arXiv subjects

J. M. Heuser

Publications and source records attributed to J. M. Heuser.

11 recordsLinked to original sources

arXiv2025

Minimal material, maximum coverage: Silicon Tracking System for high-occupancy conditions

Silicon strip sensors have long been a reliable technology for particle detection. Here, we push the limits of silicon tracking detectors by targeting an unprecedentedly low material budget of 2%-7% $X_0$ in an 8-layer 4 m$^2$ detector designed for high-occupancy environments ($\leq$ 10 MHz/cm$^2$). To achieve this, we employ Double-Sided Double Metal (DSDM) silicon microstrip sensors, coupled with readout electronics capable of precise timing and energy measurements. These 320 $\mu$m thick sensors, featuring $2\times 1024$ channels with a 58 $\mu$m pitch, are connected via ultra-lightweight aluminium-polyimide microcables for signal transmission and integrated with a custom SMX readout ASIC, operating in free-streaming mode. This system enables the simultaneous measurement of time ($\Delta t \simeq 5$~ns) and charge deposition (0.1-100 fC), significantly enhancing the detector's capacity for high-precision track reconstruction in high-occupancy and harsh radiation field environments. The primary application of this technology is the Silicon Tracking System (STS) for the CBM experiment, with additional potential in projects like the J-PARC E16 experiment and future uses in medical physics, such as advanced imaging telescopes. In this contribution, we present the current status of CBM STS construction, with almost one-third of the modules produced and tested. We also discuss immediate applications and explore promising prospects in both scientific and medical fields.

physics.ins-det↗

arXiv2023

From 3D to 5D tracking: SMX ASIC-based Double-Sided Micro-Strip detectors for comprehensive space, time, and energy measurements

We present the recent development of a lightweight detector capable of accurate spatial, timing, and amplitude resolution of charged particles. The technology is based on double-sided double-metal p+\,--\,n\,--\,n+ micro-strip silicon sensors, ultra-light long aluminum-polyimide micro-cables for the analogue signal transfer, and a custom-developed SMX read-out ASIC capable of measurement of the time ($Δt \lesssim 5 \,\mathrm{ns}$) and amplitude. Dense detector integration enables a material budget $>0.3\,\% X_0$. A sophisticated powering and grounding scheme keeps the noise under control. In addition to its primary application in Silicon Tracking System of the future CBM experiment in Darmstadt, our detector will be utilized in other research applications.

physics.ins-det↗

arXiv2021

Optical Inspection of the Silicon Micro-strip Sensors for the CBM Experiment employing Artificial Intelligence

Optical inspection of 1191 silicon micro-strip sensors was performed using a custom made optical inspection setup, employing a machine-learning based approach for the defect analysis and subsequent quality assurance. Furthermore, metrological control of the sensor's surface was performed. In this manuscript, we present the analysis of various sensor surface defects. Among these are implant breaks, p-stop breaks, aluminium strip opens, aluminium strip shorts, surface scratches, double metallization layer defects, passivation layer defects, bias resistor defects as well as dust particle identification. The defect detection was done using the application of Convolutional Deep Neural Networks (CDNNs). From this, defective strips and defect clusters were identified, as well as a 2D map of the defects using their geometrical positions on the sensor was performed. Based on the total number of defects found on the sensor's surface, a method for the estimation of sensor's overall quality grade and quality score was proposed.

physics.ins-det↗

arXiv2020

Nuclear dependence of light neutral meson production in p-A collisions at 400 GeV with NA60

The NA60 experiment has studied low-mass muon pair production in proton-nucleus collisions with a system of Be, Cu, In, W, Pb and U targets, using a 400 GeV proton beam at the CERN SPS. The transverse momentum spectra of the $ρ/ω$ and $ϕ$ mesons are measured in the full $p_\mathrm{T}$ range accessible, from $p_\mathrm{T} = 0$ up to 2 GeV/$c$. The nuclear dependence of the production cross sections of the $η$, $ω$ and $ϕ$ mesons has been found to be consistent with the power law $σ_\mathrm{pA} \propto \mathrm{A}^α$, with the $α$ parameter increasing as a function of $p_\mathrm{T}$ for all the particles, and an approximate hierarchy $α_η\approx α_ϕ> α_ω$. The cross section ratios $σ_η/σ_ω$, $σ_ρ/σ_ω$ and $σ_ϕ/σ_ω$ have been studied as a function of the size A of the production target, and an increase of the $η$ and $ϕ$ yields relative to the $ω$ is observed from p-Be to p-U collisions.

hep-ex↗

arXiv2012

Optimization of various isolation techniques to develop low noise, radiation hard double-sided silicon strip detectors for the CBM Silicon Tracking System

This paper reports on the design optimization done for Double Sided silicon microStrip Detectors(DSSDs) to reduce the Equivalent Noise Charge (ENC) and to maximize the breakdown voltage and Charge Collection Efficiency. Various isolation techniques have been explored and a detailed comparison has been studied to optimize the detector performance. For the evaluation of the performance of the silicon detectors, a radiation damage model has been included. The neutron fluence is expected to be 2x10^{13}n_{eq} cm$^{-2}$ per year for five years of expected CBM run with intermediate periods of warm maintenance, cold maintenance and shutdown. Transient simulations have been performed to estimate the charge collection performance of the irradiated detectors and simulations have been verified with experimental data.

