Abstract A monolithic pixel sensor test chip for the PANDA micro-vertex detector has been implemented in a 180 nm HVCMOS technology on a high resistivity substrate. The sensor should have very high time resolution (1 ns sigma) and high dynamic range (up to 1000). The pixel electronics contains a charge sensitive amplifier, a feedback circuit and two comparators. One comparator receives the fast signal and enables accurate time measurement. The other comparator receives the low pass filtered signal and is used for precise amplitude measurement. This publication presents several novel features of the PANDA ASIC, its characterization and several measurement results.
A HV/HR CMOS detector prototype called LF-CPIX, has been designed in LFoundry 150nm technology. The front-end electronics has been implemented using both NMOS and PMOS transistors, inside the charge collection diode, with a pitch of 250 μm × 50 μm. This demonstrator is an implementation of a matrix of smart pixels where the diode is composed by a Deep Nwell, and P-type substrate is used as a depleted sensor. Three types of pixels have been developed: passive pixels, analog-digital pixels, analog pixels. The analog pixels can be connected to the FE-I4 IC, which is the present readout IC of the innermost ATLAS pixel layers. The different versions of the LF-CPIX demonstrators are described, characterization of the different pre-amplifiers flavors with external injection signal and 55 Fe source are presented for the digital pixels. Finally radiation hardness results are discussed.
The degree of circular polarization of soft X-rays emitted from the multi-polarization-mode undulator of BL17SU at SPring-8 has been deduced by means of magnetic circular dichroism in core-level X-ray absorption spectroscopy for a ferrimagnetic Gd-Fe-Co amorphous thin film. The results of reference measurements performed using well characterized undulator radiation of BL25SU at SPring-8 have also been utilized. The degrees of circular polarization were presumed for all the available operational modes and were compared with simple theoretical calculations. It was found that the calculated degrees of circular polarization were validated by the measurements reasonably well and will be useful in further experiments at BL17SU.
Depleted Monolithic Active Pixel Sensor (DMAPS) prototypes developed in the TowerJazz 180 nm CMOS imaging process have been designed in the context of the ATLAS upgrade Phase-II at the HL-LHC. The pixel sensors are characterized by a small collection electrode (3 $\mu$m) to minimize capacitance, a small pixel size ($36.4\times 36.4$ $\mu$m), and are produced on high resistivity epitaxial p-type silicon. The design targets a radiation hardness of $1\times10^{15}$ 1 MeV n$_{eq}$/cm$^{2}$, compatible with the outermost layer of the ATLAS ITK Pixel detector. This paper presents the results from characterization in particle beam tests of the Mini-MALTA prototype that implements a mask change or an additional implant to address the inefficiencies on the pixel edges. Results show full efficiency after a dose of $1\times10^{15}$ 1 MeV n$_{eq}$/cm$^{2}$.
Monolithic CMOS pixel detectors have emerged as competitive contenders in the field of high-energy particle physics detectors. By utilizing commercial processes they offer high-volume production of such detectors. A series of prototypes has been designed in a 180$\,$nm Tower process with depletion of the sensor material and a column-drain readout architecture. The latest iteration, TJ-Monopix2, features a large 2$\,$cm x 2$\,$cm matrix consisting of 512 x 512 pixels with 33.04$\,$um pitch. A small collection electrode design aims at low power consumption and low noise while the radiation tolerance for high-energy particle detector applications needs extra attention. With a goal to reach radiation tolerance to levels of $10^{15}\,1\,$MeV n$_\text{eq}\,$cm$^{-2}$ of NIEL damage a modification of the standard process has been implemented by adding a low-dosed n-type silicon implant across the pixel in order to allow for homogeneous depletion of the sensor volume. Recent lab measurements and beam tests were conducted for unirradiated modules to study electrical characteristics and hit detection efficiency.
