During past five years VTT has actively developed edgeless detector fabrication process. The straightforward and high yield process relies on ion-implantation to activate the edges of the detector. A recent fabrication process was performed at VTT to provide p-on-n edgeless detectors. The layout contained DC- and AC-coupled strip detector and pixel detectors for Medipix/Timepix readouts. The fabricated detector thicknesses were 50, 100 and 150 μm. Electrical characterization was done for 5 × 5 mm ² edgeless diodes on wafer level. All measured electrical parameters showed a dramatic dependence on the diode thickness. Leakage current was measured below 10 nA/cm ² at full depletion. Calculation using a theoretical approximation indicates the diode surface generation current of less than 300 pA. The breakdown voltages were measured to be above 140 V and increased as a function of diode thickness. Reverse bias of 10 V is enough to fully deplete designed edgele...

Two color laser diagnostics using THz laser sources are under development for a high performance operation of the Large Helical Device and for future fusion devices such as ITER. So far, we have achieved high power laser oscillation lines simultaneously oscillating at 57.2 μm (1.6 W) and 47.7 μm (0.8 W) by using a twin optically-pumped CH ₃OD laser. And, we confirmed the usefulness of this two color laser operation for two-color laser interferometry in a test stand. For the measurement of the Faraday rotation angle we have developed a photo-elastic modulator (PEM) operating around 50 μm, and performed bench tests of the polarimeter with dual PEMs and demonstrated the feasibility of the polarimeter. The achieved angular resolution is 0.01 degrees with a time resolution of 1 ms, which satisfies diagnostic requirements for q-profile measurements on ITER (0.05 deg. at 10 ms time resolution). In this symposium, recent hardware developments and simultaneous measurements of a ph...

Median point calculation (MPC) method for scintillator neutron detectors operating in photon-counting mode has been developed. The method was applied to a wavelength-shifting (WLS)-fibre-based neutron detector in order to improve its pixel size and spatial resolution. The original detector was modified for a demonstration experiment performed using the SENJU neutron diffraction instrument at J-PARC (Japan Proton Accelerator Research Complex). The detector head comprised 64 × 2 WLS fibres arranged in the x and y directions at a pitch of 4 mm. The WLS fibres were sandwiched between two ZnS/ ¹⁰B ₂O ₃ scintillator screens. The developed MPC method used the number of photons detected by each WLS fibre as a weight when calculating the positions of neutrons. The test detector implemented with the MPC method demonstrated that the effective pixel size and the spatial resolution were improved to 2 mm, corresponding to half the pitch of the W...

A 16-channel Time-to-Digital Converter (TDC) was implemented in a general purpose Field-Programmable Gate Array (FPGA). The fine time calculations are achieved by using the dedicated carry-chain lines. The coarse counter defines the coarse time stamp. In order to overcome the negative effects of temperature and power supply dependency bin-by-bin calibration is applied. The time interval measurements are done using 2 channels. The time resolution of channels are calculated for 1 clock cycle and a minimum of 10.3 ps RMS on two channels, yielding 7.3 ps RMS (10.3 ps/√2) on a single channel is achieved.

As silicon detectors in high energy physics experiments require increasingly complex assembly procedures, the availability of a wide variety of interconnect technologies provides more options for overcoming obstacles in generic R&D. Gold ball bonding has been a staple in the interconnect industry due to its ease of use and reliability. However, due to some limitations in the standard technique, alternate methods of gold-stud bonding are being developed. This paper presents recent progress and challenges faced in the development of double gold-stud bonding and 0.5 mil wire gold-stud bonding at the UC Davis Facility for Interconnect Technology. Advantages and limitations of each technique are analyzed to provide insight into potential applications for each method. Optimization of procedures and parameters is also presented.

Upgrade plans for the ATLAS hadronic tile calorimeter (TileCal) at the LHC include full granularity readout to the 1 ^st level trigger. R&D activities at different laboratories target different parts of the upgraded system. We are developing a possible implementation of the future readout electronics to be included in a full functional demonstrator. This must be capable of adapting to each of the three different front-end alternatives being considered. Prototypes of the two PCBs that will be in charge of digitization, control and communication have been developed. The design is redundant and uses FPGAs with fault tolerant firmware for control and protocol conversion. Communication and clock synchronization between on and offdetector electronics is implemented via high speed optical links using the GBT protocol.

In the deep n-well (DNW) monolithic active pixel sensor (MAPS) a full in-pixel signal processing chain is integrated by exploiting the triple well option of a deep submicron CMOS process. This work is concerned with the design and characterization of DNW MAPS fabricated in a vertical integration (3D) CMOS technology. 3D processes can be very effective in overcoming typical limitations of monolithic active pixel sensors. This paper discusses the main features of a new analog processor for DNW MAPS (ApselVI) in view of applications to the SVT Layer0 of the SuperB Factory. It also presents the first experimental results from the test of a DNW MAPS prototype in the GlobalFoundries 130 nm CMOS technology.

Cooled antiproton beams of unprecedented intensities in the momentum range of 1.5-15 GeV/c will be used for the PANDA experiment at FAIR to perform high precision experiments in the charmed quark sector. The PANDA detector will investigate antiproton annihilations with beams in the momentum range of 1.5 GeV/c to 15 GeV/c on a fixed target. An almost 4π acceptance double spectrometer is divided in a forward spectrometer and a target spectrometer. The charged particle identification in the latter is performed by ring imaging Cherenkov counters employing the DIRC principle.

In this study, an experimental method based on theory is used to develop photoconductor that can replace the a-Se currently used as X-ray conversion layer in digital mammography. This is necessary because a-Se produced by the commercial fabrication method, of physical vapor deposition, has exhibited several problems when applied to digital mammography: instability due to crystallization and defect expansion due to high operating voltages, which is called the aging effect. Therefore, our work focused on developing a method of fabricating X-ray conversion films that do not suffer from crystallization and X-ray damage and optimizing the factors affecting the properties of the candidate photoconductors in order to acquire sufficient electrical signals to detect minute calcifications. The photoconductors were initially selected after the requirements for X-ray conversion materials, such as high atomic absorption, density, band-gap energy, work function, and resistivity, were examined. W...

This paper presents the design and implementation of a system for remote reconfiguration and reprogramming of the FPGAs in the off-detector electronics of the Electromagnetic Calorimeter (ECAL) of the CMS detector.

The main benefits of this system are: the reduced time needed to reprogram the FPGAs firmware; the increased mechanical safety avoiding hardware manipulations when the update is performed; and the possibility of performing the firmware update in several boards in parallel.

The access to the ECAL off-detector boards makes use of the Module Test and Maintenance (MTM) bus existing on the VME64X crates. The JTAG Distribution Board (JDB) board is the central unit of this system. The functionality and implementation of the system, as well as the corresponding software tools, are described in this paper.