PHENIX High pt Upgrades -- Overview -- Yasuo MIAKE for High pt Upgrade Team highpt

PHENIX High pt Upgrades-- Overview --

Yasuo MIAKE for High pt Upgrade Team

http://utkhii.px.tsukuba.ac.jp/~highpt/

2 Yasuo MIAKE, Univ. of Tsukuba

Proposal

• To enhance the PID capability of PHENIX, we like to install Aerogel counters (160 segments) on the West Arm.

• Together with the Aerogel, TOF and RICH, we can extend the PID beyond 5 GeV/c.


Proposed Extention of PID with Aerogel

Pion-Kaon

separation

Kaon-Protonseparation

TOF ~100 ps 0 - 2.5 - 5

RICH n=1.00044

th~34

5 - 17 17 -

Aerogel n=1.011

th~6.8

1 - 5 5 - 9

0 4 8

0 4 8

0 4 8 0 4 8

0 4 8

0 4 8

Note ; Aerogel together with TOF can extend the PID capability upto 10 GeV/c(Without TOF, no K-proton separation at < 5 GeV/c)


Physics Motivations

• From basic strategy, it is natural extension for PHENIX to extend its PID in higher pt region.

• Strong motivation given;– Jet Quenching!?

– Large suppression of pions at high pt , while protons show binary scaling!?

• Meson/baryon puzzle?

• Need to extend PID > 5 GeV/c


Transition Region to Jet Fragmentation

• Hadronic Flow vs Flow at Quark Level?

• Seems to important to measure the transition region to Jet fragmentation.

• PID (pion, kaon, proton) beyond 5 GeV/c is the goal.


What STAR is doing

• We like to go beyond 6 GeV/c with pion, kaon and proton.


Aerogel Panel o the West

• 4.5 m from the vertex.

• Coverage ; full z, ** degree in phi.

• Space available for new TOF.

RφＺ

160 Cells

Aerogel(11x22x11 cm^3)

Integration Volume

PMT

PMT


Design of Aerogel Panel

• Direction of every other cell is reversed, so that– Aerogel locates at the same distance from

the vertex,– No dead space in between.

Side View

400 cm (16 Cells)

118 cm(10 cells)

30 cm

Z

Top View

rφ

r


Cell Design

11cm

11cm

22cm

Aerogelair

n=1.0112+- 0.0002

Prototype in run3-pp


PMT assembly (prototype)


Silica Aerogel

• Best index with RICH(CO2) is n< 1.007, too small.

• SP-12M (Matsushita) – Silica aerogel with Lowest

refractive index commercially available.

– Hydrophobic

• Long term stability proved by KEK-Belle.

Refractive Index (Measured) 1.0114 +- 0.0008

Density [g/cm^3] 0.04

Transmission for 10 mm (Measured) 64 % @ 400 nm88% @ 550 nm

Tile Size [mm] 112.5 x 112.5 x 11.0


1 p.e.

2 p.e.

PMT

• 3” PMT for photon counting

• Gain of > 10^6 at 1500 V w. 1-1-1-1- voltage divider

• One p.e. resolution


Bleeder

• Hand made bleeder– Thinner material– Less space– Less power (330 mW@1500V) than Hamamatsu standard– Tested upto 3.2 kV for 6 hours


Magnetic Field on the West

• Magnetic field of the location measured as < 8 G.– Goal set as 16 Gauss !

• Thickness & Size of the mu-metal shield has been optimized using Helmholz Coil.


Mu-metal Shield

• Magnetic shield of 0.2 mm thick breaks down at around 10 G. – Loss of Gain &

– Loss of Q.E.

• Magnetic shield of 0.5 mm survive till 20 G.


Final Prototype Test at KEK

• SP-12M

• R6233-01HA w. Bleeder

• Pre-Amp w. cables

• Dubna Box

• Normal ~ 14 p.e.

• Reverse ~ 12 p.e.


Observed Clean Signal

• Very clean separation– Amount of photons other than Aerogel Chrenkov is small!

+2 GeV/c

1 p.e. peak

~0.4 p.e./PMT

~6.6 p.e./PMT

Final Prototype Test


Observed Uniform Response

• Uniform response, thanks to Integration Volume– Important to separate in the momentum region of slow rise

• ~10% diff. between normal/reverse, due to diffusive nature of aerogel

Normal Reverse

Oops!


