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TRANSCRIPT
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A. Malinin1, A. Petrov1, V. Shevchenko1
For the LHCb collaboration
A SciFi production center in NRC KI for LHCb upgrade
Abstract: The Scintillating Fibre Tracker, SciFi for short, will be the main new tracking detector in LHCb. It will provide better than 100 µm spatial resolution, and
high rate capability and radiation hardness enabling a fast, 40 MHz, trigger rate with a capability to withstand 50 fb-1 integrated luminosity, delivered by LHC,
without a major performance degradation. The main active element of the tracker is a scintillating fibre ribbon with the SiPM readout. The ribbons consist of 6
layers of the 250 µm scintillating fibres Kuraray SCSF-78MJ, assembled by winding and bound together by the epoxy glue. NRC Kurchatov Institute, Moscow,
together with the colleagues from ITEP, CERN, TU of Dortmund and RWTH of Aachen are developing dedicated production centers with the aim to reach by 2016
production rate one ribbon per day per center, necessary to supply more than 1300 fibre ribbons (mats) needed for a new LHCb tracker.
SciFi detector concept and performance SciFi Tracker design and construction
[1] CERN-LHCC-2014-001 ; LHCB-TDR-015 , https://cds.cern.ch/record/1647400[2] P. von Doetinchem, H. Gast, Th. Kirn, G. Roper Yearwood, S. Schael,
Nucl.Instrum.Meth.A581:151-155, 2007, arXiv:astro-ph/0702567v1
[3] Th. Kirn et al., Production of Scintillating Fiber Modules for high resolution tracking
devices TIPP2014, Conference proceedings, Amsterdam, 5th June 2014[4] CERN-LHCb-PUB-2015-008, LHCB-EDR-M-M http://cds.cern.ch/record/2004811
The 3rd Annual Large Hadron Collider
Physics Conference
St. Petersburg, Russia
August 31st – September 5th , 2015.
SciFi modules series production and the quality assurance (QA)
winding, as well as many
other technological and
QA units which are being
developed together by the
groups of the SciFi project.
The production of the
SciFi fibre mats and
modules is organized at
This work is supported by Contract with Ministry of Education and
Science of Russia № 14.610.21.0002 and RFBR grant 14-02-03030. We
wish to thank CERN for their excellent beam facility and services.
Acknowledgements and References
Figure 1. The Outer Tracker position in the LHCb
experiment to be replaced by the SciFi Tracker.
Figure 10. The fibre QA scanner principal scheme. Figure 11. KI fibre quality scanner 3D-model. Figure 12. The fiber ribbon winding machine.
Figure 13. SciFi modules production flow-chart
developed for LHCb VELO
upgrade (with 10 µm track
resolution) and the SciFi
modules. themselves. The
result is shown in Fig.6. The
double Gaussian fit to the
residuals distribution for the
charge weighted cluster hits
gives σ1 = 59 μm σ2 = 203
μm with 79 µm weighted
average effective sigma.
.
Module Centre
Fibre Quality Centre (CERN)
10,000 km scintillating fibre
Fibre Winding Centre
Fibre Winding Centre
Fibre Winding Centre
Fibre Winding Centre
Aachen Dortmund Lausanne Moscow
Tested fibre
Module Centre
Heidelberg
Amsterdam
1300 tested fibre mats
144 tested modules
CERN
Half-panel: Honeycomb (Nomex) + CFRP skin
Mirror side
Readout side
Figure 6. SciFi module spatial resolution
with one side mirror (beam track residuals)
Figure 9. 128-ch SiPM to readout SciFi signals
Figure 7. Modular design: 1 of 3 SciFi stations
Figure 8. SciFi module consists of 8 fibre mats
1NRC Kurchatov Institute, akademika Kurchatova sq.,1
Moscow, 123182, Russia
Figure 3. The SciFi detector fabrication conceptFigure 2. The radiation environment of the LHCb tracker area, which
corresponds to the integrated dose of 50 fb-1 : a) The total dose, and b) the
1 MeV equivalent neutron fluence per cm2 .
Figure 5. The Kuraray SCSF-78MJ scintillating fibre
irradiation tests summary: The ratio of the irradiated fibre
attenuation length Λirr to initial attenuation length Λ0, as a
function of the integrated dose in kGy.
