Image of Flex01-08D.  The dimension of the external enclosure is approximately 3.25x2.5x0.8".

Functions:

Flex01-0D is a photon counting digital hardware that can be used as

  1. Single high resolution real time MT-64 multiple tau digital correlator (AxA or AxB).  Minimum sample time 8ns.
  2. Dual medium resolution MT-32 multiple tau digital correlator ({AxA, BxB}, or {AxB, BxA}), .  Minimum sample time 8ns.
  3. Quad standard resolution MT-16 multiple tau digital correlator {AxA, BxB, AxB, BxA}.  Minimum sample time 8ns.
  4. One channel photon history recorder.  System clock speed: 60MHz. Average intensity limit: 910KHz
  5. Dual channel photon history recorder.  System clock speed: 40MHz. Average intensity limit: 450KHz

In photon correlation mode, it calculates the correlation function(s) in real time covering delay times from the 12.5ns to about an hour.  

In photon history recorder mode, it records the time between successive photon events.  This is measured by counting the number of ticks of the system clock between the photon events.  This time is then transferred to the host personal computer via high speed Universal Serial Bus (USB).   The amount of information to be transferred is proportional to the count rate of the incoming photons.  Using a lossless compression technique, Flex01-08D transfers complete time series without gaps for average count rate from 0 to approximately 910 kcps in one channel mode.  At high count rates the overflows are displayed in real time.

Flex01-12D hardware specifications:

  1. Input signal: standard TTL pulses.
  2. Two BNC connectors
  3. One USB connector.
  4. Easy to use FlexWindows software and software for Windows98 libraries included.

Correlation mode specifications:

1. Single MT-64 multiple tau channel layout ( sample time denoted at T, data width W):

  1. Auto/cross correlations.
  2. 12.5 ns minimum sample.
  3. 1088 real time channels.
  4. Delay time range: 8ns to 1 hour in multiple tau channel layout.
  5. First 64 channels: T = 8ns, W = 1 bits, delay times T to 64*T;
  6. Second 32 channels: T = 2*8ns, W = 2 bits, delay times 66*T to 128*T
  7. Third 32 channels: T = 4*8ns, W = 3 bits, delay times 66*T to 128*T;
  8. Fourth 32 channels: T = 8*8ns, W = 4 bits, delay times 66*T to 128*T;
  9. Sample time doubles every 32 channels and data width increment 1 bit to prevent overflow.
  10. The longest delay time is about one hour.

2. Dual MT-32 multiple tau channel layout ( sample time denoted at T, data width W):

  1. Auto/cross correlations.
  2. 8 ns minimum sample.
  3. 608x2 real time channels.
  4. Delay time range: 8ns to 1 hour in multiple tau channel layout.
  5. First 32 channels: T = 8ns, W = 1 bits, delay times T to 32*T;
  6. Second 16 channels: T = 2*8ns, W = 2 bits, delay times 34*T to 64*T
  7. Third 16 channels: T = 4*8ns, W = 3 bits, delay times 34*T to 64*T;
  8. Fourth 16 channels: T = 8*8ns, W = 4 bits, delay times 34*T to 64*T;
  9. Sample time doubles every 16 channels and data width increment 1 bit to prevent overflow.
  10. The longest delay time is about one hour.

3. Quad multiple tau channel layout ( sample time denoted at T, data width W):

  1. Dual Auto and dual cross correlations.
  2. 8 ns minimum sample.
  3. 288x4 real time channels.
  4. Delay time range: 8ns to 1 hour in multiple tau channel layout.
  5. First 16 channels: T = 8ns, W = 1 bits, delay times 0 to 16*T;
  6. Second 8 channels: T = 2*8ns, W = 2 bits, delay times 9*T to 16*T
  7. Third 8 channels: T = 4*8ns, W = 3 bits, delay times 9*T to 16*T;
  8. Fourth 8 channels: T = 8*8ns, W = 4 bits, delay times 9*T to 16*T;
  9. Sample time doubles every 8 channels and data width increment 1 bit to prevent overflow.
  10. The longest delay time is about one hour.

4. Single photon history recorder mode specifications:

  1. System clock: 60 MHz in one channel mode.
  2. 16.7 ns pulse pair resolution.
  3. Complete time series recorded on a PC hard drive for average count rate up to 910 KHz in one channel mode.  The maximum count rate is somewhat host PC dependent.

5. Dual photon history recorder mode specifications:

  1. System clock: 40 MHz in two channel mode.
  2. 25 ns pulse pair resolution.
  3. Complete time series recorded on a PC hard drive for average count rate up to 450 KHz in one channel mode.  The maximum count rate is somewhat host PC dependent.

More about multiple tau theory.

Multiple tau theory was invented by Klaus Schätzel.  The following papers discuss the theory and the advantage of the multiple tau scheme.

  1. Klaus Schätzel. Single Photon Correlation Techniques. Dynamic Light Scattering: The method and some applications, Edit by Wyn Brown, Clarendon Press, Oxford, P 76, 1993.
  2. Klaus Schätzel etNoise on Multiple-Tau Photon Correlation Data.   SPIE Vol. 1430, P109, Photon Correlation Spectroscopy: Multicomponent Systems, 1991.
  3. Klaus Schätzel. New Concept in Correlator Design. Inst. Phys. Conf. Ser. No. 77, P175, 1985.
  4. Klaus Schätzel etPhoton Correlation Measurements at Large Lag Times.  Journal of Modern Optics, Vol. 35, No. 4, P711, 1988.