The PANDA Experiment will be one of the key experiments at the Facility for Antiproton and Ion Research (FAIR) which is under construction and currently being built on the area of the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt, Germany. The central part of FAIR is a synchrotron complex providing intense pulsed ion beams (from p to U). Antiprotons produced by a primary proton beam will then be filled into the High Energy Storage Ring (HESR) which collide with the fixed target inside the PANDA Detector.

The PANDA Collaboration with more than 420 scientist from 18 countries intends to do basic physics research on various topics around the weak and strong forces, exotic states of matter and the structure of hadrons. In order to gather all the necessary information from the antiproton-proton collisions a versatile detector will be build being able to provide precise trajectory reconstruction, energy and momentum measurements and very efficient identification of charged particles

Currently the collaboration with Russian Institutes is suspended. For details see statement from GSI.

Anna Alicke received the PANDA PhD Prize 2023
during the Collaboration Meeting in Münster

The PANDA PhD Prize 2023 was awarded to Anna Alicke (FZ Jülich/Germany) for her thesis “Development of fast track finding algorithms for densely packed straw tube trackers and its application to Ξ hyperon reconstruction for the PANDA experiment". In the course of her thesis, she developed two new tracking algorithms and combined these primary and secondary trackers to achieve the highest efficiency, which was tested on reactions with multiple secondary vertices. But the algorithm can also be used for other densely packed straw tube trackers. The prize was presented by the spokesperson during the PANDA Collaboration Dinner in Münster on March 6, 2024.

The Panda Collaboration has awarded the PhD Prize once per year since 2013 in order to honor the best dissertation written in connection with the Panda Experiment. In her dissertation, Physicist Anna Alicke studied hyperon production and reactions within the Panda detector, which is being built at the FAIR accelerator facility.

The Panda Collaboration awards the PhD Prize to specifically honor students’ contributions to the Panda project. Candidates for the PhD Prize are nominated by their doctoral advisors. In addition to being directly related to the Panda Experiment, the nominees’ doctoral degrees must have received a rating of “very good” or better. Up to three candidates are shortlisted for the award and can present their dissertations at the Panda Collaboration meeting. The winner is chosen by a committee that is appointed for this task by the Panda Collaboration.

Prof. Dr. Helmut Koch at the Collaboration
Meeting 2018, where he received the
PANDA Lifetime Membership Award.

On April 8th, 2024 our friend, colleague, teacher and mentor Helmut Koch has died. 

It was a shocking moment for many of us when we realized that Helmut Koch is no longer with us. We learnt so much from him and knew him as an excellent scientist, teacher, mentor, leader and a very friendly person. We will always remember him for his gentle, human nature and for his numerous contributions to the field of hadron physics.

Many of us have stories with or about him to share or just want to express their feelings and thoughts.

Therefore we prepared an online Book of Condolences which we want to hand over at the end to his wife.

Please, slow down your daily routine for a moment and share some memories with us. You can do so very easily if you are logged in: Just follow this link. If you have photos from Helmut Koch, you can share them as well. They will be visible by PANDA users only, whereas the condolence text is readable for anybody. 

In case of technical problems, please contact Udo.   

Helmut Koch began his physics studies at the Technical University of Aachen in 1960. The 1960s were also the time in which the quark model was developed and accelerators continued to deliver new, surprising results. It is not known whether this motivated Helmut Koch to devote himself to strong interaction, i.e. the physics of quarks and gluons, but he devoted the rest of his scientific life to this subject.

At CERN, in Prof. Backenstoss' group, he therefore devoted himself to exotic atoms, in which for example the electron was replaced by a pion and the strong interaction influences the orbits of the pions. His dissertation was entitled "Determination of the width of pionic 2p levels from intensity measurements on 2p-1s X-ray lines.”.

After strange quarks became available, Helmut Koch investigated kaonic atoms and hypernuclei at the first low-energy kaon beam at the CERN PS. The subsequent availability of antimatter in the form of antiprotons immediately began to fascinate him. He co-authored a publication on the “Observation of Antiprotonic Atoms”. Antiprotons were with him ever since and the search for exotic forms of matter determined his research from then on. He searched for baryonium states at CERN, and very quickly recognized the potential of a new storage ring for antiprotons, the Low Energy Antiproton Ring (LEAR).