Increased luminosity of the LHC requires a substantial upgrade of
the LHCb experiment [1]. One of the first detectors to be
completely replaced is the LHCb Outer Tracker (Fig.1). A much
higher radiation dose and neutron fluence, which correspond to
50fb-1 (Fig.2a,b) require a new tracker concept. The concept of the
scintillating fibre tracking detector is not new, but the SciFi highest
resolution and largest area detector with the direct multichannel
SiPM readout, providing better than 100 µm spatial resolution over
several square meters area, comes from the PEBS experiment
tracker proposal [2] by RWTH group. They, together with other
LHCb members of the SciFi
project, developed the winding
technique, using a precise,
threaded with 275 µm pitch,
rotating drum a winding wheel,
(Fig.3,4) to produce a 6 layer,
2500 mm long and 132 mm wide
Figure 6 shows a new
modular layout of the SciFi
tracker’s one out of three
(Fig.1) tracking stations.
Each station consist of four
layers of SciFi modules
mounted on C-frames with
two vertical (X) and two
stereo (U,V), at ± 5º to the
vertical, fiber orientations.
The modules (Fig.7) have
the same design except for
two innermost in each layer,
and consist of 8 mats
readout from one side by
four 128-channel SiPMs
(Fig.8), directly connected to
the end of the mat. Other
ends of the fiber mats are
equipped with mirrors. The
structure is closed by two
half-panels which are made
from a honeycomb core and
single carbon skin by gluing.
A readout box with front-end
electronics is attached to the
top and bottom of each
module. It has an insulated
cold compartment to keep
the SiPMs at -40°C working
temperature during the run.
Figure 14. Production clean zone of 240 m2
ISO7-ISO8 class is being constructed at NRC KI
Figure 15. NRC KI production clean room layout
The series production of the SciFi mats requires a clean room and a
set of equipment (Fig.10-12) for fibre quality assurance, and mat’s
seven centers (Fig.13) four of which are set up to produce over 1300
mats. The center at NRC Kurchatov Institute is shown in Fig.14,15.
The clean zone (Fig.15) is divided in four compartments, for entrance,
the QA fibre scanner (Fig.11), winding machine (Fig.12), and
assembly. The fibre QA scanner measures the fibre diameter, with high
frequency and 1 μm accuracy, it monitors the attenuation length and
light yield, and detects eventual structural defects such as the bumps,
necks and cracks. Its principal scheme is shown in Fig.10. The main
part of the production is winding. The mixture of Epotec 301-2 epoxy
glue and the TiO2 powder (20% by weight) is prepared in the winding
compartment and applied 6 times after each fibre layer is completed.
The curing process takes 48 hours and 3 precision wheels (Fig.4) are
needed to make 1 mat per day to ensure the required production rate
per shift. At NRC KI center, work in 2 shifts is foreseen.
mats out of 250 µm diameter scintillating optical
fibre [3], packaged in a dense, hexagonal structure
and bounded together by epoxy glue. The fibre was
carefully chosen after many tests. It is SCSF-78MJ,
produced by Kuraray company in Japan. Its
radiation hardness (Fig.5) was measured with
different linear energy transfer beams and dose
rates. The data demonstrates less than 20% of
expected transparency loss for the highest dose
near the LHCb beam pipe, covering only a few tens
of cm in Y direction (fibre direction in the mats).
a) b)
The SciFi spatial resolution was measured in the test beam at SPS
[4]. The beam tracks were reconstructed using the Si-pixel tracker
Figure 4. The NRC KI precision winding wheel
Shape accuracy: 70 µmOuter Ø = 817 mm
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