RE: Muon-On-Request

[Michael Barnes <barnes@triumf.ca>]

Dear Francoise,

Before I answer your questions I would like to make sure I fully
understand them, so please excuse me reiterating some of your statements
in a different way:
a) The muon beam has a time structure of between approximately 33us
(30kHz) and 12.5us (80kHz) between muon's.
b) After a muon is detected the following beam is deflected for a time of
25us (i.e. the deflector plate voltage is switched to a high level for
25us). After the 25us the plate voltage returns to 0V and remains here for
at least 400ns before returning to a high voltage;
c) The duration of time for which the deflector plate voltage is low
(approximately 0V) depends on when the next muon is detected so could be
as short as 400ns and as long as approximately 33us.

Please let me know if any of the above statements are incorrect. Thanks.

I am not clear what is meant by the following: "The idea of Peter is to
send an inhibit signal from the counting room to the crate in the zone,
such that by adding this signal, we could turn the kicker OFF".
Does "Turn the kicker OFF" mean to hold the deflector plates at, ideally,
0V? (i.e. basically AND a 0V inhibit signal with the muon detection
signal??). Would you still run muon beam, and take data, in this mode?.
Would the kicker be in this mode "indefinitely"?.

Thanks and best regards,
Mike

PS: Please note I will be in a meeting for the next few hours, so I will
not be able to respond further until later this afternoon.


> Dear Mike,
>
> We discussed a little bit with Peter Kammel the kicker situation in this
> new
> Muon-On-Request mode. We are sending around 30-80kHz of muon in the beam.
> We
> are setting the kicked time to 25mus. After the end of a kicker period, we
> wait at least 400ns to allow the next muon to trigger the kicker.
>
> Situation: We are NOT using the magix box as in MuLan. We are sending the
> muon entrance counter NIM signal (after the electronic scheme developped
> by
> peter to take into account all requests) to a converter located in the
> crate
> next to the kicker. There, we send the TTL to the kicker directly
>
> Questions:
> 1- Du to the non periodic function, do you believe that the kicker real
> voltage is varying a lot from shot to shot? (Are we in the same situation
> as
> what was planned at the beginning of MuLan run?)
> 2- When there is no or small amount of beam, the kicker is just waiting
> for
> a next signal to kick. I believe that zero-volt is at zero (with the flat
> top circuit there too) and does not fluctuate so much. Basically there,
> the
> kicker is in DC mode. Am I right?
> 3- The idea of Peter is to send an inhibit signal from the counting room
> to
> the crate in the zone, such that by adding this signal, we could turn the
> kicker OFF from the counting room, leaving the "hardware" setting at
> 12.5kV,
> but not sending any pulse. Do you see any reason not to do so?
>
> Comments:
> We could reduced the 280ns delay by 10ns, if we change the cable that I
> used
> from the splitter box to the cabinet.
>
> Thanks and best regards
>
> Francoise
> -----Original Message-----
> From: Michael Barnes
> To: Francoise Mulhauser
> Cc: barnes@triumf.ca; francoise.mulhauser@psi.ch; kammel@npl.uiuc.edu;
> hertzog@uiuc.edu; michael.barnes@triumf.ca; peter.winter@psi.ch;
> wait@triumf.ca; carey@bu.edu; anatoly@g2pc1.bu.edu; rmcnabb@uiuc.edu
> Sent: 20/11/05 20:15
> Subject: Re: Muon-On-Request
>
> Dear Francoise,
>
> This sounds like great progress. The 280ns is slightly longer than I
> would
> have expected but in the right region.
>
> The 9ns delay that Gary and I originally added to the HV input TTL lines
> was to allow for the beam transit time from the input of the upstream
> plates to the input of the downstream plates, such that having two sets
> of
> plates did not result in distortion of the deflection rise or fall. As
> you
> say, the relative timing of the plates can readily be adjusted by adding
> the appropriate length of BNC cable to the TTL cables of, for example,
> the
> MV cabinets.
>
> Best regards,
> Mike
>
> PS: did you have time to check that the 6 spare MOSFET cards are at PSI?
>
>> Dear Mike,
>>
>> We have made the measurement today. We obtained for each of
>> the capacitive pick-up the same delay, within +- 2ns. You
>> can say that we have 280ns delay between the TTL input and
>> the deflector plate.
>>
>> Also, we have turned the kicker in the muon on request
>> mode. It seems to work well. We are trying to diagnose what
>> we see and find way to make sure that there is no "bad"
>> pulse.
>>
>> I am using the Trip monitor to see the capacitive pick-up
>> signals in the counting room. One sees nicely the random
>> behaviour of the next muon, with the block time of 25mus in
>> between.
>>
>> Best regards
>> Francoise
>>
>>
>
>