M. Bonesini - MICE Collaboration Meeting 9/10/06

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M. Bonesini INFN Milano

TOF status (mainly TOF0/1)

M. Bonesini - MICE Collaboration Meeting 9/10/06

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Outline

TOF2 (brief summary) upstream TOF (TOF0/1) Costs updates TOF0 design TOF1 design (PMT shielding) BTF testbeam

Conclusions

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TOF2 (brief summary)

project is a clone of upstream TOF0/1 design, aside dimensions (it was 48 x 48 cm2 now …) funds NOT requested to INFN for 2007: it will be staged to 2008 but it may be put together KLOE1 as a preshower, giving a lot of savings (discussions are going on with Ludovico). In this way a TOF2 in 2007 with recuperated PMTs … to be updated in 2008 (TOF2A).

M. Bonesini - MICE Collaboration Meeting 9/10/06

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Upstrean TOF0/TOF1: revised costs

TOF0 TRD design costs TOF0 updated costs

Conv. PMTs 64 KE Conv. PMTs 64 KE

mechanics 5KE mechanics 5KE

Scintillators+light guides 10KE Scintillators+light guides 5KE

cables 3KE Cables 3KE

Patch panels … 5KE Patch panels … 5KE

Laser syst (1/3) 22KE Laser syst (1/3) 10KE

FE electronics (QADC+TDC+L.E. discr+ splitters)

25KE FE electronics (TDC+CF discr)

18KE

HV voltage (1/3) 12 KE HV voltage (1/3) 9 KE

Total 146 KE 119KE

M. Bonesini - MICE Collaboration Meeting 9/10/06

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TOF1 TRD design costs

TOF1 revised design

PMTs fine mesh 87.5 KE Conv. PMTs 52KE

mechanics 5KE mechanics 8KE

Scintillators+light guides

10KE Scintillators+light guides

5KE

cables 3KE Cables 3KE

Patch panels … 5KE Patch panels … 5KE

Laser syst (1/3) 22KE Laser syst (1/3) 10KE

FE electronics(QADC+TDC+L.E. discr.+splitters)

25KE FE electronics(TDC)

18KE

HV voltage (1/3) 12 KE HV voltage (1/3) 9 KE

Total 169 KE 110KE

CAVEAT: prototyping, in-house manpower, lab test expenses and small consumables excluded

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FUNDS were requested for TOF0/1 from Mi Bicocca and Pavia groups to INFN for 2007 (~250 KEuro)

• not yet granted (but situation seems hard): for commissione V MICE does not exist for 2007 and at best they may come randomly

• 2006 funds (only for Milano) cover prototyping work + BTF testbeam+ partially TOF0 (really they were allocated for prototyping work NOT construction)

• all has influence on schedule: that is budget-bound not technically-bound (clearly NOW on a best effort base)

• The arrival of some new group (that can help partially INFN funding of TOF+MUCAL) can help much situation also with INFN management

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TOF0/1 design

mechanics+counters: defined aside dimensions for TOF1 (reduce them from 48x48 cm2 to 42x42 cm2 if possible). TOF1 counter width defined as 6 cm. PMTs: we advocate (with some caveats) same choice for TOF1 and TOF0 (see later) FE electronics:

TDC V1290 seems valuable choice, but needs interactions with CAEN

discriminators: under study, we have to finalize BTF analysis + possibly some tests with a cosmics testbench in Milano (LE vs CF)

Time walk correction: needs to finalize BTF testbeam study, to see if it is really needed: if so extra costs for QADC

M. Bonesini - MICE Collaboration Meeting 9/10/06

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Conventional PMTs shielding

TOF0 PMTs requires no shielding, aside 1 mm -metal due to small B field (B < 50 Gauss, Kevin private communication)

TOF1/2 even after the 100 mm global iron shielding needs some additional shielding to use conventional PMTs (as B// ~ 200 Gauss, B _|_ ~.1 T)

