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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M.
Mironova
,
K.
Metodiev
,
P.
Allport
,
I.
Berdalovic
,
Daniela
Bortoletto
,
C.
Buttar
,
R.
Cardella
,
V.
Dao
,
M.
Dyndal
,
P.
Freeman
,
L.
Flores Sanz De Acedo
,
L.
Gonella
,
T.
Kugathasan
,
H.
Pernegger
,
F.
Piro
,
R.
Plackett
,
P.
Riedler
,
A.
Sharma
,
E. J.
Schioppa
,
I.
Shipsey
,
C.
Solans Sanchez
,
W.
Snoeys
,
H.
Wennlöf
,
D.
Weatherill
,
D.
Wood
,
S.
Worm
Diamond Proposal Number(s):
[2206]
Abstract: This paper outlines the results of investigations into the effects of radiation damage in the mini-MALTA depleted monolithic pixel sensor prototype. Measurements were carried out at Diamond Light Source using a micro-focus X-ray beam, which scanned across the surface of the device in 2
μm
steps. This allowed the in-pixel photon response to be measured directly with high statistics. Three pixel design variations were considered: one with the standard continuous
n−
layer layout and front-end, and extra deep p-well and
n−
gap designs with a modified front-end. Five chips were measured: one unirradiated, one neutron irradiated, and three proton irradiated. The standard design showed a decrease of 12% in pixel response after irradiation to 1e15
neq∕cm2
. For the two new designs the pixel response did not decrease significantly after irradiation. A decrease of pixel response at high biasing voltages was observed. The charge sharing in the chip was quantified and found to be in agreement with expectations.
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Mar 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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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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H.
Pernegger
,
Richard
Bates
,
Craig
Buttar
,
M.
Dalla
,
J. W. Van
Hoorne
,
T.
Kugathasan
,
D.
Maneuski
,
L.
Musa
,
P.
Riedler
,
C.
Riegel
,
C.
Sbarra
,
D.
Schaefer
,
E. J.
Schioppa
,
W.
Snoeys
Open Access
Abstract: The upgrade of the ATLAS [1] tracking detector for the High-Luminosity Large Hadron Collider (LHC) at CERN requires novel radiation hard silicon sensor technologies. Significant effort has been put into the development of monolithic CMOS sensors but it has been a challenge to combine a low capacitance of the sensing node with full depletion of the sensitive layer. Low capacitance brings low analog power. Depletion of the sensitive layer causes the signal charge to be collected by drift sufficiently fast to separate hits from consecutive bunch crossings (25 ns at the LHC) and to avoid losing the charge by trapping. This paper focuses on the characterization of charge collection properties and detection efficiency of prototype sensors originally designed in the framework of the ALICE Inner Tracking System (ITS) upgrade [2]. The prototypes are fabricated both in the standard TowerJazz 180nm CMOS imager process [3] and in an innovative modification of this process developed in collaboration with the foundry, aimed to fully deplete the sensitive epitaxial layer and enhance the tolerance to non-ionizing energy loss. Sensors fabricated in standard and modified process variants were characterized using radioactive sources, focused X-ray beam and test beams before and after irradiation. Contrary to sensors manufactured in the standard process, sensors from the modified process remain fully functional even after a dose of 1015neq/cm2, which is the the expected NIEL radiation fluence for the outer pixel layers in the future ATLAS Inner Tracker (ITk) [4].
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Jun 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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