# Presentation: 034881

## Prototype Performance of Novel Muon TelescopeDetector at STAR

- Outline:
** ****Motivation**
** **
** ****Simulation **
** ****Intrinsic timing and spatial resolution:**
**         ****  **Cosmic ray results
-              Beam test results at Fermi-lab
** ****Detector performance at STAR**
** ****Summary **

- Lijuan Ruan (for the STAR Collaboration)
- (*Brookhaven ** National Laboratory*)

- Lijuan Ruan (WWND2008)

- 04/11/2008

## The STAR Detector

**The STAR Detector**

**Magnet**
**Coils**
**Central **
**Trigger**
**Barrel **
**(CTB)**
**ZCal**
**Time **
**Projection **
**Chamber**
**(TPC)**
**Year 2000**

**Barrel EM Cal (BEMC)**
**Silicon Vertex Tracker (SVT)****Silicon Strip Detector (SSD)**
**FTPC****Endcap EM Cal****FPD**
**TOFp, TOFr**
**FPD**
**Year 2001+**

**PMD**

- _Large acceptance: 2____ coverage at mid-rapidity_

**Future upgrade: Time of Flight, DAQ1000, Heavy Flavor Tracker, Muon Telescope Detector**

- Lijuan Ruan (WWND2008)

- 04/11/2008

## Physics Goals at RHIC

-     _***Penetrating probes***_	         _***Bulk probes***_
**       **- “jets” and heavy flavor                           - v2  partonic collectivity
-                                  	                              - spectra at low pT, particle ratios.
-       _***Electromagnetic probes:***_
-         -  vector meson properties (,e+e-)  chiral symmetry restoration
-         -  thermal dileptons and photons  TQGP
-         -  quarkonia (J/e+e-)  color screening

**Physics Goals at RHIC**

- Lijuan Ruan (WWND2008)

- 04/11/2008

## Muons: Penetrating Probes 

- A large area of muon telescope detector
- (MTD) at mid-rapidity, **allow****s**** for**** ****the **** **
**detection of**
**di-muon pairs **from QGP thermal
-       radiation, quarkonia, light vector mesons,
-       possible correlations of quarks and gluons
-       as resonances in QGP, and Drell-Yan
-       production** **
**single muons **from their semi-
-       leptonic decays of heavy flavor
-       hadrons
**advantages over electrons: **no 
-       conversion, much less Dalitz decay
-       contribution, less affected by
-       radiative losses in the detector
-       materials

- Quarkonium dissociation temperatures – Digal, Karsch, Satz

- Lijuan Ruan (WWND2008)

- 04/11/2008

## Concept of Design

**Concept of Design**

**A**** pseudo**** ****detector**** ****with scintillator covering the whole iron bars and left the gaps in-between uncovered. **
- muon efficiency: 35-45%, pion efficiency: 0.5-1%
- muon-to-pion enhancement factor: 50-100
- muon-to-hadron enhancement factor: 100-1000  including track matching, tof and dE/dx
- dimuon trigger enhancement factor from online trigger: 10-50 ***(Guoji Lin, DNP06)***

- Detection efficiency

- pT (GeV)

- pion

- muon

***This **together with **DAQ1000** will greatly enhance our capability of J/**** ** **and other dilepton program in RHIC II and future QCD Lab ** *

- Lijuan Ruan (WWND2008)

- 04/11/2008

## Hadron Rejection at Intermediate pT

**Hadron Rejection at Intermediate p****T**

- pT (GeV)

-  Part of the hits come from the secondary muons from hadron decay. Some can be removed by using distance of closest approach (DCA) to the vertex on the corresponding track. ***Guoji Lin, DNP06***
-  Pion efficiency is ~0.5%, pion rejection is about 100 at intermediate pT; Kaons and protons can be rejected by TOF and dE/dx in TPC, hadron rejection is ~300.

- π+

- π-

- pT (GeV)

- Lijuan Ruan (WWND2008)

- 04/11/2008

## Novel & Compact Muon Detector for QCDLab 

**Novel and compact --------  Convention**  timing, position    track segments + fastHits
**Muon **is penetrating probe **J/****** trigger,  separate +- states
**QCDLab (RHIC II, eRHIC) **** **
- Works with accelerator **h****igh luminosity** upgrades
- R & D to address: spatial and time resolution, muon identification capability, trigger capability and hadron rejection power

- Lijuan Ruan (WWND2008)

- 04/11/2008

## Cosmic Ray Results: Long-Strip Multi-gap Resistive Plate Chamber Technology

- Long MRPC Technology with double-end readout
**HV: ********6.3 KV**
**gas mixture: 95% Freon + 5% isobutane**
**time resolution: ~60 ps**
**spatial resolution: ~1cm**
**efficiency: >95%**