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B field with one 100 mm iron shield (current design)

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B field is ~ 200 G //; ~ 1000 G _|_

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Problem: R4998 can bare B_|_ but not B//

B//< 50 Gauss fine; B_|_ < 100-120 Gauss fine

add soft iron PMTs shielding

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B field with 2 iron shields sandwiching TOF (100 mm gap)

PMTs will be put at ~ 33-35 cm

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•B// ~ 40 Gauss, B_|_ ~ 1200 Gauss

•Problem: B-field perturbation from individual PMTs shielding has not been simulated: this implies a 3-D calculation

•Valuable option to be finalized (conventional PMTs cheaper + better performances)

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Br

B-field for different gaps

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Scanning the gap:

Near 100 mm shielding

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Scanning the gap II

center near 10 mm shielding

Remember: TOF1 PMTs volume will be inside a +- 25 mm box from gap center

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From presentation by G. Gregoire at PC-224 and J.Cobb at PID // session Close outer gap between to discs; thicker 2nd disc (50mm)

Somewhat more complex – engineering / mounting TOFs….

G. Gregoire Shield

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B_r

B_z

G. Gregoire scheme givesvery effective shielding for TOF1/2

500 gauss

-- 500 gauss

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Conclusions for TOF1 PMTs

use of conventional PMTs with ~1 mm -metal shielding + additional 10/50 mm global iron shield (Jon&Holger original proposal or modified G. Gregoire one)

valuable option for TOF1

Better timing Much lower cost (factor 2) and guaranteed production from

Hamamatsu Same PMTs all around Needs mounting of PMTs at r>30-33 cm: this is fine for present

design (TOF1 48 x 48 cm2), but if we reduce dimensions of TOF1 (say TOF1 42x42 cm2) needs revised design of lightguides (longer ones). NO REAL PROBLEM.

Bad: some extra work for additional global shielding, it may be integrated in TOF1 support structure

But need a 3-D field computation to check perturbation from PMTs individual shielding on B field

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The BTF testbeam

Testbeam at BTF for 12 days in July 06Data taken both with MCA (fast analysis) and full DAQ setup (full analysis) We have tested TOF resolutions, not rate effects (for this we can do only lab tests with our laser system) and some items of FE electronics

Energy range

25-750 MeV e-/e+

Max rep rate

50 Hz

Pulse duration

10 ns

Current/pulse

1-1010 particles

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electron beam finger 1

Bar 1

Bar 2

Bar 3 finger 2

PMT left scintillator PMT right

TOF bar

Discr PLS711

TAC Ortec 566

MCA Ortec Trump 8K

TAC measures (t_L-t_R): left start, right stop

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MCA Maestro analysis

data were analized online with the MAESTRO program (WINDOWS based) and later they were reanalized offline. You can measure only counter intrinsic resolutions, without corrections for time-walk.

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Comparison MCA analysis-PAW reanalysis

Left is BC420 re-analized data, next slide the original MCA Maestro data t~56 ps

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tps

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4cm width bars: UPS95F

t~56 pst~50 ps

Lightguide is a Winston cone

Lightguide is fishtail

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4cm bars: BC420

t~56 ps t~ 63 ps

Lightguide fishtail BC800

Lightguide fishtail REPSOL glass

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6cm bars: BC404, BC420, BC408

t~46 ps

t~45 ps

t~60 ps

Long non-gaussian tails

BC-404 / BC-420 seem equivalent, BC-408 (as expected) worse

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Position scan along a BC420 bar

• resolution is worse at the edges probably due to the PMT rough gain calibration (but still ~ 60 ps)

• x=0 cm is the edge of the bar, x=20 cm the center

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Conclusions for fast MCA analysis

BC420 scintillator seems more than adequate, but also low-cost UPS95F or BC404 are valid alternatives no gain from complicate lightguide design (Winston cone) as respect to simple fish-tail oneResolution with FAST conventional PMTs (R4998) seems better than with 1” fine-mesh PMTs results depend heavily on BTF beam instabilities, but intrinsic counter resolution is fine ~60 ps.

