# Presentation: 226161

## experiment at RHIC, part 1 Achim Franz

- First Results from the

- experiment at RHIC, part 1 Achim Franz

**Notes:**
First part of a two part presentation highlighting first results from the PHENIX experiment at RHIC.

## Where is RHIC

- located at Brookhaven National Laboratory
- Long Island,
- New York

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

**Notes:**
RHIC is (was) visible from space and is located on Eastern Long Island

## Goals of the Relativistic Heavy Ion Collider

- Goals of the Relativistic Heavy Ion Collider

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

**Notes:**
One of the goals of RHIC is the search for and study of the QGP. A state of matter that existed at the beginning of the universe.
RHIC is very versatile with the possibility of accelerating many species of ions, but also polarized protons to study the spin properties of protons.

- The Quark Gluon Plasma, a phase transition

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

**Notes:**
Looking at the phase diagram of water as a function of temperature and pressure and sees the different phases, ice, liquid and vapor of water. When plotting a phase diagram of nuclear matter, ‘normal’ nuclear matter would be at low temperatures and ‘standard’ density. A neutron star would be very cold but very dense, the early universe very hot.

## Where is PHENIX

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

**Notes:**
This photo shows the BNL acceleratror complex with the Tandem, Linac, Booster, Alternate Gradient Synchr. And RHIC all playing together to bring heavy ions and polarized protons to RHIC. The 4 experiments are distributed along the ring with PHENIX at the 8o’clock position.

## Collaboration

**Brazil:   ****	****Sao Paolo**
**Canada: ****	****McGill**
**China:   ****	****Academia Sinica, CIAE**
**France:   ****	****SUBATECH**
**Germany:****	****Münster**
**India:      ****	****BARC, Banaras Hindu University **
**Israel:     ****	****Weizmann Institute**
**Japan: ****	****CNS, Hiroshima, KEK, Kyoto, **
**	**** ****	****Nagasaki, RIKEN, TITech., **
**	****	****Tokyo, Tsukuba, Waseda**
**Korea:****	****Korea, Myongji, Yonsei**
**Russia:****	****IHEP Protvino, JINR Dubna, **
**	****         ****	****Kurchatov, PNPI, **
**                  ****	****St. Petersburg STU**
**Sweden:  ****	****Lund**

**U.S. National Labs: BNL, LANL, LLNL, ORNL**
**U.S. Universities:  Abilene Christian, **
**	****Alabama-Huntsville,  California-Riverside, **
**	****Columbia, Florida State, Georgia State, **
**	****Iowa State, New Mexico,  New Mexico State,            **
**	****SUNY-Stony Book, Tennessee, Vanderbilt**

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

**Notes:**
PHENIX is a large international collaboration with about 250 scientists from 44 institutes and 12 countries.

## Collaboration Dec. 99

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

**Notes:**
This is about half the collaboration in out experimental hall at the end of last year, in the back you can see our central magnet and the beampipe.

## What is PHENIX 

- Search for and study of quark gluon plasma in relativistic **heavy ion** collisions @ s = 200 A GeV/c.
- Focus on lepton and photon signatures to probe early time in collision (but some hadrons signatures also)
- High rate, sophisticated triggers  rare and high pT processes

- What is PHENIX

- Study of spin physics in **polarized p - p** interactions
- 	@ 50  s  500 GeV/c.
- Spin of the proton; structure functions (e.g., G)
- Parity violating asymmetries (e.g., in W production) as a probe of new physics

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

**Notes:**
The name PHENIX 

## What does PHENIX do

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

## What does PHENIX do

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

## Successful Spin commissioning

- Single Snake Operation

- Injection with Spin Flipped : Asymmetry Flipped
- Adiabatically Snake on: horizontal polarization
- Accelerate equivalent to 180o rotation: 180o rotated

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

**Notes:**
Polarimeter worked nicely (CNI: coloumb/nuclear interference
                                            polarimeter, pC scattering, observe Carbon
                                            at 90 degree and t=0.1-1MeV. Analyzing power
                                           of polarimeter about 2% at 200keV (as measured
                                           in E950 last year -> AGS experiment to test
                                           CNI polarimeter.
the plots show the 2  measured polarization  components-> polarization vector 
The polarization rotates from the vertical to the horizontal if the snake is turned on (as expected). If the accelerated the phase of the spin at the position
of the polarimeter changes as expected (px->-px).

