eic detector r&d simulation workshop summary

EIC Detector R&D Committee Meeting, October 2012

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EIC Detector R&D Simulation WorkshopSummary

E.C. Aschenauer

EIC Detector R&D Committee Meeting, October 2012 2

Simulation Workshop Workshop@BNL 8th & 9th of October

https://wiki.bnl.gov/conferences/index.php/EIC_RD_Simulation/Agenda

Covered Topics Physics case for the EIC Golden measurements to benchmark the detector

performance Software

simulation tools (physics generators,fast smearing generator,..)

physics generators not discussed here summarized perfectly in

https://wiki.bnl.gov/conferences/images/d/db/TollEICRnDOctober2012.pdfdetector simulations (FairRoot@BNL, GEMC@JLab, ….)computing power and environment

eRHIC and ELIC/MEIC IR designstracking of protons and neutrons through IR

machine backgrounds (hadronic, synchrotron radiation, …)

E.C. Aschenauer





What needs to be covered

E.C. Aschenauer

e’

t

(Q2)e

gL*x+ξ x-ξ

H, H, E, E (x,ξ,t)

~~

g, p,J/Y

p p’

Inclusive Reactions in ep/eA: Physics: Structure Fcts.: F2, FL Very good electron id find scattered lepton Momentum/energy and angular resolution of e’ critical scattered lepton kinematics

Semi-inclusive Reactions in ep/eA: Physics: TMDs, Helicity PDFs flavor separation, dihadron-corr.,… Kaon asymmetries, cross sections Excellent particle ID: p±,K±,p± separation over a wide range in h full F-coverage around g* Excellent vertex resolution Charm, Bottom identification

Exclusive Reactions in ep/eA: Physics: GPDs, proton/nucleus imaging, DVCS, excl. VM/PS prod. Exclusivity large rapidity coverage rapidity gap events ↘ reconstruction of all particles in event high resolution in t Roman pots


Inclusive DIS

E.C. Aschenauer

Measure of resolution powerMeasure of inelasticityMeasure of

momentum fraction of struck quark

e- p/A

0o 180o

+h -h

diverges forye0

depends on E’e

diverges forq’e180o

depends on E’e and q’e

Note: to measure x, y, and Q2 at low Q2 ~ 1 GeV2

Electron method

precise energy and angular resolution for q’e 180o and

high y

At low y use hadron methodHadron method:


DIS Kinematics

E.C. Aschenauer

Even for colliders: Strong x-Q2 correlation high x high Q2

low x low Q2

low y-coverage: limited by E’e resolution hadron method

high y limited byradiative correctionscan be suppressed byrequiring hadronicactivity HERA

y>0.005

Possible limitations in kinematic coverage:


Lepton Kinematics

E.C. Aschenauer

Increasing Lepton Beam Energy:5 GeV: Q2 ~ 1 GeV h ~ -210 GeV: Q2 ~ 1 GeV h ~ -4

highest E’e at most negative rapiditiesindependent of Eh

√s


Scattered Lepton Kinematics

E.C. Aschenauer

CUTS: Q2>0.1GeV2 && 0.01<y<0.95

higher √s:scattered lepton has small scattering angle negative rapidities


Pion Kinematics

E.C. Aschenauer

Cuts: Q2>1 GeV, 0.01<y<0.95, z>0.1

Increasing Hadron Beam Energy: influences max. hadron energy at fixed hIncreasing 30 GeV < √s < 170 GeV hadrons are boosted from forward rapidities to negative rapidities the same for p±, K±, p±

