Link to PDF of poster shown above
This summer, the Sarah Lawrence Summer Science Program was back! Three brave students came into the lab to continue the work of designing and building an affordable and accessible MRI system. They created the poster above to highlight their various projects, and links to their more detailed reports of their work can be found below.
Improving Upon Our Optimization Algorithm Xandra Long (future computer science engineer) was our main computer programmer.
(Written by Xandra Long)
Intro This summer as a part of Merideth Frey’s research team, I approached computer science projects, both furthering some of Aaron Connover’s work as well as creating my own. At the beginning of the program I collected data from our TeachSpin NMR and by the end wrote an optimization genetic algorithm (GA) for our MANDHALA’s inner magnets.
TeachSpin NMR Data I started off this summer gathering NMR data, using the TeachSpin, from samples of various materials we had in the research lab.
(Written by Lee Brown)
Making an account and getting started First, you’ll want to create a free account on TinkerCad. You’ll want to make a personal account instead of joining a class with a student account.
Then you should try going through the “Direct Starter” tutorials to get familiar with the program.
TinkerCad is pretty simple and easy to use, so it can be tempting to skip all the tutorials and just hop in and learn by doing.
(Written by Arav Misra and Computational Work by Aaron Conover)
This summer, the Sarah Lawrence Summer Science Program was cancelled due to COVID-19. However, that didn’t stop some intrepid students from tackling some research problems remotely, with posts on Slack and occasionally Zoom meetings with Merideth to debug issues or discuss next steps.
Below are summaries of two projects worked on by rising high-school senior, Arav Misra, and rising undergraduate senior, Aaron Conover.
(Written by Jonathan Sheppard and Aaron Conover)
This summer, Jon Sheppard and Aaron Conover joined Merideth Frey’s physics research team through the Sarah Lawrence Summer Science Internship program. Last summer, the team focused on setting up the new TeachSpin equipment and optimizing the Halbach Mandhala design. They were successful in both endeavors. Thus, this summer, the attention has been on designing and creating a Radio Frequency transceiver and an easily manipulated gradient field (while also attempting to optimize all magnetic fields even further).
(Written by Jonathan Sheppard)
Intro This summer the team took the previous year team’s RF probe design and both updated and upgraded it, in an attempt to optimize its functions. As with last year’s design, we used the text Experimental Pulse NMR: A Nuts and Bolts Approach by Eiichi Fukushima and Stephen B. W. Roeder as a guide. The main sections used will be noted throughout this post.
As noted in the previous post, below are some general guidelines on the inductor coil specifications (from the section “V.
This work was a follow-up to the work discussed in the previous post from 2018 on optimizing positions of magnets in the NMR MANDHALA based on a close reading of of Soltner and Blumler’s 2010 article “Dipolar Halbach Magnet Stacks Made from Identically Shaped Permanent Magnets for Magnetic Resonance”. There the dipole approximation is used for each cubic magnet in order to optimize magnet position to take into account inhomogeneities in the magnetic moments of the magnets used in the Mandhala (see ‘Variation of Magnet Properties’ section of article).
In order to more easily share the data analysis templates we produce to analyze our data, we have created a GitHub respository.
Most of these are Jupyter notebooks, but if you don’t have Jupyter installed, no worries! Click on the `launch binder’ button that appears in the opened README file, and this will launch an external server with Jupyter so you can run and interact with the notebooks yourself. (Make sure to save/download a copy of the notebook if you want to save any changes you make!
(Written by Jianlong (Ken) Zhu)
RF Probe We designed our own RF probe with the aid of a manual, Experimental Pulse NMR: A Nuts and Bolts Approach (Eiichi Fukushima and Stephen B. W. Roeder). Below are some takeaways from the section “V.C.4. Probes” (p.p. 373-385):
A good coil for RF probe has a large inductance, which is given by the equation: $L = \frac{n^2 a^2}{23a+25b}$ μH, where n is the number of loops, and a and b are the radius of the loop and the length of the coil measured in centimeters.
(Written by Nicholas Torres)
An important aspect of conducting NMR analysis is finding two time-constants: T1 and T2. The T1 constant represents the longitudinal relaxation time or how long it will take for a proton that has been energized by a radiofrequency (RF) pulse to go back to realign with the magnetic field, whereas the constant T2 or transversal relaxation time tells us roughly how long it will take for a proton that has been struck with a 90° RF pulse to dephase from its neighboring protons due to different local magnetic environments.