## What is PHENIX

- 2 “central” spectrometers

- 2 “forward” spectrometers

- 3 magnet

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

## Detectors installed/active this year

- BB 	Beam Beam Counter
- MVD 	Multiplicity Vertex Detector
- DC 	Drift Chamber
- PCx 	Pad Chambers
- RICH 	Ring Image Cherenkov counter
- TEC 	Time Expansion Chamber
- TOF 	Time Of Flight detector
- PbSc 	Lead-Scintillator Cal.
- PbGl 	Lead-Glas Calorimeter

- Central magnet:
-  ~9m high, 500t
- ∫ B dl = 0.78Tm @ 90°

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

## Detectors installed this year

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

## History

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

## IR

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

**Notes:**
At each of the 6 intersection regions the ‘blue’ and ‘yellow’ beams are brought together by a set of ‘D0’ and ‘DX’ magnets. Just after the DX magnet where the beampipes separates again all experiments have a common piece of equipment called the ‘zero degree calorimeter’ which is used for luminosity measurements and trigger purposes. Phenix uses in addition two Cherenkov counters called BBC, but more about this, in a minute.

## How to Characterize a collision

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

**Notes:**
First let me introduce a few keywords. The distance between the centers of the two nuclei about to collide
 is called impact parameter, once the nuclei collide the nucleons in the overlap regions are called participants all others spectators. 

## Zero Degree Calorimeter

-  Common to all experiments (Luminosity)
-  measure neutral energy within a 2 mrad cone about the beam direction, centrality trigger

- Zero Degree Calorimeter

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

## Beam Beam Counter

-  2x64 Quartz Cherenkov counter   wrapped around the beam pipe
-  start timing (40ps), vertex location
-  multiplicity

- Beam Beam Counter

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

## Trigger

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

## DataAQuisition

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

**Notes:**
A confusing picture and that is the intend. The PHENIX DAQ is set up to handle our many subsystems independently. The main points are the 350000 channels read out, the storage being a few miles away with a final data rate of 20MB/s and about 250TB per RHIC yr and hundreds of GB for calibrations.

## 							First Event

- 							First Event

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

**Notes:**
All this lead to the first Au Au collision observed in PHENIX. Tracks in the partly read-out drift chamber, hits in the BBC, Pad Chamber and energy clusters in the EMCal.

## 				Data

- RHIC machine studies and experiment commissioning: March thru June
- First collisions: June 15, 2000 at about half beam energy
- Initial operation (June) with 6+6 bunches yielded 500,000 PHENIX collisions.
- Final operation (July-September) with 55+55 bunches yielded nearly 45,000,000 PHENIX collisions!
- About five million events were put on tape, ~ 3TB of data !

- 				Data

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

## Correlations

- PC3 (east) vs PC1 (east)

- nTOF vs PC1 (east)

- PC1 (east) vs DC

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

**Notes:**
With so many subsystems PHENIX has t be sure we are looking at the same events. Plotted here are examples of number of hits for two detectors and some reconstructed tracks.

## Ring Image CHerenkov detector

- Ring Image CHerenkov detector

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

## TOF Particle Identification

**Note: **
**  ***** No slewing correction**
**  ***** Applied track association cut**
**               ****: ***********r *****= 5 cm**
**  ***** No acceptance/efficiency/decay **
**     ****corrections**

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

- So far for the first part;continue with
- Herr Prof. Dr. J. G. LajoieIowa State University

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

##  The Detection of the Quark-Gluon Plasma 

- A major challenge facing experimenters in the field is that signatures of plasma formation are numerous and theory gives no single clear direction.
- Some primary examples include:
- Deconfinement
- R() ~ 0.13 fm < R(J/) ~ 0.29 fm < R(’ ) ~ 0.56 fm
-  Chiral Symmetry Restoration
- Mass, width, branching ratio of   to e+e-, K+K-  with M < 5 Mev
- Baryon susceptibility, color fluctuations, anti-baryon production
- DCC’s, Isospin fluctuations
- Thermal Radiation of Hot Gas
- Prompt , Prompt * to e+e-, +-
-  Strangeness and Charm Production
- Production of K+, K-  mesons
- Production of , J/, D mesons
-  Jet Quenching
- High pT jet via leading particle spectra
-  Space-Time Evolution
- HBT Correlations of ± ±, K± K±

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

## Acceptance

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

## PHENIX Overview

- So far for the first part;continue with Prof. J.LajoieIowa State University

_**Central Arms**_
**Coverage (E&W)**
** ****-0.35< y < 0.35**
**   ****30****o**** <|********|< 120****o**
******M(J/********)=  20MeV**
******M(********)     =160MeV**

_**Muon Arms**_
**Coverage (N&S)**
** ****-1.2< |y| <2.3**
**  ****-********  < ********<******
******M(J/********)=105MeV**
******M(********)     =180MeV**
**3 station CSC**
**5 layer MuID (10*****X*****0****)**
**p(********)>3GeV/c**

