phenix high pt upgrades recent progress

PHENIX High pt Upgrades

Recent Progress

Yasuo MIAKE

For High pt Upgrade Teamhttp://utkhii.px.tsukuba.ac.jp/~highpt/

2 Yasuo MIAKE, Univ. of Tsukuba

Plan Guestimate

• Coverage of 4 TOF panel equivalent as a first stage– 150 modules

– 300 PMT’s ; 12,000,000 yen

– 400 liter; 20,000,000 yen

– Total ; ~40,000,000 yen

• Since no space on the East, we install on the West.– Remove 2 lower TOF panels from

the East after successful pp measurements

– 1 spare panel

– 1 panel to be constructed

• TOF 1 panel ; 13,000,000 yen

TOF 1 panel ; 0.5 m x 2 m

If we install on the East,


Additional Cherenkov

• RICH– CH4;1.00044– CO2;1.00041

th= 34• Pion ; 4.7

GeV/c

• Aerogel– Best match at

1.005 – Commercially

available for 1.007 - 1.07

• Samples for test– 1.007– 1.01– 1.015

Pion

Kaon


Extended PID

Pion-Kaon

separation

Kaon-Protonseparation

TOF ~100 ps 0 - 2.5 - 5

RICH n=1.00044

th~34

5 - 17 17 -

Aerogel n=1.007

th~8.5

1 - 5 5 - 9

0 4 8

0 4 8

0 4 8 0 4 8

0 4 8

0 4 8

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


Aerogel Cherenkov at KEK-B BELLE

• Non-imaging Cherenkov

• 960 modules at Barrel, 228 at Endcap.

• Index n = 1.01 - 1.03

• 12 x 12 x 12 cm3

• 2 Fine-mesh PMT (1.5T)– R6683(3”) for n = 1.01

– R6682(2.5”) for n = 1.015

– R6681(2”) for n = 1.02

• ~ 10 - 20 p.e.

Journal of Non-Crys.225(1998)369


KEK Beam Test Setup

• Particle Identification– Gas C for electron– TOF for hadron ID

• KEK pi-2 channel– 1 - 4 GeV/c for momentum scan

Gas C for electron tagging

TOF for hadron PID

KEK-PS T496 Dec. 12 - 21, 2001


Photos (1)

• Many vistors, many students! It was fun!


Photos (2)

M. KonnoT. Takagi

T. TakagiT. Ohki

M. Ono


PMT selections

• PMT Requirements– Photon counting

• Gain; > 10**6• Low dark current

– Larger diameter– Cost

• Hamamatsu recommended– 2” ; R6231– 3” ; R6233

• UV PMT for the KEK test– R2059 ( 160 - 650 nm)

• Russian PMT’s ?

R329

R6231 R6233

No. Cost A few >400 >800

R6231 45,000 40,500 31,500 29,200

R6233 52,000 46,800 36,400 33,800

Nucl.Inst.Meth. 406(1998)213


Pulse height distr.of single p.e.’s

• 2” R6231

• Clean single photoelectron peak seen.

• Gain of 2x10**6 will be obtained.– Done by

Hamamatsu

– Will be tested at Tsukuba


Index of Aerogel

• Commercially available– Matsushita-Denko

• ~50k yen / litter• For the test experiments,

n=1.007 -8, 1.015, 1.020 have been purchased for the tests.

• Index measurements done.– Masahiro Konno

No. Index Measured

SSP-30D

1.007 - 8 1.007

+-0.002

SP-15A 1.015 1.018

+-0.002

SP-15B 1.015 1.017

+-0.003

SP-20A 1.020 1.020

+-0.001

SP-20B 1.020 1.021

+-0.001

SP-25 1.025

SP-30 1.030


Measurement of Refractive Index

• Surface condition of the sample dominates the error.

Masah

iro K

onn

o

n=sin(φ2+

α2)

sin(φ2)


Measurements of Transmission

• Shorter transmittance for shorter wave length.

• Shorter transmittance for smaller index.

Laser 355nm415nm532nm

355 nm415 nm

532 nm

Index 1.007 1.018 1.02

355 nm 0.6 1.0 1.3

415 nm - 2.0 4.4

532 nm 6.4 5.6 8.3

Measured Transmittance [cm]


Calibration of PMT

• Using solid state laser pulser (415 nm), PMT’s were calibrated before and after the KEK test.

• Measurements at various HV’s give consistent results.

HV 1800V

4.2 pe

)exp(!

