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DETERMINATION OF DETERMINATION OF ELEMENTAL COMPOSITIONS ELEMENTAL COMPOSITIONS
BY USING NEUTRON BY USING NEUTRON RESONANCE SPECTROSCOPICRESONANCE SPECTROSCOPIC
MAHMOUD GAAFARMAHMOUD GAAFAR
TEACHING ASSISTANT, PHYSICSFACULTY OF SCIENCE, MENOUFIA UNIVERSITY
OUTLINOUTLINEE
ECR ION ECR ION SOURCESSOURCES
INTENSE RESONANCE NEUTRON SOURCE INTENSE RESONANCE NEUTRON SOURCE (IREN)(IREN)
• NEUTRON RESONANCE CAPTURE NEUTRON RESONANCE CAPTURE ANALYSISANALYSIS
• EXAMPLE -> CU-ZN ALLOYEXAMPLE -> CU-ZN ALLOY
ECR Ion Source
4Ion sourceIon source
Axial injection systemECR ion source
5
The ECR ion source
ωECR
~ B×e /me
2])[(101024.124
2GHzf
e
mec
n
6
DECRIS-2 – U-400M cyclotron – 1995
ECR-4M – U-400 cyclotron – 1996 (collaboration FLNR – GANIL (France))
DECRIS-3 – TESLA Accelerator Installation (Belgrade) -1997
DECRIS-2m – BIONT Inc. (Bratislava) – 2003
DECRIS-SC – CI-100 cyclotron - 2004
DECRIS-3 - DC-60 accelerator complex (Astana, Kazakhstan) – 2006
DECRIS-4 – in operation at the test bench - 2006
DECRIS-2m – tested DC-72 cyclotron (Bratislava)
DECRIS-SC2 – new ion source for U-400M – under commissioning
DECRIS-SC3 – for DC-350 cyclotron - project
DECRIS - Dubna ECR Ion Sources
DECRIS-2, DECRIS-2m, DECRIS-3, DECRIS-4 are “room temperature” ECR ion sources. The axial magnetic field is created by two coils with independent power supplies. The radial magnetic field is created by permanent magnet hexapole, made from NdFeB.
DECRIS-SC – axial magnetic field is created by superconducting solenoids
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FLNR (JINR) CYCLOTRONS WITH ECR ION SOURCES
FLNR (JINR) CYCLOTRONS WITH ECR ION SOURCES
NEW CYCLOTRONSNEW CYCLOTRONS NEW CYCLOTRONSNEW CYCLOTRONS
CI-100 + DECRIS-SCU400 + ECR4M U400M + DECRIS-2
DC-72
DECRIS-2m
DC-60
DECRIS-3
INTENSE RESONANCE NEUTRON SOURCE (IREN)
Pulsed Source for Applied and fundamental Investigations
The IREN source of three basic parts:
1) Vertically electron linear accelerator (linac) LUE-200.
2) Vacuum pipeline for transportation of the electron beam to the electron-neutron converter.
3) Electron – neutron converter located in the center of material absorbes charged radiation (blanket).
The IREN Source
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MAIN PARAMETERS OF THE LINAC LUE-200
Max. Electron Energy 75 MeV
Av. electron energy 30 MeV
Pulse current 2.8 A
Pulse width 100 ns
Repetition rate 50 Hz
Beam power ~1kW
Neutron intensity ~1012 n/s
Neutron Resonance Capture Analysis
used to determine the elementalcomposition of materials and artifacts
Interaction of neutrons with nuclei as a function of neutron energy shows sharp peaks, known as resonances, at energies specific for each isotope .
Resonances are thus the fingerprints of elements. They can be visualized in the neutron capture spectrum
as a function of neutron energy.
The energy of a neutron can be determined by measuring the time of flight ( the time it needs to travel a known distance L in m).
With a pulsed neutron source the time-of-flight (T in µs) can be determined from the start pulse of the source and a stop pulse generated by detection of the prompt capture gamma rays.
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TIME OF FLIGHT NEUTRON SPECTROSCOPY
Detector
Flight path L, mSource
Collimator
Sample
dt
EXPERIMENTAL FACILITY
1.Photo multiplier , 2. Sample, 3. scintillator section Large volume liquid scintillator detector consisting of 6 sections 20 liters each was placed at 60 meters flight path. Sample installed inside the detector.
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The energy of a neutron can be determined by
2
310227.5
st
mLeVEn
232108.2 nn E
mL
sdteVE
2222
L
dL
t
dt
E
E
n
n
Time of flight Energy channel .no (TDC)
0 200 400 600 800 1000 12000
20
40
60
80
100
120
140
160
180
200
220
240
cou
nts
channel
Before Calculation
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RAW EXPERIMENTAL DATA
THE CALIBRATION LINE
ACKNOWLEDGEMACKNOWLEDGEMENTENT
SPECIAL THANKS TO PROF. PAVEL SPECIAL THANKS TO PROF. PAVEL SEDYSHEV (FLNP)SEDYSHEV (FLNP)
THANKS TO THANKS TO JINRJINR
THANKS TO ASRT - THANKS TO ASRT - EGYPTEGYPT
SPECIAL THANKS TO PROF. BORIS SPECIAL THANKS TO PROF. BORIS (FLNR)(FLNR)
THANKS THANKS