Design and Performance of Prototype Telescopefor NuTel project

Yuri VelikzhaninNTUHEP, Taiwan

Outline

Schedule 2002Design of detector/electronicsLuLin testCalibrationResultsConclusionSchedule 2003

Global schedule 2002: design and fabrication a simple

telescope & electronics for measurement a background from mountain

2003: design and fabrication a final telescope & electronics with simple DAQ

2004: construct many telescopes, creating final DAQ (for many telescopes system separated few kilometres from each other)

Note: For start up a design of final telescope & electronics we need a results of background measurement and results of simulation.

Schedule of 2002

May – July: design and fabrication of electronics + creating software + design and making telescope

August – September: debugging full system

October: LuLin observatory test October – December: processing data +

calibration

Note: We decided to make LuLin test at October (before calibration) due the good weather at that time.

Design of detector/electronics Main task of this design – create a simple

equipment for the measurement of background light from a mountain

Design of detector/electronicsOptics

– Commercial Fresnel Lens (NTK-F300, f30cm, size=30cm*30cm, pitch=0.5mm, PMMA UV),

– UV filter (BG3)

Design of detector/electronics Preamplifier parameters:

– Gain: ~ 100 mV/pe– Rising front: ~35 nS– Falling front: exp(t/T), T = RC = 500 nS– Power supply: +/- 5V, 3.8W (240mW/channel)

+-

FromPMT

To Receiver

Design of detector/electronics Receiver parameters:

– Gain: 1 (~100mV/p.e.)– Noise: ~1-2 mV r.m.s.– There is a small problem: noise after

comparator due long falling front

+-

Shaper

ComparatorLVDS

transmitter

To Trigger

From

preamp.

100 nSDelay line

ToADC

Design of detector/electronics Trigger: using our TTM2 module made for

BELLE experiment (in VME + FPGA based) changing firmware code – one week only!

– Use this LVDS-level connector

Design of detector/electronics ADC – use industrial one (Acromag ADC):

– Inputs: differential 32 channels for simultaneous conversion

– Dead time: ~10 S (8 S – from data sheet!)

– Operation clock: 8MHz (there is a jitter 125nS)

– Range: +/- 10V (14 bit, 1.25 mV/bin)– Noise: ~1 mV (from data sheet)

Design of detector/electronics DAQ:

– use VME connected with PC via SBS system– Code: Visual C++, Windows

ADC SBS PCWindows,

Visual C++

ADCdata

On linetrigger

Buffer RAMHarddisc

HistogramsHarddisc

Triggerdata

Trigger

VMEHardware of DAQ

Software of DAQ

Design of detector/electronics DAQ: some print-screens from software

LuLin Test Field of view

E

LuLin test Some pictures from night shifts

Calibration Electronics test with test pulse:

– Sensitivity: ~100mV/3.3*10^6 e (1 photoelectron)

ADC data with optimized timing. A most noise is due jitter in ADC

ADC data with non-optimized timing. Strobe to ADC is delayed on 100 nS from optional timing

Calibration Electronics test with test pulse:

– Cross-talk due electronics: very small

It’s very difficult to observe cross-talk due electronics

But we observed a change in pedestals in some channels ~0.3 mV when a signal on neighboring one is ~1.5 V (0.02% !!! cross-talk)

Calibration Electronics test with pulse to LED + fiber + PMT:

– Cross-talk due PMT: ~1% (from data sheet)

Cross-talk ~ 0.6%

Cross-talk ~ 0.2%

Pedestal Dark current Light Limit (overflow)

Calibration Test using LED pulse 100 nS x 1kHz:

– Typical histogram in case of big photon flux

Calibration Calibration Trigger rates

– There is a limit ~4MHz for Trigger used during LuLin test due “OR of all channels” logic:

Channel AChannel B

A OR B

Results

0°3°

7°

15° S FOV testLooking at Sirius

Field of view – 3 elevation angles: 3°,7°, 15°– 2 conditions: w/o BG3 filter

Results Sirius

• Study:– Effective field of view

– Lens transmittance as function of off-axis angle.

• In the future, – Calibrate the pointing

accuracy

– Monitoring telescope health

Results Background photon flux

0

100000

200000

300000

400000

500000

600000

700000

800000

experiments with and without BG3

phot

on fl

ux (K

) [c

m -2

, s -1

, sr -

1 ]

3deg+BG3 3deg7deg + BG3

7deg

15deg+BG3 15deg

BefireSirius

Sirius

After Sirius

Consistent with some previous measurements, – Sky: ~ 150-180 photons/(m2 ns sr)– mountain: ~15 photons/(m2 ns sr)

Conclusion We made a telescope & electronics for

measurement background photon flux from mountain

A results of our measurement coincide with results from another group with good accuracy. Difference ~ 10-20 % could be easy explained by difference in conditions (attenuation length, difference in reflection from mountain and from a sky due atmosphere and mountain characteristics, different sky etc.)

We will use these results for creating a final electronics & telescope (together with results of simulation)

Plan on 2003 February – March: hardware design April – June: creating first iteration of

electronics + simple firmware + software for calibration/debugging

July: debugging full system August – October: making a second iteration of

electronics (final) + creating a final firmware + simple DAQ for single detector

November: debugging a second iteration of electronics

December: start mass production + start design a final DAQ (multi-detector’s version)

Note: A schedule for telescope design/producing depends of this schedule and of the detector configuration (number of pixels, size), which is strongly depends from funding.