)()( n

n

nnP

n−=

Picosec Pulser(Hamamatsu)

415 nm

PMT


Two Type of Designs

• Belle Type – Collect scattered photons

• Non-directional lights

• Area of photocathode/cell size

• 2 PMT per cell– more expensive

Belle Type Mirror Type

• Mirror Type– Collect direct photons

• Directional lights• Efficient way to get light!?

• Sophisticated mirror design?!• Easy to get larger cell size• 1 PMT per Cell

– Cheaper


Aerogel Signal for protons and pions

• Clear separation of protons and pions observed.

β = 0.9989

β = 0.9544

PID by TOF successful

+3 GeV/cPions

Protons

n=1.017


Features of Cherenkov Emission

• It is Cherenkov Emission.

⎟⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛ +−=

2

22

2max1

1p

pm

nNN

Belle; Tyvek

m = 0.14

p = 3.0

Belle ;Goretex

m = 0.14

n = 1.017

Np.e. vs. Momentum Np.e. vs. Index

€

N photonvisible ≈ 500sin2ϑ c [1/cm]

ϑ c = Cos−1(1

nβ)

€

Nmax = 500 ×q.e.×12 [cm]

≈1200 p.e.


Belle Type (1) Reflector

• Three types of reflector.– Tyvek

– Millipore

– Goretex

• Offline optical measurements at BNL says “Tyvek is good”

• Effect of reflector– Without reflector, < 1/4

• Reflector is essential for Belle Type

ReflectorPMT1 (p.e.)

PMT2 (p.e.)

Total (p.e.)

Goretex 12 13 25

Millipole 9 10 19

Tyvek 8 8 16

Black Paper

2 3 5

3 GeV/c pions

n = 1.017R6233(3”,non-UV)


Belle Type (2) Position Dep.

• With Goretex, >25 p.e. obtained everywhere.

• In each PMT, exponential behaviour is observed.– Goretex ; λ= 7.0 cm

– Tyvek ; λ= 5.5 cm

• Exponential shape may not be trivial issue?

3 GeV/c pions

n = 1.017R6233(3”,non-UV)

Goretex

€

e−x−xPMTλ

x


Belle Type (3) Angular Dep.

• Seems to be proportional to the thickness of the aerogel.– Scattered photons have no

directionality.

3 GeV/c pions

n = 1.017R6233(3”,non-UV)

θ


Belle Type (4) Area of Photocathode

• Put Iris-plate in front of the photocathode.

• Roughly proportional to the area of photocathode, S– Scattered photons have no directionality.

• Then, saturate with larger PMT coverage

3 GeV/c pions

n = 1.017R6233(3”,non-UV)

IrisS


Belle Type (5) Thickness Dep.

• Photons proportional to the thickness of the aerogel.– Consistent with;

• Angular dependence

• No directionality

3 GeV/c pions

n = 1.017

R6233(3”,non-UV)

L


Larger Cell of Belle Type

• Using exponential behaviour, we can estimate the performance for larger cell of Belle Type.– Smallest at the center

• We can estimate performance of Belle Type for any size, any thickness.

3 GeV/c pions

n = 1.017

R6233(3”,non-UV)

D

D

Npe at

theCenter


Mirror Type (1) Shape of Mirror

• Flat vs Parabola Mirror– Aluminized mylar sheet with

styro foam backing (hand made)

• No significant difference at the center as expected from the cone angle of 10 degree.

Mirror Shape Npe

Flat 9

Parabora 9

Mirror Type

3 GeV/c pions

n = 1.017R6233

(3”,non-UV)


Mirror Type (2) Position Dep.

• Expected Position Dep.– Relation of Cone angle ~ 10.1

deg. and PMT size

– Expected diameter ~ 3” PMT

• Broad peak at the center

• No significant difference between Flat and Parabola mirrors.

3 GeV/c pions

n = 1.017R6233

(3”,non-UV)


Mirror Type (3) Thickness Dep.

• Saturate!– Difficult to get more p.e.

– Due to short transmittance

3 GeV/c pions

n = 1.017R6233

(3”,non-UV)

L

Mirror Type


Bell vs Mirror

• Even with Mirror type, reflector is important !

Mirror Shape Npe

Flat (Tyvek) 9

Parabora (Tyvek) 9

Parabora (Goretex) 14

3 GeV/c pions

n = 1.017R6233

(3”,non-UV)

ReflectorPMT1 (p.e.)

PMT2 (p.e.)

Total (p.e.)

