2020

Quality Assurance methodology for the ATLAS Inner Tracker strip sensor production
M.Ullán, P. Allport, K. Dette, V. Fadeyev, J. Fernández-Tejero, C. Fleta, L. Gonella, I. Kopsalis, R.S. Orr, Y. Unno.Nuclear Instruments and Methods in Physics Research Section A. Volume 981, 21 November 2020, 164521.

doi.org/10.1016/j.nima.2020.164521

Abstract: The production of the strip sensors for the ATLAS Inner Tracker (ITk) will start in 2020. Nearly 22,000 large area sensors will be produced over a period of about five years by Hamamatsu Photonics K.K. (HPK). The institutes involved in the sensor development and production are committed to deliver and maintain the highest quality sensors for the experiment. A Quality Assurance (QA) strategy has been prepared to be carried out during the whole production period. Once the process has been characterized as providing the required pre-irradiation specifications and the proper radiation hardness, the onus is on the manufacturer to rigidly stick to that qualified process. Still, sample testing with specific device-element structures and irradiation of devices should be implemented by the ITk sensor collaboration.

A detailed irradiation and testing plan has been prepared by the ATLAS-ITk Collaboration, together with a newly designed test chip with specific structures to monitor different key technological and device parameters during the whole production. The tests and irradiations will be carried out on a sample basis. In order to have a practical methodology, samples from alternating batches will be sent for irradiations with protons, neutrons and gammas, and then tested in order to check that the characteristics remain within specifications. The detailed plan and the design and test methods for the structures in the test chip are presented here.

2019

Evaluation of characteristics of Hamamatsu low-gain avalanche detectors
Sayaka Wadaa, Kyoji Ohnarua, Kazuhiko Haraa, Junki Suzukia, Yoshinobu Unnob, Koji Nakamurab, Kazunori Hanagakib, Yoichi Ikegamib, Kazuhisa Yamamurac, Shintaro Kamadac, Yuhei Aboc, Hitomi Tokutaked, Daiki Yamamotoe
Nuc. Instr. Meth. A , Volume 924, 21 April 2019, Pages 380-386
doi.org/10.1016/j.nima.2018.09.143

Abstract: Low-gain avalanche detectors (LGADs) are attractive because of their fast response to realize a 4-dimensional (4D) tracker in future experiments in high energy physics and other applications. We fabricated LGAD diodes and strip sensors. Their responses before and after irradiation to gamma rays or neutrons were evaluated with light-emitting diodes (LEDs) of various wave lengths and with an infrared laser. The sensors showed a gain of more than 10 before irradiation. Little reduction of gain was observed with gamma irradiation. A substantial reduction of gain was observed after neutron irradiation. A gain increase observed in the interstrip region after neutron irradiation, whereas the gain was equal to one before irradiation.

Radiation tolerance study on irradiated AC-coupled, poly-silicon biased, p-on-n silicon strip sensors developed in India
S. Kuehn, T. Barber, G. Casse, P. Dervan, A. Driewer, D. Forshaw, T. Huse, K. Jakobs, U. Parzefall
Nuc. Instr. Meth. A , Volume 913, 1 January 2019, Pages 97-102
doi.org/10.1016/j.nima.2018.10.118

Abstract: The silicon sensors to be deployed in the next generation high energy physics experiments for operation in high luminosity scenarios, will require a high level of radiation tolerance. AC-coupled silicon strip sensors integrated with biasing poly-silicon resistors have been fabricated in collaboration with the Bharat Electronics Limited foundry using 4 inch n-type wafers in p-on-n configuration. Several sensors were irradiated with protons at different fluences at the Karlsruhe Cyclotron facility under the Advanced European Infrastructures for Detectors at Accelerators (AIDA) program. This paper reports on these radiation hardness study performed on the AC-coupled silicon sensors fabricated in India. The characterization comprises of electrical tests, including total current, voltage and strip scans and charge collection studies.

