m. bonesini - 08/06/06 fermilab1 m. bonesini infn milano mice tofes construction & planning

M. Bonesini - 08/06/06 Fermilab

1

M. Bonesini INFN Milano

MICE TOFes construction & planning


2

Outline

Present design of TOF0 (TP endorsed)

BTF testbeam plans TOF1 design TOF2 design


3

Rates (Singles per ms) target insertion reduced to get 600 good mu+/sec (AUG05)

LAHET Geant4 MARS Average

TOF0 1722 1762 1508 1664

TOF1 813 832 712 786

Tracker1 771 790 675 745

Tracker2 629 644 551 608

TOF2 627 641 549 606

Good μ+ (Ev/sec)

621 635 544 600

6 pi beam from T. Roberts


4

1pi beamline design from D. Adams

TOF0 Distribution8 cm collimation, upstream of TOF0

Rate ~ 1.8 MHz (6 pi was 2.1 MHz)Xrms ~ 3.29 cm , yrms ~ 6.05 cm (6 pi was 3.5, 5.95)


5

Present design of TOF0From D. Adams & T. Roberts simulations a

40 x 40 cm2 active area and a 4 cm segmentation seems a good choice BC-420 scintillator bars 40 x 4 x 2.5 cm3 ordered at Bicron (emission peak ~390 nm) simple fish-tail lighguides UVT plexi


6

A detailed description of TOF0 and related tests (PMT, cosmics …) is in preparation and will be delivered soon as MICE note


7

TOF0 prototype mechanics:

Some barrettes (BC420 40 x 4 x2.5 cm3) ready with fish-tail lightguides + PMTs (R4998)

Additional barrettes with different scintillators (BC408/BC404/BC420/EJ230) and size (6cm witdth) ready

electronics + DAQ : QADC + TDC (V792 + V1290) in hands; no Nino-

chip DAQ (ftom JS) in hands


8

TOF frond-end electronics

3 choices, in order of difficulty:

1. CF discriminator + TDC only2. Splitter + L.E. discriminator/TDC +

QADC3. ALICE Nino chip (integrator+ fast

discriminator) + TDC


9

Discriminator choiceChoice between:

1. CF discrimininator : no need of time-walk correction no QDC line/splitter needed, but t is usually worse

2. L.E. discriminator: t is usually better, but a QDC is needed

3. ALICE NINO chip: it includes a discriminator + an integrator to make possible TOT correction (slightly equivalent to p.h. correction). According to ALICE coll. solution 3 is equivalent to 2

Problem: while solutions 1-2 are commercial ones (CAEN or …); solution 3 needs some R&D


10

The BTF testbeam

Testbeam 10-20 July allocated at BTFWe will have our DAQ based on CAEN V2718 (not use default BTF one, Labview based) We can test TOF resolutions, not rate effects (for this we can do only lab tests with our laser system)

Energy range

25-750 MeV e-/e+

Max rep rate

50 Hz

Pulse duration

10 ns

Current/pulse

1-1010 particles


11

What we plan to test in BTF, as regards TOF FEE

MICE baseline-1 solution: V1290 TDC + CF discriminator CAEN V812B (Mb-1)MICE baseline-2 solution: Harp splitter + V1290 TDC + QADC + L.E. discriminator. For the time being QADC will be V792, waiting for new CAEN QADC based on V1724, to be delivered end of this year (Mb-2)


12

Some considerations for TOFFE

MICE baseline-1 solution is easy and if works minimize manpower (our more delicate issue) we can try to adopt Mb-1 to proceed later to Mb-2 (still reduce manpower)

Real delicate point: choice of CF discriminator


13

What is needed for TOF at BTF

TOF0 prototypes equipped with R4998 PMTS – ready additional counters to be tested ( diff scintillator, lengths, fine mesh PMTs): useful for TOF1/2 – readyFinger counters to define precisely beam impact point available from MEG tests - requested HV/signal cables, splitters, NIM discriminators, VME modules – to be checked, but available CAEN VME CF discriminators – to be requested (EP Pool ?) DAQ (JS) – ready, cloned in Milano monitoring (JS) – ready pre-test with cosmics to debug full size counters: in preparation in Milano


14

TOF testbeam targets:

TOF0 with simple MCA Test time resolution at various positions with single particles

TOF0 with full DAQ Test time resolution at various positions with single particles Test time resolution with particle pile-up Make comparisons with TDC+CF discriminators and TDC+QADC

measurements

TOF1/2 with full DAQ Test time resolution with cheaper UPS-95F counters Test time resolution with bigger detectors Test time resolution with fine-mesh 1”,1.5” PMTs (if possible)


15

Some side considerations for TOF1/TOF2

up to know only fine-mesh PMT solution consideredBut problem: their cost has increased as respect to previous quotations by 50% !!!! (increase of cost of fine-mesh grids, according to Hamamatsu) , R4998 are better (smaller TTS, rate capability, …) and in a short time Hamamatsu may discontinue their production studies by J. Cobb+ H. Witte to see if we can change B// (not shieldable in conventional PMTs) into B_|_ (shieldable)


16

TOF 2 PMT geometry

Most of the following is just paste&cut from John&Holger notes/studies credits&questions to them


17

B field components at TOF2: no iron shield

From John&Holger 2-D computations


18

B field at TOF2: one 100 mm iron shield


19

B field is ~ 200 G //; ~ 0.1 T _|_


20

B field at TOF2 with 2 iron shields sandwiching TOF2


21

•B// ~ 40 Gauss, B_|_ ~ 0.13 T

•Problem: individual PMTs must be shielded with soft iron, but this implies a 3-D calculation to be completely sure

•Valuable option to be finalized

(conventional PMTs cheaper + better performances)


22

TOF1 baseline

48 x 48 cm2 active area (still OK?) if 2nd global shielding adopted: conventional PMTs request funds for 2007 (+ TOF0 electronics)


23

TOF2 baseline

60 x 60 cm2 active area (it was 48 x 48 cm 2 active area, as based on previous MC simulations …) if 2nd global shielding adopted: conventional PMTs request funding for 2008


24

Conclusions

up to now we are in schedule good news: Pavia (G. Cecchet et al.) will join us on TOF bad news: still pending full INFN approval (this gives problems for thesis, workshops use …) realistic requests: 2007 TOF0 electronics+ TOF1 ; 2008 TOF2

m. bonesini - 08/06/06 fermilab1 m. bonesini infn milano mice tofes construction & planning

Documents

adams slide

roberts slide

rd slide

cf discriminator tdc

qadc tdc v792 v1290

btf testbeam testbeam

new caen qadc

present design of tof0