√s


Hadron, lepton, Photon Separation

E.C. Aschenauer

5 GeVx50 GeVhadronphotonelectron

no cuts applied

hadron/photon suppression factor needed for pe’>1GeV:-3<h<-2: ~10-2<h<-1: > 100-1<h<0: ~1000

pmax hadron for PID:-5<h<-1: < 10 GeV-1<h<-1: < 5 GeV 1<h<5: < 50 GeV


Lepton Identification

E.C. Aschenauer

20 GeVx250 GeVhadronphotonelectron

no cuts applied

hadron/photon suppression factor needed for pe’>1GeV:-4<h<-3: >100-3<h<-2: ~1000-2<h<-1: > 104

pmax hadron for PID:-5<h<-1: < 30 GeV-1<h<-1: < 10 GeV 1<h<5: < 100 GeV


Fast Simulator: What was modeled Magnetic field: Solenoid with 3.0 Tesla Tracking:

“Central” +/-1: TPC-like: 45 fit points; 0.03 radiation length, position resolution: 80 m

“Forward” 1-3: GEM-like: 6 planes; 0.03 radiation length, position resolution: 80 m

“Far Forward” 3-4.5: Si-Pixel-like: 12 planes; 0.03 radiation length, position resolution: 20 m

radiation length needs to be checked no bremsstrahlung for electrons yet

Ecal “Central” +/-1: like submitted proposal

10%√E+1.5% hadron: MIP + 0.4Eh with s=0.2Eh (50:50) “Forward” 1-5: like submitted proposal

10%√E+1.5% hadron: MIP + 0.4 with s=0.2Eh (50:50) “Backward” -1 to -5: PWO crystal calorimeter

2.5%/√E + 0.9% + 1%/E hadron: MIP + 0.4Eh with s=0.2Eh (50:50) “Hcal:

Forward” 1-5: like current STAR forward R&D project: 38%√E+3%

E.C. Aschenauer


Fast Simulator: Check Used fast smearing simulator

multiple scattering and momentum smearing included according to PDG

check against STAR results at central region looks okay for details: https://wiki.bnl.gov/conferences/images/d/d1/R%26DOctoberSmearing.pdf

-1< h <1assumed 0.05 radiation lengths

E.C. Aschenauer


Momentum resolutions

E.C. Aschenauer

0.5<h<1.5 1.5<h<2.5

2.5<h<3.5 3.5<h<4.5

To improve momentum resolution for

h>3need to look in Magnet design with

more radial field

EIC Detector R&D Committee Meeting, October 2012 14E.C. Aschenauer

compare performance of tracking to F_L requirements as determined by Chiapas

want plot to compare Calo. resolutions with tracking for different rapidity


Improve Momentum Resolution: Magnet Design

E.C. Aschenauer

Discuss on one slide our results for the ILC-concept 4 magnet vs. normal Solenoid


Resolution for E/p

E.C. Aschenauer

Ee: 5 GeV Q2>1 GeV -1<h<-1 Ee: 20 GeV Q2>1 GeV -1<h<-1

1<p<3

7<p<9

1<p<2

4<p<5


Resolution for E/p

E.C. Aschenauer

Ee: 5 GeV Q2>1 GeV -2.2<h<-1 Ee: 20 GeV Q2>1 GeV -3.7<h<-1

1<p<3

7<p<9

1<p<2

4<p<5


LHC-b: possible RICH design concepts

E.C. Aschenauer

RICH-1 (modern HERMES RICH) RICH-22<p<60 GeV 17<p<100 GeV25-300 mrad 10-120 mrad5cm Aerogel (n=1.030) ~200 cm CF4 (n=1.0005)85 cm C4F10 (n=1.0014)


Cerenkov and momentum resolution

dp/p<0.1% dp/p< 1.0% dp/p< 3.0%

p K p

E.C. Aschenauer

no resolution due to photon detector is yet modeled momentum resolution absolutely critical for good p, K, p separation

Exclusive Reactions: Event Selection

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proton tag method

o Measurement of t o Free of p-diss backgroundo Higher MX rangeo to have high acceptance (roman

