2018 BFY III Abstract Detail Page

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Abstract Title: W20: Alpha Particle Energy Loss in Air
Abstract: Nuclear and particle physics experiments tend to be expensive, requiring expensive sources, detectors, multi-channel analyzers and amplifiers.  This often means that there is only one set of apparatus per experiment, so that students must sequentially rotate through several experiments.  In our redesigned third year lab course we wanted all students to do a sophisticated particle physics experiment at once, so that they would be prepared to work on open-ended projects later.  With a budget of under $20,000 we were able to build 20 sets of apparatus as described below.

In this experiment students measure the energy spectrum of alpha particles as a function of distance between source and detector.  An americium-241 source (from a commercial smoke detector) is used as a source of alpha particles and a $10 PIN photodiode is used as a detector.  The output of the photodiode is amplified with a simple op-amp charge amplifier and measured with a multi-channel analyzer (MCA) to get the alpha particle energy spectrum.  A key component of the apparatus is the open-source MCA software which runs on a Red Pitaya STEMlab single board computer/FPGA system (www.redpitaya.com).  Students calibrate their system, converting channel number to particle energy, and design their experiment to measure the particle energy spectrum as the source is separated from the detector by up to 5 cm.  This loss is compared with predictions from simple models and tabulated data.

Students use this as their first nuclear/particle physics experiment.  They are introduced to counting and spectroscopy of particles, learn the concepts of detector efficiency and resolution, and how to work safely with radioactive sources.  Curve fitting in MATLAB or Python is reinforced and students get comfortable using the STEMlab instruments for future projects.  In the workshop we will do a subset of this, and the rest of the procedures will be explained.  We will describe the Red Pitaya STEMlab open-source system, and how we are using it at Queen's.
Abstract Type: Workshop

Author/Organizer Information

Primary Contact: Robert Knobel
Queen's University
64 Bader Lane
Kingston, Ontario, Non U.S. K7L 3N6
Phone: 6135332672
and Co-Presenter(s)
Sean Musclow, Queen's University
William Thompson, Queen's University
Bei Cai, Queen's University

Workshop Documents

Workshop Doc 1: Download the Workshop Doc 1
Workshop Doc 2: Download the Workshop Doc 2
Workshop Doc 3: Download the Workshop Doc 3
Workshop Doc 4: Download the Workshop Doc 4
Workshop Doc 5: Download the Workshop Doc 5