ATLAS Phase-1 Upgrades Overview, Status and Prospects

ATLAS Phase-1 Upgrades Overview, Status and Prospects

April 17 2019 S. Zimmermann 1

Stephanie ZimmermannUniversity of Freiburg

for the ATLAS Collaboration

• Introduction: Upgrade phases & Atlas upgrade projects, reasons & goals

• Status of the Phase-1 projects (will focus on TDAQ, NSW, LAR and mostly skip FTK)

• Next steps, installation

• Summary and Outlook

LHC: Towards the High luminosity era


• After the successful discovery of the Higgs particle, CERN has a ambitious program to further take data and exploit the LHC to the fullest until ~2035 or beyond ….

• Don’t just continue running wit the same conditions as now, but move to original design energy (14 TeV), and increase the luminosity to an ultimate 5-7 x 1034 cm-2 s-1

• Higher statistics broaden access to rare processes + precision measurements

LHC Upgrade takes place in 2 phases:1. During present LS2 shutdown (2019/20): Injectors, civil engineering2. In 2024 – 2026 (LS3) with the HL-LHC installation

ATLAS Experiment and Upgrade Phases


ATLAS upgrade planning matches the LHC schedule, with

• Phase-1 upgrades referring to what is planned to be installed in 2019/20 Scope of this presentation

• Phase-2 upgrades referring to those new detectors/detector replacements that get installed in 2024 – 2026.

Covered by Andreas Hoecker

ATLAS is the largest of the 4 LHC detectors, and the only one located on the Swiss part of the CERN site

44m

25m

ATLAS: What get’s upgraded in phase-1


1. Liquid Argon Calorimeter: Electronics & Trigger2. Innermost Muon endcap stations (Small Wheels) replace by New Small Wheels (NSW)

3. TDAQ – Trigger and data Acquisition4. (Fast Track Trigger (FTK))

Muon NSW

Hardware outside the ATLAS experimental cavern, in the various counting houses

Upgrades

Motivation & GoalsScope, Components, System Overview


LAR Upgrade: Goals & Scope I


• With the present system, the detector granularity is not fully exploited when forming trigger objects, since granularity in the trigger chain is more coarse

Refine current trigger towers, moving from x = 0.1 x 0.1 to having 10 super-cells with from x = 0.025 x 0.1 in the front and middle layer

Form super-cells in the frontend shaper sum ASIC, digitize cells individually

LAR Upgrade: Goals & Scope II


• Doing so allows to use a more sophisticated shower shape algorithm which uses information from different cell layers,

• Which results in a drastically reduced rate of fake L1 triggers !

µ = 81Keeping trigger rates under control is a major requirement for preparing ATLAS for HL-LHC phase !

Better rejection against fakes allows to keep optimal (low) thresholds on energy/momentum for selected objects !

Same principle NSW

Target is to keep L1 rate for EM objects below 20 kHz

LAR Upgrade: Overview/ComponentsLAR Phase-1 Upgrade is an electronics upgrade.


• New layer sum boards (LSB)

• New base-planes

• New frontend LAR trigger digitizer board (LTDB)

• New backend digital processing system: carrier + LATOME

• “Old” trigger tower info is kept and sent via L1Calo process-sor (legacy path)

LAR Upgrade: LSB & LTDB


• Super cells are formed by the new Layer sum boards, using analogue signal processing

• Super cell information is sent to new LTDB• LTDB digitizes the super cell energy

information, and sends info at 40 MHz to back-end

• LTDB also reroutes the analogue signals to the legacy path

LAR Upgrade: Carrier & LATOME


• Carrier and LATOME computes energies at 40 MHz and does energy summations,• LATOME being a AMC board with a large FPGA

Readout path, unchanged

Trigger path

Legacy chain

Phase-1 chain

NSW Upgrade: Goals & Scope I


• Present Small Wheel consists of CSC and MDT chambers for tracking, and TGC chambers for 2nd coordinate measurement and (limited) triggering

• TGC chambers in the MDT area only

• ATLAS original muon endcap trigger is based on track segments in the Big Wheel only, with a requirement on tracks being compatible with coming from the IP and having momentum above threshold

Can not distinguish against delta rays (B) or multiple-scattering (C) !

Trigger rates would explode at HL-LHC, forcing one to increase the threshold

NSW Upgrade: Goals & Scope II


• Extending the trigger coverage in the Inner station (Small Wheel) to = 2.4 (present CSC region),

• and requiring a matching of the incident angle between SW and BW

• drastically reduces the fake rate, which presently is close to 90%

Basic principle/basic reason for a new detector, the NSWs !

