studies: status and plans
Advancement of the SPL study depends upon:
the study of the Neutrino Factory (interest of a Linac + Accumulator based proton driver compared to an RCS solution, detailed specifications for the Linac, …)
the expected supplementary requirements for experiments using directly low energy protons
the strength of the study team ! (priority issue)
Firm deadline: provide recommendations early enough (mid-2000) for the CERN management to be fully informed before deciding upon the future of the LEP hardware
Constraint on a potential SPL project: no adequate resources available at CERN before ~ 2006 !
R. Garoby 18/11/99 14
SPL at CERN
3. Conclusion
The interest of a Superconducting Proton Linac at CERN is revived because of its potential as a proton driver for a neutrino factory
Detailed analysis and design optimisation of the SPL are required, but it needs waiting for a stabilisation of the users’requests…
Internal CERN resources are mobilised by LHC: collaboration with teams already busy designing similar machines is essential for the advancement of the SPL project.
R. Garoby 18/11/99 15
SPL at CERN