#
Neutron Multiplicity Counting with the Analysis of Continuous Detector Signals
Doktorsavhandling, 2021

fission chamber

fissile material assay

neutron multiplicity counting

Kolmogorov equation

master equation

nuclear safeguards

## Författare

### Lajos Nagy

Chalmers, Fysik, Subatomär, högenergi- och plasmafysik

### An extended theory of multiplicity counting from fission chamber signals in the current mode

International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering, M and C 2017,; (2017)

**Paper i proceeding**

### Two- and three-point (in time) statistics of fission chamber signals for multiplicity counting with thermal neutrons

Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment,; Vol. 929(2019)p. 148-155

**Artikel i vetenskaplig tidskrift**

### Multiplicity counting using the two- and three point statistics of fission chamber signals – Theory and experimental demonstration

International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering, M and C 2019,; (2019)p. 2866-2875

**Paper i proceeding**

### Multiplicity counting from fission chamber signals in the current mode

Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment,; Vol. 839(2016)p. 92-101

**Artikel i vetenskaplig tidskrift**

### Multiplicity counting from fission detector signals with time delay effects

Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment,; Vol. 884(2018)p. 119-127

**Artikel i vetenskaplig tidskrift**

### Measurements and simulations to investigate the feasibility of neutron multiplicity counting in the current mode of fission chambers

EPJ Web of Conferences,; Vol. 225(2020)

**Paper i proceeding**

**A new method to measure the mass of fissile materials**

Fissile materials (e.g. uranium and plutonium) are used to generate electricity in nuclear power plants, however – with the wrong intentions - they can also be used to produce nuclear weapons. To ensure that they are used for peaceful purposes only, the International Atomic Energy Agency sends inspectors to nuclear facilities around the World regularly, who measure the mass of all the fissile materials present and compare the results with their own records.

Determining the mass of fissile materials requires special methods. One of them, called neutron multiplicity counting, utilizes a special property of these materials: they emit neutrons in groups of varying sizes at random times, which can be detected. When a neutron is detected, a voltage impulse is produced in the detector. The value of the mass can then be obtained from the number of pulses observed in a certain amount of time. In some cases, however, neutrons are detected so frequently, that pulses overlap and cannot be counted anymore.

To solve this problem, this thesis presents a new version of neutron multiplicity counting which, instead of counting individual pulses, relies on analyzing the statistical properties of the entire voltage signal of the detector. Besides describing the theoretical mathematical basis of this method, the thesis investigates its properties with computer simulations and demonstrates its use in an experiment.

### Drivkrafter

Hållbar utveckling

Innovation och entreprenörskap

### Ämneskategorier

Subatomär fysik

### Styrkeområden

Energi

### ISBN

978-91-7905-448-9

Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4915

### Utgivare

Chalmers tekniska högskola

Online via Zoom

Opponent: Honorary Professor Iván Lux, Hungarian Atomic Energy Authority, Hungary