NSC KIPT participation in the CMS (CERN) collaboration
In conformity with the Agreement of 03.04.1993 between the Government of Ukraine and CERN, the National Science Center Kharkov Institute of Physics & Technology (NSC KIPT) takes part in the international CMS program. Its collaboration duties include: the manufacture of scintillation elements for...
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2001
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| Zitieren: | NSC KIPT Participation in the CMS (CERN) Collaboration / L.G. Levchuk, S.V. Marekhin, A.A. Nemashkalo, V.P. Popov, P.V. Sorokin, A.E. Zatserklianiy // Вопросы атомной науки и техники. — 2001. — № 1. — С. 7-9. — Бібліогр.: 11 назв. — англ. |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1859711478633857024 |
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| author | Levchuk, L.G. Marekhin, S.V. Nemashkalo, A.A. Popov, V.P. Sorokin, P.V. Zatserklianiy, A.E. |
| author_facet | Levchuk, L.G. Marekhin, S.V. Nemashkalo, A.A. Popov, V.P. Sorokin, P.V. Zatserklianiy, A.E. |
| citation_txt | NSC KIPT Participation in the CMS (CERN) Collaboration / L.G. Levchuk, S.V. Marekhin, A.A. Nemashkalo, V.P. Popov, P.V. Sorokin, A.E. Zatserklianiy // Вопросы атомной науки и техники. — 2001. — № 1. — С. 7-9. — Бібліогр.: 11 назв. — англ. |
| collection | DSpace DC |
| container_title | Вопросы атомной науки и техники |
| description | In conformity with the Agreement of 03.04.1993 between the Government of Ukraine and CERN, the National Science Center Kharkov Institute of Physics & Technology (NSC KIPT) takes part in the international CMS program. Its collaboration duties include: the manufacture of scintillation elements for the forward hadron calorimeter and investigation of their characteristics; the simulation of physical processes in the CMS detector; the preparation for processing experimental results.
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| first_indexed | 2025-12-01T05:02:26Z |
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NSC KIPT PARTICIPATION IN THE CMS (CERN) COLLABORATION
L.G. Levchuk, S.V. Marekhin, A.A. Nemashkalo, V.P. Popov, P.V. Sorokin, A.E. Zatserklianiy
National Science Center “Kharkov Institute of Physics and Technology”, Kharkov, Ukraine
In conformity with the Agreement of 03.04.1993 between the Government of Ukraine and CERN, the National
Science Center Kharkov Institute of Physics & Technology (NSC KIPT) takes part in the international CMS
program. Its collaboration duties include: the manufacture of scintillation elements for the forward hadron
calorimeter and investigation of their characteristics; the simulation of physical processes in the CMS detector; the
preparation for processing experimental results.
PACS: 07.77.Ka.
CREATION OF SCINTILLATION
MATERIALS
Kharkov scintillating plates for the tile/fiber system
were produced by injection molding technology. The
industrial granulated polystyrene PSM-115 was mixed
with primary 1.5% pTP and secondary 0.02% POPOP
scintillating dopants. The mixture was loaded into a
standard injection molding machine including a
peculiarly designed mold. Special studies were made to
find optimum molding parameters for producing best-
quality scintillating plates at given conditions. The plate
dimensions were 240×210×4 mm3.
To investigate the properties of scintillators and
fibers, research setups with appropriate software were
created. They were used to measure the absolute light
yield in units pe/MIP, the attenuation length, the light
yield uniformity, the response time of the tile/fiber
system, the plastic scintillator light yield dependence on
the magnetic field and the radiation hardness of the
tile/fiber system, when irradiated by bremsstrahlung
photons from 20 MeV electron linac.
Scintillation and optical characteristics of the
Ukrainian Plastic Scintillator, Kharkov Injection-
molded Scintillators, Kuraray SCSN-81 Scintillators
and other scintillators and WLS fibers are presented.
a) Spectrum characteristics of the Kharkov UPS-
923A scintillator are practically the same as those of
Bicron and Kuraray scintillators. Scintillator emission
spectra match quite well the absorption spectra of the
INR (Moscow), Bicron and Kuraray WLS fibers [1]. In
Kharkov, 400 scintillator tiles with the size of 22×
22 cm2 , and 4mm thick and with the “sigma” key-
shaped grooves were manufactured. The tile-to-tile light
yield deviations is 3.8%. The tiles with the fiber (100
cm length) were wrapped with white paper. The light
yield studies of the tile / the mirrored WLS fiber end /
PMT systems are as follows:
- the lateral uniformity is ≈ 6%;
- the absolute light yield [2] in units pe/MIP is 4.7;
- time for 90% of signal collection is 22.2 nsec and
decay time – 6.3nsec.
b) We have carried out comparative measurements
for scintillating tile/fiber systems with Kharkov
injection - molded scintillators [3,4] and Kuraray
SCSN-81 scintillator, using Y11 fibers with length
70 cm and diameter 0.83 mm. The fiber end was non-
mirrored. All the tiles were wrapped with Tyvek. The
tile size was 131 mm × 122 mm × 4 mm.
