arXiv subjects

Federico Golmar

Publications and source records attributed to Federico Golmar.

10 recordsLinked to original sources

arXiv2026

FPGA-based TDC for SiPM Timing and Amplitude Measurements

Silicon photomultipliers (SiPMs) are widely used in photon-counting applications, such as positron emission tomography or particle physics, where precise timestamps and photoelectron number information are both required. In this work, a Time-to-Digital Converter with amplitude measurement capabilities was designed using an Artix-7 XC7A35T FPGA. For amplitude measurements, the internal xADC of the FPGA was chosen over other alternatives for simplicity. This design has two channels and can operate in timestamp-only mode or timestamp + amplitude mode. In turn, channels can be operated independently or in coincidence. The Integral Non-Linearity and Differential Non-Linearity of the design were studied, along with its time resolution, which is $(19 \pm 1)$ ps. Using a CAEN DT5810 pulse emulator, the design was tested further in timing-only mode, timing + amplitude mode and in coincidence mode to showcase its performance when using Poisson distributed SiPM-like pulses of various amplitudes.

physics.ins-det↗

arXiv2026

Front End Amplifiers for Simultaneous Dual Readout of SiPM Sensors

In this work, we present two fully open Analog Front End (AFE) designs for the simultaneous readout of the standard and fast outputs of ONSemi MicroFC-10035 Silicon Photomultipliers and report their main figure-of-merit parameters. The standard output AFE has a 1 p.e. amplitude of $(394 \pm 1)$ mV, which results in a Signal-to-Noise ratio of 30 dB. In addition, the fast AFE has a rise time of $(1.3\pm 0.1)$ ns and a median electronic jitter of $34^{+7}_{-5}$ ps, resulting in an excellent timing performance. Using these amplifiers for simultaneous dual readout, we demonstrate a proof-of-concept application, in which fast output timing information is used to suppress correlated noise events or pileup events present in the standard output charge measurements. This suppression results in a reduction of non-prompt correlated noise (delayed crosstalks and afterpulses) in dark conditions and an increase up to $\sim$14 in single photon discrimination under a continuous incident photon rate of 7.8 MHz/mm$^2$. These results show that dual SiPM readout provides a practical way to remove correlated noise or pileup contamination in standard output charge measurements on an event-by-event basis.

physics.ins-det↗

arXiv2025

Total Ionizing Dose Measurements in Small Satellites in LEO using LabOSat-01

LabOSat-01 is a payload designed to perform characterization experiments on electronic devices in hostile environments. Both Commercial-Off-The-Shelf components and custom nano and micro devices were studied in the last decade with this platform. The Total Ionizing Dose (TID) received by small satellites in Low Earth Orbit was measured with LabOSat-01 using p-MOSFET COTS and the results are presented in this work. Measurements were performed on two satellite missions, each totalling 1100 days, launched three years apart. Dosimeters were integrated in different satellite positions, with different shielding, and the measured TID after 1100 days ranged from 5 Gy to 19 Gy.

physics.space-ph↗

arXiv2025

Design and characterization of a fast output amplifier for Silicon Photomultipliers

A voltage amplifier, based on the BFU500XRR NPN transistor in a common-emitter configuration, was developed for the readout of the fast output of an ONSEMI MicroFC-10035 Silicon Photomultiplier (SiPM). This amplifier was tested and characterized under dark and illuminated SiPM conditions. For the design presented in this work, a Gain of $(20.0 \pm 0.7)$ dB and a rise time of $(768 \pm 10)$ ps were achieved for one amplifier stage and a Gain of $(38.3 \pm 0.7)$ dB and rise time of $(1155 \pm 16)$ ps was achieved for two cascaded stages. In addition, the linearity of both topologies was verified and the measured Signal-to-Noise Ratio (SNR) was ($21.9 \pm 0.4$) dB and ($18.8 \pm 0.5$) dB for the one-stage and two-stage amplifiers, respectively. This design provides a cheap and scalable (weight and size) alternative to other fast output amplifiers that are used when operating SiPMs fast outputs. These characteristics make this design ideal for space applications.

physics.ins-det↗

arXiv2025

Characterization of the SiPiC Payload for Photon Detection from Space

In this work, the SiPiC (SiPM Pinhole Camera) Payload is detailed. This Payload will potentially be integrated in two distinct satellite missions, which will operate in Low Earth Orbit (LEO) and in a High Altitude Orbit (HAO), respectively. The SiPiC Payload has two main objectives: to test Silicon Photomultipliers (SiPMs) as visible light sensors for stimuli originating from Earth; and to perform an in-orbit validation (IOV) of the new generation of PC104-compliant LabOSat subsystems. Preliminary measurements of the Payload's operational capabilities are performed and discussed. These include payload telemetry analysis, Field-of-View tests for the Earth imaging SiPM subsystem, and performance evaluations of the new LabOSat modules for known devices under test. The measured Angular Field of View (AFOV) for the light gathering SiPM subsystem is $(6.2 \pm 0.5)^{\mathrm{o}}$, which results in a FOV of $(4333 \pm 350)$ km on the surface of the Earth at 40000 km altitude and $(54 \pm 5)$ km at 500 km altitude.

