# Presentation: 432446

## STAR detector upgradesin relation toRHIC SPIN program

## Main Assumptions:

- The RHIC Spin Collaboration will write a report which:
- Describes the full spin program,
- provides context of beam and physics achievements and
- lists needs for future detection capabilites and instrumentation..
- The 5 and 10 week scenario’s will enter the document:
- Near the end to indicate their impact,
- i.e. not at as early constraints on the spin program!

## STAR detector upgrade program

- Requirements on the STAR detector upgrade

- Inner tracker (-1<||<1): Enhanced inner, high-rate tracking capabilities for heavy quark identification (charm/beauty) at mid-rapidity based on a precision micro-vertex detecter

- Endcap tracker (1<||<2): Improved forward, high-rate tracking capability to enable reliable charge sign discrimination for W boson decays

- Particle identification (-1<||<1): Full acceptance TOF barrel system to extend particle identification capabilities

- High rate TPC front-end electronics (FEE) readout and DAQ upgrade: Allow for maximal utilization of high luminosity RHIC operation (AuAu/pp)

- Forward calorimetry upgrade (2<<4): Enhanced capabilites to measure forward produced mesons

## Overview

- Integrated Tracking Upgrade

- APS pixel detector

- Barrel silicon tracker

- Forward silicon tracker

- STAR upgrade program

## Forward Meson SpectrometerConceptual Design

**Physics Motivations:  **
-  probe gluon saturation in p(d)+A collisions via...
-  large rapidity particle production (,,,’,,*K*0,*...*) detected through all  decays.
-  forward di-jet surrogates () probes gluons with smallest Bjorken-*x* in Au nucleus
-  di-jets with large rapidity interval (Mueller-Navelet jets)
-  disentangling dynamical origins of large xF analyzing power in p+p collisions.
-  longitudinal spin asymmetries for andrapidity correlations

- FMS is a 2m2m EM calorimeter built from existing lead-glass cells to replace the FPD west of STAR

## Forward Meson SpectrometerCost and Timetable

-  built from existing lead glass cells from IHEP, Protvino and FNAL
-  $0.8M proposal by Penn State University to FY05 NSF-MRI solicitation for high voltage, readout electronics and mechanical realization in January, 2005.
-  planned implementation in STAR by October, 2006

## Physics, status and timeline 

- STAR tracking upgrade: Physics, status and timeline

- Documented in STAR decadal plan and AGS/RHIC PAC

- The study of heavy flavors and W production: Upgrade of the STAR inner/forward tracking system
- Simulation work and design of detector layout based on silicon and triple-GEM technology (On-going R&D and prototyping effort) started
- Integrated tracking design of a new inner and forward STAR tracking system mandatory
- Staging of tracking upgrade in accordance with readiness of detector technology and beam development:
- Possible scenario:
- Stage 1: Installation of STAR Micro-Vertex Detector together with a minimal new barrel tracking detector based on silicon technology (-1 <  < 1) (Heavy Flavor Physics)
- Proposal APS Heavy Flavor Tracker early CY05
- Proposal Barrel after FY05 run
- Installation of new inner tracking system by summer 2008 (FY09 run)
- Stage 2: Upgrade of the forward tracking system (1 < < 2) (W physics)
- Proposal after FY06 run
- Installation of forward system by summer 2009 (FY10 run)
- Dedicated time for machine development with polarized protons to achieve high luminosity and high polarization is vital for the success of this novel program!

## STAR tracking upgrade: Conceptual layout

- APS pixel detector

- Barrel silicon tracker

- Forward silicon tracker

- Triple-GEM tracker

- Solidworks design

## Comments on STAR tracking upgrade

- STAR tracking upgrade in RHIC SPIN document:
- Not yet a full DOE proposal!
- Plans and work in progress!
- Relation to other DOE proposals:
- ToF
- APS Heavy Flavor Tracker
- DAQ upgrade
- Communication to DOE Nuclear Physics:
- Funding profile and sources:

## STAR RHIC-SPIN program 

- STAR RHIC-SPIN program

- Comprehensive study of the spin structure and dynamics of the proton, in particular the nature of the proton sea, using polarized protons: “RHIC SPIN Baseline program” (DOE review, June 2004)
- Gluon contribution to the proton spin using various probes involving:
- Final-state jets such as inclusive jet production and di-jet production (Short-term)
- Inclusive 0 production (Short-term)
- Prompt photon production (Long-term)
- Heavy-Flavor production (Long-term)
-  Flavor decomposition of quark and anti-quark polarization in W production (Long-term)

- Heavy flavor production

- Unique test of partonic aLL
- Sensitive to gluon helicity with low background from quark helicities
- NLO formalism available (Bojak and Stratmann)

- Low energy

- Massless-Q limit

- Typical STAR range

- M. Karliner and R.W. Robinett,
- Phys. Lett. B324 (1994) 209.

