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FMS Update FMS Update

FMS Update - PowerPoint Presentation

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FMS Update - PPT Presentation

Refurbishment for Run15 Stephen Trentalange August 16 2013 STAR Management Meeting StatusProblems with the FMS Run11 New management Run11Run13 Physics addressed Run 11 500 GeV A N for ID: 556773

pmt cells fms gain cells pmt gain fms large pmts damage problems radiation glass run lead repair time base

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Slide1

FMS UpdateRefurbishment for Run15

Stephen

Trentalange

August 16, 2013

STAR Management MeetingSlide2

Status/Problems with the FMS

Run11 New management

Run11-Run13 Physics addressed

Run 11 500

GeV

A

N

for

pions

: high

p

T

Run 12 200

GeV

A

N

for

pions

: topology/high

p

T

Run 13 500

GeV

A

LL

for

pions

; glue at low

x

Problems increasing with time:

Increase in gain variations in large cells ~50->~300

Graying of lead glass due to radiation damageSlide3

Tasks/People

Summer 2013

Remove FMS lead glass/unwrap cells (5mm)

Expose to sunlight (2mm)

Fall/Winter 2013

Fix large cell PMT bases (???)

Glue PMTs to lead glass (5 mm)

Re-wrap cells with aluminized

mylar

(3mm)

Summer 2014

Re-stack FMS (6mm)

Test electronics (3mm)

People:

Trentalange

/

Mondal

/

Dilks

/

Heppelman

/Marshall/Boone + extra UCLA/PSU/

StoneyBrook

/Valparaiso Students, as neededSlide4

FMS Problems: PMT Gain Drift

We

Gain jumps

Gain Drifts

PMT Base Circuit Diagram

LED Amplitude

vs

Time

10K Seconds

We can follow gain

vs

time with LEDs, but trigger becomes extremely unreliable.Slide5

Radiation Damage to Lead Glass

Damage inversely proportional to distance from

beamline

Radiation hardened lead glass positioned closest to

beamline

Problem much less for large cells

Run 12

Run 13

Day

Day

LED pulse

amplitudeSlide6

PMT Health

No Signal

Gain Jumps

Gain Varies

Multiple

Small cells :

Radiation damage

Large cells :

Gain problems

~41% (323) basesSlide7

Radiation Damage/Exposure to Sunlight

0 hours 15 hours 40 hours

300 500 700 900

Wavelength (nm)

300 500 700 900

Wavelength (nm)

Relative Absorption

Relative Absorption

Large Cell

Small CellSlide8

Repair of PMT bases

Bases potted in

insoluable

* rubber/ repair time is ~1+ hour/base + ~10-20 components

Risk mechanical damage to tubes, base components. Other 60% of tubes NOT repaired might fail in similar fashion.

* Checked alcohols, acetone, dimethyl chloride, gasoline, oils, acetic acid, heatSlide9

PMT Repair: Suggest new PMTs

(

Elke

Aschenauer

’’s contacts at

Fermilab

)

CDF D

ecommisioning Manager Jonathan Lewis offers 750 EMI 9954 (51mm) PMTs100 EMC 9814 (51 mm) availableSuggests D0/INFN may have moreAdditional request to George Ginther, D0 Decommisioning

Manager Additional ~900 Hamamatsu R580 (34 mm) These might be useful for the preshower detector.Slide10

PMT Replacement

Each tube/base needs testing

Glue/optical coupling?

HV/signal connectors and cables? Current FMS uses “bayonet”-style HV connector. May need to find/buy 788 SHV bulkheads for patch panel, plus 788

lemo

cables/

lemo-bnc

adapters

Additional problems?Slide11

Conclusions

FMS

Disassembly:

finished

Exposure to sunlight: in progress

100% for small cells

12%

of large cells

Repair of PMTs too difficult; exploring promising sources for new PMTs

Budget depends on connectors/style of new PMTs. ROUGHLY ~$20-40K?