Summary of the Recycler Ring BPM Meeting and follow up - Brajesh Choudhary

Date: 01st October 2002
Time: 2:45PM in Huddle

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AGENDA: General Discussion on test evaluation of the EchoteK Digital
        Receiver Board.

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In Attendance:

1. Brajesh Choudhary
2. James Crisp
3. Bill Foster
4. Martin Hu
5. Peter Limon
6. Craig Mcclure
7. Shekhar Mishra
8. Stephen Pordes
9. Peter Prieto
10.Marc Ross (**)
11.Vic Scarpine
12.Warren Schappert
13.Jim Sebek (**)
14.Till Straumann (**)
15.Peter Wilson
16.Sergio Zimmermann
17.djm@slac.stanford.edu (**)

(**) - Visitors from SLAC

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PETER PRIETO presented the test status of the EchoTek digital receiver board.
Two digital receiver board came from EchoTek. One did not work. It was sent
back to EchoTek.

The second board is beind tested. The board was tested for background flash, 
flash and turn by turn mode. The board works but the DMA on the board failed.
It did work earlier. DUANE VOY and TOM MEYER are working around it to modify
the front end software and readout. No time estimate was given. Hopefully will
be done in couple of days. 

*** 2nd October 2002, Summary of E-Mail fron DUANE VOY *******

They (PETER, TOM and DUANE) just finished working on 4 channels (one digital 
receiver board from EchoTek). They plan to coordinate with Craig Mcclure 
and install the board at MI-50 on 3rd Oct. They expect the system to be 
operational by the end of the day.*********

*** 2nd October 2002, Summary of E-Mail from TOM MEYER *******

He hopes to have a four BPM test at MI-50 sometime on Friday (4.OCT.02). ****

*** 3rd October 2002, Summary of E-Mail from JIM CRISP ******

Many software problems were fixed. The VMS64X crate loaned to the SLAC/BLT
effort has been returned and one of the digital receivers will be moved to the
ring on thursday (3rd Oct.). They expect to measure the beam positions on
Friday (4th Oct.)

The other digital receiver card will arrive by Friday (has arrived today, 
4th Oct) and will be used to continue work in the transfer gallery. Once its 
functionality is assured it will be moved into the ring for evaluation. ****

*** 4th October 2002, E-Mail from  PETER PRIETO *******

The digital down coveter board is being evaluated by Tom Meyer and Duane Voy. 
As installed in MI-50 the board should perform flash, turn-by-turn and 
background flash. What is left to do is to adjust timing with respect to the
beam with 2.5MHz bunches in the recycler. I would be ready to do this at your 
convenience. *************

PETER PRIETO described his plan to change the present preamp switches 
with JFET switch. 

From PETER PRIETO "The preamp modifications consist of removing all resonant 
components, that is chokes. Replace the 1.5KOhn shunting resistor with a 
150 Ohm resistor. Add a lead network in series with the 150 Ohm to lower the 
corner frequency and increase the signal size for 89KHz by a factor of 5."

It was agreed that if the test boards meet the specification, logamps on 
216 BPMs in RR and 14 BPMs each in both the tranfer lines will be replaced. 
That will require 216+2X14=244 channels or 61 digital receiver board. 
Warren Shappert needs 4 digital boards for his BLT's. It was agreed to buy 
70 boards if the board meets the specification.

Preamps associated with these 244 channels will be modified from resonant mode
to non-resonant mode.

It was also agreed that all the preamp switches will be replaced with JFET
switch so that there is no possibility of switch failure due to radiation.

******JIM CRISP wrote back on 4th October 
"Unless we have to, I will not burden the project 
with upgrading preamps that will not be used". ********** 


MARTIN HU presented the functional specification and requirements that the 
updated BPM system using digital receiver board should meet. It led to lively 
discussion. Marc Ross from SLAC talked about beam based alignment technique 
to measure absolute position measurement of the beam using quadrupole 
shunting method with powered quads. He also talked about calibrating the 
BPM system. Jim Sebek talked about feedback system and the resolution of the 
BPM.