We present new exclusion bounds obtained at the European X-ray Free Electron Laser facility (EuXFEL) on axion-like particles (ALPs) in the mass range 10^-3 eV < m_a < 10^4 eV. Our experiment exploits the Primakoff effect via which photons can, in the presence of a strong external electric field, decay into axions, which then convert back into photons after passing through an opaque wall. While similar searches have been performed previously at a 3^rd generation synchrotron, our work demonstrates improved sensitivity, exploiting the higher brightness of X-rays at EuXFEL.

The Low Gain Avalanche Detectors (LGAD) has become the preferred technological choice for fast track timing detectors in High Energy Physics applications. Additional uses of such sensors are currently being investigated, ranging from Light Detection and Ranging (LIDAR) to Low Let particle dosimetry in medical and space applications. This paper describes the development and test of LGAD devices, fabricated using a commercial process from Teledyne e2v silicon foundry. Motivation behind the project, and details of the TCAD simulations of the manufacturing process and of the electrical performances of the devices will be provided. Test results on gain and time resolution using laser injection will also be shown.

LGAD devices from Teledyne e2v (a long-established commercial manufacturer of scientific imaging sensors) have been fully characterised before and after irradiation. Irradiations were performed with 27MeV protons at the MC40 cyclotron in Birmingham to deliver a fluence from 5.6 × 1013 up to 8.3 × 10141MeVneq/cm2 to seven LGADs. Te2v LGADs were shown to exhibit the expected trends in breakdown voltage, gain and time resolution as seen in literature. Time resolution and gain performance before and after irradiation are reported here and compared with published results for other manufacturers of such devices.

The ATLAS Inner Tracker (ITk) upgrade for the High-Luminosity LHC (HL-LHC) requires a radiation-tolerant pixel readout chip, which must withstand a total ionising dose (TID) of up to 1 Grad. The readout ASIC for the ITk upgrade has been designed by the RD53 collaboration using 65 nm CMOS technology. In order to characterise the radiation tolerance of the chip digital logic, the RD53 ASICs include ring oscillators, which can be used to measure gate delay degradation. Extensive X-ray irradiation studies of the ring oscillators have been performed on the ITk Pixel pre-production readout ASIC, ITkPixV1. A dependence of radiation damage on dose rate has been observed in 65 nm CMOS technology. This paper aims to quantify the dose rate dependence of TID damage to the ITkPix ring oscillators and, therefore, the ITkPix ASIC digital logic. X-ray irradiations at different dose rates between 20 krad/h and 30 Mrad/h are compared. A dose rate dependence is observed, with 2-3 times more damage at the lowest dose rate of 20 krad/h, compared to 4 Mrad/h. The dose rate dependence was also observed to be dependent on transistor size and type.

The need for ultra-fast timing is a result of the expected pile-up at the High-Luminosity LHC General-Purpose Detectors. Track timing resolution of the order of tens of picoseconds is required to sufficiently resolve individual vertices. In collaboration with Teledyne e2v, 22 six-inch wafers with Low Gain Avalanche Detectors, featuring a 50 mu m thick high-resistivity epitaxial layer and different gain layer implants, have been completed successfully. Using transient current technique, the charge gain of a 1 x 1 mm(2) LGAD device from one of the wafers was found to be higher than 10, with jitter reaching 10 ps when biased at 240 V. Tests with other wafers are under way.

This paper presents initial testing of the first batch of LGAD sensors fabricated by Teledyne e2v in collaboration with the University of Birmingham, University of Oxford, Rutherford Appleton Laboratory and the Open University. Wafers with different energy and dose of the gain layer implant have been characterised with IV, CV and gain measurements. The same set of measurements were made using PiN diodes fabricated on the same wafer as a reference. Results are in-line with expectations and with LGADs produced at more established vendors. Preliminary results suggests Te2v LGADs have a moderate gain in the order of 10 to 50 before irradiation at operational voltages well below breakdown, as required for optimal timing resolution.

