Electron Paramagnetic Resonance (EPR) [wiki] is a powerful spectroscopic and imaging technique applied for a wide range of scientific problems. The incomplete list of EPR applications includes food quality control and radiation dosimetry, study of protein structure and dynamics, medical imaging, semiconductors research and observation of chemical kinetics.

The experimental approach to EPR observation can be classified according to the way microwave power applies to the sample. Continuous wave EPR employs continuously applied microwave irradiation whereas pulse EPR utilizes pulse excitation and time-domain signal acquisition. The choice of methodology is problem-dependent and in many cases both methodologies provide complimentary information.

Rapid progress in high power microwave sources and control electronics during the last years dramatically improved the performance of pulse EPR equipment. The scarcity of commercial solutions has motivated many research groups to develop their own instruments. Construction of pulse spectrometer requires a broad expertise both in microwave electronics and acquisition hardware. However what turns the assembly of equipment into robust and useful tool is it's front-end, the control software.

Actively working in the field of EPR for many years our team has accumulated vast experience in interfacing various microwave bridges to computer-based control systems. Despite significant differences in hardware, the similarity of experimental approaches in EPR allowed us to create a single versatile high performance software capable to control virtually any EPR spectrometer. Together with dedicated hardware for pulse generation and signal acquisition SpecMan4EPR compliments the microwave part of the spectrometer and turns it into scientific tool accessible to users with various degrees of EPR experience.

The idea to write a spectrometer control software came to Boris Epel and Stefan Stoll at Spring 2001 in Weizmann Institute of Science, Israel. At that time groups of Prof. Daniella Goldfarb, Weizmann Institute of Science and Prof. Arthur Schweiger, Swiss Federal Institute of Technology (ETH), Switzerland had been used the spectrometer control program written by Jaap Shane. To perform some tricky experiment Jaap's program required a modification. After completing their task and having free time and good deal of a fantasy Boris and Stefan established some basic principles of new and advanced program design and made a prototype of the graphic user interface. It was decided to use the pulse programming language (PPL) and experiment structure of Jaap Shane's program but completely modify the communication with devices and add new level of PPL customization. It was decided to implement these ideas 'sometimes'.

Project became more realistic after discussion with Igor Gromov, ETH. He also wanted to make some modification for Jaap's program and joined the SpecMan4EPR team at Fall, 2001. The programming language and main objectives were chosen at that time.

First code of SpecMan4EPR was written during the visit of Boris to ETH at Spring 2002. This visit became possible due to the agreement between Prof. Daniella Goldfarb and Prof. Arthur Schweiger. At the end of the visit the first presentation about SpecMan was given.

The prototype of the program was ready at Summer 2002. Still unstable and full of bugs, the program was found very useful for pulse ENDOR due to the random acquisition feature suggested by Stefan on early stages of development.

The first completely stable release of SpecMan4EPR (ver. 0.5) came from Max-Planck Institute for Bioinorganic Chemistry, Germany when Boris joined the group of Prof. Wolfgang Lubitz at Spring, 2003. In this release the static linkage of vendor's device libraries was substituted by the dynamic link. This made the program completely environment independent.

At the end of 2003 (ver. 0.6.1) the pulse and device configurations wizards were implemented. New implementation of phase cycling allowed to perform CYCLOPS. At the beginning of 2004 the Scope was added to monitor transient signals.

After the period of gradual improvement the structure of the program was completely redesigned at Spring of 2006 on request from Dr. Reef Morse, Scientific Software Services. The development of client-server network edition (ver. 0.8.5) was started. Since then SpecMan4EPR has two different editions. The client-server edition became stable close to Spring of 2007 (ver. 1.1.1). At that time Boris joined the group of Dr. Howard J. Halpern, University of Chicago. Number of improvements has been made to apply the program for pulse EPR imaging.

In 2009 nine EPR/NMR research groups around the world used the program.

Another three groups showed an interest in purchasing of the SpecMan4EPR for their research (2010).