physics.ins-det↗

arXiv2011

J/psi production in proton-nucleus collisions at 158 and 400 GeV

The NA60 experiment has studied J/psi production in p-A collisions at 158 and 400 GeV, at the CERN SPS. Nuclear effects on the J/psi yield have been estimated from the A-dependence of the production cross section ratios sigma_{J/psi}^{A}/sigma_{J/psi}^{Be} (A=Al, Cu, In, W, Pb, U). We observe a significant nuclear suppression of the J/psi yield per nucleon-nucleon collision, with a larger effect at lower incident energy, and we compare this result with previous observations by other fixed-target experiments. An attempt to disentangle the different contributions to the observed suppression has been carried out by studying the dependence of nuclear effects on x_2, the fraction of nucleon momentum carried by the interacting parton in the target nucleus.

nucl-ex↗

arXiv2011

A comparative measurement of $ϕ\rightarrow K^+K^-$ and $ϕ\rightarrow μ^+μ^-$ in In-In collisions at the CERN SPS

The NA60 experiment at the CERN SPS has studied $ϕ$ meson production in In-In collisions at 158A GeV via both the $K^+K^-$ and the $μ^+μ^-$ decay channels. The yields and inverse slope parameters of the $m_T$ spectra observed in the two channels are compatible within errors, different from the large discrepancies seen in Pb-Pb collisions between the hadronic (NA49) and dimuon (NA50) decay channels. Possible physics implications are discussed.

nucl-ex↗

arXiv2008

First results on angular distributions of thermal dileptons in nuclear collisions

The NA60 experiment at the CERN SPS has studied dimuon production in 158A GeV In-In collisions. The strong excess of pairs above the known sources found in the complete mass region 0.2<M<2.6 GeV has previously been interpreted as thermal radiation. We now present first results on the associated angular distributions. Using the Collins-Soper reference frame, the structure function parameters λ, μand νare measured to be zero, and the projected distributions in polar and azimuth angles are found to be uniform. The absence of any polarization is consistent with the interpretation of the excess dimuons as thermal radiation from a randomized system.

nucl-ex↗

arXiv2008

Evidence for the production of thermal muon pairs with masses above 1 GeV/c^2 in 158A GeV Indium-Indium Collisions

The yield of muon pairs in the invariant mass region 1<M<2.5 GeV/c^2 produced in heavy-ion collisions significantly exceeds the sum of the two expected contributions, Drell-Yan dimuons and muon pairs from the decays of D meson pairs. These sources properly account for the dimuons produced in proton-nucleus collisions. In this paper, we show that dimuons are also produced in excess in 158 A GeV In-In collisions. We furthermore observe, by tagging the dimuon vertices, that this excess is not due to enhanced D meson production, but made of prompt muon pairs, as expected from a source of thermal dimuons specific to high-energy nucleus-nucleus collisions. The yield of this excess increases significantly from peripheral to central collisions, both with respect to the Drell-Yan yield and to the number of nucleons participating in the collisions. Furthermore, the transverse mass distributions of the excess dimuons are well described by an exponential function, with inverse slope values around 190 MeV. The values are independent of mass and significantly lower than those found at masses below 1 GeV/c^2, rising there up to 250 MeV due to radial flow. This suggests the emission source of thermal dimuons above 1 GeV/c^2 to be of largely partonic origin, when radial flow has not yet built up.

nucl-ex↗

arXiv2008

NA60 results on thermal dimuons

The NA60 experiment at the CERN SPS has measured muon pairs with unprecedented precision in 158A GeV In-In collisions. A strong excess of pairs above the known sources is observed in the whole mass region 0.2 rho -> mu+mu- annihilation. The associated rho spectral function shows a strong broadening, but essentially no shift in mass. For M>1 GeV, the excess is found to be prompt, not due to enhanced charm production, with pronounced differences to Drell-Yan pairs. The slope parameter Teff associated with the transverse momentum spectra rises with mass up to the rho, followed by a sudden decline above. The rise for M<1 GeV is consistent with radial flow of a hadronic emission source. The seeming absence of significant flow for M>1 GeV and its relation to parton-hadron duality is discussed in detail, suggesting a dominantly partonic emission source in this region. A comparison of the data to the present status of theoretical modeling is also contained. The accumulated empirical evidence, including also a Planck-like shape of the mass spectra at low pT and the lack of polarization, is consistent with a global interpretation of the excess dimuons as thermal radiation. We conclude with first results on omega in-medium effects.

nucl-ex↗

arXiv2007

Highlights from the NA60 experiment

The NA60 experiment is a fixed-target experiment at the CERN SPS. It has measured the dimuon yield in Indium--Indium collisions with an In beam of 158 AGeV/c and in p-A collisions with a proton beam of 400 and 158 AGeV/c. The results allow to address three important physics topics, namely the study of the rho spectral function in nuclear collisions, the clarification of the origin of the dimuon excess measured by NA50 in the intermediate mass range, and the J/psi suppression pattern in a collision system different from Pb-Pb. An overview of these results will be given in this paper.

nucl-ex↗