• Design/”ultimate” NSW angular resolution requirement: 1 mrad

• Full reach of the fake rejection will only achieved after LS3 (in phase-2), when angular resolution of BW segments will be 1 mrad

• Until then, NSW confirms BW tracks with a angular cut +- 7 mrad

NSW Upgrade: Goals & Scope III


MDT segment eff.

MDT tube eff.

Measurements GIF

2nd reason for NSW Upgrade: Tracking efficiency

• MDT tube efficiency reduces linearly with rate•

• MDT/CSC chamber track reconstruction efficiency decreases at high rate, with decrease becoming more pronounced the higher the rate

• Limit of 200 – 300 kHz/tube would be exceeded above ~2 or 2.5 x 1034 cm-2 s-1

Increase number of layers, and move to much smaller granularity of the readout elements

preserve excellent tracking efficiency which we currently have in ATLAS

NSW Upgrade: Overview – Layout/Mechanics


• Since being installed in the existing Small Small Wheel space, basic geometry and dimensions are preserved

• 16 sectors per wheel, 8 small, 8 large ones• 2 different detector technologies: Micromegas (MM)

and small strip Thin Gap Chambers (sTGC)

• Sectors each consist of 4 “pie-shaped” detector wedges – sTGC – MM – MM – sTGC,

• Mounted to a central spacer frame made from aluminium,

• Which in turn is mounted on the overall NSW support structure and JD shielding disk

NSW Upgrade: Overview -- Sectors


• sTGC wedges consist of 3 different chambers (quadruplets) each

• MM wedges consist of 2 different chambers (quadruplets) each, on both side of the spacer frame

• Both sTGC and MM chambers have 4 detection layers

16 space points in total for track reconstruction!

• Quadruplet construction happens in 5 construction consortia for the MM (Germany, Italy, CEA Saclay, Thessaloniki, Dubna),

• and in 5 places for sTGC (IL, Canada, China, Chile and PNPI)

• Integration of chambers into wedges, installation of electronics, and final mounting on the NSW mechanical structure happens at CERN.

• In the end, the NSWs are transported to ATLAS and installed as one single object/side

sTGCMM

sTGC

~4m

NSW Upgrade – Detector Technologies I


MicroMeshGaseous Structures (Micromegas)

• Standard PCB boards, with fine strip pattern (425/450 µm pitch),

• equipped with 128µm high insulating pillars

• Which support a metallic mesh in fixed distance, to form a amplification gap when HV is applied between readout PCB and mesh. Chambers are operated with Ar:CO2.

• Detector closed by 2nd PCB plane as cathode, with a 5 mm drift space formed.

NSW Micromegas are resistive MMs for spark protection. They are also of the floating mesh type, due to the large size (prohibits to integrate the mesh into the pillars during PCB prod.)

NSW Upgrade – Detector Technologies II


sTGC• Detector technology is a well established

one, same as was used in OPAL @ LEP, and for the ATLAS TGCs

• Wire chambers with a wire – wire distance

• and with a resistive layer as part of the cathodes (Graphite spraying)

• sTGC operate in quasi-saturated mode, with a n-pentane : CO2 flammable gas mixture very fast response, crucial for BCID identification and trigger under high rates

• Strip pitch for NSW sTGC is 3mm resolution of 100 –120 µm can be achieved with a charge centroid reconstruction

• Chambers have 4 gas gaps, each with a strip and a pad segmented cathode,

• Pad signals used in the trigger to define a trigger tower and initiate readout of a limited number of strips to the NSW trigger processor ….

NSW Upgrade – Chamber construction


Both MM and sTGC chambers are precision objects, need to know the location of each strip with a accuracy <(<) the resolution (100-120 µm)

For the Micromegas, achieved through• Precision jigs which position the individual readout

PCBs precisely on a granite table during panel gluing,

• Precision pins and references which position different layers w.r.t. each other during gluing 2nd of panels, and when closing chambers

• Sophisticated alignment and validation tools (Rasfork, CMM, Laser tracker, …)

For the sTGC, • strip boards are one piece – up to 2 x 1.2m, made in

industry !• Accuracy during pressing the insulating pre-preg

layers not guaranteed all boards measured by CMM/Faro

• Chamber construction on a granite table with precision reference jig to ensure correct alignment

NSW Upgrade – Electronics


NSW has more than 2 million channels --- electronics is another challenge !

• 4 custom ASICs, in 130 nm technology

• 5 different on-detector elx cards

• Additional sTGC trigger electronics on the detector rim

• FPGA based trigger processor in the Atlas service cavern, ATCA

TDAQ Upgrade: Goals & Scope

TDAQ Upgrade is the most “scattered” of the Atlas phase-1 projects.


