^(3)He proportional counter development for thermal neutron detection

Neutron detection is used in a wide range of applications in nuclear physics,radiation protection,nuclear fuel cycle,reactor instrumentation,security and industrial measurement.Among the detectors used in this field,we notice the gas-filled 3He proportional counters which have been one of the main detecting tools for thermal and cold neutron detection for many years.This last characteristic has ensured that this detector is one of the best tools for thermal neutron flux measurements in a nuclear reactor control.In the instrumentation and detection laboratory of the Nuclear Research Center,of Birine,we are working toward the design and the development of this type of detectors,indeed,several prototypes of neutron detectors have been realized including the 3He proportional counters.Through this paper,we will present the experimental steps and the obtained results to carry out a 3He proportional counter prototype that was fully developed and tested in our laboratory.A comparison study was made between our detector and a commercial cylindrical 3He neutron detector which was considered in this work as a reference detector:LND252(3He)-PC.The results showed that the characteristics of the gas amplification and the counting plateau for the two counters reference LND 252(3He)-PC and our prototype was of the same order of scale.The experimental tests show that our developed prototype perfect fit with the standard International Electrotechnical Commission(IEC,www.iec.ch)in the operating principle,the technology adopted and obtained technical specifications.

Boron-10 lined proportional counter development for thermal neutron detection

Purpose Neutrons detection is of paramount importance in nuclear physics experiments,reactor physics,monitoring and control of nuclear reactors and in radiation protection.Among the neutron detectors used are Proportional Counters(PC to BF3,boron deposition,3He),Our Detection and Measurements laboratory has embarked on a project to develop,design and build proportional counters with boron deposition mainly for gas filling,several prototypes of which have been produced.Method This work presents the Boron-10 Lined Proportional Counters(PC),developed and produced in the Detection and Measurements Department(DDM19).The PC was designed by adopting,for the electrodes,a stainless steel cathode 0.5 mm thick and a gold-plated tungsten anode with diameter of 25μm.The detectors are filled with an Ar-CH4 mixture(10%)at a pressure of 20 cmHg.The boron deposition is performed by the technique of electrophoresis.Result The results obtained using the DDM19 prototype PC(Detector produced in our Detection and Measurement laboratory,2019),show the advantage of electrophoresis as a better boron deposition technique,and the limitation of the surface mass of 10B to optimal values is around 0.5 at 0.6 mg/cm2.Conclusions The characteristics of the gas amplification in the mixture(Ar-CH4(CH410%)),were measured by different methods and compared with the values of the proportional reference counter LND232.The counting plates for the two reference meters LND232 and our DDM19 prototype from 200 to 300 V have slopes ranging from 6.5 to 10%/100 V,and gas amplification factors from 1436 to 1380,respectively.

Artificial neural network algorithm for pulse shape discrimination in 2πα and 2πβ particle surface emission rate measurements

To enhance the accuracy of 2πα and 2πβ particle surface emission rate measurements and address the identification issues of nuclides in conventional methods, this study introduces two artificial neural network(ANN) algorithms: back-propagation(BP) and genetic algorithm-based back-propagation(GA-BP). These algorithms classify pulse signals from distinct α and β particles. Their discrimination efficacy is assessed by simulating standard pulse signals and those produced by contaminated sources, mixing α and β particles within the detector. This study initially showcases energy spectrum measurement outcomes, subsequently tests the ANNs on the measurement and validation datasets, and contrasts the pulse shape discrimination efficacy of both algorithms. Experimental findings reveal that the proportional counter's energy resolution is not ideal, thus rendering energy analysis insufficient for distinguishing between 2πα and 2πβ particles. The BP neural network realizes approximately 99% accuracy for 2πα particles and approximately 95% for 2πβ particles, thus surpassing the GA-BP's performance. Additionally, the results suggest enhancing β particle discrimination accuracy by increasing the digital acquisition card's threshold lower limit. This study offers an advanced solution for the 2πα and 2πβ surface emission rate measurement method, presenting superior adaptability and scalability over conventional techniques.

Simulation of the response functions of an extended range neutron multisphere spectrometer using FLUKA

In this paper, the distribution of radiation field in the CSNS spectrometer hall at Dongguan, China, was simulated by the FLUKA program. The results show that the radiation field of the high energy proton accelerator is dominated by neutron radiation, with a broad range of neutron energies, spanning about eleven orders of magnitude.Simulation and calculation of the response functions of four Bonner spheres with a simplified model is done with FLUKA and MCNPX codes respectively, proving the feasibility of the FLUKA program for this application and the correctness of the calculation method. Using the actual model, we simulate and calculate the energy response functions of Bonner sphere detectors with polyethylene layers of different diameters, including detectors with lead layers, using the FLUKA code. Based on the simulation results, we select eleven detectors as the basic structure for an Extended Range Neutron Multisphere Spectrometer（ERNMS）.