The average uniformity of tile/fiber systems is 5.3%
for the Kharkov scintillator and 3.6% for the SCSN-81
scintillator. This difference is due to the fact that the
attenuation length of Kharkov scintillator is smaller.
- The light yield of tile/fiber systems made from
scintillators of both types is nearly the same, about
5.5 pe/MIP.
- Sets with tile/fiber systems from Kharkov and Kuraray
scintillators were irradiated up to 3.0, 4.0 and 5.3 Mrad
by bremsstrahlung photons from 10 MeV electron linac.
After two weeks of recovery, the light yield was
practically the same for the two tile/fiber systems. The
light yield uniformity (RMS) increases by a factor of 3.
c) The relative light yield change of polystyrene-
and acrylic-based scintillators versus magnetic field
have been investigated [5,6]. The magnetic field
changes from 0 up to 2.2 T. Scintillators samples of
different thickness from 1 up to 8 mm were exited by
photons (60Co, 137Cs), electrons (90Sr) and by α particles
(239Pu).
- In the case polystyrene the light yield increases up to
6%, for acrylic – up to 10% at a magnetic field of 2.2 T,
reaching saturation.
- Under irradiation of polystyrene-based scintillators by
α particles, the relative light yield change is close to
zero.
The response of the tile/fiber calorimeter light yield
to incident muons (100 and 300GeV), electrons
(100GeV), and pions (100, 200 and 300 GeV) was
studied in transverse magnetic field up to 3 T. The light
yield rises with magnetic field by about 20% [7].
MONTE-CARLO SIMULATIONS
OF THE CMS ENDCAP CALORIMETER
RESPONSE
The GEANT 3.21 program has been applied to
simulate showers produced in the CMS ENDCAP
calorimeter by single pions with energies ranging from
20 to 300 GeV [8]. Hadron calorimeter (HCAL) taken
for our calculations consisted of two sampling
scintillator/copper compartments with separate readouts
(see Ref. [9]). This HCAL module was considered also
in a conjunction with a crystal PbWO4 electromagnetic
calorimeter (ECAL). To optimize the shape of
PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. 2001, № 1.
Series: Nuclear Physics Investigations (37), p. 7-9.
7
distributions of the showers over deposited energy,
energy independent weights were assigned to signals
coming from different calorimeter compartments.
Within the energy range considered, for the calorimeter
energy resolution, we obtained: σ/E=105/√E⊕5.7% and
σ/E=87/√E⊕6.5% in case of HCAL only and the joint
ECAL + HCAL system, respectively. These results are
in agreement with the beam test data [7] (see Fig. 1).
A special version of the HCAL with a uniform
sampling has been also considered. It has been shown
that the energy resolution in this case is insensitive to
the way of subdivision of the HCAL into two
compartments [10].
Fig. 1. CMS calorimeter energy resolution: open
circles refer to our calculations, and beam test data [7]
are marked by asterisks
We also simulated the influence of dead zones of the
HCAL upon the calorimeter response (see ref. [11]). It
has turned out that the dead zones with thickness of 2cm
could substantially suppress (by 50%) the HCAL signal
and deteriorate (by factor of 3) its energy resolution.
SIMULATIONS OF CMS PHYSICS
One of the main goals of the CMS collaboration is to
find the Higgs boson in pp collisions at the LHC (see,
e.g., ref. [9]). While existing theoretical and
experimental restrictions upon Higgs mass values MH
are rather indefinite, it is still difficult to pick out one or
another mode of Higgs decay as most preferable for its
observation. A thorough search of “optimal”
kinematical conditions for the decays providing the
maximum signal/background ratio can be accomplished
with the help of computer simulations.
We investigated observability of a very heavy
Higgs (MH=500 GeV/c2) in the decays HZ0Z0→ l+l-νν
using PYTHIA6.1 as an event generator and
CMSJET4.7 to simulate the CMS detector response.