3 Main areas:

• Muon L1 trigger & MuCTPI

• Calorimeter trigger (L1Calo, L1Topo, Feature extractors)

• Frontend link interface exchange (FELIX): New readout path

Goals/Motivation:

• Prepare Muon trigger for receiving NSW input, accommodate other additional inputs

• Reduction in latency (move from electrical to optical inputs)

• Support more power full calorimeter triggers incl. information from LAR Upgrade

TDAQ Upgrade: New sector logic boards


• Checking segment matching between NSW and Big Wheel not possible with present SL, also can not handle all the additional inputs

• New endcap Sector Logic consists of a central FPGA and lots of input/output links

• 90 boards in total, + 10 TTC boards

• New Barrel sector logic board needed since new MUCTPI requires optical input

• 64 FPGA based boards, with FPGA needed to handle the data serialization on the optical fiber (up to 6.4 Gps) and additional logic

Barrel SL Endcap SL

TDAQ Upgrade: FELIX readout


FELIX is the readout scheme foreseen in ATLAS for phase-2, Backend hardware, located in the counting house/ATLAS service caverns

• Much higher data rate with increase of pile-up/luminosity, and L1 trigger rate

• Get away from multiple custom hardware solutions for the readout backend, dependent on the sub-detector

• Move to uniform and as much as possible COTS hardware – powerful servers and network switches

• Single hardware to handle distribution of clock, trigger, configuration, monitoring, readout and slow control data

TDAQ Upgrade: L1Calo


• Feature extractors are powerful FPGA based boards which make full use of the finer granularity information from the LAR Upgrade: 10 super-cells per trigger tower

• eFEX identifies isolated e/ and candidates

• jFEX identifies jets, calculates Etmiss and Et

miss

• gFEX identifies and processing large radius jets

• FOX maps ~7500 fibers from the calorimeter frontend on the feature extractors as needed

10 super cells per trigger tower

Project Status


Even before going into any details, can say that a huge amount of work has gone into making things happen over the last years, and that ongoing activities both at the institutes and at CERN are intense !

LAR Upgrade Status: Front-end

• LSB: All boards have been produced, soon will have all @ CERN

• Cooling plates: First batch in hand (from old spares), series production for test is ongoing.

• Exchange work is ongoing @ CERN, proceeding well

• LTDB:

– Passed the Production Readiness Review (PRR) last December

– 4 boards for the barrel assembled and tested (BNL)

– Full barrel series production started early February

– Expecting boards @ CERN is imminent

– Non-barrel boards: Production starting in France (CEA Saclay)

• Baseplanes:

– Barrel: 30% already @ CERN, all ok

– Endcap: 80% if standard cards @ CERN, production

for special cards is starting


All on track.

LAR Upgrade Status: Back-end


LATOME:

• Pre-production boards received and cabled, validation ongoing and so far proceeding ok

• Production on schedule

Carrier: • Production proceeding on schedule• So far received boards are ok

LAR Upgrade Status: Integration/Commissioning


Demonstrator:

• Full phase-1 slice LTDB + LATOME + Carrier installed and tested in ATLAS during 2018 data taking

• Data recorded successfully• Pulse, baseline and error monitoring

throughout the run improvements taking into account for LATOME firmware dev

In very good shape, since full chain already established, incl. ATLAS integration !

Installation:

• Work in ATLAS has started for EC-A • Boards have been extracted from first

>= 4 crates• Baseplanes disconnected, exchanged

and reconnected• Delicate operation, proceeding well

so far !

Ongoing !

NSW Status: Engineering

NSW chambers and electronics are in construction phase, chamber construction will continue to mid/end 2020

Integration phase @ CERN has started and is ramping up


• Support structures and shielding disks are ready for both NSW-A and C, waiting for the detectors

• Including alignment instrumentation/ bars

NSW Status: sTGC chambers


• Steady chamber completion in all construction sites

• Production rate varies between 1 chamber/7 days to 1 chamber/~3 weeks

Of the 192 sTGC chamber required in total

86 have been assembled34 have all there electronics adaptor cards mounted20 have been fully tested

Example: Chile

Example: China

On track, huge team taken people at all sites together !

NSW Status: MM chambers


• Panel production is proceeding well• For drift panels 2 sites (Germany, Thessaloniki) have

finished or are close to finish the bare panel gluing• Readout panels:

• Getting close to having all panels for NSW-A (~40%) done,

• Site average 1 panel every 1 – 1.5 weeks

Total: 128 MM chambers needed

• Progress on in chamber assembly is somewhat less advanced, presently ~25 chambers assembled, not all of them will go forward to integration

Still fighting with the fact that operational HV margin is small, and chamber HV shows more discharges than expected based on smaller prototypes …..

Good progress, but not yet off the critical path !

