Transcript and the Laboratoire de l`Accélérateur Linéaire (Linear

LAL future programs
Bruno Touschek Memorial Lectures 2013
Orsay 13/09/2013
Alessandro Variola, LAL Orsay
To talk about the future we first have to remember the past…
LAL has been doing accelerators physics for 60 years !!!
1967 The rings
starts:
collider
ring,
ACO => first
experiment
in 1967. of 157 MeV, and Linear Accelerator).
1958-1965
Thehistory
first beams
ofOrsay
the new
French
accelerators
were
delivered performed
(synchro-cyclotron
In 1971
the synchrotron-radiation
facility
started
=> 540-MeV
ACO had
storage
ring, its very first beam, a 3 MeV electron beam.
On
24 December
1958, almost 45 years
earlier
to the
day, the Linac
delivered
thenyear
the DCI
de collisions
dans
l'igloo),
commissioned
in 1976-1977;
finally
the the
Super-ACO
ring, to begin.
One
later,(Dispositif
the first section
of the
machine
achieved
an energy
of 165 MeV,and
thus
enabling
experiments
After World War 2, the rapid growth of fundamental physics needed more and more powerful accelerators,
fully dedicated to the production of synchrotron radiation, with its first experiment in 1988. From 1985 onwards
which required large areas. The Université de Paris, the Ecole Normale Superieure and the College de France
the Linac
usedenergy
exclusively
as an injector
for the
latter
two
rings. In
case
of the
DCI: 26
of exploitation - first
The
Orsaywas
linac's
was gradually
increased
in this
way,
reaching
1.3the
GeV
in 1964
- which
foryears
a short
looked for space in the south of Paris near Orsay.
for particle
and then
as anfor
X-ray
source.
time
was thephysics
world energy
record
electron
linacs - and 2.3 GeV in 1968. As of 1963, the accelerator was also equipped
to deliver a positron beam, whose initial energy of 250 MeV was later increased to 1 GeV.
October 1954 The Parc de Launay in Orsay (160 hectares) was bought by the State.
1978-1986
The LAL
accelerator
in the LEP to
(CERN)
effort
by designing
and delivering
the LIL injector.
1962
In early
summergroup
1962,participates
AdA was transferred
France,
at LAL,
the Laboratoire
de l'Accélérateur
Linéaire at Orsay,
1955 Construction began on the Laboratoire de l'Accélérateur Linéaire (Linear Accelerator Laboratory)
near Paris, where a high intensity linear accelerator (LINAC) was available. This transfer led to the first experimental
On December
19th 2003 the collisions
Laboratoire
l'Accélérateur
Linéaire
atthe
Orsay
marked
the final shutdown
evidence
of electron-positron
in a de
storage
ring, and thus
opened
era of
electron-positron
physics.of its linear accelerator.
1957 The cyclotron of the College de France, built in 1937, was moved to Orsay.
SOLEIL (St Aubin) is the new French synchrotron source. 2004 – 2013 Accelerator dismantling procedure.
At present. The LAL accelerators
department
• Accelerators department at LAL is in charge of the
coordination of the Accelerators activities of the
laboratory.
• Managing 35 FTE in the accelerators group.
University associated professors, researchers,
engineers and technicians.
• Coordinating the activity of the accelerators
projects through the different technical groups.
More than 80 agents involved.
• Support to the University teaching. 1 Master
course in NPAC, 2 Master courses APIM.
From 2006 9 PhD theses and 1 HDR
• Projects budget ~ 35 M Euros
For the future:
a shared scientific strategy
• To support and maintain the R&D activity we
need to develop technical platforms: XFEL Coupleurs, PHIL, Compton group.
• To develop and increase the knowledge of
accelerator physics it is mandatory to have a
local project => ThomX
• The first two points provide a scenario for
international projects collaborations, large
machines for big science: ILC, CLIC, SuperB,
SuperKEKb, ATF, LHC, ELI-NP
• It is also necessary to always keep an eye on
emerging acceleration technologies …. ETALON
Technology, present and future
• High power couplers for SC cavities
Developing the design, the technology and the industrial
control for XFEL.
The future is ILC, the next linear collider.
• High Brilliance photoinjectors PHIL. Design and
technology for electrons guns.
Users: Fluo – Jem Euso, CaptDiam, Leetech – Detectors….
• The future is SuperPHIL. Extension at higher energy
• Compton Group: Design and realization of passive
optical cavities for Compto sources: PLIC FP6,
Mightylaser ANR, ASTRE Platform on feedbacks.
• The future is ELI-NP, gamma source for nuclear
science
Couplers - XFEL
The European XFEL currently under construction in Hamburg-Germany. It is a over 3
