B16-Test Beamline
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E. R.
Almazan
,
A.
Affolder
,
I.
Dyckes
,
V.
Fadeyev
,
M.
Hance
,
M.
Jadhav
,
S.
Kim
,
Thomas
Mccoy
,
J.
Metcalfe
,
J.
Nielsen
,
J.
Ott
,
L.
Poley
,
T.(k.-W.)
Shin
,
D.
Sperlich
,
A.
Sumant
Diamond Proposal Number(s):
[32397]
Abstract: Future tracking systems in High Energy Physics experiments will require large instrumented areas with low radiation length. Crystalline silicon sensors have been used in tracking systems for decades, but are difficult to manufacture and costly to produce for large areas. We are exploring alternative sensor materials that are amenable to fast fabrication techniques used for thin film devices. Indium Phosphide pad sensors were fabricated at Argonne National Lab using commercially available InP:Fe 2-inch mono-crystal substrates. Current-voltage and capacitance-voltage characterizations were performed to study the basic operating characteristics of a group of sensors. Micro-focused X-ray beams at Canadian Light Source and Diamond Light Source were used to study the response to ionizing radiation, and characterize the uniformity of the response for several devices. Electrical test results showed a high degree of performance uniformity between the 48 tested devices. X-ray test beam results showed good performance uniformity within tested devices after accounting for spatially-local defects and edge fields. This motivates further studies into thin film devices for future tracking detectors.
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Nov 2024
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B16-Test Beamline
Detectors
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M. J.
Basso
,
E.
Buchanan
,
B. J.
Gallop
,
J. J.
John
,
J.
Kaplon
,
P. T.
Keener
,
P. W.
Phillips
,
L.
Poley
,
C. A.
Sawyer
,
D.
Sperlich
,
M.
Warren
Diamond Proposal Number(s):
[28368]
Open Access
Abstract: The front-end electronics of silicon detectors are typically designed to ensure optimal noise performance for the expected input charge. A combination of preamplifiers and shaper circuits result in a nontrivial response of the front-end to injected charge, and the magnitude of the response may be sizeable in readout windows subsequent to that in which the charge was initially injected. The modulation of the discriminator threshold due to the superposition of the front-end response across multiple readout windows is coined "threshold bounce". In this paper, we report a measurement of threshold bounce using silicon modules built for the Phase-II Upgrade of the ATLAS detector at the Large Hadron Collider. These modules utilize ATLAS Binary Chips for their hit readout. The measurement was performed using a micro-focused 15 keV photon beam at the Diamond Light Source synchrotron. The effect of the choice of photon flux and discriminator threshold on the magnitude of the threshold bounce is studied. A Monte Carlo simulation which accounts for the front-end behaviour of the silicon modules is developed, and its predicted hit efficiency is found to be in good agreement with the measured hit efficiency.
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Jun 2024
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B16-Test Beamline
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Diamond Proposal Number(s):
[13500, 15979, 11807, 22002]
Open Access
Abstract: The development of semiconductor sensors for new particle tracking detectors places increasing limits on sensor characteristics such as uniformity, size and shape of inefficient areas and size of active compared to inactive sensor areas. Accurately assessing these relatively subtle effects requires either measurements in particle beams or the modification of samples to be used in dedicated laser test setups.
Active Region Extent Assessment with X-rays (AREA-X) has been developed as an alternative method for the fast, efficient and precise study of the active area of a semiconductor sensor. It uses a monochromatic, micro-focused X-ray beam with a 10–20 keV energy range as provided by several synchrotron beam lines and uses the photo current induced in the sensor to measure the depth of the responsive sensor volume. It can be used to study local inhomogeneities or inefficiencies, the overall extent of the active sensor volume and its shape and its localised application, which makes the need to gather statistics over a large area unnecessary, allowing for fast readout, which enables studies of the sensor behaviour at a range of external parameters, e.g. temperature or applied bias voltage.
This paper presents the measurement concept and technical setup of the measurement, results from initial measurements as well as capabilities and limitations of the method.
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Nov 2022
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B16-Test Beamline
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A. J.
Blue
,
B.
Gallop
,
T.
Heim
,
C.
Helling
,
K.
Krizka
,
B.
Li
,
C.
Labitan
,
E.
Mladina
,
L.
