A, Baldini, Pisa 10 maggio 200511
Richieste per l’esperimento MEG (in
costruzione)a) Timing counter: illustrazione dello stato attuale: richieste sblocchi s.j. per Genova e di sblocco + ulteriore assegnazione per Pavia
b) Calorimetro a Xenon liquido. Breve stato della PMT test facility. Richiesta di contributo all’acquisto di un acc. CW per la calibrazione
(piccola richiesta di sblocco s.j. M.E. per Lecce)
A, Baldini, Pisa 10 maggio 200522
a) TC: TC Final Design• A PLASTIC (BLACK PLEXIGLASS) SUPPORT STRUCTURE ARRANGES THESCINTILLATOR BARS AS REQUESTED
• THE BARS ARE GLUED ONTOTHE SUPPORT
• “LIGHT” INTERFACE ELEMENTS ARE GLUED ONTO THE BARS AND SUPPORT THEFIBRES
• FIBRES ARE GLUED AS WELL
• TEMPORARY ALUMINIUM BEAMS ARE USED TO HANDLE THE DETECTOR DURINGINSTALLATION
• PTFE SLIDERS WILL ENSUREA SMOOTH MOTION ALONG THE RAILS
A, Baldini, Pisa 10 maggio 200533
TC final design (PMTs interface to scintillators)
• PMTs ARE ATTACHED, BYMEANS OF THE INTERFACE SOCKET, TO THESCINTILLATOR BARS
• GIVEN THE MASS, AN ELASTIC AND REMOVABLE SILICONE GLUE ISAPPROPRIATE
• THE HOLLOW INTERFACEELEMENT IS A “CUSTOMDESIGNED”PROFILE THAT ADDS A MINIMUM AMOUNT OF MATERIAL BETWEENTHE FIBRES AND THE BARS
• SLOT FOR CABLES and OPTICAL FIBERS HAVE BEEN FORESEEN TOALLOW THE CABLES FROM THE INNER PMT TO EXIT
A, Baldini, Pisa 10 maggio 200544
Construction statusUnder construction• BC 404 scintillator bars• PMT sockets• Scint. Fiber adapter
To be define soon• Definition of the supporting structure and construction (july)• Insert APD read-out system in the final design (july)• APD amplifier PCB and production (end of sept.)• Validation test at BTF of 10 elements of curved detectors-june
(we are undertaking a preliminary test with cosmics)• Final construction of whole TC (sept-nov).• Estimate delivery of the timing counter end of november• Test @ BTF: december
Under study (advance status)• TC bag• TC curved detector pattern generator• TC linear detector DRS matching electronics
A, Baldini, Pisa 10 maggio 200555
Peltier Cell
Copper Cold Finger(~20°)
Scint. Fibers
Black Coating
APD
Heat Exchanger
Electronics boards -10 channels
Transition board
Kapton Flex.
APD intercalati con passo di 5mm
Vista lato frontaleAPD, sezione per la lettura di 10 fibre scintillanti
Vista sezione trasversale con, fibre, elettronica,cooling.
A, Baldini, Pisa 10 maggio 200566
TC bag inside cobra prototype design under study. Plastics considered: EVOH,
SARAN, FEP, Nylon 6, TEP Polyamide
A, Baldini, Pisa 10 maggio 200577
TC curved (trigger & pattern):
APD test system
Pulsed Laser
Integrating CalibratedPhotometer
Fast Photodiode
Photomultiplier
1/1000 attenuator
Splitters
APDCopper block
Peltier Cell
A, Baldini, Pisa 10 maggio 200588
Test of the CMS APDs (90% acceptance)
I dark vs H.V. Temperature 20°C
1.00E-03
1.00E-02
1.00E-01
1.00E+00
1.00E+01
2.50E+02 3.00E+02 3.50E+02 4.00E+02 4.50E+02 5.00E+02
H.V. (Volts)
I Dar
k @
10M
ohm
(Vol
ts)
