Alignment of LIPAc, the IFMIF prototype high current
deuteron accelerator: requirements and current status
F. Scantamburloa, L. Semerarob, A. Lo Bueb, L. Poncetb, P. Carab, J. Knastera, Y. Okumuraa, A. Kasugaic, H. Shidarac, T. Morishitac, H. Sakakic, M. Shingalaa, K. Tsutsumic
aIFMIF/EVEDA Project
Team, Japan / bF4E / cJAEA
IFMIF
A fusion relevant neutron source is almost four decades long pending step for the
successful development of fusion energy. In commercial fusion reactors, neutrons
fluxes in the order of 1018 m-2s-1 with an energy of 14.1 MeV will occur, which will be
absorbed in its first wall, undergoing potentially >15 dpaNRT per year of operation.
This irradiation will degrade structural materials in an unknown manner.
IFMIF, the International Fusion Materials Irradiation Facility, will generate a
neutron flux with a broad peak at 14 MeV by Li(d,xn) reactions thanks to two parallel
deuteron accelerators colliding in a liquid Li screen. The energy of the beam (40
MeV) and the current of the parallel accelerators (2 x 125 mA) have been tuned to
maximize the neutrons flux and reach irradiation conditions comparable to those in
the first wall of a fusion reactor and will allow qualification and characterization of
suitable materials.
LIPAC, the IFMIF/EVEDA accelerator
LIPAc LIPAc, the Linear IFMIF Prototype Accelerator,
will run in 2017:
Deuteron beam
9 MeV
125 mA in CW
will validate IFMIF’s (same current at 40 MeV).
Alignment tolerance of ±0.1 mm are required to:
allow stand on maintenance, limiting beam
losses up to 1 W/m to reduce component
activation
meet beam halo requirement
Measurement instrumentation:
Leica AT401 Laser Tracker:
 MPE distance accuracy: ± 10 µm
 MPE angular accuracy: ± (15 µm +6 µm/m)
 Level accuracy: ± 1 arcsec
Upgrade of the network in June 2013
According to ITER metrology Handbook, a factor 5 should be
guaranteed between tolerance and measurement uncertainty. A
target uncertainty below 0.02 mm shall be guaranteed in the
accelerator vault, quite
at the limit of current available
instrument performance.
SA existing network: SA simulated uncertainty 0.134 mm
Metrology Software:
NIST, ISO, GUM claim that a measurement is complete only when
accompanied by an uncertainty statement. Spatial Analyzer (SA) Ultimate
has been adopted as metrology software:
 USMN algorithm combines different measurements from
different measurement systems with advenced techniques
to increase accuracy.
 USMN algorithm can estimate uncertainty . It is GUM and
ISO compliant
 USMN algorithm estimates instrument uncertainty and
verify instrument performance in the real environment.
 Capability to fabricate measurements simulating instrument
performance.
Injector alignment
The installation of the injector (source + LEBT) was completed in May 2014.
The alignement has been performed with Taylor Hobson telescope. The
references has been aligned to the beam line frame by AT401. Source and
LEBT were surveyed and fiducialized after their installation with uncertainty
less than 40 mm at 2s.
8 available targets
SA new network simulations with 130 fiducials: ucert. < 0.02 mm
Thermal expansion of the building
A procedure has been established to evaluate the thermal expansion of
the building and if needed to compensate the measurements.
Date
2014.05.02
2014.05.08
2014.05.20
2014.07.09
2014.07.24
2014.08.01
2014.09.30
FL1-FL48 Dist [mm]
USMN
23562.744
23562.744
23562.744
23562.744
23562.744
23562.744
23562.744
Measured
23562.107
23562.184
23562.37
23562.986
23563.151
23563.332
23563.595
Upgrade of the nework and survey
Network update
Scale bar
Delta [mm]
-0.637
-0.56
-0.374
0.242
0.407
0.588
0.851
Scale factro to USMN
0.999973
0.999976
0.999984
1.000010
1.000017
1.000025
1.000036
alfa [m/°C]
5.1598E-06
7.572E-06
5.91284E-06
5.90107E-06
5.99452E-06
5.81084E-06
T floor Average [°C]
13.2
13.8
14.6
19.5
20.7
21.8
24.0
Temp. [°C]
13
13.5
14.7
19.7
21.3
22
23.9
Nom. Dist. [mm]
800.001
800.001
800.005
800.009
800.01
800.01
800.012
Meas. Dist. [mm]
800.005
800.007
800.014
800.015
800.008
800.015
800.01
T air [°C]
14.3
14.8
16.5
20.8
22.2
23.2
25.3