forward calorimetry taskforce report

Forward Calorimetry Taskforce Report

Brad Cox and Randy Ruchti29 April 2010

Calorimetry Upgrade Taskforce Report and Comments

Brad Cox and Randy Ruchti

•While the work of the Taskforce is largely distinct from the short term plans of the •calorimetry groups, nevertheless the Taskforce represents an important voice and •Communication link between the ECAL and HCAL communities.

•The long range schedule has dramatically changed: approximately 2 years of running•(till Christmas of 2011 or 1 fb-1 of data), followed by a long (one year ?) shutdown. •This shutdown will be a target for upgrade work but not the major upgrade that this •Taskforce was assembled to address.

It is our feeling that the objective of the Taskforce should expanded to include improvements of performance (for example work toward compensating calorimetry) as well as radiation hardness issues.

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Revised Timescale for the Phase II Upgrade (interpreted)

2010 - Decide on Physics objectives and begin simulations, taking into account any data available.

~2013 - TDR

~2012-15 - “Directed” R&D for rad hardness of components (in addition to any already performed prior to the design phase)

~2015-2020 Five years to build two endcaps

IF 2020 is the goal to have new endcaps, ready to roll in this schedule is tight even with the delays of the SLHC

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Since the last workshop…

• Taskforce Meetings– CMS Weeks: Dec ‘09, Mar ‘10– Upgrade Days: Feb ’10

• Topical Meetings– Simulations: Jan ‘10– GaAs Photosensors: Feb ’10

Forward Calorimetry Taskforce Report - 29 April 2010

• Themes for this meeting…– Benchmarks and simulations– BSC System– Detector options

•Themes for June CMS Week• Test Beam efforts• Detector developments• Simulations updates

Task Force Simulation Group

A meeting was held with Neu, Cox, Jessop, Bannerjee, Heltsley, Hildreth, Ruchti(January 2010, prior to Dasu taking on his new role)

(Input from Greg Landsberg, Oct/Dec 2009)

A first major observation is that we should do the simulations to see if we can determine when the detector will surely be degraded to the point that a halt must be declared to replace elements such as the forward calorimetry.

A second major observation out of the discussion was that pileup should be addressed at the same time or even before radiation damage degradation sincepileup may mask a significant portion of the degradation.

Thirdly we will start by seeing what the effect of pileup and radiation damage will be in the context of the present detector as evaluated for the modes listed onthe following page


SM: Rare top decaysSM EW and QCD - Triple gauge boson productionSM EW and QCD - Triple differential cross section for jetsSM Observation of Higgs->Z

Beyond the SM: Heavy SUSY b jets or photons plus METBeyond the SM: CompositenessBeyond the SM: Vector-Vector scattering

Additional question; Does the extra luminosity gain you anything?

Benchmark Signals


From S. Dasu - Establishing Upgrade Case

• Study existing analyses and identify where and when the current detector limits performance– Review PAS notes and physics TDR v.2

• Simulate the analyses at various pileup levels and identify where it breaks down without further improvements– Most analyses documented in recent times did not include pileup– Pileup can be simulated now, but we need to organize production

• Additional degradation due to detector aging needs to be simulated– Include estimates in simulation now, and expect real data experience in

future simulations• Simulate couple of “standard” upgraded configurations

– Study how they remedy the analyses– Study how they can improve analyses if installed early


S. Dasu - Simulation Status

• Core CMSSW simulation program is ready– Including pileup simulation (later talks)

• New geometries, materials and readout description for various detectors will remain in flux for a while– Key is to settle on one or two configurations for initial studies– One configuration is the current CMS – firstly, it is already there

• Let’s get the work started with it• We need to compare newer upgrade configurations to it any way, so

we can begin with that baseline• Organized simulation

– There is really no dearth of resources at the moment• Many Tier-2s are under utilized

– Wisconsin group can offer to produce data and host it


Personnel Issues

• How do we recruit people to work on upgrades, when the data is just started to be provided by LHC?– We need to rely on new students and postdocs who will work on analysis

with beyond 2012 data• Can we provide them service credits for working on upgrade

definition?• Nominally, this is physics work – so no service credit. But, this needs

to change.• Recruiting is possible

– Most crucial: Who are the experienced physicists who can help?


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From Mike Hildreth…event mixing

• MixingModule:• “pure MC” pileup simulation; overlay simHits• multiple input sources (generators) can provide minbias, cosmics,

and beam halo as backgrounds• can select range of BXs (before and after target beam crossing)

that are “sampled” to add energy/noise to event of interest• fixed or poisson mean of number of interactions is a parameter• routinely run in Release Validation by offline production team• will be used for large scale production for ICHEP 2010• “Playback” mode allows access to MC Truth information for pileup


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Hildreth…second approach…

• DataMixingModule:– can overlay any event on any other; at Digi level

• data zerobias events, for example, can be overlaid on MC– could use Data for all sources of beam-related backgrounds– could use Data for uncorrelated noise– fixed or poisson mean of overlay events is a parameter

• uses same base code as MixingModule for event handling

• ….would like to encourage dialogue between the Upgrade Simulation effort and the “standard” Simulation effort for sharing expertise, experiences– large knowledge base for “standard” simulation exists– upgrade should be able to leverage this


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Simulation updates at this meeting…

• From Doug Berry –– Simulate the performance of the detector under high luminosity

conditions– Verify that pileup simulation using mixing at SIM and Digi levels

produce comparable results– Starting pileup simulations – an electron gun event on top of 25 min

bias events– Simulate a large number of events (100k) with medium (8) and heavy

(25) mixing of min bias using both SIM and Digi level mixing.– Look at basic reconstruction quantities (RecHit energies and basic

cluster distributions) in all generator conditions.


I. Radiation Damage Projects:a)Detector Technologies

1)Crystals for ECAL PbWO4 loaded with Mo LYSO CeF3

2) Plate calorimetry Quartz tiles with wavelength shifter3) Gas calorimetry4) QQ fibers for the HF5) Liquid scintillator6) Liquid Scintillator in quartz tubes

b) Photodetector technologies (Geiger-mode devices)1) SiPM2) GaAs

II. Performance improvements projects:a) Detector Technologies

1) Separation of Cerenkov light from scintillation light by timing and or wavelength2) Quartz and scintillator combination for radiator to improve e/h

b) Photo detector technologies1) GaAs pixelated chips sensitive different bandwidths to separate Cerenkov light from scintillation light by wavelength

Report on Task Force Technology R&D

The message - interests are not only in radiation hardening but also improving the detector.It is clear that the ~75 task force participants are interested in much more than just radiation damage.


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From Alan Bell - BSC Update


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BSC radiation environment


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Comments on the BSC


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Among the options… a test cell for liquid scintillators as the detection media…



Planned Future Meetings of The Taskforce

Upgrade Weeks25 - 29 October

Upgrade Days24 June15 July

30 Sep*18 Nov

During Upgrade Weeks27 April*, 27 October*

During CMS WeeksJune 17*, Dec 9*

* Task Force meeting dates

Next discussion will be held atUS CMS meeting at Brown

May 8

forward calorimetry taskforce report

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