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Nanda, S.

Publications and source records attributed to Nanda, S..

9 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Performance of Pixel and Strip AC-LGAD Sensors with Different Design Parameter on a 120 GeV Proton Beam

We present the results of an extensive evaluation of strip and pixel AC-LGAD sensors tested with a 120 GeV proton beam, focusing on the influence of design parameters on the sensor temporal and spatial resolutions. Results show that reducing the thickness of pixel sensors significantly enhances their time resolution, with 20- ΞΌm-thick sensors achieving around 20 ps. Uniform performance is attainable with optimized sheet resistance, making these sensors ideal for future timing detectors. Conversely, 20-ΞΌm-thick strip sensors exhibit higher jitter than similar pixel sensors, negatively impacting time resolution, despite reduced Landau fluctuations with respect to the 50-ΞΌm-thick versions. Additionally, it is observed that a low resistivity in strip sensors limits signal size and time resolution, whereas higher resistivity improves performance. This study highlights the importance of tuning the n+ sheet resistance and suggests that further improvements should target specific applications like the Electron-Ion Collider or other future collider experiments. In addition, the detailed performance of four AC-LGADs sensor designs is reported as examples of possible candidates for specific detector applications. These advancements position AC-LGADs as promising candidates for future 4D tracking systems, pending the development of specialized readout electronics.

Lara, Carlos Pérez↗
DOE OSTI2023

First Measurement of the EMC effect in 10 B and 11 B

The nuclear dependence of the inclusive inelastic electron scattering cross section (the EMC effect) has been measured for the first time in 10 B and 11 B. Previous measurements of the EMC effect in A ≀ 12 nuclei showed an unexpected nuclear dependence; 10 B and 11 B were measured to explore the EMC effect in this region in more detail. Results are presented for 9 Be, 10 B, 11 B, and 12 C at an incident beam energy of 10.6 GeV. The EMC effect in the boron isotopes was found to be similar to that for 9 Be and 12 C, yielding almost no nuclear dependence in the EMC effect in the range A = 4–12. Furthermore, this represents important new data supporting the hypothesis that the EMC effect depends primarily on the local nuclear environment due to the cluster structure of these nuclei.

6 ≀ A ≀ 19β†—
DOE OSTI2023

Constraints on the onset of color transparency from quasielastic 12 C ⁑(𝑒,𝑒′⁒𝑝) up to 𝑄 2 = 14.2 (GeV/𝑐) 2

Quasielastic scattering on 12 C ⁑(𝑒,𝑒′⁒𝑝) was measured in Hall C at Jefferson Lab for spacelike four-momentum transfer squared 𝑄 2 in the range of 8–14.2(GeV/𝑐) 2 with proton momenta up to 8.3GeV/𝑐. The experiment was carried out in the upgraded Hall C at Jefferson Lab. It used the existing high-momentum spectrometer and the new super-high-momentum spectrometer to detect the scattered electrons and protons in coincidence. The nuclear transparency was extracted as the ratio of the measured yield to the yield calculated in the plane wave impulse approximation. Additionally, the transparency of the 1⁒𝑠 1/2 and 1⁒𝑝 3/2 shell protons in 12 C was extracted, and the asymmetry of the missing momentum distribution was examined for hints of the quantum chromodynamics prediction of color transparency. Furthermore, all of these results were found to be consistent with traditional nuclear physics and inconsistent with the onset of color transparency.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2023

First survey of centimeter-scale AC-LGAD strip sensors with a 120 GeV proton beam

We present the first beam test results with centimeter-scale AC-LGAD strip sensors, using the Fermilab Test Beam Facility and sensors manufactured by the Brookhaven National Laboratory. Sensors of this type are envisioned for applications that require large-area precision 4D tracking coverage with economical channel counts, including timing layers for the Electron Ion Collider (EIC), and space-based particle experiments. A survey of sensor designs is presented, with the aim of optimizing the electrode geometry for spatial resolution and timing performance. Several design considerations are discussed towards maintaining desirable signal characteristics with increasingly larger electrodes. The resolutions obtained with several prototypes are presented, reaching simultaneous 18 ΞΌm and 32 ps resolutions from strips of 1 cm length and 500 ΞΌm pitch. With only slight modifications, these sensors would be ideal candidates for a 4D timing layer at the EIC.

47 OTHER INSTRUMENTATION↗
DOE OSTI2021

Ruling out Color Transparency in Quasielastic 12 C(e,e'p) up to Q 2 of 14.2 (GeV/c) 2

Quasielastic $^{12}$C$(e,e'p)$ scattering was measured at space-like 4-momentum transfer squared $Q^2$ = 8, 9.4, 11.4, and 14.2 (GeV/c)$^2$, the highest ever achieved to date. Nuclear transparency for this reaction was extracted by comparing the measured yield to that expected from a plane-wave impulse approximation calculation without any final state interactions. Additionally, the measured transparency was consistent with no $Q^2$ dependence, up to proton momenta of 8.5 GeV/c, ruling out the quantum chromodynamics effect of color transparency at the measured $Q^2$ scales in exclusive $(e,e'p)$ reactions. Furthermore, these results impose strict constraints on models of color transparency for protons.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2020

Probing the Deuteron at Very Large Internal Momenta

We measure H-2(e, e' p)n cross sections at 4-momentum transfers of Q(2) = 4.5 +/- 0.5 (GeV/c)(2) over a range of neutron recoil momenta p(r), reaching up to similar to 1.0 GeV/c. We obtain data at fixed neutron recoil angles theta(nq) = 35 degrees, 45 degrees, and 75 degrees with respect to the 3-momentum transfer (q)over-right-arrow. The new data agree well with previous data, which reached p(r) similar to 500 MeV/c. At theta(nq) = 35 degrees and 45 degrees, final state interactions, meson exchange currents, and isobar currents are suppressed and the plane wave impulse approximation provides the dominant cross section contribution. We compare the new data to recent theoretical calculations, where we observe a significant discrepancy for recoil momenta P-r > 700 MeV/c.

Yero, C.β†—
DOE OSTI2020

Exclusive Ο€ 0 p electroproduction off protons in the resonance region at photon virtualities 0.4 GeV 2 ≀ Q 2 ≀ 1 GeV 2

The limited electroproduction process e p β†’ e ' p ' Ο€ 0 was measured in the range of photon virtualities Q 2 = 0.4 – 1.0 GeV 2 and the invariant mass range of the p Ο€ 0 system of W = 1.1 – 1.8 GeV. These kinematics are covered in exclusive Ο€ 0 electroproduction off the proton with nearly complete angular coverage in the p Ο€ 0 center-of-mass system and with high statistical accuracy. Nearly 36 000 cross-section points were measured, and the structure functions Οƒ T + Ξ΅ Οƒ L , Οƒ L T , and Οƒ T T , were extracted via fitting the Ο† Ο€ 0 dependence of the cross section. A Legendre polynomial expansion analysis demonstrates the sensitivity of our data to high-lying N * and Ξ” * resonances with M > 1.6 GeV. As part of a broad effort to determine the electrocouplings of the N * and Ξ” * resonances using both single- and double-pion electroproduction, this dataset is key for the reliable extraction of the high-lying resonance electrocouplings from the combined isospin analysis of the N Ο€ and Ο€ + Ο€ - p channels.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