APD0210117506_20ID_MAPD0107115426_20ID_MAPD8411087442_20ID_MAPD8418088162_20ID_MAPD8223084713_20ID_MAPD8201082393_20ID_MAPD1910145247_20ID_MAPD8024081013_20ID_MAPD8007079173_20ID_MAPD791478311_20ID_MAPD1908145087_20ID_MAPD1905144927_20ID_MAPD1906145007_20ID_MAPD1909145167_20ID_MAPD1913145407_20ID_MAPD1902144767_20ID_MAPD1903144847_20ID_MAPD1911145327_20ID_MAPD8206082873_20ID_MAPD1222134415_20ID_MAPD1212133615_20ID_MAPD1211133535_20ID_MAPD1213133695_20ID_MAPD1218134175_20ID_MAPD8710092535_20ID_MAPD8810094569_20ID_MAPD8822095449_20ID_MAPD8709092455_20ID_MAPD8722093575_20ID_MAPD8711092615_20ID_MAPD8811094649_20ID_MAPD8619091391_20ID_MAPD8601089791_20ID_MAPD1512138823_20ID_MAPD1511138743_20ID_MAPD1822144554_20ID_MAPD1812143994_20ID_MAPD1704141813_20ID_MAPD1720142933_20ID_MAPD1613140756_20ID_MAPD1611140596_20ID_MAPD1612140676_20ID_MAPD1616140996_20ID_MAPDJA0296_20ID_MAPDJA0302_20ID_MAPDJA0288_20ID_MAPDJA0307_20ID_MAPDJA0312_20ID_MAPDJA0308_20ID_MAPDJA0309_20ID_MAPDJA0311_20ID_MAPDJA0295_20ID_MAPDJA0289_20ID_MAPDJa0290_20ID_MAPDJA0292_20ID_MAPDJA0294_20ID_MAPDJA0316_20ID_MAPDJA0304_20ID_MAPDJA0305_20ID_M
A, Baldini, Pisa 10 maggio 200599
Richieste• Ge: sblocco di 2 K€ (inv.) + 32 K€ (app.) + 15 K€ (consumo) per elettronica e meccanica sistema APD• Pv:
•21 K€ (app.) per sistema di test PMT contatore long. • 20 K€ (app.) per realizzazione sistema di misura a doppisa soglia di discriminazione (utilizzabili 20K€ s.j. per RGA)• sblocco 10 K€ M.E. S.j.
• Le:• Sblocco 10 K€ M.E: s.j.
A, Baldini, Pisa 10 maggio 20051010
b) LXe calorimeter: Pisa PMT test facility
•Solution to the Zener noise problem OK•First 30 PMTs received at pisa on may 6th•PMT testing (3-4/day)
A, Baldini, Pisa 10 maggio 20051111
QE systematics
A, Baldini, Pisa 10 maggio 20051212
Purity dependence
• Despite the overall determination within 5% there are systematic dependences
• Amplitude dependence • Purity dependence
– can be explained with different distance from source
gain corrected
A, Baldini, Pisa 10 maggio 20051313
Nota interna MEG (MEG-TN027) per la CSN1
Metodi di calibrazione e monitor per il calorimetro di MEG e per tutto l’esperimento
A, Baldini, Pisa 10 maggio 20051414
Il controllo del calorimetro e.m. di MEG a rate di decadimento elevati e variabili
• frequent checks of calorimeter energy scale, linearity and stability• checks of LXe optical properties • energy resolution and spacial resolution• shower properties• at the right energy ( 53 MeV), but also at other energies.....
no single calibration method has all the required characteristicsuse complementary (and redundant) methods,
make the best use of their intrinsic properties emphasize the reliability of our experiment !
BR e ~10-13 Beam Intensity~5 107 /s
richiede
A, Baldini, Pisa 10 maggio 20051515
Wire presently mounted in “Large Prototype”
1) Am SOURCES ON WIRE AND WALLS
Potentialities :• PMT quantum efficiencies• Xenon optical properties• low-energy position and energy calibration• use in Xe gas and liquid• stability checks ?• a unique method for cryogenic liquid detectors !!
Sources in production.Soon available for all LXe devices.
Open problems:• will the method be usable under full intensity beam conditions ? To be verified by test !
A, Baldini, Pisa 10 maggio 20051616
reconstruction of the 8 -source positions in gaseous Xe. Recent measurement with the large-prototype.
(Po-source produced in Genoa)
A, Baldini, Pisa 10 maggio 20051717
RINGS IN
LIQUID XENON
the ring radiushas some dependence on
the Rayleigh scattering lengthin LXe
-range (2m) andwire shadow (100 m)
reflection on Al
A, Baldini, Pisa 10 maggio 20051818
Determination of the relative QE for 4 different PMTs of the large-prototype bythe use of 4 dot-wire-sourcesin Xe gas
the relative QEs are given by the slope of the linear fits.