Energy loss of protons from MedAustron in silicon strip sensors
P. Paulitsch, T. Bergauer, D. Blöch, A.Burker, M. Dragicevic, J. Großmann, V. Hinger, A. Hirtl, A. König, F. Ulrich-Pur
Nuc. Instr. Meth. A, Volume 958, 1 April 2020, 162280
doi.org/10.1016/j.nima.2019.06.021

Abstract: MedAustron is a hadron synchrotron primarily designed and built for tumor treatment. Besides its clinical purpose, it is equipped with a dedicated beam line for non-clinical research. This beam line can be used for beam tests utilizing protons with an energy up to 252.7 MeV at the moment, but 800 MeV protons and carbon ions will become available through 2019. We conducted first beam tests at MedAustron in order to understand the usability of this beam line for testing silicon detectors. This includes the design and commissioning of a trigger setup based on scintillators and PMTs, which is meant to stay permanently there. This allowed us to measure energy deposition utilizing silicon strip sensors read out by the ALiBaVa system. Nominal beam energies were varied between 62.4 and 252.7 MeV and verified by determining the specific energy loss of protons in silicon. As these energies are rather low compared to typical HEP beam tests, the proton beam through the setup was simulated to determine the necessary energy correction due to losses through matter and air in front of the Si sensor. These approaches yielded good agreement with reference data from NIST, so MedAustron is considered as a reliable facility for future beam tests.

Characterization of Si Detectors
Ajay Kumar Srivastava
doi.org/10.1007/978-3-030-19531-1_9

Abstract: The LHC (LARGE HADRON COLLIDER) at CERN, Geneva is one of the prestigious High-Energy physics (HEP) collider experiment. The LHC (pp Collider, 14 TeV, 25 ns bunch spacing) is foreseen to be upgraded to HL-LHC , where the luminosity increases of up to ten times i.e., 1035 cm−2 s−1 [1, 2]. At HL-LHC up to 400 interactions per bunch crossing are expected. This causes a major increase in track density, requiring for intermediate and larger radii smaller detection elements with higher granularity than the present the CMS silicon tracker. The radiation damage effects in the Si sensors at HL-LHC will be more challenging to cope with such hostile radiation environment therefore the Compact Muon Solenoid (CMS) experiments will require a new CMS tracking detectors in the phase 2 upgrade (2026) of the HL-LHC.

Characterization of FBK small-pitch 3D diodes after neutron irradiation up to 3.5 × 1016 neq cm−2
R. Mendicino, M. Boscardin, and G.-F. Dalla Betta
iopscience.iop.org/article/10.1088/1748-0221/14/01/C01005/meta

Abstract: We report on the characterization by a position resolved laser system of small-pitch 3D diodes irradiated with neutrons up to an extremely high fluence of 3.5 × 1016 neq cm−2. We show that very high values of signal efficiency are obtained, in good agreement with the geometrical expectation based on the small values of the inter-electrode spacings, and also boosted by charge multiplication effects at high voltage. These results confirm the very high radiation tolerance of small-pitch 3D sensors well beyond the maximum fluences expected at the High Luminosity LHC.

The upgraded microstrip silicon sensor characterization facility of the University of Sheffield
Kourlitis, E, Lohwasser, K, French, R, Edwards, S.O.
doi.org/10.22323/1.343.0028

Abstract: A major component of the ATLAS Phase-II upgrade is the Inner Tracker, an all-silicon detector featuring novel microstrip sensors. Motivated by the current research efforts in silicon sensor technology, a characterization facility has been recently upgraded at the University of Sheffield. A description of the facility along with initial benchmark measurements of sensors before and after their irradiation are presented. The results were found to be in agreement with similar measurements conducted by other facilities in the UK and support the successful commissioning of the facility.