The presence of cooled, background-free antiprotons allowed the study of the strong interaction to be taken to a whole new level. The annihilation of quarks and antiquarks in the form of protons with antiprotons to gluons is a unique way to understand the strong interaction. A detector based on modern high-energy experiments, the Crystal Barrel Detector, was installed at LEAR under Helmut Koch's leadership. From then on, there was a new quality feature for the spectroscopic investigation of hadrons with light quarks. As a well-known particle physicist at CERN, Lucien Montanet, once remarked only half-jokingly, the quality criterion "4-star resonance" only existed if the particle had been observed accordingly by Crystal Barrel. Many high-quality publications resulted from the experiment during its seven-year run.

At the same time, Helmut Koch was planning for the time after Crystal Barrel. He was a member of a study group that wanted to build a European Hadron Facility, which like the SuperLEAR project went unrealized, as both were in financial competition with larger CERN expansions. However, Helmut Koch was able to continue the spectroscopic investigation of hadrons with the Babar experiment in Stanford, California, and at the ELSA accelerator in Bonn. When the opportunity arose to build another dedicated antiproton machine on European soil, Helmut Koch was fully committed to the project. It is thanks to his contribution that antiproton physics is part of the new FAIR facility in Darmstadt. The “A” in FAIR stands for antiprotons. Unfortunately, the PANDA experiment, which offers new and unique opportunities to study hadrons, is coming too late for him.

Finally, a word about the man and university professor Helmut Koch. He earned his Habilitation in Karlsruhe while working at CERN, and then became a C3 professor in Karlsruhe before accepting a C4 professorship in Bochum in 1990—something he never regretted because he felt very welcome here. Above all, Helmut Koch was a true gentleman and humanist, always friendly and caring, someone who appreciated and supported his students and colleagues. He has always been willing to serve the hadron physics community, be it as a reviewer, conference organizer or DPG section chairman. Even in critical situations, he always remained level-headed and never a bad word came from him. His considerate and gracious demeanor also made him a popular companion on sailing trips, which were one of his favorite pastimes on vacation. Beautiful sailing trips and gourmet dinners followed by a good glass of red wine are also among my personal unforgettable memories of a great person and mentor: Helmut Koch.

Ulrich Wiedner

Particle detectors are the essential tools for physicists to study the properties and interactions of the smallest building blocks of matter in our universe. A next generation particle physics detector will be the PANDA detector. The PANDA experiment will study one of the fundamental forces of nature, the strong interaction, in reactions where anti-matter and matter annihilate. Antiproton Proton reactions, $\overline{\textrm{p}}\textrm{p}$-reactions, at the future international research facility FAIR located in Darmstadt will for example be used to investigate the complex bound states of the strong interaction and to search for exotic states. The forward endcap of the electromagnetic calorimeter (FWEC) is an essential part of the PANDA detector and is used to measure the energy of electrons, positrons and photons with very good resolution 
How is such a calorimeter set-up and how is it put into operation? 
These questions can be answered by the members of the research groups of Prof. Ulrich Wiedner in Bochum and Prof. Ulrike Thoma in Bonn. Both groups together successfully assembled and tested the FWEC during two test-beam times at the proton accelerator COSY at Forschungszentrum Jülich in the second half of 2023.

