Physics Maths Engineering

Investigating the average kiloelectron-volt emission of partially observed events in nuclear physics through distance weighted mean based censored control chart





  Peer Reviewed

Abstract

The average lifespan of particles, a crucial parameter in nuclear physics, is essential for identification purposes. Modern particle detectors excel at recognizing individual radioactive nuclei arrivals and their subsequent decay events. However, challenges arise when matching arrivals with departures, especially when departures are only partially observed. One inefficient approach involves conducting experiments with very low arrival rates to facilitate matching. The kiloelectron-volt E(keV) emission is obtained during this radio active process. This study focuses on the meticulous surveillance of the average keV emission from partially observed events within the domain of nuclear physics. To accomplish this, the methodology employs the statistical approach known as Distance Weighted Mean (DWM), integrated with the application of censored control charts. The utilization of censored control charts allows for the effective management of incomplete data, enabling researchers to make informed decisions despite potential limitations in observation. We propose a DWM based exponentially weighted moving average-cumulative sum (DWM-EC) control chart for monitoring kiloelectron-volt E(keV) data. The proposed charts is developed for Weibull lifetimes under type-I censoring. For the construction of an efficient control charting structure, we employed the conditional median (CM) methods. The goal is to find changes in the mean of Weibull lifetimes with censored data with known and estimated parameter conditions. The performance of the proposed DWM-EC chart is evaluated by the average run length (ARL). Besides a simulation study, a real-life data set on E(keV) related to the alpha decays of 177 Lutetium isotope is also discussed.

Key Questions

1. What is the purpose of using DWM-EC control charts for monitoring keV emissions?

DWM-EC control charts are used to monitor the variability in kiloelectron-volt (keV) emissions from partially observed nuclear events. They allow for effective management of incomplete data and can detect shifts in the process mean more efficiently than traditional control charts.

2. How does the proposed DWM-EC chart differ from existing control charts?

The DWM-EC chart incorporates the Distance Weighted Mean approach with exponentially weighted moving average and cumulative sum techniques. It is specifically designed for censored data following a Weibull distribution, making it more suitable for nuclear physics applications than traditional charts.

3. What are the advantages of using the conditional median (CM) method in this context?

The CM method is less sensitive to extreme observations compared to the conditional expected value, leading to fewer false alarms. It also performs better for skewed distributions like the Weibull, which are common in nuclear decay data.

4. How is the performance of the DWM-EC chart evaluated?

The performance is primarily evaluated using the Average Run Length (ARL) metric. The study compares the ARL values of the DWM-EC chart with those of existing charts like CM-EWMA and CM-CUSUM under various censoring rates and shift magnitudes.

5. What real-world application is demonstrated for the DWM-EC chart?

The study applies the DWM-EC chart to a real-life dataset of keV emissions related to the alpha decays of Lutetium-177 isotope. This demonstrates the practical applicability of the proposed method in monitoring actual nuclear decay processes.