Position dependence of charge collection in prototype sensors for the CMS pixel detector

Bortoletto, D.; Chiochia, V.; Cremaldi, L.; Cucciarelli, S.; Dorokhov, A.; Konecki, M.; Prokofiev, K.; Regenfus, C.; Sanders, D. A.; Son, Seunghee; Speer, T.; Swartz, M.

doi:10.1109/tns.2004.829487

Cited by 16 publications

(14 citation statements)

References 15 publications

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“…Conversely, the CFE is reduced when a track intercept is far from a strip and near to a routing line. Similar effects have been observed in other experiments [17,18].…”

Section: Charge Loss To the Second Metal Layersupporting

confidence: 91%

Radiation damage in the LHCb Vertex Locator

Harrison

2012

2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC)

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The LHCb Vertex Locator (VELO) is a silicon strip detector designed to reconstruct charged particle trajectories and vertices produced at the LHCb interaction region. During the first two years of data collection, the 84 VELO sensors have been exposed to a range of fluences up to a maximum value of approximately 45 × 10 12 1 MeV neutron equivalent (1 MeV n eq ). At the operational sensor temperature of approximately −7 • C, the average rate of sensor current increase is 18 µA per fb −1 , in excellent agreement with predictions. The silicon effective bandgap has been determined using current versus temperature scan data after irradiation, with an average value of E g = 1.16±0.03±0.04 eV obtained. The first observation of n + -on-n sensor type inversion at the LHC has been made, occurring at a fluence of around 15×10 12 of 1 MeV n eq . The only n + -on-p sensors in use at the LHC have also been studied. With an initial fluence of approximately 3 × 10 12 1 MeV n eq , a decrease in the Effective Depletion Voltage (EDV) of around 25 V is observed, attributed to oxygen induced removal of boron interstitial sites. Following this initial decrease, the EDV increases at a comparable rate to the type inverted n + -on-n type sensors, with rates of (1.43 ± 0.16) × 10 −12 V/ 1 MeV n eq and (1.35 ± 0.25) × 10 −12 V/ 1 MeV n eq measured for n + -on-p and n + -on-n type sensors, respectively. A reduction in the charge collection efficiency due to an unexpected effect involving the second metal layer readout lines is observed.

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“…Conversely, the CFE is reduced when a track intercept is far from a strip and near to a routing line. Similar effects have been observed in other experiments [17,18].…”

Section: Charge Loss To the Second Metal Layersupporting

confidence: 91%

Radiation damage in the LHCb Vertex Locator

Harrison

2012

2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC)

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“…The CFE is reduced most significantly when a track intercept is far from a strip and near to a routing line. Similar effects have been observed in other experiments [9,10].…”

Section: Charge Loss To the Second Metal Layersupporting

confidence: 91%

Radiation damage on the LHCb-VELO

Casse

2013

Nuclear Instruments and Methods in Physics Research Section A:

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“…Two inter-pixel isolation techniques were evaluated for the barrel sensors: Open p-stops [17] and moderated p-spray [18]. The moderated p-spray technique was eventually chosen because of the superior charge collection properties obtained with the prototype sensors [19]. The p-spray consists of a medium dose boron implantation "sprayed" without mask over the whole wafer.…”

Section: Technological Choicesmentioning

confidence: 99%

“…Signal reduction caused by trapping presently limits the use of silicon detectors in environments exposed to fluences higher than 10 15 n eq /cm 2 . The optimization of the CMS barrel pixel sensors was achieved through an extensive comparison of several technological choices [11][12][13][14][15][16]. In particular, pixel sensors with p-spray and p-stop isolation of the collecting electrodes were compared and the p-spray technique was chosen for the barrel design [16].…”

Section: Introductionmentioning

confidence: 99%

Design and performance of the silicon sensors for the CMS barrel pixel detector

Allkofer

Amsler

Bortoletto

et al. 2008

Nuclear Instruments and Methods in Physics Research Section A:

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The CMS experiment at the LHC includes a hybrid silicon pixel detector for the reconstruction of charged tracks and of the interaction vertices. The barrel region consists of n-in-n sensors with 100 × 150 µm 2 cell size processed on diffusion oxygenated float zone silicon. A biasing grid is implemented and pixel isolation is achieved with the moderated p-spray technique. An extensive test program was carried out on the H2 beam line of the CERN SPS. In this paper we describe the sensor layout, the beam test setup and the results obtained with both irradiated and non-irradiated prototype devices. Measurements of charge collection, hit detection efficiency, Lorentz angle and spatial resolution are presented.

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Position dependence of charge collection in prototype sensors for the CMS pixel detector

Cited by 16 publications

References 15 publications

Radiation damage in the LHCb Vertex Locator

Radiation damage in the LHCb Vertex Locator

Radiation damage on the LHCb-VELO

Design and performance of the silicon sensors for the CMS barrel pixel detector

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