tof monitor system status f. harris u. of hawaii june 13, 2006
TRANSCRIPT
TOF Monitor System Status
F. HarrisU. of Hawaii
June 13, 2006
BESIII TOFCrucial for particle ID• Barrel
– Two layers, 88 counters each layer.– 50mm x 60mm x 2500 mm (inner layer).– Radius from 810 to 930 mm.– BC408
• Endcap– 88 fan shaped pieces – each end.– BC404
• Time resolution 1-layer (intrinsic):– Belle: 70 to 80 ps – Beam tests: < 90 ps– Simulation: < 90 ps
• K/ separation2 separation up to 0.9 GeV/c
TOF – IHEPTOF electronics - USTC
TOF Calibration System• Hawaii is building a TOF calibration system for BESIII.
(Fred Harris, Lucas Nguyen, Steve Olsen, Marc Rosen, and Gary Varner)
• Built such systems for both BESII and Belle. • Proposal approved in March 2006.• Important as system monitor and for calibration.
BESII system:
• Replace N2-dye laser with Laser Diode (405 or 440 nm)?– Simpler to use and
maintain.– Longer lifetime.– ~5 x 107 photons/pulse.– Peak power at low rep.
rate:• 405B -- 0.3 W• 405M – 0.6 W (new)
BESIII TOF Calibration System
PicoQuant GmbH LDH-P
Dark box
ADC
for LD
LD driver
TDC
...
CLK
Gate.G.
NIM TTL
attn.
Gate.G. NIM
TTL
attn.
start
gate
in
stop
Ref. PMT (ADC check)
diffuser fiber
bundle
LD
Ushiwaka Magnet Dark
boxfor R5924-70
Will it work?U. Tokyo Measurement System
Generation of Laser Pulse
NIM TTL
CLK
Gate.G.
NIM TTL
attn.
Gate.G.
attn.
LD driver
~ 1.8V(max.)
Trigger pulse
~ 10ns
LD
for LD
threshold
~ 1μs
Bias pulse
~550mV
~400mV
Laser Pulse!!
When we provide bias pulse and triggerpulse , LD generates intensive
pulse !
Uses non-standard pulsingsystem. Safe for BESIII?
Choice of Laser
• LD has many advantages; but is light sufficient with standard pulser?
• N2/dye laser has plenty of light and is considerably cheaper.
• Tentatively choose N2/dye laser initially. LD may be an upgrade.
• Measure efficiency of U. of Tokyo system to determine if LD with standard pulsing has enough light. Gary Varner.
TOF Monitor System
TOF endcap 48 fibers
TOF endcap 48 fibersLaser Light splitter
TOF barrelPMT PMT
PMT
TDC startADC gate
Fiber
TOF barrel 176 fibers
TOF barrel 176 fibers
Electronic switch
fiber
Fiber bundles
fiber
connector Wrapped with steel tube
Use mirror to steer beam – like BESII. Purchase fiber cable bundles (2 cables).
Use Spiricon Beam Analyzer to analyze beam and design optics – laser into fiber bundle.
Optimum design?
BESIII TOF Calibration System
• Many companies interested:– Ogmentum Inc., Sales and Marketing for FiberLabs– CeramOptec– Romack– Fibertech-optica– Fiberguide Industries
• Many choices: (tentative)– Fiber size (100 micron core).– Connectors (FC/PC).– Single fiber jacketing (PVC furcation).– Outer jacketing (SSTL stripwound).– Multiconnector type.– Ferrule.
Fiber Bundle Cables
8.7 m
248 fibers (cores + cladding only)with ferrule on end
2-96 fiber bundles
2 - 28 fiber bundles(24 + 4 spares)
96 fibers with connectors(88 + 8 spares)
106 (18 spares) cables 7.5 m long withconnector on one end and ferrule on other.
Distribution boxes – one side clamps bundle cable;Other side has single feed through connectors
30 (6 spares) cables 2.0 m long withconnector on one end and ferrule on other.
5.4 m
Distribution boxes – one side: multi connectorOther: single connectors (box 40 mm thick max)
9 m
Total length= 21.6 m
Total length= 19.7 m
Cable Dimensions (May 2, 2006)
Fiber Bundle Cables (need 2)Barrel TOF
EC TOF
Fiber Connection to TOF
Cable Routing?
Have plan; need to check cable dimensions carefully
Test Setup at UH• Need TOF counter and
readout for testing TOF laser calibration system.
• Have Belle BC408 TOF counter and 2 BES fine mesh phototubes.
• Use cosmic ray telescope.• Have Caen VME TDC with
computer to readout.• Caen VME QDC ordered.• Will use BESIII readout
when ready.
TBTop counter
Bottom counter
Delay boxes
50 mv, 28 ns out
PS755scalers
TOFPMT
T
B
Test Setup
N S
S
40 mv, 30 ns out
TBS
PS711
4 ns
HV S = 1200 VHV N = 1150 VHV T = 1400 VHV B = 1450 V~2 counts/min
TDC trigger
Test Setup – first resultsTelescope near middle of
TOF
N – B timeσ = 0.87 ns
S – B timeσ = 0.81 ns
N – S timeσ = 0.61 ns
No time walk correction. Need to understand resolution.
Much to do• Complete test setup.• Measure power out and pulse width of UT laser
diode. Will laser diode work for us?
• Decide on laser. Order by end of summer.• Finalize cable design, connectors, etc. Get
quotes. - Order by end of summer.• Install N laser, fiber cables in UH test setup. Test
and finalize design. – Summer 2006.• Test cable in Hawaii. Oct/Nov 2006.• Ship everything to IHEP – Dec. 2006.• Begin installation – Jan. 07
Thanks
Light Source◆ Violet Laser Diode (LD)
Wave Length : 408nm
Violet LD Unit
LD driver
LD head
wavelength (nm)
rela
tive
ou
tput
Typical Spectrum (by Nichia)
LD Intensity Distribution
x (mm)
Npe
the diameter of the bundle
Cable
• CeramOptec (Kevin Bakhshpour):– Fiber: step index MM
• P/N UV90/100/107P (P-polyimide) (~20 – 25 K$/cable)
• P/N UV200/210/235P (~25 – 30 K$/cable)
– 6 – 8 weeks
• Romack (Peter Gordon):– Fiber: step index
• 100 micron ($1.5/m)
• 50 micron ($2.5.m); graded index ($0.5)
– PVC Furcation tubing for single fiber cables– FC/PC connectors– jacketing?
Cable
• Fibertech-optica (Rafal Pawluczyk)– Fiber
• AS100/110UVPI ($0.9/m -> $9900 for fibers)• AS200/220UVPI ($1.35/m -> $14,850 )• 65.2/125 ($0.13/m -> $1430)
• Fiberguide Industries (Tom Christie)– Fiber
• SFS100/110• SFS200/220 (50% more)• AGI6.25/125T (13% more than SFS100)
• Fiber Labs (Jake Weise)– Fiber:
• 190 micron ($7K)• 100 micron (11K)• 62.5 micron ($14K)
Poor efficiency