The installation of the High-Luminosity Large Hadron Collider (HL-LHC) presents unprecedented challenges to experiments like the Compact Muon Solenoid (CMS) in terms of event rate, integrated luminosity and therefore radiation exposures. To cope with this new environment, new detectors will be installed during the CMS Phase 2 Upgrade, including the replacement of the calorimeter endcaps with the “High Granularity Calorimeter” (HGCAL), which contains silicon sensors and scintillators as active elements. The silicon sensors will be produced in an 8” wafer process, which is new for high-energy physics, so it demands extensive quality verification. A first batch of prototype sensors underwent electrical tests at the institutes of the CMS Collaboration. Testing revealed major problems with the mechanical stability of the thin backside protective layer, that were not seen in earlier 6” prototypes produced by a different backside processing method. Following these results, the HGCAL group introduced the concept of ”frontside biasing”, allowing testing of the sensors without exposing its backside, verified the applicability, and adapted the prototype design to apply this method in series production.

Ion beam therapy has become a frequently applied form of cancer therapy over the last years. The advantage of ion beam therapy over conventional radiotherapy using photons is the strongly localized dose deposition, leading to a reduction of dose applied to surrounding healthy tissue. Currently, treatment planning for proton therapy is based on X-ray computed tomography, which entails certain sources of inaccuracy in calculation of the stopping power (SP). A more precise method to acquire the SP is to directly use high energy protons (or other ions such as carbon) and perform proton computed tomography (pCT). With this method, the ions are tracked prior to entering and after leaving the patient and finally their residual energy is measured at the very end. Therefore, an ion imaging demonstrator, comprising a tracking telescope made from double-sided silicon strip detectors and a range telescope as a residual energy detector, was set up. First measurements with this setup were performed at beam tests at MedAustron, a center for ion therapy and research in Wiener Neustadt, Austria. The facility provides three rooms for cancer treatment with proton beams as well as one which is dedicated to non-clinical research. This contribution describes the principle of ion imaging with proton beams in general as well as the design of the experimental setup. Moreover, first results from simulations and recent beam tests as well as ideas for future developments will be presented.

MedAustron is an Austrian cancer treatment facility using protons in the energy range from 62.4MeV to 252.7MeV and carbon ions with energies up to 400 MeV/u for external beam radiotherapy. The facility features a unique beam line exclusively for non-clinical research, which will be commissioned for even higher proton energies of up to 800MeV. A demonstrator of a proton computed tomography system consisting of a tracking telescope and a residual energy detector is being developed and will be tested in beam at MedAustron. Currently, this demonstrator consists of a beam telescope composed of four double-sided silicon-strip detectors. A rotating table serving as sample holder is placed between the second and third detector. The tracking telescope is triggered by two scintillation detectors operated in coincidence and is placed downstream behind the silicon detectors. This telescope was tested in beam to obtain a radiography of an aluminium sample. Additionally, the tracking telescope was modelled in Geant4 to simulate particle tracks. An image reconstruction method exploiting material dependent variations of the scattering angle of protons was used to obtain a three dimensional image of an irradiated sample.

Its radiation resilience has established p-type silicon as tracking detector baseline material in upcoming high-luminosity physics experiments. Electric isolation of n+ electrodes with p+ implants (p-stop or p-spray) is crucial for segmented p-type sensor quality. P+ doping concentration, implantation depth, and geometry determine the achievable resistance between segments. Typically, inter-strip resistance is measured directly on the strip sensors. Large resistances on the order of 100 GΩ require precise, low-noise current measurements, which are strongly influenced by parasitic currents. To provide a comparably simple alternative to measurements on strip sensors, this contribution seeks to relate Metal-Oxide–Semiconductor Field-Effect Transistor (MOSFET) threshold voltage to sensor inter-strip resistance. We utilize circular MOSFET test structures fabricated on the same wafers as the strip sensors. This paper compares measurements of MOSFETs and strip sensors on wafers with different n- and p-spray implantations and presents comparative TCAD simulations. MOSFET test structures could present a fast option to judge silicon sensor inter-strip resistance and strip isolation properties. Process quality control during future series productions can benefit from this technique.

MedAustron is a hadron synchrotron primarily designed and built for tumor treatment. Besides its clinical purpose, it is equipped with a dedicated beam line for non-clinical research. This beam line can be used for beam tests utilizing protons with an energy up to 252.7MeV at the moment, but 800 MeV protons and carbon ions will become available through 2019. We conducted first beam tests at MedAustron in order to understand the usability of this beam line for testing silicon detectors. This includes the design and commissioning of a trigger setup based on scintillators and PMTs, which is meant to stay permanently there. This allowed us to measure energy deposition utilizing silicon strip sensors read out by the ALiBaVa system. Nominal beam energies were varied between 62.4 and 252.7 MeV and verified by determining the specific energy loss of protons in silicon. As these energies are rather low compared to typical HEP beam tests, the proton beam through the setup was simulated to determine the necessary energy correction due to losses through matter and air in front of the Si sensor. These approaches yielded good agreement with reference data from NIST, so MedAustron is considered as a reliable facility for future beam tests.