Concept idea for a future telescope array observatory
Download
1 / 12

Concept idea for a future telescope array observatory - PowerPoint PPT Presentation


  • 97 Views
  • Uploaded on

Concept idea for a future telescope array observatory. CTA meeting Berlin May 4-5, 2006 Thomas Schweizer. Goals and constraints. Specification of CTA observatory Energy range 10 GeV to 100 TeV Available budget: 100-150 Mio Euro Sensitivity ~ 5-10 times better than previous instruments

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Concept idea for a future telescope array observatory' - kael


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Concept idea for a future telescope array observatory

Concept idea for a future telescope arrayobservatory

CTA meeting Berlin

May 4-5, 2006

Thomas Schweizer

May 4-5, 2006 T.Schweizer, CTA meeting Berlin


Goals and constraints
Goals and constraints

  • Specification of CTA observatory

    • Energy range 10 GeV to 100 TeV

    • Available budget: 100-150 Mio Euro

    • Sensitivity ~ 5-10 times better than previous instruments

  • It is impossible to span 7 orders of magnitude (10 GeV - 100 TeV)by one single detector and keep optimal performance (because of limited dynamic range and steep spectra)

    • One array 10 GeV to 1 TeV (LEA)

      • low energy threshold, ~10-20 large telescopes

      • 75 % of budget (North and South)

    • One array 1 TeV up to 100 TeV (ULTRA II)

      • very large effective area, ~100-150 small telescopes

      • 25 % of budget (only South)

      • E. Lorentz talk

May 4-5, 2006 T.Schweizer, CTA meeting Berlin


Two arrays together
Two arrays together

  • Overlap in energy between both arrays for cross-calibration- Simultanous observation with small and large array- Parallel observation of several sources with parts of array- Longterm monitoring of sources with single telescopes

Lowest possible energy threshold

and highest sensitivity

1-2 km2, large eff. area

May 4-5, 2006 T.Schweizer, CTA meeting Berlin


Low energy array lea
Low energy array (LEA)

  • What do we want for available budget (~70 Mio Euro) ?

    • As many telescopes as possible for high sensitivity and parallel observation of sources

    • As low energy threshold as possible

  • Possibilities:

    • 30 m telescopes (710 m2 mirror) with classical PMTs

    • 23 m telescope (415 m2 mirror) with SiPM light sensors

  • 23 m telescope

    • Increase in photon-detection efficiency rather than mirror area high mirror reflectivity (90%), high QE (SiPM, 50%)

    • Smallertelescopes and lighter telescopes are cheaper, < 120 tons weight, 70 tons possible

    • Big question: is it possible to build 16-20 telscopesfor 70 Mio Euros ?

May 4-5, 2006 T.Schweizer, CTA meeting Berlin


Possible telescope parameters
Possible telescope parameters

Active mirror control with improved optical

quality (PSF)

  • FOV=5°

  • F/D = 1.2:

  • acceptable aberation (5° FOV)

D= 23 m diameter

parabolc mirror

 430 m2

F= 28 m

  • Protection against

  • wind lift-up

  • Lighter & cheaper telescope

May 4-5, 2006 T.Schweizer, CTA meeting Berlin


Possible parameters for camera design
Possible parameters for camera design

FOV 5°

  • D= 2.4 m

  • A=4.5 m2

  • Roundish camera, FOV 5°

  • Square pixels

  • Assume QE=50 % flat from 300-600 nm

May 4-5, 2006 T.Schweizer, CTA meeting Berlin


Some numbers
Some numbers

  • Case study: square pixels with 4 SiPM chips à 1 cm x 1 cm

    • Light concentration 3.25 (with microlensing foil)

    • Light concentration 5

  • Absolute maxim allowed dark rate for SiPM: 20% of NSB

     Assume 100-200 kHz/1mm2 for future SiPM

May 4-5, 2006 T.Schweizer, CTA meeting Berlin


Data volume generated by telescope system
Data volume generated by telescope system

  • Assume 2.5 GHz FADC (capacitor array) sampling

  • Assume 50 samples per pixel à 16 Bits  100 Bytes

  • Assume trigger rate of 2 kHz (at 10 GeV)

  • Assume 3000 Pixels

  • Assume 20 Telescopes

  • Assume an average of 8h observation time

  • About 10.5 Petabytes per month !!

  • Even with modern computers in 10 years this amountwill be a serious problem

May 4-5, 2006 T.Schweizer, CTA meeting Berlin


Data reduction
Data reduction

  • Necessity for online data reduction

  • Online signal extraction from FADC slices Amplitude, Arrival time, Pulse width of largest pulse3 floats (can be reduced)  12 Bytes

  • Zero suppression  Low level image cleaningassume reduction factor 20 (maybe more ?)

  • Reduced data rate: 65 Terrabytes per month

    (Still a lot ! )

    Comment: Data reduction (signal processing) maybe already inside camera

May 4-5, 2006 T.Schweizer, CTA meeting Berlin


Readout ideas
Readout ideas

  • All the readout electronics inside the camera reduces the cost of the camera (maximum weight 2 tons)

  • No heavy cabeling, simplified construction

  • Data reduction (signal processing) already inside the camera

1 Gbit Ethernet ?

Switch

Modules of 100 pixels

100 channeldomino sampling

Signal processorto extract signalsand data reduction

Collect data from all modules & ultrafast data transfer to DAQ

May 4-5, 2006 T.Schweizer, CTA meeting Berlin


Cost estimates
Cost estimates

  • The camera housing + mechanics + Cooling and temperaturestabilization + Light concentrators: 400 k€

  • Price for 4 SiPM chips (one pixel): ~ 300 € (Hamamatsu)

  • Price for readout (Cap. array + signal processing) per channel: ~ 300

  • Sum price/channel: ~600 €

  • Sum all pixels (2250): ~1.4 Mio €

  • Total: 1.8 Mio €

  • Maxim price for camera + readout: 2 Mio €

  • Price for telescope frame 2-3 Mio €

  • Price for one telescope: 4-5 Mio €

  • 70 Mio €/4-5 Mio €  14-17 telescopes

May 4-5, 2006 T.Schweizer, CTA meeting Berlin


Timing
Timing

  • First light within 5-6 years ?

  • SiPM chips probably available within 2 years

  • Use standard mechanics/electronics as much as possible

  • Time plan

    • Camera development with SiPM: 4 years

    • Development time for mechanics 2-3 years

    • Production and installation of 16 telescopes: 2-3 years

  • All together: 5 years until first telescope installed ?

May 4-5, 2006 T.Schweizer, CTA meeting Berlin