AIDA Meeting - CCLRC DL - 20 June 2006
--------------------------------------

Present:	Tom Davinson					Edinburgh
		Rob Page, Jim Thornhill, Dave Seddon		Liverpool
		John Simpson, Ian Lazarus			CCLRC DL
		Marcus French, Mark Prydderch, Stephen Thomas	CCLRC RAL

Summary of meeting
------------------

TD

First of a series of meetings whose objective is to define a detailed technical specification for AIDA - DSSSDs, ASICs, FEE PCB, DAQ etc. This will provide the
framework for all subsequent engineering and development effort.

Once the detailed technical specification is agreed, it will be circulated within
the AIDA project, the DESPEC collaboration (and perhaps more widely) for comments
and suggestions.

At this early stage of the process, the detailed technical specification should be regarded as a blank sheet of paper.


To start the discussion, TD provided an overview of the application (see attached
brief document) discussing what the physicists think they want/need from AIDA.
Much of the subsequent discussion focussed on the ASIC and DSSSDs. The ASIC was
often discussed with reference to the schematic (attached) produced by Ian Lazarus
at a previous meeting at CCLRC DL to discuss AIDA prior to the submission of the proposal to EPSRC.

The following points emerged during the discussion:

o A measurement of the energy of the implanted ion (~50-150MeV/u) would be useful
  to discriminate fully stripped ions from H-like and He-like ions. It had previously
  been assumed that it would only be necessary to measure the energy of the implanted
  ion in the front dE and back veto detectors - the ion would be tracked through the
  intermediate ion planes by monitoring which channels were in overload recovery.

  [Subsequent discussion by RDP and Zsolt Podolyak (Surrey) indicates that the
   energies of fully stripped and H-like (A=200) ions differ by 3%.

   I presume this means that we need to measure the energy the implanted ion to    
   an accuracy of in the region of 0.1-1% ?]

o We do not need to switch between the high and intermediate gain settings on an
  event by event basis. We expect these to be set/configured by slow control.

o Following the discussion above about the measurement of the energy of the implanted
  ion there was talk of using the current from the overload circuit as a measure
  of the implanted ion energy.

  What accuracy would be possible is unclear.

  For a 16-channel (say) ASIC would this mean that the MUX has 16, 16+1 or 32 or 
  ... inputs?

o Information about the current pulse from the detector to the preamp for such
  high-energy ions is required - shape, amplitude, duration? How do adjacent
  strips behave? etc. 
  JS pointed out that the active target campaign at RISING represents an excellent
  opportunity to gain such information.

  We need to determine how to do such measurements.

o The timing trigger would need to have an intrinsic time resolution (jitter)
  ~1ns FWHM - <<1ns seems unlikely to be achievable with a CMOS ASIC - >>1ns
  and we can use the lab's BUTIS 200MHz clock.

  Amplitude walk of the timing trigger could be corrected for by data analysis
  software.

o Cooling and rotation of the stack position of the DSSSDs were discussed to
  extend the operational lifetime of the silicon with respect to radiation damage.

  We probably do not need to operate the DSSSDs at vacuum. Therefore require 
  cooling system to circulate, dry, inert gas for cooling purposes.


T.Davinson - 1 July 2006