5 Nov. 2008 Univ. Padova, Physics Department, Plenary Meeting
FPI WP Status
Short summaryR. Mirzoyan
MPI Munich
5 Nov. 2008 Univ. Padova, Physics Department, Plenary Meeting
FPI
• FPI WP includes the front part of the imaging camera: PMTs (light sensors), pixels, clusters, HV power supply, postamplifier, light guide system, protective/sealing window, the camera mechanics and its junction with the mount of the telescope
• FPI is working in a very close contact with the ELEC WP
5 Nov. 2008 Univ. Padova, Physics Department, Plenary Meeting
PMT
• Select the most probable size of PMTs (with the help of other WPs: MC, Mount & Mirror) and start development work with companies
• Make a request to the CTA consortium to look for possibilities to allocate some finances for the development work in th years 2009-2010
Min. request: 160.-k€/1 yearMax. request: 400.-k€/2 years • The major goals: try to achieve a peak
PDE ≥ 40 % (PDE = QE x Charge Coll. Eff.)
Afterpulsing ≤ (0.03 – 0.01) %
5 Nov. 2008 Univ. Padova, Physics Department, Plenary Meeting
PMTs
• Offers from major PMT manufacturers are obtained. We plan to check in the coming ~4 months some ~ 10 type PMTs of 1-2 inch size at least from 2 manufacturers, in 2 locationsSiPM
• Evaluate SiPMs from all possible manufacturers that have the promise to become a candidate sensor for CTA. Pay attention to cost, cost/performance issues. Ongoing study
5 Nov. 2008 Univ. Padova, Physics Department, Plenary Meeting
Light Guides
• Which type of production, costs, ease of manufacturing, automatic production, reflectivity, angular acceptance, ageing, ...
• Single ones or plates of LGs• Lining or evaporating technique
5 Nov. 2008 Univ. Padova, Physics Department, Plenary Meeting
Protective plexiglas window
• The thickness, uv transmission, minimize the reflection by antireflective coating:
• Ask CTA for some funds for the last task; the development scale seem to be
30-50.-k€ (this could reduce the reflectivity from (8-
10) % down to ~ 1 % level)
5 Nov. 2008 Univ. Padova, Physics Department, Plenary Meeting
Slow control aspects of FPI
• What shall be read out and controlled, how frequent ?
– Single rates above a given threshold– Anode currents– Calibration pulses– Check HV, dc-dc converter supply,
control voltages, temperature, humidity, ...
5 Nov. 2008 Univ. Padova, Physics Department, Plenary Meeting
Mechanics
• Weight optimisation, cost issues.• Temperature (stab. ?) and related issues• Humidity and temperature sensors• Sectioning• Protection from dust, humidity (plex. window)• LED system for pointing• Camera doors (lids)• Pop-up mylar foil, maybe also reflective target
5 Nov. 2008 Univ. Padova, Physics Department, Plenary Meeting
Interaction with other WPs
• MC: inputs on pixel size(s), FoV of the camera(s)
• Optics: light spot sizes over the camera area, LG and its concentration
• Mount: camera weight constraints • Try to provide for the other WPs cost
estimates on the pixel, also including the mechanics =>
• Together narrow the range of candidate PMTs, start development work with the industries
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