Uniformity Confirmed at Dubna

• Tested at Dubna with final prototype, but with SP-15.

• Independent setup & calibrations


Cherenkov Light from PMT window

• Cherenkov from PMT window;– Huge pulse height – Faster Timing (> 5 ns)

Time

Time

P. H.

P. H.Aerogel

(n=1.011)

PMT glass (n=1.5)


Background Rejection

• Photons from PMT windows can be identified/recognized by itself,– Faster Timing (>5 ns)

• Consistent with optical simulation

– ADC-ADC correlation

• Other sources of photons are carefully surveyed and <1p.e.

• TDC-TDC difference can be used for track association.


Simulation for PID Performance

• Assumptions;– HIJING Au+Au 200 GeV

– Aerogel;

• n =1.011

• Saturated at 14 p.e. w. poissson distr.

• Occupancy 10%

– RICH ;

• n =1.0044 (CO2)

• Saturated at 10 p.e. w. poissson distr.

• Occupancy 3.4 % (NIM)


Expected Proton Identification

• Require No-Aerogel & No-RICH

Occupancy


Expected Kaon Identification

• Require Aerogel & No-RICH (Need TOF for < 5 GeV/c)


PISA Activity

• All the known material put into PISA.

• Occupancy ~ 8 %

#of fired cell/ central event

~ 8% occupancyback ground sourcesseen in aerogel detector


Radiation Length by PISA

• <Lrad> ~20 %– Similar to TOF

Radiation Length [%] -->


Safety Issues

• Known issues; PMT-holder, HV protector

Item Fire Electrical

Status

1) Aerogel 2) Nyron(MC901) 3) Aluminum 4) Mylar5) Gore-tex6) PMT-Bleeder (G10)

-Estimated ?-?--

-----3.2 kV

NewNew---Tested

7) Signal connector PreAMP8) Signal connector Box9) H. V. Connector10) LED connector

UL94V-0UL91V-0/ UL94-0UL94V-0UL94V-0

300 V3 kV3 kV600 V

NewUsed at EMCalUsed at EMCal (but 3-pin)(Small type of )

11) Signal cable to PreAMP12) Signal Cable from PreAMP13) High voltage cable14) LED cable15) L. V. cable for PreAMP

UL ???UL-E108898?

?

?

NewNewLAN cable (Category-5E)?


Aerogel/PMT Preparation at Tsukuba


Box Production/Inspection at Dubna


Dubna Contributions

• Dubna contributions have been very important from R&D’s to productions.


Backups


Jet Quench via Flavor Dependences

• Gluons in QCD stronger interaction than quarks

– Gluon density in nucleon larger in small x, & gg > qq

• Larger energy loss of gluons than that of quarks

• dEq/dx < dEg/dx

• At high pt, some particles are fragmented more from gluon than quark jet.

– Gluon jets fragment into same number of particles and anti-particles.

– Gluon jets produce more particles ; softer distr.

• Effect of jet qunching can be seen in particle ratios.

• As an example, anti-proton/proton ratio..

PRC58(98)2321

Nucl.Phys B420(94)583PRD51(95)3436

Good demonstration of importance of PID at high pt

region


Occupancy Estimation

• TOF– ~ 100 cm2 at 5 m– Sensitive to all > 150 MeV/c– Backgrounds (low energy e/’s

from yoke & EM cal)– Occupancy 10% in Au+Au

• Aerogel of n = 1.01– Sensitive to all > 7.1– Delta rays in Aerogel (~%)– Muon from decayed pion– Backgrounds

• Using RQMD pt distr., occupancy of Aerogel estimated;– 10 % for 300 cm2 @ 4m– 5 % for 150 cm2 @ 4m

Estimation from pt distr. (RQMD)

TOF

Aer

TOF

(pt>0.18)

Aerogel

(pt>0.75)

Multiplicity 158 k 33 k

Segmentation 100 cm2 at 5m 300 cm2 at 4m

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PHENIX High pt Upgrades -- Overview -- Yasuo MIAKE for High pt Upgrade Team highpt