# Presentation: 415391

## Detector Designs for eRHIC

*Renee Fatemi*
*Massachusetts Institute of Technology*
*October 24, 2004*

## In case you missed it... eRHIC will provide:

- Longitudinal/Transversely Polarized electron beam (5-10 GeV)
- Possibility for polarized positron beam (10 GeV)
- Longitudinal/Transversely Polarized Proton beam (50-250 GeV)
- Light and Heavy nuclei species beams and possibility for He3!        (100 GeV/nuclei)
- Variable cm energies = 30-100 GeV
- e-p Luminosities ~1032-1034 cm-2s-1
- e-A Luminosities ~ 1030-1032 cm-2s-1
- Access to Q2=0-104 GeV2 +               0.7 > x > 10-4

- PANIC05

- Renee Fatemi

## Polarized DIS Program

| PHYSICS | Channel |
| --- | --- |
| 
G | Inclusive e’     
High pT di-hadron
Inclusive single+di-jet |
| Bjorken + GDH Sum Rules | Inclusive e’ from p/n |
| s | Scaling violations of g1 |
| s, c | g5 (deduce missing neutrino)
Semi-Inclusive Kaon A1 |
| Transversity | Dijets |
| Generalized Parton Distributions | Exclusive process e++Meson |
| Photon Structure function | G input -> detect single+di-jets |

*Need broad kinematic reach in x* *and Q**2 *

- PANIC05

- Renee Fatemi

## Unpolarized e-p/A

| PHYSICS | Channels |
| --- | --- |
| q from neutron | Inclusive e 
(high x/Q2) |
| Color Glass Condensate | Inclusive e (high Z + low x) |
| Multi-gluon exchange | Diffractive X-sec
(detect forward remnant) |
| FL  -> Gluon Distribution | High y inclusive e |
| s | Scaling of F1 
(constrain high x region) |

*First  possibility for e+ion collider *

- PANIC05

- Renee Fatemi

## Detector Requirements

- Precisely measure e' for large Q2 and x range
- Hadronic final state              (jets+meson PID)
- Missing Energy  Hermetic Design
- 0°  detector  radiative corrections
- Tagging of forward particles
- Proton remnant tagger
- Zero Degree Neutron Detector
- Incorporate all of this into 1 DETECTOR?  Talk about 2 Designs!

- Simulated ep DIS event (LEPTO)

**e******

**jet**

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- Renee Fatemi

## Region I:

- Q2 < 1, x > 0.01
- electron rear
- proton forward

- Region II:
- Q2 < 1, x < 0.01
- electron rear
- proton rear

- Region III:
- Q2 > 1
- electron barrel
- proton barrel

- Scattering Event Topology

**FORWARD**

**REAR**

**BARREL**

- PANIC05

- Renee Fatemi

## Design I:  MIT     ELECTRon-A

- A general purpose polarized/unpolarized detector

- B. Surrow
- J. Pasukonis

- Hermetic Detector inside +/-3m of machine element free region
-  Barrel and Rear Si-Tungsten EM Calorimeter
-  Forward Pb-Scintillator EM/hadron Calorimeter
-  Inner Tracker - high precision Si detector
-  Outer Tracker -  Triple GEM/micro-pattern technology (35ns Xing!)
-  Barrel Calorimeter and tracking in Solenoid Magnetic Field

- STARTING point...

- ~4.2 m

- PANIC05

- Renee Fatemi

**Notes:**
Typical HE detector with unique contraints - > LHC rate requires fast tracking (ATLAS/CMS)
Starting point - being fleshed out (35 ns crossing) 28 MHz  LHZ-> 40 MHz

## ELECTRon-A Design/Simulation Status:

- ELECTRon-A Design/Simulation Status:

- GEANT simulation of central detector (tracking + calorimetry) available
- Calorimeter cluster and track reconstruction implemented
-  Code available at: _[http://starmac.lns.mit.edu/~erhic/electra/](http://starmac.lns.mit.edu/~erhic/electra/)_
-  Next Tasks:
- Evaluate and optimize detector configuration
- Design forward tagging systems
- Incorporate PID detectors for exclusive processes
- Optimize forward detector for high-multiplicity eA  environment