Poley
,
P. W.
Phillips
,
S. N.
Santpur
,
C. A.
Sawyer
Diamond Proposal Number(s):
[22002]
Open Access
Abstract: Modules for the ATLAS Inner Tracker (ITk) strip tracker include a DC-DC converter circuit glued directly to the silicon sensor which converts the 11 V supplied to the module to the 1.5 V required for the operation of the readout chips. The DC-DC converter unit, consisting of a copper solenoid and custom ASIC, is located directly above the silicon strip sensor and therefore needs to be shielded to protect the sensor from EMI noise created during the operation of the circuit. Despite dedicated shielding, consisting of an aluminium shield box with continuous solder seams encompassing the surface components and a copper layer in the PCB beneath it, module channels connected to sensor strips located beneath the converter circuit were found to show a noise increase. While the DC-DC converter unit causing the underlying EMI noise operates at a frequency of 2 MHz, module characterisation measurements for ITk strip tracker modules are typically performed asynchronously to the DC-DC switching and are therefore averaged over the full range of time bins with respect to the converter frequency. In order to investigate the time dependence of the noise injection relative to the DC-DC switching frequency, a dedicated setup to understand the time-resolved performance change in modules was developed. By using a magnetic field probe to measure the field leaking through the shield box and triggering on its rising edge, data taking could be synchronised with the DC-DC switching. This paper illustrates the concept and setup of such time-resolved performance measurements using magnetic triggering and presents results for the observed effects on signal and noise for ATLAS ITk strip modules from both laboratory and beam tests.
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Jun 2021
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B16-Test Beamline
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S.
Santpur
,
A. J.
Blue
,
C.
Buttar
,
V.
Fadeyev
,
B.
Gallop
,
C.
Helling
,
C.
Labitan
,
P. W.
Phillips
,
L.
Poley
,
C.
Sawyer
,
M.
Ullán
,
Y.
Unno
Diamond Proposal Number(s):
[18807, 22002]
Abstract: Silicon strip sensors for the ATLAS Inner Tracker (ITk) have been designed to provide reliable particle detection in the high-radiation environment of the High-Luminosity Large Hadron Collider. One important design criterion for their development is the minimization of inactive sensor areas, which affect the hermiticity of particle detection inside the detector. In previous measurements of ATLAS silicon strip sensors, the charge-collecting area of individual strip implants has been mapped and found to agree with the sensor strip pitch and strip length. For strip implants next to the sensor bias ring, the extent of their charge-collecting area towards the inactive sensor area was previously unknown, which limited the accuracy of both overall detector hermiticity estimates and the position resolution for particle detection at the sensor edge. Therefore, measurements were conducted to map the area of charge collection for sensor strips at the edge of the active sensor area using a micro-focused X-ray beam. This publication presents measurements showing the extent of charge collection in the edge strips of silicon strip sensors for two generations of ATLAS ITk strip sensor modules. The measurements confirmed that charge deposited in a strip implant that is neither connected nor grounded leads to capacitive coupling to the adjacent strip, where it is indistinguishable from a hit in that strip.
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Sep 2020
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B16-Test Beamline
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L.
Poley
,
A. J.
Blue
,
C.
Buttar
,
V.
Cindro
,
C.
Darroch
,
V.
Fadeyev
,
J.
Fernandez-Tejero
,
C.
Fleta
,
C.
Helling
,
C.
Labitan
,
I.
Mandić
,
S. Ne.
Santpur
,
D.
Sperlich
,
M.
Ullán
,
Y.
Unno
Diamond Proposal Number(s):
[18807, 22002]
Abstract: A significant aspect of the Phase-II Upgrade of the ATLAS detector is the replacement of the current Inner Detector with the ATLAS Inner Tracker (ITk). The ATLAS ITk is an all-silicon detector consisting of a pixel tracker and a strip tracker. Sensors for the ITk strip tracker have been developed to withstand the high radiation environment in the ATLAS detector after the High Luminosity Upgrade of the Large Hadron Collider at CERN, which will significantly increase the rate of particle collisions and resulting particle tracks. During their operation in the ATLAS detector, sensors for the ITk strip tracker are expected to accumulate fluences up to 1.6
1015neq/cm2 (including a safety factor of 1.5), which will significantly affect their performance. One characteristic of interest for highly irradiated sensors is the shape and homogeneity of the electric field inside its active area. For the results presented here, diodes with edge structures similar to full size ATLAS sensors were irradiated up to fluences comparable to those in the ATLAS ITk strip tracker and their electric fields mapped using a micro-focused X-ray beam (beam diameter 2
3
m2). This study shows the extension and shape of the electric field inside highly irradiated diodes over a range of applied bias voltages. Additionally, measurements of the outline of the depleted sensor areas allow a comparison of the measured leakage current for different fluences with expectations for the corresponding active areas.
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Aug 2020
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B16-Test Beamline
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L.
Poley
,
A.
Blue
,
I.
Bloch
,
C.
Buttar
,
V.
Fadeyev
,
J.
Fernandez-Tejero
,
C.
Fleta
,
J.
Hacker
,
C. Lacasta
Llacer
,
M.
Miñano
,
M.
Renzmann
,
E.
Rossi
,
C.
Sawyer
,
D.
Sperlich
,
M.
Stegler
,
M.
Ullán
,
Y.