A, Baldini, Pisa 10 maggio 20051919
A, Baldini, Pisa 10 maggio 20052020
MEG internal note e poi NIM collaboration paper
A, Baldini, Pisa 10 maggio 20052121
9 MeV Nickel γ-line
NaI 20 x 20 x 36 cmNaI 20 x 20 x 36 cm33
neutron generator
• Intensities from 106 n/s to 108 n/s• Typical pulse rate and pulse width 10 Hz and 1 μs • Time separation of direct from delayed reactions• Single pulse mode
2)THERMAL NEUTRON CAPTURE ON NICKEL
Potentialities :• switchable on-off• frequent (s, m,...) stability checks• system out of the calorimeter• Ni and Xe, prompt and delayed signals• probably: visible signal at full beam intensity• time reference
Open problems:• monitoring from calorimeter back• only at one location ?• some dispersed neutrons and radioactivity• test of the method at high beam intensity• useful test with the “large prototype” (already foreseen....., with Am/Be source)
D + 2H 3He + n Q = 3.27 MeV
D + 3H 4He + n Q = 17.59 MeV
Polyethylene
0.25 cm Nickel plate3 cm 20 cm
e5 beam onTg-on
Tg-off
A, Baldini, Pisa 10 maggio 20052222
large-prototype
in the large-prototypethe line is worse.....the measurement must berepeated, protecting LXe fromthermal neutrons by a Boron-foil
NaI
/E=2.5%
9 /(generated neutron)2x10-3
A, Baldini, Pisa 10 maggio 20052323
0 calibration…
Target
Anti Counter
up
tilt
down
Support structure: straightly up and downTilt mechanism at every height for NaI front to face target direction.
target
00
• Proton beam: 1.8mA• 0 Rate: 106 0/sec• Collimate: 2PMTs x 2PMTs ~ 150cm2
(1 position)• 1 /sec• # of PMTs on incident face: 216 PMTs (54 positions)• required: 10,000 evts/position
• takes 10,000 x 54=540,000 s ~ 6 d + time for movements !!
How often can it be How often can it be performed?performed?
A, Baldini, Pisa 10 maggio 20052424
an interesting possibility to speed-up the calibration
• abandon collimators and NaI detector in coincidence• illuminate the whole calorimeter at the same time with -1• convert the -2 in a 0.1 X0 converter close to the H2 target• detect conversion and measure conversion point with a Si-detector• measure e+ branch of the pair in the chambers• use part of the information for selecting -2 by trigger
angle between ’s defined by impact points on LXe-Cal and Si-detector(angles 1800 useful for calibrating at different energies)
loss at conversion but huge increase in solid angle
MC METHOD SIMULATION RESULTSA FULL TEST OF THE WIRE CHAMBERS
CAN ALSO BE PERFORMED !
A, Baldini, Pisa 10 maggio 20052525
Un evento
PhotonPhoton PositronPositron
ElectronElectronHydrogen target Hydrogen target + Tungsten converter+ Tungsten converter
A, Baldini, Pisa 10 maggio 20052626
Rough estimate of the time needed for the LXe
calibration <<>> (20 (20 30)/10 30)/1055/10 = /10 = (20 (20 30) x 10 30) x 10-6-6 RR = R = R00 x < x <> = > = (R(R00/10/1066)) x 10x 1066 x (20 x (20 30) x 10 30) x 10-6-6 = = (20 (20 30) x (R 30) x (R00/10/1066) Hz) Hz Events/dayEvents/day 8.64 x 10 8.64 x 1044 R R 2 x 102 x 1066 x (R x (R00/10/1066)) Assuming Assuming 50 locations50 locations to be calibrated to be calibrated (216 PMTs in groups of 4): (216 PMTs in groups of 4):
Events/day/location Events/day/location 4 x 10 4 x 1044 x (R x (R00/10/1066)) largely sufficient....largely sufficient....
Solid angle factorSolid angle factor
A, Baldini, Pisa 10 maggio 20052727
but also the Cockroft-Walton allows a calibration of the LXe Cal and of the wire-chambers
• CW use is much simpler than calibration ! • LXe Cal illuminated by 17.6 MeV ’s at high rate• Use of -converter for testing the wire-chambers• but maximum COBRA field for LXe Cal test• half COBRA field for wire-chamber test
WIRE CHAMBERS TEST
(at full COBRA field)by - p 0 n and -2 conversion into an e+ e–
pairand also
by - p n and conversion into an e+ e– pair
A, Baldini, Pisa 10 maggio 20052828
4) 500 KV PROTON ACCELERATOR AND LITIUM TARGET FOR A
17.6 MEV GAMMA LINE
Potentialities :• a unique nuclear reaction with a high energy -line • obtainable : at resonance (E p = 440 keV 14 keV) 106 /s (isotropic) for Ip 50 A• from LiF target at COBRA center; ’s on the whole cal. entrance face • energy and position calibration; shower properties; all over LXe cal.• monitoring at the back of the calorimeter• possibly front: rather frequent use , back: frequent use
Open problems:• compatibility with normal beam and target ?• COBRA field, accelerator and focusing element positions• project for easiness of target-tube mounting • p-beam divergence and protons on target; p29 MeV/c • post-acceleration to scan the resonance
[P.R. 73, 666 (1948), N.P. 21 1 (1960), Zeitschrift f. Physik A351 229 (1995)] 3
7Li (p,)48Be
A, Baldini, Pisa 10 maggio 20052929
37Li (p,)4
8Be
resonant at Ep= 440 keV =14 keV peak = 5 mbE0 = 17.6 MeVE1 = 14.6 6.1Bpeak 0/(0+ 1)= 0.720.07
NaI 12”x12” spectrum
1
0
Crystal Ball Data
A, Baldini, Pisa 10 maggio 20053030
511B (p,)6
12C
lower proton energy !lower rate at 50 A !!