The main background contributions to the l+l-νν
signature come from channels Z0+jets→l+l-+X, t t →
l+l-+X, Z0W± → l+l-+X and nonresonant production of
Z0 pairs (Z0Z0 →l+l-+X). The calculations were
performed for the total energy of the colliding protons
s =14 TeV. Cuts T
lp ≥20 GeV/c for the transverse
momenta of the detected leptons and |η|≤2.4 for the
pseudorapidity range were predetermined by the CMS
detector performances. Only events with missing
transverse energy ETmiss and invariant mass of the
lepton pair Mll close enough to that of Z0 boson (|Mll
-MZ| ≤ 6 GeV) were selected for further analysis. To
suppress more the background contributions, the
requirement of the absence of jets with ETjet ≥200 GeV
at |η|≤2.4 was taken, and cuts θll≤90° and θTll≤90° for
the angle between total and transverse momenta of the
detected leptons were imposed. Some of our results are
shown in Fig. 2. It is seen that in spite of a fairly good
S/B ratio, the shapes of she signal and the background
are similar to each other making it difficult to observe
Higgs via the signature under consideration. Further
investigation is needed to get a definite conclusion
about observability of Higgs in this case.
Fig. 2. Distribution of signal (H→Z0Z0→ l+l-ν
ν ) and background events over the total
momentum of the detected lepton pair
PRODUCTION OF TILES
The National Science Center “Kharkov Institute of
Physics & Tehcnology” (NSC KIPT) and the Institute
for Single Crystalls (ISC) as one team are responsible
for Quantity production of the tiles for Hadron
Calorimetetry at CMS (LHC).
The NSC KIPT and ISC scientists have developed
the process for quantity production of Kuraray SCSN−
scintillator tiles with using the CNC machines. As a
result, now nearly 120 tiles of required quality can be
produced per day.
The manufacture of tiles is produced at Scientific
Research Department of Alkaly Halide Crystals of ISC.
8
NSC KIPT is involved during many years in the HE
CMS scintillator tile R&D and organized the Quality
program and final Quality tests of tiles.
The first package of scintillator tiles was delivered
to NSC KIPT from Institute ISC October 15, 2000.
So far the quality control was done for 1100 tiles.
The outer dimension, quality of the grooves, light yield,
transverse light yield were measured for two tiles from
each megatiles: for small one (about 0.4 cm × 11 cm ×
18 cm) and large one (about 0.4 cm × 23 cm × 31 cm).
The tiles were non-wrapped with Tyvek, using Y11
fibers, ∅ 0.94 mm, 90 cm in length for small tiles and
120 cm in length for large tiles without clear fiber. The
fiber end was non-mirrored. Relatively light yield of
fiber/control tile assemblies were measured before
insertion into tiles. The RMS of this distribution is
2.5%. Results are:
- the outer tiles dimensions correspond to the
drawings;
- the thickness of the tiles (RMS<3%) corresponds to
the TDR requirement;
- the light yield is the same for the small and large
tiles about 2.2 p.e. with the RMS = 6.2% (Fig. 3);
- the transverse uniformity is better than 4.2% for all
the tiles measured.
Fig. 3. Light yield distribution of 1062 tiles or 15
layers × 72 (36 small size + 36 large size) tiles and its
graphical cut (lower figure). The RMS of this
distributions is 6.2%, MEAN= 2.2 p.e.
So, the mass quality control of the tiles produced by
“Monocrystall” is going well. The main characteristics
of the tiles satisfy to the CMS TDR2 (1997).
At present, the main prerequisite for efficient
participation of Ukraine and, in particular, NSC KIPT in
the CMS collaboration is to provide necessary
conditions for active work on the CMS physics
program. First of all, it is the creation of a computer
Linux cluster powerful enough to perform simulations
of CMS physics, partial processing of data provided by
the CMS detector with installation of the software
developed for this purpose, and training of young
scientists.
REFERENCES
1. A. Nemashkalo, V. Popov, P. Sorokin, A. Zatser-
klyany et al. Sigma Tile/Fiber Production and
Investigation for the CMS Hadron Calorimeter
Prototype. TN/94-168, April 20, 1994, 17 p.
2. A. Zatserklyany, A. Nemashkalo, V. Popov, The
measurements of the light yield in number of the
photoelectrons. VANT, 1999. №1 (33), p. 44-44.
3. A. Nemashkalo, V. Popov, A. Rubashkin, P. Sorokin,
A. Zatserklyany A. Borisenko, V. Senchishin,
O. Skrebtsov, V. Bolotov. Comparisen Studies of
Tile/Fiber Systems Manufactured from Kharkov
Injection-molded and Kuraray SCSN-81 Scintillators.
CMS TN/97, 1997, 14 p.