physics.ins-det↗

arXiv2024

Characterization of SiPM Performance in a Small Satellite in Low Earth Orbit using LabOSat-01

In this work, the performance of SensL MicroFC-60035 SiPM devices was studied during a 1460-day mission in Low Earth Orbit (LEO) using the LabOSat-01 characterization payload. Two of these platforms, carrying two SiPMs each, were integrated into the ÑuSat-7 satellite (COSPAR-ID: 2020-003B). Analysis revealed that these SiPMs experienced an increase in dark current over time due to damage from trapped and solar proton radiation. The total ionizing dose received by the payload and the SiPMs was measured using p-MOSFET dosimeters, with a resulting value of 5 Gy, or a 1 MeV neutron equivalent fluence of $ϕ_n = 5 \cdot 10^9$ n/cm$^2$. The dark current was observed to increase up to 500 times. Parameters such as Gain and Photon Detection Efficiency remained unchanged throughout the mission. These findings align with previous performance reports involving different SiPMs irradiated with various particles and energies.

physics.ins-det↗

arXiv2024

Silicon Photomultipliers for Detection of Photon Bunching Signatures

In this work, photon bunching from LED light was observed for the first time using SiPMs. The bunching signature was observed with a significance of $7.3~σ$ using 97~hs of data. The light was spectrally filtered using a 1~nm bandpass filter and an Etalon filter to ensure temporal coherence of the field and its coherence time was measured to be $τ_C = (19 \pm 2)$~ps. The impact of SiPM non-idealities in these kinds of measurements is explored, and we describe the methodology to process SiPM analog waveforms and the event selection used to mitigate these non-idealities.

physics.ins-det↗

arXiv2020

COTS MOS Dosimetry on the MeMOSat Board, Results After 2.5 Years in Orbit

We present the results after 2.5 years in or-bit of Total Ionizing Dose (TID) measurements done using Metal Oxide Semiconductor (MOS) dosimeters on the MeMOSat board. The MeMOSat board was launched on July 19th 2014 at the BugSat-1 "Tita" microsatellite developed by Satellogic to stay at LEO. We used as dosimeters p-channel Commercial Off The Shelf (COTS) MOS transistors with gate oxides of 250~nm. Before launch, a subset of transistors with similar drain current to voltage (I-V)curves where selected from a group of 100 devices. The temperature dependence of the (I-V) curves was studied to find the minimum temperature coefficient biasing point. Then, a calibration subgroup of sensors was irradiated using a $^{60}$Co gamma source to study their response to TID, showing responsivities of $\sim$75~mV/krad when the sensors are irradiated without gate bias. Also, the post irradiation response of the sensors was monitored, in order to include a correction for low dose rate irradiations, yielding 30~mV/krad. A biasing and reading circuit was developed in order to allow the reading of up to 4 sensors.The threshold voltage was monitored during different periods of the mission. After 2.5 years in orbit,the threshold voltage of the sensor mounted on the MeMOSat Board had a V$_\mathrm{T}$ shift of approximately 35~mV corresponds to a dose of 1.2~krads.

physics.ins-det↗

arXiv2014

Spin Hall magnetoresistance at Pt/CoFe2O4 interfaces and texture effects

We report magnetoresistance measurements on thin Pt bars grown on epitaxial (001) and (111) CoFe2O4 (CFO) ferrimagnetic insulating films. The results can be described in terms of the recently discovered spin Hall magnetoresistance (SMR). The magnitude of the SMR depends on the interface preparation conditions, being optimal when Pt/CFO samples are prepared in situ, in a single process. The spin-mixing interface conductance, the key parameter governing SMR and other relevant spin-dependent phenomena such as spin pumping or spin Seebeck effect, is found to be different depending on the crystallographic orientation of CFO, highlighting the role of the composition and density of magnetic ions at the interface on spin mixing.

cond-mat.mes-hall↗

arXiv2012

How reliable are Hanle measurements in metals in a three-terminal geometry?

We test the validity of Hanle measurements in three-terminal devices by using aluminum (Al) and gold (Au). The obtained Hanle and inverted Hanle-like curves show an anomalous behavior. First, we measure Hanle signals 8 orders of magnitude larger than those predicted by standard theory. Second, the temperature and voltage dependences of the signal do not match with the tunneling spin polarization of the ferromagnetic contact. Finally, the spin relaxation times obtained with this method are independent of the choice of the metallic channel. These results are not compatible with spin accumulation in the metal. Furthermore, a scaling of the Hanle signal with the interface resistance of the devices suggests that the measured signal is originated in the tunnel junction.

cond-mat.mes-hall↗