2018

Development of AC-coupled, poly-silicon biased, p-on-n silicon strip detectors in India for HEP experiments
Geetika Jain, Ranjeet Dalala, Ashutosh Bhardwaja, Kirti Ranjana, Alexander Dierlammb, Frank Hartmannb, Robert Eberb, Marcel Demarteauc
Nuclear Inst. & Meth. A, Vol. 882, 21 February 2018, Pages 1-10
doi.org/10.1016/j.nima.2017.10.010

2017

P-Type Silicon Strip Sensors for the new CMS Tracker at HL-LHC
Tracker Group of the CMS Collaboration; Akgün, B.; Ecklund, K.M.; Kilpatrick, M.; Nussbaum, T.; Zabel, J.
doi:10.1016/j.nima.2013.06.067

Abstract: The upgrade of the LHC to the High-Luminosity LHC (HL-LHC) is expected to increase the LHC design luminosity by an order of magnitude. This will require silicon tracking detectors with a significantly higher radiation hardness. The CMS Tracker Collaboration has conducted an irradiation and measurement campaign to identify suitable silicon sensor materials and strip designs for the future outer tracker at the CMS experiment. Based on these results, the collaboration has chosen to use n-in-p type silicon sensors and focus further investigations on the optimization of that sensor type. This paper describes the main measurement results and conclusions that motivated this decision.

Apparatus and methods for measuring delivered ionizing radiation
Alejandro Carabe, Fernandez Consuelo, Guardiola Salmeron, Diana Davila Pineda
patents.google.com/patent/US20170299732A1/en

Abstract: The upgrade of the LHC to the High-Luminosity LHC (HL-LHC) is expected to increase the LHC design luminosity by an order of magnitude. This will require silicon tracking detectors with a significantly higher radiation hardness. The CMS Tracker Collaboration has conducted an irradiation and measurement campaign to identify suitable silicon sensor materials and strip designs for the future outer tracker at the CMS experiment. Based on these results, the collaboration has chosen to use n-in-p type silicon sensors and focus further investigations on the optimization of that sensor type. This paper describes the main measurement results and conclusions that motivated this decision.

2015

Long term performance stability of silicon sensors
R. Moria, C. Betancourta, S. Kühna, M. Hausera, I. Messmera, A. Hasenfratza, M. Thomasa, K. Lohwasserb, U. Parzefalla, K. Jakobsa
Nuc. Instr. Meth. A.Available online 3 March 2015
doi:10.1016/j.nima.2015.02.053

Abstract: The HL-LHC investigations on silicon particle sensor performance are carried out with the intention to reproduce the harsh environments foreseen, but usually in individual short measurements. Recently, several groups have observed a decrease in the charge collection of silicon strip sensors after several days, in particular on sensors showing charge multiplication. This phenomenon has been explained with a surface effect, the increase of charge sharing due to the increment of positive charge in the silicon oxide coming from the source used for charge collection measurements. Observing a similar behaviour in other sensors for which we can exclude this surface effect, we propose and investigate alternative explanations, namely trapping related effects (change of polarization), and annealing related effects. Several n-on-p strip sensors, as-processed and irradiated with protons and neutrons up to 5×1015 neq/cm2 have been subjected to charge collection efficiency measurements for several days, while parameters like the impedance have been monitored. The probable stressing conditions have been changed in an attempt to recover the collected charge in case of a decrease. The results show that for the investigated sensors the effect of charge sharing induced by a radioactive source is not important, and a main detrimental factor is due to very high voltage, while at lower voltages the performance is stable.

10µm thin transmissive photodiode produced by ALBA Synchrotron and IMB-CNM-CSIC
Journal of Instrumentation, Volume 10, March 2015, Article C03005
16th International Workshop on Radiation Imaging Detectors
C. Cruz, G. Jover-Manas, O. Matilla, J. Avila, J. Juanhuix, G. Pellegrini, D. Quirion and J. Rodriguez
doi:10.1088/1748-0221/10/03/C03005

Abstract: Thin silicon photodiodes are common X-ray beam diagnosis devices at synchrotron facilities. Here we present a new device featuring an extremely thin layer that allows X-ray transmission over 90% for energies above 10 keV. The diode has a radiation-hard silicon junction with silicon dioxide passivation and a protective entrance window. These outstanding features make this device suited for diagnostic applications in X-ray synchrotron beamlines. Hereby preliminary results of X-ray transmission, responsivity and uniformity are presented.

