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

A tool for calculation of 7 Li(p,n) 7 Be neutron spectra and the development of 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 2 — Introduction — RF Power Measurement Technique ¡ Motivation ¡ Results — Development of neutron energy spectrum code ¡ Database Formalism ¡ Results – Validation & Distribution 10/12/17 ICTP-IAEA Workshop 02/10/2017 - 13/10/2017

INTRODUCTION : N uclear and H ydrogen E nergy R esearch G roup (NHERG) 3 — Measurement of 70 Zn(n,g) 71 Zn m cross section at E p = 2.25, 2.60, 2.80 and 3.50 MeV using 7 Li(p,n) 7 Be 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 10/12/17 ICTP-IAEA Workshop 02/10/2017 - 13/10/2017

1. RF Oscillator 4 — Application ¡ Particle accelerators ¡ NBI systems for fusion devices ¡ Bio-medical Sciences, etc… — Motivation ¡ RF power stability ¡ RF power measurement 10/12/17 ICTP-IAEA Workshop 02/10/2017 - 13/10/2017

Circuit Description 5 C. D. Moak, H. Reese, Jr., and W. M. Good, Nucleonics 9(3), 18 (1951). 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; R S = 20 k Ω , 20 W; R g1 = R g2 = 6.8 k Ω , 1 W; C g1 = C g2 = 1 pF, 1 kV; C = 50 µF, L 1 = 586 µH; L 2 = 589.5 µH. 10/12/17 ICTP-IAEA Workshop 02/10/2017 - 13/10/2017

Circuit Description 6 Figure 2 : Circuit diagram of 1 kV DC Figure 3 : Experimental setup for RF power measurement. power supply . T = 100 VA Step-Up Transformer; D = IN 4007, 700 V (PIV); C = 330 µ F, 450 V; R = 1.18 M W . 10/12/17 ICTP-IAEA Workshop 02/10/2017 - 13/10/2017

Results 7 — 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 oxidation. 10/12/17 ICTP-IAEA Workshop 02/10/2017 - 13/10/2017

90 100 80 Peak voltage method 80 Photometric method 70 RF Output Power (W) 60 AC Power (W) 60 50 40 142 V 120 V 40 113 V 20 80 V 30 0 20 10 0 20 40 60 80 100 0 200 400 600 800 1000 Inductive Reactance (Ohm) DC Plate Voltage (V) Figure 5 : Variation of AC power Figure 4 : Variation of RF output power with plate voltages (350-900 V) for 829B dissipated by 100 watt incandescent according to photometric and peak voltage lamp at different values of inductive measurements. reactance and applied voltages. 10/12/17 ICTP-IAEA Workshop 02/10/2017 - 13/10/2017

9 — Power correction of 12 watts comes from the 140 inductive reactance Peak voltage measurement 120 Photometric measurment with 12 watts correction X L of the bigger coil Photometric measurment with 24 watts correction Photometric measurment with 35 watts correction 100 alone having inductance RF Output Power (W) 80 141 nH. 60 40 — With this correction, the 20 total output power of the oscillator at 900 V 0 plate voltages becomes 0 200 400 600 800 1000 91 watts . DC Plate Voltage (V) 10/12/17 ICTP-IAEA Workshop 02/10/2017 - 13/10/2017

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2. Development of neutron energy spectrum code 11 Ø 7 Li(p,n) 7 Be reaction -neutron source. Ø Subtraction of (p,n 1 ) - neutron-induced reaction cross section. We developed a new deterministic code EPEN-E nergy of P roton E nergy of N eutron ( ) ( ) q 2 dY E d Y , E ( ) ( ) ( ) ò = W q q n n d w w E , E W 1 2 p n dE dE d n n Differential Cross-sections o E p > 1.95 : Evaluated data - Liskien et. al. Weighting o E p near threshold : Functional form – Macklin functions & Gibbons Solid angle covered by sample ( w 1 ) o Proton energy spread ( w 2 ) o 1.92 MeV< E p <1.95 MeV : Cubic Spline fits o 10/12/17 ICTP-IAEA Workshop 02/10/2017 - 13/10/2017

http://epen.nhergmzu.com/epen/# 12 10/12/17 ICTP-IAEA Workshop 02/10/2017 - 13/10/2017

RESULTS 0.016 E p =1912 keV 13 EPEN Lederer+ Validation 0.012 Ratynski+ dY/dE n (Arb-units) Feinberg+ 0.008 0.004 0.000 0 20 40 60 80 100 120 140 E n (keV) 1.0 0.8 d 2 Y/dE n d W (Arb-Units) EPEN 0.6 reproduces E p =1940 keV Kononov+ 0.4 experimental 0 ±0 0 EPEN-0 0 ±3 0 EPEN-0 0 ±5 0 spectra well EPEN-0 0.2 0 ±7 0 EPEN-0 0 ±9 0 EPEN-0 0.0 0 20 40 60 80 100 120 140 160 180 E n (keV) ICTP-IAEA Workshop 02/10/2017 - 13/10/2017 10/12/17

0.003 E p = 3500 ± 20 keV Comparison of Li thickness = 60 µ m q max = 26.8 degree 14 dY/dE n (Arb-units) EPEN (p,n 0 ) EPEN with 0.002 SimLiT (p,n 0 ) PINO (p,n 0 ) Monte Carlo codes EPEN (p,n 1 ) SimLiT (p,n 1 ) 0.001 PINO (p,n 1 ) 0.000 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 E n (keV) 0.005 E p = 3500 ± 20 keV Li thickness = 38 µ m • EPEN always agree with SimLiT 0.004 q max = 26.8 degree EPEN (p,n 0 ) perfectly SimLiT (p,n 0 ) dY/dE n (Arb-units) PINO (p,n 0 ) 0.003 • PINO – narrow (p,n 1 ) spectrum EPEN (p,n 1 ) SimLiT (p,n 1 ) centred near the upper boundary PINO (p,n 1 ) 0.002 of the (p,n 1 ) energy spectra of 0.001 EPEN & SimLit 0.000 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 E n (keV) 10/12/17 ICTP-IAEA Workshop 02/10/2017 - 13/10/2017

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Acknowledgement 16 — Dr. B. Lalremruata, Supervisor — Dr. Hranghmingthanga, Joint Supervisor — Other members of NHERGs 10/12/17 ICTP-IAEA Workshop 02/10/2017 - 13/10/2017

Thank you.. 10/12/17 ICTP-IAEA Workshop 02/10/2017 - 13/10/2017