Pots) challenging IR design

Diffractive peak

x L=p' zp z

≈1− x IP

Large Rapidiy Gap method

oX system and e’ measuredoProton dissociation backgroundoHigh acceptance

MY

Q2

W

How can we select events: two methods

Need for roman pots

spectrometer

Need for Hcal in the

forward region

Scattered proton acceptance

E.C. Aschenauer


Main detector

Roman Pots

leading protons are never

in the main detector acceptance at

EIC (stage 1 and 2)

eRHIC detector acceptance

Cuts: Q2>1 GeV, 0.01<y<0.95, Eg>1 GeV

Increasing Hadron Beam Energy: influences max. photon energy at fixed hIncreasing 30 GeV < √s < 170 GeV photons are boosted from symmetric to negative rapidities

5x100 GeV 5x100 GeV20x250 GeV

t-Measurement using RP

E.C. Aschenauer


Accepted in“Roman Pot”(example) at s=20mPlots from J-H Lee

Quadrupoles

acceptance

10s from the beam-

pipe

• high‐|t| acceptance mainly limited by magnet aperture

• low‐|t| acceptance limited by beam envelop (~10σ)

• |t|‐resolution limited by– beam angular divergence ~100μrad for small |t|– uncertainties in vertex (x,y,z) and transport– ~<5-10% resolution in t (RP at STAR)

Simulation based on

eRHIC

REQUIREMENTS• Acceptance at large-|t|

proper design of quadrupole magnets

• Acceptance in the whole solid angle

• High momentum resolution

• radiation hardness

Photon-Lepton discrimination

E.C. Aschenauer


g

eDq

N.B. - Need for a ECal with a granularity to distinguish clusters down to Dq=1 deg

This is also important for Df calculation in asymmetries

measurement an for BH rejection in the xsec measurement

BH rejection

E.C. Aschenauer


In DVCS most of the photon are less “rear”Than the electrons:(θel-θg) > 0 rejects most of the BH

BH and DVCSBH dominated

BH Rejection

E.C. Aschenauer


Eel

EγEel

Eel

Eel

Eγ

Eγ

Eγ

1. BH electron has very low energy (often below 1 GeV)

2. Photon for BH (ISR) goes often forward (trough the beam pipe)

Important: ECal must discriminate clusters above noise down to 1 GeV


Start full Geant Simulations

E.C. Aschenauer

Postdoc Alexander Kiselev started 3rd of Dec. 2012 Framework: virtual MC using FairRoot


Cross section:

Pythia sep: 0.030 – 0.060 mbLuminosity: 1034 cm-1 s-1 = 107 mb-1 s-1

Some thought about rates

E.C. Aschenauer

low multiplicity4-6 √s = 40-65 GeVNch (ep) ~ Nch (eA) < Nch(pA) no occupancy problem

Interaction rate:300 -600 kHz


Summary

E.C. Aschenauer


BACKUP


Executive Summary-----------------------------Physicists representing several of the current EIC R&D efforts met for two days at Brookhaven Lab. Thepurpose of the meeting was to consolidate simulation efforts to most efficiently formulate:

1) Physics-driven detector performance constraints.2) Radiation dose estimates (including machine-specific backgrounds).3) Coherent simulation strategies.

Presentations included discussion on:

* The physics scope of EIC.* Processes that drive detector performance.* Current software efforts.* Available computing resources.* Detailed machine designs.* Current machine-background estimates.

In the concluding session, the participants formulated both their broad goals and a short-term To-Do list.

BROAD GOALS:1) Formulate Requirement Tables/Maps.Each requirement table/map stipulates the limiting values of a detector performance parameter (e.g. dp/p,material budget, PID purity) as functions of both polar angle and particle momentum. These tables/maps inprinciple can be made for each driving physics process.

2) Formulate a Dose Table/Map.Dose Tables/maps specify the radiation load on detector systems from various sources (collisions,backgrounds) as functions of detector location.

3) Build a Full Simulation.The full simulation should follow modern coding practices as a "virtual simulation framework" (e.g. FairRootor GEMC) and incorporate both physics and background sources.


