Thomas Witzel

A4IM OSI² SAR Power Monitor µC Interface PCB

Hello OCRA, Tabletop and OSI² community, In this blog post I want to share our SAR Power Monitor µC Interface for the OSI² 2MHz Halbach MRI as part of the A4IM project. The PCB uses the ADL5511 RF-to-RMS IC to convert the applied RF power to a envelope RMS voltage. This voltage gets sampled with…

20 Dec

OCRA Tabletop MRI System Status Update 2024

Hello OCRA and Tabletop community, in this blog I will share the actual development status of the OCRA Tabletop MRI System hardware and the OCRA/Relax2.0 software. The 2024 OCRA Tabletop MRI System hardware development was mainly driven by the AgriPETMRI project at the Research Campus STIMULATE, were I work as leader for the MR System…

04 Dec

A4IM OSI² STM32L476RGT compute module

Hello OCRA, Tabletop and OSI² community, In this blog post I want to share my micro controller STM32L476RGT compute module for the OSI² 2MHz Halbach MRI as part of the A4IM project. The module will be used for the open-source SAR hardware monitor to sample the applied RF power, calculate the running averages and switch…

11 Oct

A4IM OSI² TR-Switch

Hello OCRA, Tabletop and OSI² community, In this blog post I want to share my Transmit-Receive (TR) switch design for the OSI² 2MHz Halbach MRI as part of the A4IM project. The A4IM OSI² TR-Switch is based on my OCRA Tabletop MRI System TR-Switch. The schematic is basically the same and only a few components…

07 Nov

Power supply of the OCRA console

Hello OCRA and Tabletop community, In this blog post I want to share our console power supply for the OCRA Tabletop MRI System. The console is driven by a Mean Well RT-50C switching mode power supply with a universal 110/230V AC input and +15V, -15 and +5V DC outputs. To connect the power supply to…

26 Apr

Gradient Coils for the OCRA Tabletop MRI System

Hello OCRA and Tabletop community, In this blog post I want to share our gradient coil design for the OCRA Tabletop MRI System. Gradients fields are necessary to encode spatial information to the spin signal. As the origin of the spin signal is the homogeneous magnetic field (B0) it is possible to variate this field…

Welcome to the OCRA blog!

What started in a little corner of my tiny Boston apartment, and then later advanced with the help of numerous students that shall be listed soon on this page has now become a project bigger than just my hobby, with users and contributors in both Europe and the USA. In order to keep the community…

Author: Thomas Witzel