- STAR tracking upgrade - Heavy flavor production

## Flavor decomposition of quark and anti-quark polarization 

- W± production in pp collisions forms the best means to probe the flavor structure of the proton sea

- Flavor decomposition of quark and anti-quark polarization

- STAR tracking upgrade - W production

- Semi-inclusive DIS - sensitivity reduced by fragmentation functions and e2q weighting

- B. Dressler, Eur. Phys. J. C14 (2000) 147.

- Q2=2.5GeV2

- Q2=2.5GeV2

- Parity violating single-spin asymmetries at RHIC provide access to the quark flavor structure of the proton spin:

- J. Kiryluk

## Simulated forward pT resolution (1 <  < 2)

- Simulated fast tracking configuration:
- Inner (fast) configuration: 3 silicon layers
- Outer (fast) configuration: 2 triple GEM layers

- Forward pT reconstruction: -
- True pT = 30 GeV
- Range in : 1 <  < 2

- Reconstructed pT for various detector configurations:

- STAR tracking upgrade
- Integrated tracking approach of pixel upgrade and inner silicon upgrade in combination with forward GEM tracker!

- N. Smirnov (Yale)

- STAR tracking upgrade - Forward tracking

## STAR tracking upgrade - Organization matters

- Goal of STAR tracking upgrade working group:
- Work out the case for a proposal towards an upgrade of the STAR inner (-1<<1)  and forward (1<<2) tracking system which is required for the study of heavy flavor (AuAu/pp) and W production (pp)
- W physics case: Flavor decomposition of quark/anti-quark polarization
- Heavy flavor spin case (Strong dependence of partonic asymmetry on heavy quark mass- study of heavy flavor tagged jets): STAR Heavy flavor program driven by STAR’s relativistic heavy-ion  program
- Integrated tracking design of a new inner and forward STAR tracking system is mandatory
- Staging of tracking upgrade in accordance with readiness of detector technology and beam development
- Set-up of simulation tools, physics simulation studies and R&D work on triple-GEM technology has been started
- Participation so far from: ANL, BNL, IUCF, LBL, MIT, Yale, Zagreb,...
- Graduate students/Postdocs: 3
- Staff physicists/faculty: 15
- Engineers/technicians: 2
- Convenors: Ernst Sichtermann (LBL) and B.S. (MIT)
- Steering committee: G. v. Nieuwenhuizen (MIT), N. Smirnov (Yale), S. Vigdor (IUCF), H. Wieman (LBL)

## STAR tracking upgrade - Heavy flavor case

- Remarks on the physics case (1)
- AuAu heavy-flavor physics drives the STAR inner tracking upgrade
- Pixel detector proposal which requires a new pointing device (STAR SVT review)
- Potential heavy flavor spin physics case (gluon polarization) in polarized pp collisions
- Requirements:
- Secondary vertex reconstruction capabilities for central region (-1 <  < 1) in combination with the APS Heavy Flavor Tracker
- Intrinsically fast detector / readout system
- To be defined: Number of silicon barrel layers at what radius? Resolution? Readout speed? Occupancy?