km long facility with a superconductive linear accelerator of about 1.7 km bringing
electron energy up to 17GeV. A mini-ILC !!!!
The linac will consist of 100 Cryo-modules equipped with 670 (800) power couplers (8
coupler/module).
A coupler is a very high technology object.
It has 3 functions to fulfill:
•
•
•
RF power transmission
Vacuum barrier
Thermal transition
Complex mechanical and RF design (high peak power, thermal aspects)
Different materials use (ceramic, Cu ,SS 316L) and nm layer coating (TiN, Cu),
Very strict specifications to meet
6
XFEL Couplers
In the past LAL worked on:
-
conditioning time: reduction from 80h to 24h average
-
design: TTFV and TW60
-
nm TiN coating by magnetron sputtering
The future :
The LAL will contribute to the XFEL project by performing the following tasks:
 The industrial monitoring and coupler fabrication control at production
sites.
 The RF conditioning of the 670 (800) produced couplers at LAL.
 In parallel we will develop the know-how for a large scale production followup and for the stabilization of a low average conditioning time. This is a
mandatory process in view of the ILC.
7
PHIL
Energy
9 MeV
Max energy
Bunch length
5-10 ps
Laser dependent
Repetition frequency
5 Hz
Charge / bunch
0.1 – 2 nC
Photocathode dependent
Emittance
5 - 15 p mm mrad
Gun dependent
Beam sizes
2-10 mm
Line end
Compton group - Mightylaser
2 spherical mirrors
12 encapsulated Motors
Mounting in class 10 room
laser
Gimbal
mirror
mounts
For
vacuum
e-
2 flat mirrors
Invar base
to ensure
length
stability
9
Compton group: recirculators and cavities
ELI-NP Gamma System
• The Challenge we are facing: design the most advanced
Gamma Beam System based on state-of-the-art
components, to be commissioned and delivered to users by
mid 2017, reliable, cost-effective (60 M€ total cost),
compatible with present lay-out of ELI-NP building (it is
not a joke…)
• Prototype of a New Generation (Light) Gamma-ray Sources:
Bright, Mono-chromatic (0.3%), High Spectral Flux (> 104
ph/sec.eV), Tunable (1-20 MeV), Highly Polarized, based on
Compton Back-Scattering of High Phase Space Density
Electron Beams by Lasers
Simplification of the
System for ELI-NP
Parabolic reflectors
2 parabola
In confocal geometry
no aberrations after
32 passes
But few µm, µrad tolerances
on the alignment
Tight tolerances
few µrads on parallelism
Parallel
mirror pair
 Optical alignment ‘issues’
11
ThomX
• ThomX is a compact Compton source in the X range.
• It consists of a low energy storage ring coupled with a
high power laser and a high gain optical cavity.
• The goal is to produce 1012-1013 X/s average flux for users
• Financed by EQUIPEX, SESAME Ile de France, in2p3
CNRS, Université Paris Sud XI. 15 MEuros
• For our policy it is the ‘dream’ machine. It has all the
complexity of a large size device (maybe more due to the
low energy), but the small size allows to reduce the cost of
maintenance and exploitation. It boosts the aspects of
pluridisciplinary research in our team and in the laboratory
framework.
• This project must be part of the future of our laboratory
(see M. Jacquet Talk)
International collaborations
• The next linear collider
 We are in charge of the industrial contract of the XFEL SC couplers. Test for the
ILC production. We have developed different positron sources design. At present the
LAL ‘Hybrid source’ is the baseline for the CLIC (design of 2GHz sections) and
alternative design for ILC. Compton sources are alternative design for both projects.
We have actively participated in the ATF program, for the final focus stabilization. In
parallel we have conducted exhaustive studies on the MDI.
• LHC
 For the LHC high luminosity the collimation is one of the most important systems. We
have joined the UA9 collaboration, charged with the development of a crystal assisted
collimation system (channeling). We provide the beam tracking simulations, the study
and measurements of the impedances and data analysis.
• SuperKEKB
 After the unlucky SuperB experience we are proposing to study and develop the
luminosity measurement in SuperKEKB by means of a diamond monitor.
• Laser Plasma acceleration.
 As far as the future plasma accelerators are concerned, one of the most challenging
technologies is the diagnostics. Need to measure shot by shot low charge, low
emittance beam…not always repeatable, with a large dynamical range. Smith Purcell
techniques developed in collaboration with SLAC, SOLEIL, SPARC.
UA9 – At present: multi stage collimation in LHC
The halo particles are removed by a cascade of amorphous targets:

1.
Primary and secondary collimators intercept the diffusive primary halo.
2.
Particles are repeatedly deflected by Multiple Coulomb Scattering also producing hadronic
showers that is the secondary halo.
3.
Particles are finally stopped in the absorber.
4.
Masks protect the sensitive devices from tertiary halo.
0
beam core

6
7
6.2
10
tertiary halo
& showers
masks
secondary
collimator
1m CFC
secondary
collimator
1m CFC
secondary halo
& showers
tertiary
collimator
absorber 1m W
secondary halo
& showers
Sensitive
devices
(ARC, IR
QUADS..)
>10
Normalizes
aperture [σ]
primary collimator
0.6 m CFC
primary halo
Collimation efficiency in LHC ≅ 99.98% @ 3.5 TeV

Probably not enough in view of a luminosity upgrade

Basic limitation of the amorphous collimation system

p: single diffractive scattering

ions: fragmentation and EM dissociation
UA9 - Crystal assisted collimation

Bent crystals work as a “smart deflectors” on primary halo particles

Coherent particle-crystal interactions impart large deflection angle that minimizes the escaping
particle rate and improves the collimation efficiency
θch ≅ αbending
3 mm si
1 m CFC
amorphous
channeling
<θ>MCS≅3.6μrad @ 7 TeV
θoptimal @7TeV≅ 40 μrad
0
beam core
primary halo
6
7
Collimators partially retracted
secondary halo
& showers
masks
absorber
1m W
secondary
collimator
1m CFC
10
secondary
collimator
1m CFC
primary collimator
0.6 m CFC
Dechanneled particles in the crystal volume
6.2
Absorber retracted
Sensitive
devices
(ARC, IR
QUADS..)
>10
Normalizes
aperture [σ]
Silicon bent crystal
Multiple Coulomb scattered halo (multi-turn halo)
ATF 2 : Routine production if a 70 nm beam!
ATF2 = LC collision point prototype
Nominal parameters :
N = 10 10
σy = 37 nm
72.8 + 5.4 - 4.7 nm
Compton backscattering photons:
counting rates modulations on the
interference fringes
P.Bambade
ETALON: longitudinal profile measurements
for future accelerators
Principle: use coherent Smith-Purcell radiation to
measure the length of electron bunches.
On the SOLEIL linac: accurate mapping of coherent
Smith-Purcell radiation to design a single shot
longitudinal profile monitor.
Later: test of a single shot
profile monitor at SPARC
(LNF).
On FACET at SLAC: multi
shot measurements of
sub-picoseconds bunches.
Smith-Purcell radiation as a longitudinal
profile beam diagnostic
Application:
Plasma wakefield
accelerators (laser driven
and beam driven) and FELs.
17
Future dreams
• An integrated experimental hall with
different power systems for RF and HV
structure tests. The ACCELTECH pole
(Plan Vallée).
• SuperPHIL. High energy extension of PHIL
(200-300MeV) for new beam techniques
and diagnostics.
• Integrated platform for surface
treatment and analysis. Mandatory and
complementary for accelerators
technology R&D.
Conclusions and outlook…our future
• The Accelerators department has a clear and
shared scientific policy. In line with this strategy
we have many interesting activities and projects.
• ThomX local project…back to the past / towards
the future -> the LAL is an accelerators laboratory
• Scientific future: international collaborations LHC,
ILC/CLIC, ELI-NP, SuperKEKb coupled with ThomX
upgrades
• Future ‘strategy’ goals:
 Training... we need to attract students and hire
(quality!!!) to develop our program.
 Increasing the impact and the available resources
at LAL and in the in2p3.