This article describes the development of the Tristan 10 M detector for time-resolved synchrotron experiments. Tristan 10 M has an unprecedented time resolution (ns time scale) over long-duration continuous acquisition (days). The detector is constructed from an array of 160 Timepix3 readout application-specified integrated circuit (ASIC; about 10 million pixels) flip chip bonded to ten monolithic silicon sensors, which enable it to cover an area large enough to effectively carry out crystallography experiments. The large array of ASICs resulted in a number of severe technical challenges that had to be overcome during the development of the detector. The minimization of the dead area between sensors required the development of a very challenging mechanical and electronic packaging. Such a packaging had to be able to route the large number of data and power lines within the footprint of a sensor, had to effectively sink the heat generated by the ASICs, and had to be able to position the sensors accurately. In addition, the packaging of the detector was designed to be scalable in consideration of possible future larger versions of this detector, which added a further challenge. The data-driven nature of Timepix3 and the sheer data volume produced by the array of ASICs required us to devise a dedicated hardware, firmware, and software data acquisition architecture. This architecture proved very effective during the commissioning of Tristan 10 M when time-resolved crystallography experiments were carried out.

Ion microscopy allows for high-throughput mass spectrometry imaging. In order to resolve congested mass spectra, a high degree of timing precision is required from the microscope detector. In this paper we present an ion microscope mass spectrometer that uses a Timepix3 hybrid pixel readout with an optimal 1.56 ns resolution. A novel triggering technique is also employed to remove the need for an external time-to-digital converter (TDC) and allow the experiment to be performed using a low-cost and commercially available readout system. Results obtained from samples of rhodamine B demonstrate the application of multimass imaging sensors for microscope mass spectrometry imaging with high mass resolution.

The Mu3e experiment aims to find or exclude the lepton flavour violating decay mu -> eee at branching fractions above 10(-16). A first phase of the experiment using an existing beamline at the Paul Scherrer Institute (PSI) is designed to reach a single event sensitivity of 2.10(-15). We present an overview of all aspects of the technical design and expected performance of the phase I Mu3e detector. The high rate of up to 10(8) muon decays per second and the low momenta of the decay electrons and positrons pose a unique set of challenges, which we tackle using an ultra thin tracking detector based on high-voltage monolithic active pixel sensors combined with scintillating fibres and tiles for precise timing measurements.

This erratum corrects measurements of the prompt and secondary (from-b).

The brighter-fatter effect is a well known phenomenon in thick, back illuminated CCDs, causing asymmetric increase in the observed size of point sources via correlated charge collection with higher signal levels. Over recent years, the effect of various operating parameters (such as the back bias applied) on the size of measured correlations has been well established. Less well studied is the consequence of changing the effective collection gate width of the CCD, which is of limited accessibility to experiment though several values are available in 3 or 4 phase devices. In this proceeding we present collection gate width experiments using both flat field and spot projection illuminations on a thick back illuminated device as used for the LSST project. We report on the size of the variation of measured correlations with gate width as compared with backside bias voltage, and find that gate width constitutes a small but significant contribution. In light of these results, we give comment on device optimisation when minimising correlated charge collection effects is desired.

The upgrade of the ATLAS tracking detector for the High-Luminosity Large Hadron Collider at CERN requires the development of novel radiation hard silicon sensor technologies. The MALTA Monolithic Active Pixel Sensor prototypes have been developed with the 180 nm TowerJazz CMOS imaging technology. This combines the engineering of high-resistivity sub- strates with on-chip high-voltage biasing to achieve a large depleted active sensor volumes, to meet the radiation hardness requirements of the outer barrel layers of the ATLAS ITK Pixel de- tector (1.5× 1015 1 MeV neq/cm2 and 80 MRad TID). MALTA combines low noise (ENC < 20 e−) and low power operation (1 uW / pixel) with a fast signal response (25 ns bunch crossing) in small pixel size (36.4 × 36.4 μm2), and a small collection electrode (3 μm), with a novel high- speed asynchronous read out architecture to cope with the high hit rates expected at HL-LHC. The latest developments, embedded in so-called Mini-MALTA chip, address the issues observed in previous designs to meet the desired radiation hardness requirements. This contribution will summarize the design and recent improvements of this technology, together with the measure- ments of analog and digital performance, as obtained in test beams and lab and radioactive source tests.

This contribution outlines the results of investigations into the effects of radiation damage in the mini-MALTA depleted monolithic pixel sensor prototype using a micro-focus X-ray beam at Diamond Light Source. The in-pixel photon response was measured for three different pixel design variations: one with the standard continuous $\mathrm{n^-}$ layer layout and standard front-end, and extra deep p-well and $\mathrm{n^-}$ gap designs with a modified front-end. The standard design showed a decrease of 12\% in pixel response after irradiation to 1e15 $\mathrm{n_{eq}/cm^2}$. The two new designs did not show a significant decrease in pixel response after irradiation.