## STAR tracking upgrade - W physics case

- Remarks on the physics case (2)
- Study of flavor decomposition drives an upgrade of the STAR forward tracking system
- Endcap calorimeter in combination with a new proposal towards a forward tracking system
- Complication in STAR with TPC: Tracking/Charge discrimination for high energy leptons break down in the forward direction
- Welcome ideas for use in Heavy Ion running,
- Requirements:
- e-/e+ charge sign discrimination in forward direction (1 <  < 2)  (Sagitta ~2.5mm for high pT ~30GeV tracks)
- Intrinsically fast detector / readout system
- To be defined: Number of silicon disks and location? Resolution? Impact of dead material in front of EEMC
- For both upgrades: Integrated mechanical design: **Integrated Tracking Upgrade **

## General considerations

Start from the beginning with an integrated tracking design approach which is based on:

Integrated mechanical design for the APS Heavy Flavor Tracker, barrel layers and forward disks
Design which is reflected by many silicon based inner tracking systems at collider detectors such as:  CDF/DO (Tevatron), ZEUS/H1 (HERA) and ATLAS/CMS (LHC)
First setup: APS Heavy Flavor Tracker and minimal barrel system 
Flexibility to upgrade inner-forward system and inner-barrel system at a later stage 
Assumption: TPC stays as such, FTPC is phased out and DAQ/FEE upgrade is completed 

Rely as much as possible on existing well established technology: 

Detector technology (Conservative choice: Conventional silicon strip and triple-GEM technology)
Readout systems (APV25-S1)

Report towards a full proposal to document the conceptual layout of an integrated tracker for STAR under preparation:

Physics motivation
Conceptual layout and technical realization
Timeline and Manpower
Infrastructure
Cost estimate

Profit from potential resources at existing STAR institutions in terms of man-power and infra-structure 

- Start from the beginning with an integrated tracking design approach which is based on:
- Integrated mechanical design for the APS Heavy Flavor Tracker, barrel layers and forward disks
- Design which is reflected by many silicon based inner tracking systems at collider detectors such as:  CDF/DO (Tevatron), ZEUS/H1 (HERA) and ATLAS/CMS (LHC)
- First setup: APS Heavy Flavor Tracker and minimal barrel system
- Flexibility to upgrade inner-forward system and inner-barrel system at a later stage
- Assumption: TPC stays as such, FTPC is phased out and DAQ/FEE upgrade is completed
- Rely as much as possible on existing well established technology:
- Detector technology (Conservative choice: Conventional silicon strip and triple-GEM technology)
- Readout systems (APV25-S1)
- Report towards a full proposal to document the conceptual layout of an integrated tracker for STAR under preparation:
- Physics motivation
- Conceptual layout and technical realization
- Timeline and Manpower
- Infrastructure
- Cost estimate
- Profit from potential resources at existing STAR institutions in terms of man-power and infra-structure

- Triple-GEM activities

- STAR tracking upgrade - Design

## STAR tracking upgrade: Simulation status

- Overall status of simulation

- Fast simulation
- PYTHIA input
- Poor man’s “geant”
- Study detector number, placement, resolution, etc.
- Develop basic track reconstruction tools:
- “standard” helix fit
- First application of standard helix fit to W decay electrons
- Full simulations (W+background)
- Heavy flavor

- Import design in GSTAR, ITTF:
- Full GEANT3 model (barrel/forward disks)
- Strip simulator
- Detector geometry in ITTF (New STAR track reconstruction)
- ITTF tracking in barrel region (Au-Au simulations)
- GEM tracker in GSTAR
- Forward ITTF tracking

## STAR tracking upgrade: Simulation status

- Fast simulator setup (Y-Z view)

## Status of triple GEM R&D effort

- Design of at least three triple-GEM chambers to be installed and tested at STAR under beam conditions:
- Profit from experience by COMPASS with triple-GEM technology (fast, precise)
- Establish collaboration to a US company to develop and manufacture GEM foils
- Manufacture 2D-readout structures
- Design of readout system using existing chip: APV25-S1

- R&D team:
- Collaboration between STAR/PHENIX: ANL, BNL, MIT, Yale
- Tech-Etch Inc. (Plymouth, MA):
- TechEtch is capable of producing GEM foils
- First results are encouraging in terms of overall gain values achieved
- SBIR proposal to DOE from TechEtch in collaboration with R&D team: Submitted December 10, 2004

- 7.1mm

- 8.1mm

- APV25-S1 chip

- STAR tracking upgrade: R&D status

## STAR tracking upgrade: R&D status

- Triple-GEM prototype chamber

- gas inlet

- gas outlet

- PC board incl. 2D readout-board and chip readout

- Triple-GEM volume

- 2D-readoutboard: Under preparation at Compunetics Inc.
- Hybrid: Available
- DAQ system: Under preparation
- Chamber mechanics: Under preparation

## Cost estimate for STAR Barrel and Endcap Trackers