Testbeam studies of pre-prototype silicon strip sensors for the LHCb UT upgrade project using the Alibava System Classic

A. Abba, M. Artuso, S. Blusk, T. Britton, A. Davis, A. Dendek, B. Dey, S. Ely, T. Evans, J. Fu, P. Gandini, F. Lionetto, P. Manning, B. Meadows, R. Mountain, N. Neri, M. Petruzzo, M. Pikies, T. Skwarnicki, T. Szumlak, J.C. Wang

Available online 17 October 2015, pages 244-257

doi:10.1016/j.nima.2015.10.031

Abstract: The LHCb experiment is preparing for a major upgrade in 2018–2019. One of the key components in the upgrade is a new silicon tracker situated upstream of the analysis magnet of the experiment. The Upstream Tracker (UT) will consist of four planes of silicon strip detectors, with each plane covering an area of about 2 m2. An important consideration of these detectors is their performance after they have been exposed to a large radiation dose. In this paper we present test beam results of pre-prototype n-in-p and p-in-n sensors that have been irradiated with fluences up to /cm2.

2014

Recent results of the 3D-stripixel Si detectors

Z. Li, D. Bassignana, W. Chen, S. Liu, D. Lynn, G. Pellegrini

Nuc. Instr. Meth. A, Volume 765, 21 November 2014, Pages 103–108
doi:10.1016/j.nima.2014.05.088

Abstract: The design, fabrication process and the characteristics measurements of the new 3D-stripixel detectors are presented in this paper. The optimized detectors design is simulated and analyzed with Sentaurus TCAD toolkit. The active area of the detector was studied with the laser transient current techniques (TCT) measurement. The characteristics of detector’s 2D position sensitivity and charge collection was studied with an Alibava DAQ system.

Radiation hardness tests of double-sided 3D strip sensors with passing-through columns
NIM-A, Volume 765, 21 November 2014, Pages 155-160
G.-F. Dalla Betta, C. Betancourt, M. Boscardin, G. Giacomini, K. Jakobs, S. Kühn, B. Lecini, R. Mendicino, R. Mori, U. Parzefall, M. Povoli, M. Thomas, N. Zorzi
doi:10.1016/j.nima.2014.05.007

Abstract: This paper deals with a radiation hardness study performed on double-sided 3D strip sensors with passing-through columns. Selected results from the characterization of the irradiated sensors with a beta source and a laser setup are reported and compared to pre-irradiation results and to TCAD simulations. The sensor performance in terms of signal efficiency is found to be in good agreement with that of other 3D sensors irradiated at the same fluences and tested under similar experimental conditions.

Low-resistance strip sensors for beam-loss event protection
NIM-A, Volume 765, 21 November 2014, Pages 252-257
M. Ullán, V. Benítez, D. Quirion, M. Zabala, G. Pellegrini, M. Lozano, C. Lacasta, U. Soldevila, C. García, V. Fadeyev, J. Wortman, J. DeFilippis, M. Shumko, A.A Grillo, H.F.-W. Sadrozinski
doi:10.1016/j.nima.2014.05.089

Abstract: AC-coupled silicon strip sensors can be damaged in case of a beam loss due to the possibility of a large charge accumulation in the bulk, developing very high voltages across the coupling capacitors which can destroy them. Punch-through structures are currently used to avoid this problem helping to evacuate the accumulated charge as large voltages are developing. Nevertheless, previous experiments, performed with laser pulses, have shown that these structures can become ineffective in relatively long strips. The large value of the implant resistance can effectively isolate the “far” end of the strip from the punch-through structure leading to large voltages. We present here our developments to fabricate low-resistance strip sensors to avoid this problem. The deposition of a conducting material in contact with the implants drastically reduces the strip resistance, assuring the effectiveness of the punch-through structures. First devices have been fabricated with this new technology. Initial results with laser tests show the expected reduction in peak voltages on the low resistivity implants. Other aspects of the sensor performance, including the signal formation, are not affected by the new technology.