4. A. Nemashkalo, V. Popov, A. Rubashkin,
P. Sorokin, A. Zatserklyany. Study of Tile/Fiber
Systems manufacted from Kharkov injection molded
and Kuraray CSN-81 Scintillators. Nuclear
Instuments & Methods, 1998, A419, p. 609-611.
5. A. Nemashkalo, V. Popov, A. Rubashkin,
P. Sorokin, A. Zatserklyany. Plastic Scintillator
Light Yield Dependence on the Magnetic Field.
CMS. TN/95-81. November 29, 1995, 16 p.
6. A. Nemashkalo, V. Popov, A. Rubashkin,
P. Sorokin, A. Zatserklyany. Study of the Light
Yield of Plastic Scintillators in a Magnetic Field.
Pribory i Tekhnika Eksperimenta, №6. 1977, p. 57-
61 (in Russian).
7. V. Abramov, B. Acharya, N. Akchurin, et al. Studies
of the Response of the Prototype CMS Hadron
Calorimeter, Including Magnetic Field Effects, to
Pion, Electron, and Muon Beams, Nuclear
Instuments & Methods, 2001, A457, p. 75-100;
Status Report on Endcap Calorimeter R&D, Pisa
CMS Week, 1995.
8. L.G. Levchuk, S.V. Marekhin, P.V. Sorokin. Monte-
Carlo simulation of the CMS endcap calorimeter,
CMS TN/95-078, 1995, 8 p.
9. The Compact Muon Solenoid Technical Proposal,
CERN/LHCC 94-38, LHCC/P1, 1994, p. 76.
10. L.G. Levchuk, S.V. Marekhin, P.V. Sorokin.
Simulations of the CMS endcap calorimeter
resolution, CMS TN/95-090 , 1995, 6 p.
11. L.G. Levchuk, S.V. Marekhin, P.V. Sorokin.
Influence of inert material on parameters of the
CMS endcap hadron calorimeter CMS TN/95-113,
1995, 8 p.
9
National Science Center “Kharkov Institute of Physics and Technology”, Kharkov, Ukraine
PRODUCTION OF TILES
REFERENCES
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| id | nasplib_isofts_kiev_ua-123456789-78434 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1562-6016 |
| language | English |
| last_indexed | 2025-12-01T05:02:26Z |
| publishDate | 2001 |
| publisher | Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| record_format | dspace |
| spelling | Levchuk, L.G. Marekhin, S.V. Nemashkalo, A.A. Popov, V.P. Sorokin, P.V. Zatserklianiy, A.E. 2015-03-17T10:58:06Z 2015-03-17T10:58:06Z 2001 NSC KIPT Participation in the CMS (CERN) Collaboration / L.G. Levchuk, S.V. Marekhin, A.A. Nemashkalo, V.P. Popov, P.V. Sorokin, A.E. Zatserklianiy // Вопросы атомной науки и техники. — 2001. — № 1. — С. 7-9. — Бібліогр.: 11 назв. — англ. 1562-6016 PACS: 07.77.Ka. https://nasplib.isofts.kiev.ua/handle/123456789/78434 In conformity with the Agreement of 03.04.1993 between the Government of Ukraine and CERN, the National Science Center Kharkov Institute of Physics & Technology (NSC KIPT) takes part in the international CMS program. Its collaboration duties include: the manufacture of scintillation elements for the forward hadron calorimeter and investigation of their characteristics; the simulation of physical processes in the CMS detector; the preparation for processing experimental results. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники IHEPNF NSC KIPT in the last decade NSC KIPT participation in the CMS (CERN) collaboration Участие ННЦ ХФТИ в коллаборации CMS (ЦЕРН) Article published earlier |
| spellingShingle | NSC KIPT participation in the CMS (CERN) collaboration Levchuk, L.G. Marekhin, S.V. Nemashkalo, A.A. Popov, V.P. Sorokin, P.V. Zatserklianiy, A.E. IHEPNF NSC KIPT in the last decade |
| title | NSC KIPT participation in the CMS (CERN) collaboration |
| title_alt | Участие ННЦ ХФТИ в коллаборации CMS (ЦЕРН) |
| title_full | NSC KIPT participation in the CMS (CERN) collaboration |
| title_fullStr | NSC KIPT participation in the CMS (CERN) collaboration |
| title_full_unstemmed | NSC KIPT participation in the CMS (CERN) collaboration |
| title_short | NSC KIPT participation in the CMS (CERN) collaboration |
| title_sort | nsc kipt participation in the cms (cern) collaboration |
| topic | IHEPNF NSC KIPT in the last decade |
| topic_facet | IHEPNF NSC KIPT in the last decade |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/78434 |
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