Unno
Diamond Proposal Number(s):
[18807]
Abstract: For the Phase-II Upgrade of the ATLAS detector at CERN, the current ATLAS Inner Detector will be replaced with the ATLAS Inner Tracker (ITk). The ITk will be an all-silicon detector, consisting of a pixel tracker and a strip tracker. Sensors for the ITk strip tracker are required to have a low leakage current up to bias voltages of −500 V to maintain a low noise and power dissipation. In order to minimise sensor leakage currents, particularly in the high-radiation environment inside the ATLAS detector, sensors are foreseen to be operated at low temperatures and to be manufactured from wafers with a high bulk resistivity of several kΩcm. Simulations showed the electric field inside sensors with high bulk resistivity to extend towards the sensor edge, which could lead to increased surface currents for narrow dicing edges. In order to map the electric field inside biased silicon sensors with high bulk resistivity, three diodes from ATLAS silicon strip sensor prototype wafers were studied with a monochromatic, micro-focused X-ray beam at the Diamond Light Source (Didcot, U.K.). For all devices under investigation, the electric field inside the diode was mapped and its dependence on the applied bias voltage was studied.
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Mar 2019
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B16-Test Beamline
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Diamond Proposal Number(s):
[15979]
Abstract: For the High-Luminosity Upgrade of the Large Hadron Collider at CERN, the ATLAS Inner Detector will be replaced with a new, all-silicon tracker (ITk). In order to minimise the amount of material in the ITk, circuit boards with readout electronics will be glued onto the active area of the sensor. Several adhesives, investigated to be used for the construction of detector modules, were found to become fluorescent when exposed to UV light. These adhesives could become a light source in the high-radiation environment of the ATLAS detector. The effect of fluorescent material covering the sensor surface in a high-radiation environment has been studied for a silicon micro-strip sensor using a micro-focused X-ray beam. By positioning the beam parallel to the sensor surface and pointing it both inside the sensor and above the sensor surface inside the deposited glue, the sensor responses from direct hits and fluorescence can be compared with high precision. This contribution presents a setup to study the susceptibility of silicon strip sensors to light contamination from fluorescent materials and shows their impact on the noise and fake signal rate of a sensor operated in a high-radiation environment.
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Jul 2018
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B16-Test Beamline
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Diamond Proposal Number(s):
[15979]
Abstract: For the Phase-II Upgrade of the ATLAS detector The ATLAS Collaboration (2008) [1], a new, all-silicon tracker will be constructed in order to cope with the increased track density and radiation level of the High-Luminosity Large Hadron Collider. While silicon strip sensors are designed to minimise the fraction of dead material and maximise the active area of a sensor, concessions must be made to the requirements of operating a sensor in a particle physics detector. Sensor geometry features like the punch-through protection deviate from the standard sensor architecture and thereby affect the charge collection in that area. In order to study the signal collection of n
+
-p
−
-p
+
silicon strip sensors over their punch-through-protection area, ATLAS silicon strip sensors were scanned with a micro-focused X-ray beam at the Diamond Light Source. Due to the highly focused X-ray beam (
2×3μm2
) and the short average path length of an electron after interaction with an X-ray photon (
≤2μm
), local signal collection in different sensor areas can be studied with high resolution. This study presents results of high resolution 2D-scans of the punch-through protection region of ATLAS silicon micro-strip sensors, showing how far the strip signal collection area extends toward the bias ring and how the region is affected by radiation damage.
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Jul 2018
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B16-Test Beamline
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L.
Rehnisch
,
I.
Bloch
,
A.
Blue
,
Craig
Buttar
,
J.
Fernández-Tejero
,
C.
Fleta
,
Bruce
Gallop
,
T.
Lohse
,
K.
Lohwasser
,
P. W.
Phillips
,
L.
Poley
,
C.
Sawyer
,
M.
Stegler
,
M.
Ullán
Diamond Proposal Number(s):
[15979]
Abstract: Embedded pitch adapters are an alternative solution to external pitch adapters widely used to facilitate the wire-bonding step when connecting silicon strip sensors and readout electronics of different pitch. The pad-pitch adaption can be moved into the sensor fabrication step by implementing a second layer of metal tracks, connected by vias to the primary metal layer of sensor strips. Such a solution, however, might bear the risk of performance losses introduced by various phenomena. One of these effects, the undesired capacitive coupling between the silicon bulk and this second metal layer (pick-up) has been investigated in photon testbeam measurements. For a worst-case embedded pitch adapter design, expected to be maximally susceptible to pick-up, a qualitative analysis has visualized the effect as a function of the location on the second metal layer structure. It was further found that the unwanted effect decreases towards expected values for operating thresholds of the binary readout used. Suggestions for more in-depth and quantitative studies are also derived.
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Jun 2018
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