Bo Jakobsen

IMFUFA's contribution to INM 10 year department celebration (summer 2026)

The contribution consists of two parts, with accompanying texts:

Thermalization calorimetry — the Red Box
Thermalization calorimetry — and the hardware known as "the Red Box" — has been developed and refined at IMFUFA for more than 50 years, and is still in use today.
As a low-cost alternative to commercial calorimeters, the technique is used mainly to study glass-forming liquids, both by researchers and in numerous student projects.
It grew out of early ideas by Jens Højgaard Jensen and was developed by Niels Boye Olsen and Ib Høst Pedersen through the 1980s.

Molecular dynamics hardware
Molecular dynamics has been one of the cornerstones of research at IMFUFA for more than 30 years.
With a strong focus on state-of-the-art hardware and on developing its own simulation software, the group has been among the international leaders in simulating viscous liquid dynamics.
The display shows the hardware development, from gigaFLOP dual-core CPUs in the mid-2000s to modern teraFLOP GPUs (graphics cards) with tens of thousands of cores.

MD in a Box – Interactive Simulations of Binary Atom Mixtures

Developed an interactive 2D binary molecular dynamics simulation running on a Raspberry Pi Pico 2. Designed as a demonstration device — showing gas, liquid, and crystal phases; phase separation; and size-mismatch effects, all in real time on a handheld device with build in accelerometer and bottoms for interaction.

Full technical description and source code on: boj.dk/md-in-a-box/

B. Jakobsen and Ulf R. Pedersen. MD in a Box. Internal RUC Poster 2026. [ PDF ]

RUSC – Roskilde University Shear Code

Lead on development and publication of an open source version of the RUSC analysis code for determining frequency-dependent shear modulus using the piezoelectric shear rheometry technique (PSG devices). The technique achieves unprecedented frequency range, typically 1 mHz to 50 kHz. With his publication we present a clean and structured version of the research code, allowing for implementation at other labs.

B. Jakobsen, T. Hecksher, and T. E. Christensen. RUSC (Roskilde University Shear Code) (v 1.0). Zenodo, 2024. [ DOI ]

Huginn: A peltier-based sub-cryostat for neutron scattering.

Lead on developing a sub-cryostat insert with dual Peltier regulation, useable down to 100 K, that enables large and rapid temperature jumps of up of 10 K to 20 K in minutes or less. We demonstrated temperature stability is improvement by an order of magnitude in the presence of a variable background temperature.
The project was done in collaboration with the sample environment group at ESS.

B. Jakobsen, A. T. Holmes, T. Rasmussen, H. Schneider, A. Pettersson, A. Hiess, and K. Niss. JNR, 21:47–57, 2019. [ DOI ]