1

Readiness of Forward Muon Arms for W Detection

Itaru NakagawaFor the PHENIX Muon Trigger

Upgrade Collaboration

22

1. Muon Tracking Chambers– 3 stations of Cathode strip

chambers– Each station has multiple planes

for redundancy– Slow read out -> No trigger

2. Muon Identifier– 5 layers of Iarocci tubes in x and y– 80 cm of steel plate absorber

(total)– Provides trigger p > 2 GeV

St#1

St#2

St#3

MuTr

Same configuration in SouthSame configuration in South

MuID

B

Current Muon System

3

Observed in Run9 pp

B

p,k

n

mfake High PT m

Study done by Yoshinori Fukao (RIKEN)

4

Efficiency Measurement with Cosmic Ray

cosmic High Efficiency underClean Circumstance!

Study done by Yoshinori Fukao (RIKEN)

MuTRG System Run09 performance

5

•MuID Algorithm•Track Matching w/ MuID•Timing cut w/ RPC•Track Matching w/ RPC•Neutron Backgrounds• Yoshimitsu Imazu’s Talk

•etc ..

MuTrg-FEE x MuID

Study done by Yoshinori Fukao (RIKEN)

6

Rate Dependence of MuID Rejection Power

•Can RPC substitute MuID?•Does RPC give better Rejection Power?

7

Road Map to Run11 Production Run

MuTRGMuTRG

RPC3

Run11

RPC3

absorber

Completed Installation of Absorbers

8

North Station-1

New Hadron Absorber

North South

35cm thickSUS310(2 interaction Length)

9

Final Muon Trigger Configuration

MuTRGMuTRG

RPC3

Run12

RPC3

absorber

RPC1

10

MuTr X-Talk

11

MuTr Cross Talk

HV (1800 V)

1 MWAnode wire

1 MW

100 pF ....

Cathode strips (96 strip)

~0.1 pF/strip

Rise time of anode signal ~ 10 nsec

Removed to reduce HV trips

Anode Readout

100mV

3V

Serious Issue for Big Pulse

Pointed out by Tsutomu Mibe@KEK

Decap

Doesn’t exist.

12

ADC

MIP

MIP

Event Display of ADC Distribution　

Strip

Gap 1Stereo

Gap 2Stereo

Gap 3Stereo

Gap 1NonStereo

Gap 2NonStereo

Gap 3NonStereo

Origin of Big Pulse -> Neutrons?

13

Can be serious issue at high rate

x2 (Run 11?) x5 (design)

Current set up

Recap (1/10? cross talk)

Luminosity

Rate

per

strip

(kH

z)

Run 9, 500 GeV data

10ms Pileup at 100kHz

14

SolutionHV (1800 V)

1 MWAnode wire

100 pF ....

Cathode strips (96 strip)

~0.1 pF/strip

Rise time of anode signal ~ 10 nsec

R<<1M W1 MW

Additional Circuit to let anode current escape to ground.

15

Pads for surface mount capacitorsLeft over Solder + Coating

To Anode Wire

MuTr Station-3 Anode Card

Capacitor (Removed)

16

North Station-3 Anode Gap

25mm28mm

Geometrical Constraint

Anode cards are only accessible from their back. Front pattern can only be visible using an inspection mirror.

17

Recap Clamp PrototypesR&D byYoshinori Fukao (RIKEN) Yoshimitsu Imazu (RIKEN)Kentaro Watanabe (Rikkyo)

18

Effect of Recap

19

Test Bench Setup

90Sr Source

Anode wire

Strip

#22

w/ and w/o Clamp

20

Comparison w/ .vs w/o Terminator

22

27

17

Trigger

w/o Clamp

Strip#

22

27

17

w/ Clamp w/ Clamp

Trigger

w/o Clamp

Comparison w/ .vs w/o Clamp

w/o Clamp

With Clamp

Strip Number

Aver

age

ADC

[cha

nnel

]Conductive Rubber

21

22

Neutron Absorber

23

The full muon arm again• Only 1/20 of all PYTHIA

events• Only MuTr St1• Y-scale is from old macro• Only neutrons from

upstream of St1

Neutrons in St1 Current setup SS310 absorber +SWX207HD5 Only SWX207

Thermal Neutron

• Origin of Big Pulse

• Thermal Neutron Absorber

Thermal Neutron photonAbsorber Borated Poly 2.5cm Pb 1cm + Fe 1cm

Attenuation ~10-2 ~5x10-2

€

11B + n→7Li* +α7Li*→7 Li + γ (478keV )

€

A + n(thermal) → (A +1) + γ(≤ 8MeV )

478keV

B 25mm Pb 1cm MuTr

25meV neutron

(e,g)

Fe 1cm 24

25

Summary• High Momentum Muon Trigger (MuTrig-FEE &

RPC3) is to be commissioned in Run11• Sufficient Rejection Power can be achieved, but

trade off of efficiency.• 99% Efficiency with Cosmic at High PT • Thermal Neutron is suspect degrades MuTr

performance– Neutron Absorber Partial Install– Recapacitation Clamp Prototypes to be tested in Run11

26

Backup Slides

27

Towards Successful Installation

28Fiber Scope

Alignment

Spacer determines Transversedirection within ~ 300mm.

Possible misalignment can be found by visual inspection using a fiber scope

Fiber scope shot

29

Electrical Contact

Readout socket

Readout BoardElectrical Contact will be confirmedby measuring Voltage using temporaryreadout tool.

To be removed after the measurement.

30

Installation Proposal

To be installed North Bottom Octants

31

Clamp Coating Max Current Average Current

w/o w/ <1uA <1uA

w/ w/o >100uA Tripped after 2 min.

w/ w/ 1uA 1uA

w/ w/o >100uA Tripped after 1min.

w/ w/ 2uA 2uA

Extreme Breathing Test

HV=1900VDuration 2min

32

MuTr Station-3

33

Recapacitation (Station-3)

Capacitorはすべて取り外し済み。Station-3 Chamberを取り出すの実質的に難しい。簡易的に取り付けられるクリップでグラウンドに落とす。

34

Coating

Anode CardParylene CPrint Kote

remover

Takes time, but removable

化学的に溶かすには 175℃でクロロナフタレンに反応して溶解（１時間以上）。事実上ムリ。

De-Capacitation(コンデンサーの取り外し）の際にパリレンが溶けてるのでは？

35

DAQによる測定

ADC>1000ch以上の事象

ADC>1000以上の大きなパルスを観測したとき、周辺のストリップには逆電価のシグナルが観測される。

…,13,14 31,32,……21,22,23…

90Sr線源

ストリップ番号

ストリップ番号

ストリップ番号AD

C [c

hann

el]

ADC

[cha

nnel

]

Anode wireを共有していない

Anode wireを共有していない

線源直下のストリップ

36

Low energy neutrons• Low energies• Fluctuation before

SWX needs investigation

• Suppression of very low energies might depend on input neutrons

behind SWX207HD5

before SWX207HD5