NSW Status: Integration @ CERN• Assembled the first sTGC production wedge last November, PRR passed in December

• In production mode since then, currently working on wedges #3 and #4


• MM first double wedge assembly started early February, when chambers became available, close to completion;

• Expect to go into series operation next month

• In both cases, then waiting for final electronics in larger quantity ….

Integration is getting on track, but effort/manpower was probably under-estimated

Overlap with chamber construction is a challenge !

NSW Status: Electronics ASICs


ASICs:• All 4 custom chips are co-produced on

the same wafer• Pre-production run (150 wafers) last

spring,• Production run (600 wafers) is currently

ongoing

• TDS and ART (trigger path) ASICs are already all in hand, on track.• Suspense remains for VMM (recall, the main NSW chip, 70000 pieces) w.r.t. yield, pre-

production should rather large variations between and within wafers, suspected process issue

• Start getting new wafer batches from mid next month will see then.

NSW Status: Electronics cards


• Electronics cards design is complete for essentially all on-detector boards

• Readout driver cards (L1DDC, Greek responsibility) and trigger cards have passed the PRR, in series production Will keep the teams busy to autumn with the mass testing

• Pre-production for the MM Frontend board received, currently under testing, incl. with chambers PRR end of this month

• sTGC FEBs undergo an additional design iteration to improve noise, pre-production expected in June sufficient for first sector.

sTGC

Elx is progressing steadily, but took quite longer than planned – define 1st sector readiness !

TDAQ Upgrade Status: Sector Logic, FELIX


FELIX:• FELIX 712 final version design is complete• Pre-production received, and currently under

testing• Passed firmware and performance review in

December

• Tests and integration exercise with sub-detectors ramping up – item with a large dependency on from other upgrades, incl. NSW; firmware and software remain very active areas

• Target installation of full quantity of boards in ATLAS this summer

Sector logic:• Barrel SL board passed the PRR last December, pre-production is

ongoing, with first boards will arrive @ CERN in the next weeks for final integration test, then launch remaining production• On track for installation in ATLAS later in the year

• Endcap SL board are all produced, installation in ATLAS later this year• Current focus is on establishing and testing interfaces together with

NSW, Bother new Muon chambers, …..

Overall, components on track, FELIX is becoming important for other upgrades

TDAQ Upgrade Status: L1Calo/FEXes


gFEX: • most advanced, production is already completed• Firmware completed for handling objects for central reason. Next: forward region and

firmware integration

gFEX evolutions, more and more powerful FPGAs

eFEX: • Final board design ready since last summer, pre-production not

yet in hand• PRR now planned for late summer. • Several firmware parts to complete (final algorithm, readout

control logic, threshold handling)• Watched closely, late-ish compared to other TDAQ components Pre-prod. routing

TDAQ Upgrade Status: L1Calo/FEXes


jFEX:

• Design has been finalized during early 2018, Final Design Review was passed in May ‘18• Pre-production boards received end of last year• Under test

• Firmware in advanced state,

• Integration tests with remaining L1Calo elements planned next

• Expect to have Production Readiness Review in early summer

TDAQ L1Calo upgrade very heavy on firmware, with ATLAS following the policy of requiring complete FW as part of the production readiness review, before releasing board production.

On track for having all hardware completed and in hand for installation for beginning 2020

Next steps, prospects & Installation


Installation schedule I


• Long shutdown LS2 has started end of last year – no longer working towards it, but already in the middle of putting the phase-1 in place

• Activities in the ATLAS cavern are a complex ballet of many different tasks, intrinsically interleaved

• Guiding principle: Put NSW installation as late as possible, since the project is on the critical path

• LAR installation will complete before this Xmas, except for Barrel A

Installation schedule II


• NSW-A installation was scheduled up to now for April 2020 present projected readiness is August 2020

• NSW-C will not be ready in time for installation within the present LS2 end date ATLAS aims for a installation after the first year of run-3 instead

Summary and Conclusions

• The ATLAS phase-1 upgrade program is a very diverse one

• LAR Upgrade is very well advanced and already in the installation phase, with complete installation in spring 2020

• TDAQ Upgrade is well advanced, but with a few components still pending to launch into series production, once PRRs are successfully passed

• New Small Wheel is currently the most critical of the phase-1 upgrade projects;

• It is also the only of the 3 projects which comprises a full new sub-detector

– NSW detector chamber construction is in production phase, and proceeding well for both sTGC and MM

– Wedge integration @ CERN has started

– NSW electronics design is almost complete, last PRRs by summer, many items already in production


Certainly the next months remain challenges, with a next major milestone being the installation of the first of the 16 (side A) sectors & full in situ test !!

Documents

ATLAS Phase-1 Upgrades Overview, Status and Prospects