another interesting possibility...... Cecil et al. NP A539 75 (1992)10x10 cm NaI crystal
resonant at Ep= 163 keV= 7 keVE0 = 16.1 MeV peak = 5.5 bE1 = 11.7 + 4.4 peak = 152 b
750 0/s (isotropic) 20.000 1/s for Ip 50 A
A, Baldini, Pisa 10 maggio 20053131
the High Voltage Engineering0.5 MeV Cockroft & Walton
model: “coaxial SINGLETRON”
with H+ plasma source
A, Baldini, Pisa 10 maggio 20053232
rails
cockroft
focusing elements(magnetic or electrostatic ?)
Cal. calibration from the target position, monitoring at the cal. back
at the cal. back the proton motion in the COBRA field must be studied
A, Baldini, Pisa 10 maggio 20053333
Z(cm)X(cm)
Y(cm)ρ ~0.8cm
Plane Z = 0 cm
Θ ~ 0.5 giroradius < 1 cm (Θ ~ 8 giroradius < 12 cm)
proton MC trajectoriesEp 440 keV 28 MeV/c !!
the protons are not reflected back by the varying magnetic field
A, Baldini, Pisa 10 maggio 20053434
The old Van der Graaf of the previous e experiment .......generates an e+ e– pair, at 17.6 MeV, seen in the GLAST calorimeter
A, Baldini, Pisa 10 maggio 20053535
RADIO FREQUENCY QUADRUPOLE ACCELERATOR
• practically monoenergetic• pulsed operation; frequency 100 Hz 100 s pulses• average current 50 A , pulsed current 5 mA• beam energy bin approx. 50 keV• small vessel• beam optical properties ? 1mm ; 20 mR • RF radiation ? No• proton source ? Plasma• cost ? !!!!!• special design....time to produce ? One year• not an out-of-the-shelf machine• Companies: AccSys, Neue Technologien GMBH
A, Baldini, Pisa 10 maggio 20053636
A, Baldini, Pisa 10 maggio 20053737
attempt to grade the different C&M methods
A, Baldini, Pisa 10 maggio 20053838
Conclusioni e richieste sulle calibrazioni
• Monitorare frequentemente la risoluzione in energia di fotoni (E >15 MeV) entranti dalla faccia frontale e’ l’unico modo diretto per tenere sotto controllo il fondo accidentale • Il metodo del 0 non puo’ essere usato se non una volta ogni qualche (6 –12 ?) mese perche’ si prevede una durata di questo calibrazione per circa due settimane.• Con il CW si puo’ pensare ad una calibrazione (forse) giornaliera.• Il CW consentirebbe un ulteriore numero di possibili calibrazioni e il miglior utilizzo del tempo fascio• Costo: 500 K€. Proposta di sharing al 50% con un gruppo di UCI (Bill Molzon)
2E
A, Baldini, Pisa 10 maggio 20053939
Dal MoU di MEG
Appendix 1. INFN contribution to the different subdetectors
Item Cost (K€)
LXe cryostat 400
PMTs test and purchase
600
Timing counter
700
Splitters 100
Trigger 400
Total 2200
A, Baldini, Pisa 10 maggio 20054040
LXenon• PMT 500 K€ -100K€• Criostato 200 K€ (criostato)
160 K€ (supporto + finestre) -40K€
Trigger• Prototipi 40 K€• Sistema completo 145+115 K€
-100 K€Timing counter• APD + fibre (interno) (160) 130K€
-30 K€• PMT (100: esterno) (315) 135 K€
-180 K€• Scintillatore 50 K€• Calibrazione 100 K€• Meccanica 60 K€Risparmio totale -225K€(rispetto ai 700 K€)
Splitters• Sistema completo 115 K€
+15 K€
TOTALE MoU 2200 K€Assegnato 1602 K€Previsto finale 1992 K€Risparmio 208 K€
Stime di costo aggiornatePrevisioni Assegnazioni Risparmi
Non previsti:• Software 22 K€
• Calibrazioni 50 K€
• PMT 170 K€
242 K€
A, Baldini, Pisa 10 maggio 20054141
Budget (K€)Calorimeter PMT 1756Lxe 845Vessel 400Various items 271Xe system 369Cobra Magnet 1175
Timing counter 700Trigger 400
Drift Chambers 149Muon transport 184DAQ Electronics 405Detectors environment 172HV 39
6865
Japan 2529Italy 2200PSI 1299
6028
Running costs - 2008 1303
+700 (400 PMT)
+500 (aumento costo Xenon: non previsto)