1. Power supplies  Will need power supplies to power :  APDs  PMs  Silicon PMs  Signal amplifiers.

2. Characteristics : of power requirements.  -12 v; -6v; + 6 v 1 A each for amplifiers.  Up to 2kV, positive and negative, from 0 up in at least 1V increment for APD, 2- 3mA (for 2-3)  Up to 1.5kV, 10mA for PMT (all 6)  All of above should have the smallest ripple voltage possible (around 1-4 mV)

3. High Voltage power supplies  Model 556 from ametek-online.com  Double-NIM crate size, from ±10 to ±3000V, 2 output channels.  10 mA, output voltage remotely controlled by applying from 0 to 6.5V, noise <10mV  Not a smooth voltage increments but rather a step change on voltage – not good for APDs but sufficient for PMT  Current price as of 7/4/2003 - $1615.00

4. HV power supplies  J4-2P and J4-2N from Matsusada Precision Inc.  2P – positive 2000V, 2N – negative 2kV. Ripple of 2mV. 2mA output current.  Voltage regulated by multi-turn built-in potentiometer or remotely.  Recommended for APD.  Non-standard size.  Current price as of 3/26/2003 is $252.00 ( on picture it’s the left unit )

5. Low Voltage power supplies  S7-001 Herbach&Rademan power supply (www.herbach.com)www.herbach.com  0 - ±30V (positive and negative simultaneously, 0.5mV ripple RMS. Current limit 5A.  Regulated. Dual Panel meters.  Current price is $238.95

6. APD  Box design for cooling the APD using the peltier elements. This method will require a current of few Amps (up to 3-5A) to get the APD down to about –40 degrees Celsius. (doesn’t require very stable power supply. Can use a spare AT computer power supply.) #3 #4#4 above shows the housing of APD and not the actual box which will the shows later.

7. Peltier Elements  Low-cost – about $35 per each element or less  Allows good temperature control, as precise as 0.1 degree at around 20 o C,  Performance and precision somewhat degrade at negative temperatures because the element will require a large current (  5A) in that range, which is not easy to control.

8. Box design  The box design of the APD allows up to two peltier elements for better control and allowing to achieve lower temperatures (theoretically down to –30 o C or even lower if 4 elements are used stacked.  Usage of 2 elements allows to minimize currents for better controllability and stability. above shows the right and left sides of the box that are just smooth surfaces.

9. Box Design  The front side allows two standard optical connectors to be used for greater flexibility of the design.

10. Box Design  Bottom and top parts of the box allow the connectors and holders and the amplifier box to be attached.

11. Box Design  This is an “artistic” representation of the box that will have APD inside and the box with pre- amplifier (which is not being cooled as of current scheme but the ability to do this has been integrated into this particular design). #5 #6 #8 #13