Detector prototypes are commonly characterised in testbeams, either using charged particles or X-rays. Charged particles are used to quantify detector performance in terms of absolute efficiency, while X-rays can provide additional information about the detector structure. This paper presents an alternative approach to calculating charged particle efficiencies, using the results of an X-ray testbeam of the mini-MALTA CMOS prototype at Diamond Light Source, and additional laboratory measurements. Results are presented for an unirradiated and an irradiated sample and compared to the results of charged particle testbeams at SPS and ELSA. The extrapolated efficiencies are in agreement with the measured values. Additionally, the extrapolated efficiency maps provide more insight about the location of the pixel inefficiencies, due to the better spatial resolution of the X-ray testbeam.

Charge-coupled devices (CCDs) currently constitute the standard detector for precision astronomical telescopes such as the Large Synoptic Survey Telescope (LSST) due to their high linearity, sensitivity and dynamic range. Charge transfer properties can however be degraded by the presence of defect levels in the silicon band-gap, which can act as trapping centers for signal charge. The technique of single trap-pumping can be used as a tool to probe the underlying properties of relevant defect levels and potentially mitigate against their effects. In this paper we present a single trap-pumping study of the LSST E2V CCD250 across a temperature range of -30◦ to -110◦, a much larger range than previously studied using this approach. The predominant defect level of relevance for CCDs appearing at these temperatures is shown to be the single-acceptor level of the silicon divacancy. Using experimental data and a basic Monte-Carlo model of the trap-pumping process we examine the defect level properties, with an attempt made to account for both the capture and emission of signal charge.

Monolithic silicon sensors developed with High-Voltage CMOS (HV-CMOS) processes have become highly attractive for charged particle tracking. Compared with the standard CMOS sensors, HV-CMOS sensors can provide larger and deeper depletion regions that lead to larger signals and faster charge collection. They can provide high position resolution, low material budget, high radiation hardness and low cost that are desirable for high performance tracking in harsh collision environment. Various studies have been conducted to explore the technology feasibility for the large-area tracking systems at future collider experiments. CHESS (CMOS HV/HR Evaluation for Strip Sensor) sensor series have been developed as an alternative solution to the conventional silicon micro-strip detectors for the ATLAS inner tracker upgrade. The first prototype (named CHESS1) was to evaluate the diode geometry and the in-pixel analog electronics. Obtained test results were used to optimize the second prototype (named CHESS2). CHESS2 was implemented with a full digital readout architecture and realized as a full reticle sized monolithic sensor. In this paper, the basic characteristics of the CHESS2 prototype sensors and their performance in response to different input signals are presented.

This paper outlines the results of investigations into the effects of radiation damage in the mini-MALTA depleted monolithic pixel sensor prototype. Measurements were carried out at Diamond Light Source using a micro-focus X-ray beam, which scanned across the surface of the device in 2 mu m steps. This allowed the in-pixel photon response to be measured directly with high statistics. Three pixel design variations were considered: one with the standard continuous n(-) layer layout and front-end, and extra deep p-well and n(-) gap designs with a modified front-end. Five chips were measured: one unirradiated, one neutron irradiated, and three proton irradiated. The standard design showed a decrease of 12% in pixel response after irradiation to 1e15 n(eq)/cm(2). For the two new designs the pixel response did not decrease significantly after irradiation. A decrease of pixel response at high biasing voltages was observed. The charge sharing in the chip was quantified and found to be in agreement with expectations.

The testing of irradiated silicon detectors requires maintaining low (≤ -10 °C) temperatures, to simulate a realistic operating environment and prevent annealing effects from distorting the results of the measurement. Keeping a device cool and dry is challenging, particularly if the apparatus must be portable. This paper presents a solution for a providing a stable, cool and dry environment for testing an irradiated silicon detector, that is easy to transport and can be installed in charged particle beam areas and irradiation facilities.

This paper outlines the results of investigations into the effects of radiation damage in the mini-MALTA prototype. Measurements were carried out at Diamond Light Source using a micro-focus X-ray beam, which scanned across the surface of the device in 2 $\mu m$ steps. This allowed the in-pixel photon response to be measured directly with high statistics. Three pixel design variations were considered: one with the standard MALTA layout and front-end, and deep p-well and n-gap designs with a modified front-end. Five chips were measured: one unirradiated, one neutron irradiated, and three proton irradiated.