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Preliminary results From DAQ analysis

more complete check: you test also used TDC (CAEN V1290), used discriminators in real TOF measure, time-walk effects … ROOT files from JS analyzed by Yordan and Roumen + some hints from MB results still preliminary (some data sets not yet analyzed)

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Taken data:

data taken with 3 bars of different type data taken with different discriminators: L.E. CAEN N417, L.E. PLS 711, CF ORTEC 8000 data taken with different TDC: CAEN V1290, CAEN V775 QADC data (for time-walk corrections) available

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electron beam finger 1

Bar 1

Bar 2

Bar 3 finger 2

PMT left scintillator PMT right

TOF bar

In all the following transparencies from Yordan+Roumen with some annotations by me

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ADC pulse height distribution (left PMT of bar 1) Example of the general event selection cut

ADC spectrum inlogarithmic scaleSelection of single electron events

Part of the same spectrum in linear scale

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Intrinsic time resolution of TOF bars Run 141 – 149 Distributions of (Tleft – Tright )/2

TDC V1290

Bicron BC420 - 4cm thick impact point at 10cm from Center Discr CAEN N417σ = 63.91 ps

Bicron BC420 - 4cm thick impact point at centerDiscr CAEN N417σ = 66.18 ps

Bicron BC408 - 6cm thick impact point at centerDiscr CAEN N417σ = 109.7 ps

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Intrinsic time resolution of TOF bars Run 124 – 133 Distributions of (Tleft – Tright )/2

TDC V1290 Discr CAEN N417 Bicron BC420 - 4cm thick impact point at 15 cm from center (5 cm from edge)σ = 72.73 ps

Bicron BC420 - 4cm thick impact point at centerσ = 64.91 ps

Bicron BC408 - 6cm thick impact point at centerσ = 107.2 ps

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Intrinsic time resolution of TOF bars Run 215 – 217 Distributions of (Tleft – Tright )/2

TDC V1290

Bicron BC420 - 4cm thick impact at center Discr PLS 711σ = 44.22 ps

Bicron BC420 - 4cm thick impact point at centerDiscr PLS 711σ = 97.16 ps (PROBLEMS IN PMTs EQUALIZATION)

Bicron BC404 - 6cm thick impact point at centerDiscr PLS 711σ = 49.21 ps

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CAEN V1290 vs CAEN V775

• resolution with V775 TDC seems even better than with MCA analysis (41 ps)

• but from CAEN team intrinsic resolution of V1290 is 35 ps as compared to 28 ps of V775 (we have to understand the difference)

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TOF between two bars

Houston we have A problem (from WEB: originally reporting of a life threatening fault. Now humorously used to report ANY

problem).

TOF141-149.ps

We expect 85 ps from 60 ps single counter resolution , we see 140 ps

Remind TOF is double-plane (X/Y) so 80 ps means in reality 60 ps for real life MICE TOF measurements

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A first hint: time-walk Side plots point to a jitter/ time-walk problem of used discriminators needs to check with further testbeam data (with CF discriminator) requires some lab tests on discriminator

cutADC

ADCADC

rightPMTbar

rightPMTbar

rightPMTbar

1

21

Cut=0; 135 ps

Cut=.25 ; 125 ps

Cut=.10; 91 ps

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Time Of Flight and Time-walk effect Run 124-133

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2211left

barright

barleft

barright

bar ADCADCADCADCADC

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Conclusions

we need to finalize TOF1 size: guess 42 x 42 cm2 instead of 48 x 48 cm2

we advocate use of conventional PMTs for TOF1 + global shielding (G. Gregoire design ?) BTF analysis in course points to good intrinsic counter resolution, reasonable behaviour of V1290 TDC, but requires to think about discriminators/time walk corrections schedule $-bound