A tool for calculation of 7 Li(p,n) 7 Be neutron spectra and the - - PowerPoint PPT Presentation

A tool for calculation of 7Li(p,n)7Be neutron spectra and the development

• f

RF power measurement technique for low energy charged particle accelerators L.R. Hlondo

Nuclear and Hydrogen Energy Research Group Department of Physics Mizoram University Aizawl, Mizoram

ICTP-IAEA Workshop 02/10/2017 - 13/10/2017

Outline

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— Introduction — RF Power Measurement Technique

¡ Motivation ¡ Results

— Development of neutron energy spectrum code

¡ Database Formalism ¡ Results – Validation & Distribution

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INTRODUCTION: Nuclear and Hydrogen Energy Research Group (NHERG)

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— Measurement of 70Zn(n,g)71Znm cross section at Ep = 2.25, 2.60,

2.80 and 3.50 MeV using 7Li(p,n)7Be reaction as neutron source

— Proton beam energy spread is ±20 keV — Due to continuous proton beam structure, we have to rely on

calculated neutron energy spectrum

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• 1. RF Oscillator

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— Application

¡ Particle accelerators ¡ NBI systems for fusion devices

¡ Bio-medical Sciences, etc…

— Motivation

¡ RF power stability ¡ RF power measurement

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Figure 1: Circuit diagram of RF oscillator. Q = 829B/GI30 twin beam-power tetrode; RF Coil: tube diameter = 0.6 cm, pitch = 1 cm, coil diameter = 7 cm; RS = 20 kΩ, 20 W; Rg1 = Rg2 = 6.8 kΩ, 1 W; Cg1 = Cg2 = 1 pF, 1 kV; C = 50 µF, L1= 586 µH; L2= 589.5 µH.

Circuit Description

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• C. D. Moak, H. Reese, Jr., and W. M.

Good, Nucleonics 9(3), 18 (1951).

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Figure 2: Circuit diagram of 1 kV DC power supply. T = 100 VA Step-Up Transformer; D = IN 4007, 700 V (PIV); C = 330 µF, 450 V; R = 1.18 MW.

Figure 3: Experimental setup for RF power measurement.

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Circuit Description

Results

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— The oscillation frequency

¡ f = 102 MHz (measured with frequency counter FC 2400) ¡ Inter-electrode capacitance of ≈ 4 .4 pF reduces frequency from 169 MHz

to 102 MHz (Stable).

— Power stability

¡ RF output power is found to decrease by about 10% due to tank coil

• xidation.

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DC Plate Voltage (V)

200 400 600 800 1000

RF Output Power (W)

20 40 60 80 100 Peak voltage method Photometric method

Figure 4: Variation of RF output power with plate voltages (350-900 V) for 829B according to photometric and peak voltage measurements.

Inductive Reactance (Ohm)

20 40 60 80 100

AC Power (W)

10 20 30 40 50 60 70 80 90 142 V 120 V 113 V 80 V

Figure 5: Variation of AC power dissipated by 100 watt incandescent lamp at different values of inductive reactance and applied voltages.

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ICTP-IAEA Workshop 02/10/2017 - 13/10/2017

— Power correction of 12

watts comes from the inductive reactance XL of the bigger coil alone having inductance 141 nH.

— With this correction, the

total output power of the

• scillator

at 900 V plate voltages becomes 91 watts.

DC Plate Voltage (V)

200 400 600 800 1000

RF Output Power (W)

20 40 60 80 100 120 140 Peak voltage measurement Photometric measurment with 12 watts correction Photometric measurment with 24 watts correction Photometric measurment with 35 watts correction

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Ø 7Li(p,n)7Be reaction -neutron source. Ø Subtraction of (p,n1) - neutron-induced reaction cross section.

We developed a new deterministic code EPEN-Energy of Proton Energy of Neutron

Differential Cross-sections

• Ep > 1.95 : Evaluated data - Liskien et. al.
• Ep near threshold : Functional form – Macklin

& Gibbons

• 1.92 MeV< Ep <1.95 MeV : Cubic Spline fits

Weighting functions

• Solid angle covered by sample (w1)
• Proton energy spread (w2)

( ) ( ) ( ) ( )

( )

2 1 2

, ,

n n p n n n

dY E d Y E d w w E E dE dE d q q q = W W

ò

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• 2. Development of neutron energy spectrum code

http://epen.nhergmzu.com/epen/#

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RESULTS

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Validation

20 40 60 80 100 120 140 0.000 0.004 0.008 0.012 0.016

Ep=1912 keV EPEN Lederer+ Ratynski+ Feinberg+ dY/dEn (Arb-units) En (keV)

EPEN reproduces experimental spectra well

20 40 60 80 100 120 140 160 180 0.0 0.2 0.4 0.6 0.8 1.0

d2Y/dEndW (Arb-Units)

En(keV) Ep=1940 keV Kononov+ EPEN-0

0±0

EPEN-0

0±3

EPEN-0

0±5

EPEN-0

0±7

EPEN-0

0±9

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1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 0.000 0.001 0.002 0.003 0.004 0.005

En (keV) dY/dEn (Arb-units)

Ep = 3500 ± 20 keV Li thickness = 38 µm

qmax= 26.8 degree

EPEN (p,n0) SimLiT (p,n0) PINO (p,n0) EPEN (p,n1) SimLiT (p,n1) PINO (p,n1) 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 0.000 0.001 0.002 0.003

En (keV) dY/dEn (Arb-units) Ep = 3500 ± 20 keV Li thickness = 60 µm

qmax= 26.8 degree

EPEN (p,n0) SimLiT (p,n0) PINO (p,n0) EPEN (p,n1) SimLiT (p,n1) PINO (p,n1)

Comparison of EPEN with Monte Carlo codes

• EPEN always agree with SimLiT

perfectly

• PINO – narrow (p,n1) spectrum

centred near the upper boundary

• f the (p,n1) energy spectra of

EPEN & SimLit

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Acknowledgement

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— Dr. B. Lalremruata, Supervisor — Dr. Hranghmingthanga, Joint Supervisor — Other members of NHERGs

Thank you..

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