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 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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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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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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B16-Test Beamline
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L.
Poley
,
K.
Lohwasser
,
A.
Blue
,
M.
Benoit
,
I.
Bloch
,
S.
Díez
,
V.
Fadeyev
,
B.
Gallop
,
A.
Greenall
,
I.-M.
Gregor
,
J.
Keller
,
C.
Lacasta
,
D.
Maneuski
,
L.
Meng
,
M.
Milovanovic
,
I.
Pape
,
P. W.
Phillips
,
L.
Rehnisch
,
K.
Sawhney
,
C.
Sawyer
,
D.
Sperlich
,
M.
Stegler
,
Y.
Unno
,
M.
Warren
,
E.
Yildirim
Diamond Proposal Number(s):
[13500]
Open Access
Abstract: The High Luminosity Upgrade of the LHC will require the replacement of the Inner Detector of ATLAS with the Inner Tracker (ITk) in order to cope with higher radiation levels and higher track densities. Prototype silicon strip detector modules are currently developed and their performance is studied in both particle test beams and X-ray beams. In previous test beam measurements of prototype modules, the response of silicon sensors has been studied in detailed scans across individual sensor strips. These scans found instances of sensor strips collecting charge across areas on the sensor deviating from the geometrical width of a sensor strip. The variations have been linked to local features of the sensor architecture. This paper presents results of detailed sensor measurements in both X-ray and particle beams investigating the impact of sensor features (metal pads and p-stops) on the sensor strip response.
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Jul 2017
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B16-Test Beamline
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Kestutis
Kanisauskas
,
A.
Affolder
,
K.
Arndt
,
Richard
Bates
,
M.
Benoit
,
F. Di
Bello
,
A.
Blue
,
D.
Bortoletto
,
M.
Buckland
,
Craig
Buttar
,
P.
Caragiulo
,
D.
Das
,
J.
Dopke
,
A.
Dragone
,
F.
Ehrler
,
V.
Fadeyev
,
Z.
Galloway
,
H.
Grabas
,
I. M.
Gregor
,
P.
Grenier
,
A.
Grillo
,
B.
Hiti
,
M.
Hoeferkamp
,
L. B. A.
Hommels
,
B. T.
Huffman
,
J.
John
,
C.
Kenney
,
J.
Kramberger
,
Z.
Liang
,
I.
Mandic
,
Dzmitry
Maneuski
,
F.
Martinez-Mckinney
,
S.
Macmahon
,
L.
Meng
,
M.
Mikuž
,
D.
Muenstermann
,
R.
Nickerson
,
I.
Peric
,
P.
Phillips
,
R.
Plackett
,
F.
Rubbo
,
J.
Segal
,
S.
Seidel
,
A.
Seiden
,
I.
Shipsey
,
W.
Song
,
M.
Staniztki
,
D.
Su
,
C.
Tamma
,
R.
Turchetta
,
L.
Vigani
,
J.
Volk
,
R.
Wang
,
M.
Warren
,
F.
Wilson
,
S.
Worm
,
Qinglei
Xiu
,
J.
Zhang
,
H.
Zhu
Diamond Proposal Number(s):
[10391]
Open Access
Abstract: CMOS active pixel sensors are being investigated for their potential use in the ATLAS inner tracker upgrade at the HL-LHC. The new inner tracker will have to handle a significant increase in luminosity while maintaining a sufficient signal-to-noise ratio and pulse shaping times. This paper focuses on the prototype chip "HVStripV1" (manufactured in the AMS HV-CMOS 350nm process) characterization before and after irradiation up to fluence levels expected for the strip region in the HL-LHC environment. The results indicate an increase of depletion region after irradiation for the same bias voltage by a factor of ≈2.4 and ≈2.8 for two active pixels on the test chip. There was also a notable increase in noise levels from 85 e− to 386 e− and from 75 e− to 277 e− for the corresponding pixels.
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Feb 2017
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