_**Global**_**MVD/BB/ZDC**

- An experiment with something for everybody
- A complex apparatus  to measure
- Hadrons
- Muons
- Electrons
- Photons
- Executive summary:
_*High*_ resolution
_*High*_ granularity

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

## History

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

## MVD

-        The MVD consists of two concentric barrels of silicon strip detectors (300um thick and 200um pitch) around the beampipe and two disk-shaped endcaps of silicon pad detectors at z=+/- 35cm. The length of the silicon strip barrels is 64cm. Each barrel layer has six azimuthal panels and the two barrel layers are mounted on a common support structure made of light-weight, rigid Rohacell foam. The inner portions of the outer barrels are only partially populated with silicon in order to reduce the amount of mass in the electron arm acceptance. Each endcap is composed of 12 wedges, with each wedge manufactured from a single 4inch wafer.

- Parameters for MVD:
- Two concentric barrels of 300 m Si strips
- Two end-plates of Si pads
- Total coverage: -2.5 <   < +2.5

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

## BBC

-  2x64 Quartz Cherenkov counter   wrapped around the beam pipe
-  start timing (40ps), vertex location
-  multiplicity

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

## ZDC

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

## DC

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

## PC

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

## Ring Image CHerenkov detector

- Ring Image CHerenkov detector

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

## (Central) PID via Cerenkov

- Executive Summary:
- Superb electron/hadron discrimination
- Key Features:
- Ring imaging Cherenkov with gaseous radiator
- Radiator gas:ethane (n = 1.00082) or methane (n = 1.00044)
- Electron identification efficiency: Close to 100% for a single electron with momentum less than ~ 4 GeV/c
- Pion rejection factor: > 103 for a single charged pion with momentum less than ~ 4 GeV/c
- Ring angular resolution: ~ 1 degree in both and 
- Two ring separation:  ~  few degrees in both and 

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

## TEC

**24 TEC chambers arranged in 4, 6 chamber sectors installed on East carriage**
**Active area covers ********/2 in azimuth, ******** ******** 0.35**
**Each 3.7 m x 2.0 m chamber contains 2700  wires (~900 anodes channels each) **
**2 sectors x 4 chambers instrum. RHIC2000**
**4 sectors x 4 chambers to be instrum. RHIC2001**

**Performance Features:**
** ****High p****T**
**Single point track resolution of 250 microns**
**Large DC-TEC lever arm. Improves  mom. resolution  up to factor 5,     p****T**** > 4.0 GeV/c**
**Particle ID**
**e/π = 5% at 500 MeV/c using dE/dx (4 plnes)**
**e/π =1. 5% at 500 MeV/c using dE/dx (6 plnes)**
**Designed for TRD Upgrade . High mom.  e/π**
**Pattern Recognition**
**Robust track reconstruction at high track densities**

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

## TOF

** ****960 plastic scintillators**
** ****PMT readout at both ends of scint. ****(1920 ch.)**

_***Mechanical Design***_

_***Geometry***_

** ****located at 5 m from the vertex**
** ****-0.35 < ********< 0.35, ******** = 45 deg. **

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

## More TOF

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

## PBSC

- High particle density, broad dynamic range
- good granularity
- 	 =  = 0.01
- good energy resolution
- 	~8%/E
- good time resolution
- 	~250ps/E
- Pb-glass + Pb-scintillator
- 25,000 channels

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

## EM Calorimetry

- Executive summary:
_*High*_ resolution
_*High*_ granularity

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

## Muons

- Full instrumentation at mid-rapidity
- full hadron, electron photon program at =0
- Muons at 2.4    1.1
- good dimuon acceptance (and rate) at the J/

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000

## Muons

- Executive Summary:
- System of tracking (muTr), identifiers (muID) and absorbers (magnet yoke + muID plates) to absorb hadrons and identify muons with high resolution sufficient to separate
-  from -
- J/  from  ’  ( (M) ~ 90 MeV )
- (1s) from (2s+3s)
- muTr
- 3 stations of 3 cathode strip chambers (CSC) each
- Each CSC consists obtains s ~ 60 m from
- one fine cathode plane,  ~ 100 m
- one coarse cathode plane at a stereo angle of 22.5 degrees  to the fine cathode plane and has a resolution of ~ 3 mm
- anode plane which is perpendicular to the fine cathode plane and has a resolution of~ 3 mm.
- muID
- 6 walls of steel absorber interleaved with layers of plastic proportional tubes of the Iarocci type
- Low energy muon threshold of ~2.2 GeV.

- Achim Franz, BNL, PHENIX

- CAARI 11/02/2000