- B. Surrow
- J. Pasukonis

- =0.5

- =0.0

- PANIC05

- Renee Fatemi

## ELECTRon-A Detector Response:

- Simulated ep DIS event (LEPTO)

- LEPTO && DJANGO DIS generators implemented

- B. Surrow
- J. Pasukonis

- Simulated eCa event (VNI)

- Top view

- Need to address high forward multiplicity in ion collisions

- PANIC05

- Renee Fatemi

## Possible “CDF/CLEO set-up” for R2D / eRHIC (very preliminary, needs a lot of simulation and R&D to optimize and select)

- SC Coil;  R = 1.5 m; Bz = 1.5 T

- EMC; Fe+Sc

- Si Vertex D.

- EMC, CsI crystal, ~8 X0

- AeroGel2 Ch. D.

- AeroGel1 Ch. D.

- GEM Tracking D.

- Barrel Tracking and PiD
- Variant A:
- Two TPC+Ch.D. systems.
- Pad Detectors with CsI
-   (UV converter) in the same
-  gas volume to use TPC
- “working” gas as UV radiator.
-  First; C4H10 (C2H6) ?
-  Second: CF4
- Maximum drift time ~10 μs
- TPC readout: GEMs+pads
-   + MicroPattern Gas Detectors
- Variant B:
-  5-6 layers of Si strip Detectors
-   + MicroPattern Gas Detectors
-   + RICH gas Detector

- Possible “CDF/CLEO set-up” for R2D / eRHIC (very preliminary, needs a lot of simulation and R&D to optimize and select)

-  200.

- EMC, CsI crystal, ~16 X0

- EMC; Fe+Sc

-      0.

-  300.

-  150.

- A, p, e-

- A, p

- End Cap Tracking and PiD
-  Si + MicroPattern Gas Detectors
-  + RICH gas Detector
-   ( or TRD in “e-side” , eRHIC)

- Hadron Calorimeter / Muon Detector

- RICH / TRD.

- RICH

- R

- Z

## Design II: MPI-Munich group

- Abt, Caldwell,
- Liu, Sutiak
- MPP-2004-90,
- hep-ex 0407053

- Central Si-Tungsten EM calorimetry inside a magnetic dipole field plus hadronic and EMC calorimetric end-walls.
-  Field focuses charged particles into detector volume - extending rapidity compared to existing detectors
- Tracking focuses on forward and backwards tracks.

- No tracking in central region
-  Requires 5m machine free region
- Forward hadron calorimeter follows existing ZEUS design

- Forward unpolarized ep + eA physics

- PANIC05

- Renee Fatemi

## MPI-Munich

- 14 Si-strip tracking stations
-  pT/pT ~2% resolution
-  Assumed hit resolution 20 m
-  Forward coverage to =6 over full energy range

- Calorimeter/tracking Detail

- PANIC05

- Renee Fatemi

## MPI-MunichKinematic coverage

- Abt, Caldwell,
- Liu, Sutiak
- MPP-2004-90,
- hep-ex 0407053

-  Full tracking for || > 0.75
-  No acceptance for central || < 0.5
-  Full W range down to Q=0.01 GeV2!
-  Hole in Q2 for E >100 GeV could be “filled” in with  mid-rapidity calorimetry

-  X  tracking coverage for e+

- For Ee < 6 GeV full acceptance for  0.5<<8

- PANIC05

- Renee Fatemi

## Status and Conclusions

- eRHIC provides a necessary facility for many of the most pressing QCD related physics questions
- Zeroth Order Design Report Submitted and Reviewed at BNL
- Highly Developed Forward Detector focused on very low/high x for unpolarized and CGC studies
- Design of mutli-purpose central detector, focused on inclusive measurements, has started
- May want to install detectors separately in two different IR’s or have staged installation in single hall.
- For more information see Bernd Surrow’s talk Sunday Oct. 30th *New Frontiers at RHIC*

- PANIC05

- Renee Fatemi

**Notes:**
Received by who?