The CMS Phase II upgrade Pixel Detector. Krishna Thapa Physics 627, Spring 2016

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1 The CMS Phase II upgrade Pixel Detector Krishna Thapa Physics 627, Spring 2016 Krishna Thapa, The PLT Detector of CMS, PLT Meeting, 12 January 2016

2 Outline Why does CMS need an upgrade? Why Pixel Detectors? Operation Principle Readout Chip Operating conditions Layout Summary 2

Motivation Higgs was discovered back in 2012, but there s still a lot of unanswered questions Higgs couplings, Higgs properties, precision measurements of masses, diff.

3 Motivation Higgs was discovered back in 2012, but there s still a lot of unanswered questions Higgs couplings, Higgs properties, precision measurements of masses, diff. cross sections, etc.. Requires huge amount of data. LHC upgrade planned by the end of 2021 To reach this goal, LHC experiments are being redesigned--including the pixel detector. 3

4 Operation Principle A particle deposits some of it s energy on the detector medium creating e/h pairs Charges move in an electric field à electrical current in an external circuit For particle position measurements à gas - filled detectors, semiconductor detectors Ionization energies for gas ~ ev for semiconductors ~ 1-5 ev Ref: (6, 7) 4

5 Pixel Detector Features To study short lived particles. Some rare but interesting particles live for ~ pico second è ~0.03 mm accuracy required Also, to cope with increasing interaction rates and energies Tracks emerging from these decays should be measured as close to the interaction point as possible Pixel detectors provide both the granularity in space and time required to identify events with enough accuracy. Silicon: 1. Also used in semiconductor industryà cheaper 2. Can be operated at room temperature Ref: (1,6,7) 5

6 Pixel Detectors Read Out Chip Ref: (7) 6

7 Readout Chip Upgrade The pixel readout chip (ROC) is a major component of pixel electronics system Phase-II ROC will be ~6 time smaller pixels Will have to cope with ~5 times hit rates, 5-10 times trigger rates, and longer latency Chosen 65 nm CMOS technology to deal with the above Power consumption is ~2x. Provides significant challenges for the power delivery to the pixel chips DC/DC power conversion based on inductors cannot be integrated on the pixel modules not feasible due to space & budget constraints i) DC/DC conversion in the support cylinders 2m away (air core inductor based) Ii) drtisl poetinh eiyh on-chip shunt regulators Colling system will be an extention of Phase-I system, based on evaporative CO 2. Ref: (4) 7

8 Read Out Chip Upgrade ~ 2x Power consumption Ref: (1) 8

Operating Conditions 14 TeV beam energy, 25ns bunch spacing 5 x 10 34 cm -2 s -1, which is 10 x current inst.

9 Operating Conditions 14 TeV beam energy, 25ns bunch spacing 5 x cm -2 s -1, which is 10 x current inst. Luminosity ~10 times more radiation than phase I ~2GHz/cm 2 which is ~10-20 times the current hit rate Ref: (1) 9

Layout Goal is to improve high p T resolution à increase granularity Reduction in secondary interaction due to reduction in material To mitigate pileup effects, increase

10 Layout Goal is to improve high p T resolution à increase granularity Reduction in secondary interaction due to reduction in material To mitigate pileup effects, increase in forward acceptance (also a region for peak VBF and VBS) Pseudo Rapidity coverage, abs(η) from 2.4 à 4 3->4 barrel, 2+2-> Overall active area of 4m 2 ~ 1.5 Phase I 10

11 Summary The operating conditions for the pixel detector after upgrade is going to be extremely challenging The upgraded pixel detector should be ready for significant increase in hit rate and radiation Thin planar n-on-p silicon (possibility of diamond for innermost layer, or 3d pixels). 65nm CMOS All components and their prototyping ongoing 11

12 References 1. The pixel detector for the CMS Phase-II Upgrade ( iopscience.iop.org/ /10/04/c04019) 2. Technical Proposal for the Phase II Upgrade of the Compace Muon Solenoid (CERN-LHCC , LHCC-P-008, CMS-TDR-15-02, ISBN , 1 June 2015) 3. Pixel Detectors: From Fundamentals to Applications (Leonardo Rossi, Peter Fischer, Tilman Rohe, Norbert Wermes---Monograph--- January 24, 2005) 4. Design and Performance of the Silicon Pixel Detector Modules for the CMS Experiment (PHD Thesis, Christoph Hormann, University of Zurich, 2006) 5. Particle Detectors (Claus Grupen and Boris Shwartz, 2 nd edition) 6. Introduction to Silicon Detectors (Marc Weber, 7. Silicon Detectors (Manfred Krammer, user_upload/lehre/unterlagen/praktikum/halbleiterdetektoren.pdf) 12

Layout and prototyping of the new ATLAS Inner Tracker for the High Luminosity LHC

Layout and prototyping of the new ATLAS Inner Tracker for the High Luminosity LHC Ankush Mitra, University of Warwick, UK on behalf of the ATLAS ITk Collaboration PSD11 : The 11th International Conference