Goretex 12 13 25

Millipole 9 10 19

Tyvek 8 8 16

Black Paper

2 3 5

3 GeV/c pions

n = 1.017R6233(3”,non-UV)


Directional vs Scattered Photons

• Is the worse results with mirror type due to bad mirrors?– Note that it is hand made with

aluminized mylar sheet.

• Other way to measure Directional/Scattered photons.

• Rotate Belle Box and put the beam straight to aerogel and PMT.

• To remove signals from PMT window, subtract (b) from (a).

PMT

Aerogel Empty

Beam

(a) (b)

(a)

(b)


Measurements with 2” PMT

• Assume uniform angular distribution of scattered photons.

• Out of 17 p.e. (straight beam geometry), 8 p.e.’s are scattered photons.

17 p.e.

8 p.e.

6 p.e.

n=1.0172” PMT3 GeV/cTyvek

€

BackSide = exp(−λz)

0

10

∫ dz exp(−5λ )0

10

∫ dz

≅1.2 with λ =1/5 [1/cm]


Measurements with 3” PMT

• Guestimate of scattered components in straight geometry– 8 p.e. x *(8 p.e./6 p.e.) = 11 p.e.

• Thus, direct photons in straight geometry are 11 p.e., which is similar to direct photons observed with 2” PMT.– Consistent with cone angle of 10 degree.

22 p.e.

8 p.e.

n=1.0173” PMT3 GeV/cTyvek

Not mea

sured

!


Use of UV PMT

• Assuming cherenkov from uniform radiator, use of UV pmt will gain a factor of 2.

• Increase of 25 % observed with the straight beam measurements.– Not uniform at the level of

200 nm?

Non-UV (R6231)160 - 650 nm

17 p.e.

UV (R2059)

300 - 650 nm21 p.e.

Tyvek, n=1.015


Use of wavelength shifter

• Wavelengthshifter may increase the overall photon yield.

• Thanks to Prof. Peressedov, we could try POPOP at KEK.– Powder on aerogel surface

• Larger tail appeared with POPOP for pions!– Note POPOP localized only

on the surface of Aerogel.

!!


Use of POPOP powder

• Additional tail also appeared for protons.– Scintillation ?

• But, it is smaller tail than for those of pions.

• Need to investigate a way to uniformly distribute POPOP over the large volume not only the surface of Aerogel.


Novosibirsk vs Matsushita

With Non-UV PMT (R6231) With UV PMT (R2059)n=1.0072” PMT


Summary of KEK test

• Belle Type– It works; > 20 p.e.

– We can estimate performance of Belle Type with any cell size, any thickness.

• We understand pretty well.

• Mirror Type– ~ 10 p.e.

– Direct photons at most 10 p.e.

• Is there a better way to combine direct and scattered photons? Otherwise, Belle Type seems to be the best.

• Needs to be studied– Better mirror? (I’m pessimistic)

– UV vs. non-UV PMT

– PMT selections

• Gain too low?

• Russian PMT?

– Test of electronics

• Use of PMT amp?


GEANT Calculation

• Belle Type Aerogel counter installed in PISA.

T. Takagi

PHENIX

East ArmWest Arm


GEANT results

• Occupancy of 5 % seen in central Au+Au collisions (HIJING)

Backgrounds

z (c

m)

x (cm)

magnet

RICH mirrorAerogel

beam line

Number of fired cells per event


Optical Model


Summary of Status

(1) In December 2001, test experiment for the Aerogel Cherenkov have been carried out at KEK with visitors from Dubna.

(2) Both Belle type (aerogel w. 2 PMT's on the side) and Mirror type (mirror followed by 1 PMT behind the aerogel) have been tested. So far, best results (>20 p.e.) obtained from Belle type with 3" PMT's and Goetex as reflector, which is our backup solution now.

(3) We will continue R&D and test experiments for both mirror and Belle type. (Next test beam will be before the summer.)

(4) For the deltailed analysis of optical properties of the Aerogel, such as wavelength dependences of absorption length & scattering length, study with a laser and spectrometer is also in progress.

(5) Comparison of Aerogel from Matsushita and Novosibirsk gives interesting results; while similar results obtained when non-UV PMT was used, Novosibirsk Aerogel provides 20 - 30 % larger signal than that of Matsushita with UV PMT (Quartz window). As is reported in literature, Novosibirsk aerogel seems to have better optical transmission in UV. (According to Sumiyoshi at KEK, master of aerogel, more complicated process is adopted for production of aerogel at Novosibirsk.)

phenix high pt upgrades recent progress

Documents

index n

rich n

aerogel n

tof panel equivalent

index measurements

gevcwithout tof

smaller index

kek testr2059