4) Formulate Systematic Error Estimates.EIC will be systematics-limited, not statistics-limited. Experimental sources of systematic error(calibration, scale determination, final state radiation, machine background) should be evaluated relativeto attainable theoretical uncertainties. Clearly this task requires the detailed full detector simulationfor measurements of inclusive, exclusive, and SIDIS channels.

SHORT TERM TO DO LIST:1) Constraint Maps:Develop requirement maps for SIDIS & DVCS to complement those for inclusive cross sections.

2) Dose Maps:Starting with the physics dose map, add backgrounds from the electron beam (bremsstrahlung) and hadron beam(beam-gas).

3) Simulation Development:a- Implement a double-solenoid field map.b- Stipulate by Email and Phone Conference the radial budgets for detector subsystems.c- Assign initial coding options to people with appropriate interests.


lepton kinematics

E.C. Aschenauer


Simulation Example

E.C. Aschenauer

Cuts: Q2>1 GeV, 0.01<y<0.95, z>0.1


Integration into Machine: IR-Design

E.C. Aschenauer

space for low-Q e-tagger

Outgoing electron direction currently under detailed design detect low Q2 scattered leptons want to use the vertical bend to separate very low-Q e’ from beam-electrons can make bend faster for outgoing beam faster separation for 0.1o<Q<1o will add calorimetry after the main detector


Emerging Detector Concept

Backward SpectrometerFor very low Q2-electrons:

Magnet 2-3T

space for low-Qe-tagger

E.C. Aschenauer

high acceptance -5 < h < 5 central detectorgood PID (p,K,p and lepton) and vertex resolution (< 5mm)tracking and calorimeter coverage the same good momentum resolution, lepton PID

Barrel: MAPS & TPC, Forward: MAPS & GEMlow material density minimal multiple scattering and brems-strahlungvery forward electron and proton/neutron detection Roman Pots, ZDC, low e-tagger


Kinematics of Breakup Neutrons

E.C. Aschenauer

Results from GEMINI++ for 50 GeV Au

by Thomas Ullrich+/-5mrad acceptance seems sufficient

Results:With an aperture of ±3 mrad we are in relative good shape• enough “detection” power for t > 0.025 GeV2

• below t ~ 0.02 GeV2 we have to look into photon detection‣ Is it needed?Question:• For some physics rejection power for incoherent is

needed ~104

How efficient can the ZDCs be made?


Diffractive Physics: p’ kinematics

5x250

5x100

5x50

E.C. Aschenauer

t=(p4-p2)2 = 2[(mpin.mpout)-(EinEout - pzinpzout)]

“ Roman Pots” acceptance studies see later?

Diffraction:

p’

Simulations by J.H Lee


proton distribution in y vs x at s=20 m

20x250 5x50

E.C. Aschenauer

without quadrupole aperture limit

20x250 5x50with quadrupole aperture limit


Accepted in“Roman Pot”(example) at s=20m

20x250 5x50

E.C. Aschenauer

20x250 5x50

GeneratedQuad aperture limitedRP (at 20m) accepted

Summary:

Still a lot of work to be done

But we have started to address all the important

issues integration of detector and forward particle

reconstruction into

machine design

Synchrotron radiation

………


Exclusive Vector Meson Production Golden channel: e + A → e’ + A’ +

VM‣ Only channel where t can be

derived from VM and e’‣ Detecting neutron emission from

nuclear breakup allows to separate coherent from incoherent

Dipole Cross-Section:

J/ψf

E.C. Aschenauer


Detection efficiency of Breakup Neutrons

E.C. Aschenauer

Results:With an aperture of ±3 mrad we are in relative goodshape even for 50 GeV Au beams• enough “detection” power for t > 0.025 GeV2

• below t ~ 0.02 GeV2 we have to look into photon detection‣ Is it needed?Assumptions:• Gemini++ is correct, was verified by SMM• E* ~ -t/2mN• Can we make a ZDC 100% (>99.9999%) efficient‣ do we understand neutron detection on the 10-4 level?

eic detector r&d simulation workshop summary

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