The n-³He Experiment at SNS : Preamps

Work package manager: David Bowman

Preamp Test Board

A preamp test board: This board is nearly complete with the exception that the two 25 pin plugs in the middle of the board need to be removed. There should be a set of female pins on the bottom of the board for connecting to the flange.

We we are using this board for testing; electronic performance, find out cooling requirements, 30W is created in board.

Preamp Test Board (posted November 11)

Preamp Schematic PDF

Preamp Circuit Diagram (pdf)

Preamp Board Layout and Pin Information:

Preamp Enclosure Model:

The preamp enclosure will probably be a 1/4" wall aluminum box. There will be clearance holes through the bottom of the box for the heads of the bolts on the signal flange as well as 4 holes for joining to an adapter plate held under the bolt heads of the signal flange. There are two inputs for forced air circulation to dissipate heat, 30W, from the board, vents for air are several holes in the walls. An idea is to use house air with a nozzle which will cool expanding air. This would allow to run the components sub room temperature, this would reduce noise related to thermal variables of the circuits.

From the two 25 pin feed throughs on the signal flange there will be 18 signal wires to each 25 pin connector. On the top of each board there will be two 44 pin connectors for joining to a 36 wire cable to carry the 18 amplified signals as a differential output to the ADC. Over the 4 flanges with 2 connectors each that will be 4x2x18=144 signal wires. See the cable routing page for more information on how this attaches to the ion chamber.

Updated Enclosure Model:

An updated preamp enclosure model has be created to use a distributor block (shown in blue) with 7 nozzles as the air input. Air vents now also occurs at the left and right sides as well as underneath the cable stress relieving clamps shown on the downbeam side of the preamp enclosure

CAD Model Update for use of Adapter Plug 2014/04/10 CL001 Preamp Box with pin block.pdf CL190 Pin Holder r3.pdf CL025 preamp enclosure r6.pdf

	CAD Model PDFs of Preamp Enclosure 2014/02/11 CL000 assembly is obsolete replaced by CL001 CL000 Preamp Box r1.pdf CL025 preamp enclosure r1.pdf CL031 cable clamp half.pdf CL050 air block r1.pdf Shielding box lid r0.pdf Shielding box adapter plate.pdf
Assembled Preamp Enclosure on top of Dummy Box for Testing	Partially Assembled Preamp Enclosure

Preamp Housing Model by Bruce Warmack

CAD Model from Bruce Warmack November 5

Enclosure Modle revision 0

Preamp Enclosure from October 17 showing older ventllation scheme with larger air input and exhaust ports.

Preamp to Feed Through Model:

Cutaway of Preamp Housing showing one of 50 pins attached to feed thru that will need to be soldered to the board during installation.

Preamp enclosure from below showing the signal flange and the Mount plate that will be bolted on top of the feed through flange to attach the preamp housing to the ion chamber.

9/25/13 Teleconf

status of preamplifier design need to be found out.
Preamp:



- Preamp components installed and cables ready – mid January by Bruce
cable length – we will define length in a few day

10/2/2013 Teleconf

no news on preamp board design yet

11/6/2013 Teleconf

- we have a 32-channel preamp board which is used for testing.
- since we do not have proper cables from preamp board to ADC, the first text are not to be very reliable.
- Bruce et al have ordered the cables to junction box they will be available in January

12/04/2013 Teleconf

- electrical testing of the board we have continues - time constant less then 10 micros, RMS still large but testing needs better EM shielding and grounding
- cables between preamps and ADCs arriving in mid Jan

Probing The Hadronic Weak Interaction