***950 mm***

***256 mm***

***25 mm***

- Lijuan Ruan (WWND2008)

- 04/11/2008

## Fermi Lab Beam Test Setup (T963 May 2-15 2007)

**Test the performance of two long MRPC modules under different working conditions.  Comprehensive scans on  HV, gas mixture, position, beam energy, etc ... *****(T963 spokesman: Zhangbu Xu)***

- Lijuan Ruan (WWND2008)

- 04/11/2008

## Beam Test Results

- HV: 6.3 KV
- gas mixture: 95% Freon + 5% isobutane
- time resolution: ~60-70 ps
- spatial resolution: ~0.6-1cm
- efficiency: >95%
- consistent with cosmic test results

- Lijuan Ruan (WWND2008)

- 04/11/2008

## STAR-MTD in Year 2007

-  iron bars as hadron absorber
-  two scintillator trays as our trigger
-  403 cm away from TPC center, ||<0.25
-  gas: 95% Freon and 5% iso-butane; HV: 6.3 KV
-  MTD Triggered events: 380 K Au+Au events were taken

- Lijuan Ruan (WWND2008)

- 04/11/2008

## Performance at STAR 

-  MTD hits: matched with real high pT tracks
-  z distribution has two components:  narrow (muon) and broad (hadron) ones
-  spatial resolution (narrow Gaussian) is ~10 cm at pT>2 GeV; hadron rejection: 200-300
-  time resolution: 300 ps  Improve our electronics with full scale detector

- Lijuan Ruan (WWND2008)

- 04/11/2008

## Compared to Simulation 

- from data: pT>2 GeV/c, (z) of muon: ~10 cm
- from simulation: pT=2.5 GeV/c, (z) of muon: ~9 cm
- Data and simulation show consistent results

**muons**

**pions**

**muons**

- Lijuan Ruan (WWND2008)

- 04/11/2008

## Muon Identification: dE/dx Effect 

** ****the narrow Gaussian distribution: dominated by muons**

**|********z|<20**

- Lijuan Ruan (WWND2008)

- 04/11/2008

## Muon Identification: Cut on High Velocity 

**Muon Identification: Cut on High Velocity**** **

**1/********trackhits****- 1/********rawhits  ****>0**

- Lijuan Ruan (WWND2008)

- 04/11/2008

## Simulation: Are Muons Primary?

- From simulation:
- the hits from pion decay seem not to have a narrow Gaussian distribution in z
- further investigation by studying the DCA distribution in data and simulation

- + detection efficiency

- ● all hits
- ○ hits from π

- pT (GeV)

- Lijuan Ruan (WWND2008)

- 04/11/2008

## Summary and Future Plan 

- Cosmic and beam tests:
-                intrinsic timing resolution of long MRPC: ~60-70 ps
-                spatial resolution: ~1 cm
- The prototype of MTD works at STAR in year 2007. We observed:
-                   ---- clear narrow muon peak
-                   ---- hadron rejection: 200-300 (requiring track matching)
-                   ---- spatial resolution: ~10 cm, consistent with simulation
-                   ---- time resolution: ~300 ps
- The possible physics topics to do: electron muon correlation, muon spectra and v2 in run7 (2007) Au+Au collisions at 200 GeV
- The plan: analyze the data in run8 (2008) d+Au and p+p collisions

- Lijuan Ruan (WWND2008)

- 04/11/2008

## Towards the Future at STAR 

- Current hardware supports at STAR:
- HV supply for Long-MRPC: 2 channels from TOF
- Low voltage supply for read-out electronic boards: old TOF
- Gas system: share with TOF
- Gas control computer: share with TOF
- DAQ system: trigger, including DSM and 2 CDB
- VPD (start time detector): DSM
- This set up: run 9 at STAR as well;
- have a plan to install another tray with TOF electronics
- Towards the future:
- Collaborators for a proposal of full scale detector
-             Gas, VPD: share with TOF
-             Electronics: similar to TOF
-             HV, LV:  similar to TOF
-             Trigger: DSM and QT Boards

- Lijuan Ruan (WWND2008)

- 04/11/2008

## Novel & Compact Muon Detector for QCDLab 

**Novel and compact --------  Convention**  timing, position    track segments + fastHits
**QCDLab (RHIC II, eRHIC) **** **
- Works with accelerator **h****igh luminosity** upgrades
**Muon **is penetrating probe **J/****** trigger,  separate +- states;
-       vector meson;
-       thermal dileptons ...

- STAR Preliminary

- Lijuan Ruan (WWND2008)

- 04/11/2008