Physics 3901 Intermediate Physics Lab Blair Jamieson1, Jeff Martin1 1 The University of Winnipeg, Winnipeg, MB, Canada February 25, 2015 1 Contents 1 Radiation safety 9 1.1 Introduction . .9 1.2 Types and Sources of Radiation . .9 1.3 Radiation Dosages . 10 1.4 Calculation of Dosages . 10 1.4.1 γ-rays.......................................... 11 1.4.2 β-particles . 11 1.5 Shielding, distance and time factors . 12 1.5.1 Shielding . 12 1.5.2 The Effect of Distance . 13 1.5.3 The Effect of Time . 14 1.6 Forms of Radioactive Sources . 14 1.7 Radio-toxicity . 14 1.8 Radioactive Half-Life . 14 1.9 Radioisotope Safety Practices . 15 1.9.1 Laboratory best practices . 16 1.9.2 Sealed Sources Leak Test . 18 1.9.3 Wipe Test - Radioactive Contamination Monitoring . 18 1.9.4 Storage and Waste Disposal . 18 1.9.5 Emergencies, Theft, Loss or Spills . 18 2 Latex Lab Reports 19 2.1 Scientific Writing . 19 2.2 The basic principles and elements of scientific writing . 19 2.3 The technical aspects and style of scientific writing . 20 2.4 How to write a lab report . 21 2.5 Using LATEX for PHYS 3901/4901 lab reports . 22 2.6 Latex writing exercise . 22 3 Error analysis introduction 24 3.1 Introduction to Statistical Uncertainties . 24 3.2 Significant figures, Agreement, and Importance of Plotting Data . 25 3.3 Uncertainties in Calculated Quantities . 25 3.4 Systematic Errors . 26 3.5 Systematic Uncertainties . 26 3.6 The Normal Distribution . 28 3.7 Rejecting data . 30 3.8 Weighted averages . 30 3.9 The binomial distribution . 30 3.10 The Poisson distribution and Radioactive decays . 31 3.11 Error analysis problems . 33 2 4 Data Analysis with ROOT 34 4.1 C++basics . 34 4.1.1 Basic data types . 34 4.1.2 Making arrays of data . 35 4.1.3 Looping over data . 35 4.1.4 Object Oriented Concepts . 35 4.1.5 Reading data from file into our arrays . 36 4.1.6 Printing to the screen . 37 4.1.7 Branching and conditional statements . 37 4.1.8 Functions . 38 4.2 Using ROOT to Make Graphs and Analyze data . 38 4.3 ROOT Data Analysis Exercises . 40 5 Detection electronics lab 41 5.1 About NIM modules . 41 5.2 The oscilloscope . 41 5.2.1 Vertical controls and inputs . 41 5.2.2 Horizontal controls . 42 5.2.3 Triggering controls . 43 5.3 The Pulse Generator . 43 5.4 Detection Electronics Lab Tasks . 44 5.4.1 Equipment Used . 44 5.4.2 The Pulser and oscilloscope . 44 5.4.3 The pre-amplifier and spectroscopy amplifier . 46 5.4.4 The Single Channel Analyzer and Scaler . 47 5.4.5 The Linear Gate . 49 5.4.6 The Multi-Channel Analyzer . 51 6 Single Channel Analysis 52 6.1 Scintillation Counters . 52 6.1.1 Scintillating Materials . 52 6.1.2 Photomultiplier Tubes . 53 6.2 Response of Scintillator detectors to Gamma Rays . 54 6.3 Procedure . 56 6.3.1 SCA Informal Report . 57 7 Fitting Data 58 7.1 Fitting with Uncorrelated Errors . 58 7.2 Goodness of Fit . 59 7.3 Systematic Errors . 59 7.4 Propagation of Errors . 61 7.5 The meaning of Error Bars . 61 7.6 Relationship of Error Bar to Probability Distribution Function . 61 7.7 Covariance Matrices . 63 7.8 Example of correlated measurements . 64 7.9 Propagating Uncertainties . 65 7.10 Fitting Data Assignment . 66 3 8 Counting statistics lab 68 8.1 Objective . 68 8.2 Theory . 68 8.3 Equipment and Procedure . 71 8.4 Data Analysis . 72 9 Gamma Ray Spectroscopy 73 9.1 Gamma Ray Interactions . 73 9.2 Detector Resolution . 73 9.3 Gamma Ray Spectroscopy Experiment . 73 10 Beta Spectroscopy with Si(Li) Surface Barrier Detectors 77 10.1 Si(Li) Surface Barrier Detectors . 77 10.2 Theory . 78 10.2.1 Internal Conversion . 79 10.2.2 Fermi Theory . 79 10.3 Procedure . 81 10.4 Beta Spectroscopy Pre-Lab Homework . 83 11 Monte Carlo Techniques 85 11.1 Introduction . 85 11.2 How to do a Monte Carlo Simulation . 85 11.3 Generating random numbers . ..