Figure 2: Installed support structure
of the FWEC

Figure 1: Lifted FWEC
supportstructure at
Ruhr-Universität Bochum

In mid-March, the first step was made transporting the support structure of the FWEC from Bochum to Jülich. Four cranes were needed to move the circularly shaped support-structure with a diameter of 2.5 m and a weight of 350 kg to its interim destination at COSY. In Figure1 and the photo gallery you can see a snapshot of this spectacular event.
After arriving at Forschungszentrum Jülich, it was mounted within a massive transport frame, holding the FWEC in an upright position and preventing it from tilting. Several ground anchors were used to secure it, even in the case of small earth quakes.  In a second step the support structure had to be equipped with the detector modules. Each module consists of 16 or 8 scintillation crystals made of lead tungstate with a photodetector attached.
An incident particle deposits energy within the crystals and the energy is converted into light. This is detected via an attached photodetector that generates an electrical signal, which can be processed with further readout electronics. As the signal output is proportional to the deposited energy, the energy of the incident particle can be reconstructed. 
The design and assembly of the electromagnetic calorimeter is a truly international endeavor. The crystals were tested at the University of Gießen and CERN (Geneva, Switzerland), the photodetectors were tested at the Universities of Bochum and Bonn, as well as at GSI, (Darmstadt), the preamplifiers were designed and produced at the University of Basel (Switzerland), the mechanics were designed at the University of Groningen (Netherlands), the cooling system was designed at Orsay (France), digitization electronics were developed at and provided by the University of Uppsala (Sweden). 
The picture below illustrates assembled modules on the left as well as the single components on the right and printed circuit boards readout boards in the front. The, at the University of Bochum, assembled detector modules were tested and pre-calibrated at the University of Bonn, at their later operation temperature of -25°C to ensure proper functionality.

Figure 3: FWEC detector modules, their components and the electronic board for photodetector-HV-adjustment as well as the patch panel board

The excellent collaboration between Bochum and Bonn, finally payed off in the joint detector mounting in Jülich. In total 60 detector modules with 864 crystals were mounted and equipped with the necessary front-end electronics and cables. As the whole calorimeter must be operated at freezing -25°C, all parts were covered with insulation and a complex cooling system was installed to reach and maintain the targeted temperature. As condensation is a problem when running electronics at such cold temperatures, the FWEC was flushed with dry air and nitrogen. The different stages of the assembly are shown in the figures 4-6. 

Figure 4: FWEC front with 60 mounted
detector modules

Figure 5: FWEC back with printed
circuit boards and cables

Figure 6: FWEC front, covered in
insulation and connected cooling pipes

Remaining tasks were the installation of a detector control system to control the detector with all of its subsystems and the DAQ to read out and store the detector signals. 

In July, the system with its 864 crystal units was finally put into operation for the first time at the proton beam of the COSY accelerator in Jülich. This first test was followed by two beam times in August and September. During these beamtimes high energetic particles, including s and s, were produced at the target in the proton beam. The produced particles or their decay products were then measured with the FWEC.
With these efforts, one of the first detector components of the ANDA detector, the partially equipped FWEC, has started its operation and was carefully tested under beam conditions. Figure 7 shows the FWEC on the right, the proton beam pipe and target in between.

Figure 7: Setup of the FWEC for COSY beam

During the successful beam times 210 TB of data were recorded, which are currently being analyzed. They will be used to calibrate the detector, to study its performance in detail and to improve the software, needed to reconstruct the information on the particles detected in the FWEC. Over 15 years of careful research and hardware developments have led to this exciting moment of observing the first particles in our detector system. 

Figure 8: Energy spectrum showing
minimum ionizing particles obtained
with one crystal unit of the FWEC.

It is known by simulations that minimal ionizing particles deposit an energy of about 200MeV inside one crystal and we could confirm this prediction already at the beginning of our measurements. This energy deposition corresponds to an ADC-value of about 4000 depending on the individual amplification of each readout channel. 
This is shown as an example for one of the crystals in Figure 8. 

The next stop in the journey of the FWEC will be the electron accelerator ELSA in Bonn. First the FWEC will be commissioned with all of its 268 detector modules (3856 crystals) and is then used for hadron physics experiments. At ELSA, photoproduction experiments will be performed using a polarized beam and target and the FWEC as forward calorimeter to study the emergence of complex bound states of the strong interaction made of up, down and strange quarks. 

As soon as the antiproton beam is available at FAIR, the FWEC will finally be moved to Darmstadt to be part of the PANDA-Experiment. With the PANDA-Experiment new insights into strong interaction will be gained. This provides for interesting research especially for future generations of young scientists. 


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