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.

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
at COSY

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. 

PANDA awards a prize every two years for the best theory PhD thesis related to the PANDA experimental program. We would like to ask for nominations for the upcoming prize. The prize will include the award of 200 Euro and will be presented at the PANDA Collaboration meeting in June 2024.

 

All theoreticians who have passed the oral defense of their PhD thesis between Jan 1, 2022 and December 31, 2023 are eligible. The thesis may contain work related to other experiments, but the majority of the work in the thesis must be directly connected to the PANDA physics program.
The nomination should be made by the thesis advisor.

 

A nomination can be made until February 29, 2024 by submitting the following information to the spokesperson and the chair of the theory advisory group (Christian Fischer, christian.fischer@physik.uni-giessen.de) of the collaboration:

 

1. A nomination letter in which the content of the thesis and the importance of this work for PANDA is described. The letter should also motivate why the thesis should be considered as the best one from the selection period for PANDA.

2. The thesis must be made available online and the URL must be included in the nomination. If the thesis cannot be uploaded to the PANDA website then a PDF copy should be submitted with the nomination letter.

3. If the thesis is not written in English, then a (couple of pages) summary must be provided in English.

4. A copy of a certificate showing the grade achieved by the thesis if relevant (and a short description of the grade scale). This certificate should indicate the date of the oral exam. If that is not the case, then some other confirmation of when the oral exam was held must be provided (a letter from the thesis advisor will suffice, if a copy of a formal document is submitted before the PANDA Collaboration meeting in June 2024.)

List with all prize winners.

CERN’s LHCb experiment has donated its decommissioned outer tracker detector component to PANDA. 

   

PANDA is happy about a gift it has received from LHCb, one of the four big CERN experiments at the Large Hadron Collider. LHCb has sent their decommissioned Outer Tracker (OT) from Geneva to Darmstadt, where it has arrived at GSI (25. August 2023) after a special transport of five days via truck and ship. The LHCb colleagues at CERN prepared the detector in its transport frame with protecting plastic for a journey in three stages, due to the "package" size: Seven meter long, 3.5 meter wide, 5.5 meter high and a weight of 24 tons. The first stage of the journey by truck brought the OT from CERN to the harbour of Colmar where a Rhine ship took over the second stage and delivered the OT to Gernsheim harbour, where a truck did the last stage to GSI. 

The donation from LHCb to PANDA was initiated by by our deputy technical coordinator Anastasios "Tassos" Belias and Niels Tuning from LHCb/CERN after discussions about spare detector modules at a conference a few years ago.
Finally the LHCb collaboration decided to donate the whole OT to the PANDA collaboration, which was then formally signed in a contract between GSI and CERN/LHCb last year.

The donation was made possible thanks to the close cooperation in logistics and technical aspects between several colleagues at CERN and GSI/FAIR, in particular Niels Tuning (LHCb, Nikhef/CERN) and Anastasios Belias (PANDA, GSI/FAIR) and their relentless efforts to give the formidable outer tracker a second life. The donation was kindly agreed upon by the LHCb groups who meticulously built and operated the outer tracker, namely,

  •  the National Institute for Subatomic Physics, Nikhef, the Netherlands,
  •  the Physikalisches Institut der Universität Heidelberg, Germany,
  •  the National Centre for Nuclear Research, Warsaw, Poland,
  •  the Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Krakow, Poland,
  •  and the Technische Universität Dortmund, Germany.

The OT consists of 54.000 Straw tubes, each 2.4 m long with a diameter of 5 mm, which are arranged in staggered double layers and mounted to twelve C-shaped mechanical frames. The C-frames are inserted in the big blue transport frame (c.f. pictures).  

There are several ideas how individual parts of the OT can be re-used in different experiments and set-ups in the future.
At PANDA the tracker will be able to detect the light hadrons produced by the collisions. Hadron spectroscopy is where the physics goals of LHCb and PANDA overlap, and the two will be able to collect complementary data that can later be analysed and compared. The tracker will also be used by students and young researchers in R&D projects, as well as in outreach activities for schools and the general public.

Once again this year, the outstanding efforts of two groups were recognized by the PANDA Collaboration and awarded the annual prize for their exceptional work for the operation and realization of PANDA at FAIR.


The first award went to Tobias Stockmanns (middle photo on the right) and Anna Alicke (on the right photo) for their development of a realistic and generalized tracking algorithm for the PANDA experiment. Their development of a more generalized algorithm that is agnostic to the point of production is absolutely crucial for the foreseen hyperon physics program of PANDA and an important milestone for the PANDA software. 

The second prize went to Lars Schmitt (middle photo on the left) and Anastasios Belias (on the left) for their tireless work to realize the PANDA detector at FAIR. Their continuous persistence and creativity, which went far beyond what could have been expected, is not only an inspiration for the entire collaboration, but also a guarantee for the realization of our ambitious project eventually. Both are unparalleled in their commitment to the technical side of the project and are like a rock in the current storm

The awards were presented by the Spokesperson Ulrich Wiedner (who took the middle photo) on the occasion of a boat tour during the recent Collaboration Meeting In Prague.
 

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