Investigation of silicon sensors for their use as antiproton annihilation detectors
NIM-A, Volume 765, 21 November 2014, Pages 161-166
N. Pacifico, S. Aghion, O. Ahlén, A.S. Belov, G. Bonomi, P. Bräunig, J. Bremer, R.S. Brusa, G. Burghart, L. Cabaret, M. Caccia, C. Canali, R. Caravita, F. Castelli, G. Cerchiari, S. Cialdi, D. Comparat, G. Consolati, C. Da Vià, J.H. Derking, S. Di Domizio, et al.
doi:10.1016/j.nima.2014.06.036

Abstract: We present here a new application of silicon sensors aimed at the direct detection of antinucleons annihilations taking place inside the sensor?s volume. Such detectors are interesting particularly for the measurement of antimatter properties and will be used as part of the gravity measurement module in the View the MathML sourceAEg¯IS experiment at the CERN Antiproton Decelerator. One of the goals of the View the MathML sourceAEg¯IS experiment is to measure the gravitational acceleration of antihydrogen with 1% precision. Three different silicon sensor geometries have been tested with an antiproton beam to investigate their properties as annihilation detection devices: strip planar, 3D pixels and monolithic pixel planar. In all cases we were successfully detecting annihilations taking place in the sensor and we were able to make a first characterization of the clusters and tracks.

Radiation hard sensor materials for the CMS Tracker Phase II Upgrade – Charge collection of different bulk polarities Original
M. Printz, on behalf of the CMS Tracker Collaboration
NIM-A, Volume 765, 21 November 2014, Pages 29-34
doi:10.1016/j.nima.2014.04.042

Abstract: The upgrade of the LHC machine to deliver a significantly higher luminosity of about 5×1034 cm-2s-1 is planned to be operational after 2022. This will simultaneously increase the radiation dose for the inner detector systems, requiring new radiation hard sensor materials for the CMS Tracker. To identify the appropriate materials which are able to withstand the radiation environment in the middle to outer layers of the CMS Tracker during the full lifetime of the high luminosity LHC, a large irradiation and measurement campaign has been conducted. Several test structures and sensors have been designed and manufactured on 18 different combinations of wafer materials, thicknesses and production technologies. The structures have been electrically characterised before and after irradiation with different fluences of neutrons and protons. This paper reports the final results on strip sensor performance considering the comparison of p-in-n technology with n-in-p type. Outcomes from signal and noise measurements before and after annealing depending on the radiation dose are discussed and the final recommendation of the CMS Tracker Collaboration for the strip sensor polarity for the Phase II Upgrade is presented.

Development of n+-in-p large-area silicon microstrip sensors for very high radiation environments – ATLAS12 design and initial results
Y. Unno, S.O. Edwards, S. Pyatt, J.P. Thomas, J.A. Wilson, J. Kierstead, D. Lynn, J.R. Carter, L.B.A. Hommels, D. Robinson, I. Bloch, I.M. Gregor, K. Tackmann, C. Betancourt, K. Jakobs, S. Kuehn, R. Mori, U. Parzefall, L. Wiik-Fucks, A. Clark, D. Ferrere, et al.
NIM-A, Volume 765, 21 November 2014, Pages 80-90
doi:10.1016/j.nima.2014.06.086

Abstract: We have been developing a novel radiation-tolerant n+-in-p silicon microstrip sensor for very high radiation environments, aiming for application in the high luminosity large hadron collider. The sensors are fabricated in 6 in., p-type, float-zone wafers, where large-area strip sensor designs are laid out together with a number of miniature sensors. Radiation tolerance has been studied with ATLAS07 sensors and with independent structures. The ATLAS07 design was developed into new ATLAS12 designs. The ATLAS12A large-area sensor is made towards an axial strip sensor and the ATLAS12M towards a stereo strip sensor. New features to the ATLAS12 sensors are two dicing lines: standard edge space of 910 µm and slim edge space of 450 µm, a gated punch-through protection structure, and connection of orphan strips in a triangular corner of stereo strips. We report the design of the ATLAS12 layouts and initial measurements of the leakage current after dicing and the resistivity of the wafers.