Tavi,
Michael is correct. The way we programmed the XMLU, an event might set
multiple XMLU output bits. The TS prescales all input bits, and then
was programmed to assign the event to the least significant bit
remaining. A TOF-neutron event that fails on the bit 2 prescale may
pass on the bit 7. You have to look carefully at the XMLU programming
in the .settings file for the trigger to see what happens. I think you
also have to include trigger 6, because if the TOF that fired along with
the neutron was TOF12-15, bits 2 and 6 were set.
I've just looked at the trigger .settings file, and it looks to me like
for a nominal (e,e'n) event there are 3 possibilities:
1) TOF0-11 with Cer -- event 2, but if it fails prescale, event 7 (where
it may also fail prescale)
2) TOF12-15 -- event 2, but if it fails prescale, event 6 (where it may
also fail prescale)
3) TOF0-11 with NO Cer -- event 2, but if it fails prescale, it's lost
For events of 3) above, you'd have to multiply the # of those by the
event 2 prescale. But you don't do that for 1) or 2), because you've
already accounted for them when multiplying # of 7's (or 6's) by the
event 7 or 6 prescale.
It would probably be a good idea to check the trigger .settings file
used for certain time periods, and make sure the details of 1), 2), 3)
are the same for all runs. At some point (before the 2004 production
runs?) we changed the definition of event 7 to include the Cerenkov, and
that will be obvious from the XMLU programming.
Karen
Michael Kohl wrote:
> Hi Tavi,
>
> I agree with your second formula to combine the yield for two runs
> with different prescale factor.
>
> On the prescaling of trigger 3 (=10) and of trigger 2 (=2) for part of
> the runs: Once I had a discussion with Karen on how to correctly
> account for the prescaling of triggers 2 and 3:
> The trigger supervisor logic is such that if an event which fulfilled
> the requirement for e.g. trigger 2 did not become a trigger 2 event
> just because it was prescaled, then it may again be offered to become
> a trigger type of reduced priority, i.e. a possible trigger 7 event.
> It is not that the prescaled trigger 2 event would be discarded after
> failing the first test. Each event can have multiple trigger bits
> (here 2 and 7), and the assignment of the bit to the event happens
> according to the priority order.
>
> Subsequently, this means in turn that you must not apply the prescale
> factor to the events of trigger 2 and 3 even if they were prescaled.
> Just accounting for the prescale factor of trigger 7 makes it correct.
> Raising the prescale factor for trigger 2 or 3 would therefore
> influence the rate in trigger 7 (you can check this with real data!)
>
> Note that this means a factor of 10 less yield in trigger 3!
> Karen, please intervene if I'm wrong.
>
> Best regards,
>
> Michael
>
>
>
> On Thu, 16 Feb 2006, Octavian F Filoti wrote:
>
>>
>> I had to reanalyze again! I got some empty runs bigger than the data
>> runs!
>> This is because I added wrongly the yields: since for empty runs I
>> have different scaling factors, I did this:
>>
>> Yield = Ni1*Si1/Q1 + Ni2*Si2/Q2
>>
>> but I guess correct is:
>>
>> Yield = (Ni1*Si1 + Ni2*Si2)/(Q1+Q2)
>>
>> Then I subtract the emty yields from the data:
>>
>> Yield0 = Yield_data - Yield_empty.
>>
>> From April 2004 to September 28th 2004: trigger 7 is scaled by 3,
>> after that by 9. When I looked at N++ I divided by Q++ of course!
>> Trigger 3 (scaled by 10) has delta events too, so I added that one
>> also, so I have trigger 1, 2, 3 and 7!
>> I hope I will get good results this weekend! Give me some feedback!
>>
>> Thanks
>>
>> On Thu, 16 Feb 2006, Michael Kohl wrote:
>>
>>> Hi Tavi,
>>>
>>> I'm flying from Tokyo to Boston on Tuesday, arriving in Boston very
>>> late. Japan is 14 hours ahead, so I will already have a hard time to
>>> make it to Bates on Wednesday before noon. I'm also giving a talk at
>>> the Bates lunch meeting at noon. Sorry that I can't accomodate your
>>> request at this time. If you can make it possible to attend the
>>> meeting at 13:30 please do it. I think it would be very interesting
>>> to see your follow-up results of our recent discussion.
>>>
>>> Best regards
>>>
>>> Michael
>>>
>>>
>>>
>>> On Tue, 14 Feb 2006, Octavian F Filoti wrote:
>>>
>>>>
>>>> Next week: can you set the analysis meeting at 10:30am.
>>>> This is good for me!
>>>> Or at least once in a while!
>>>> Tomorrow I don't have anything to show, but next week I will, so I
>>>> prefer 10:30am if possible, PLEASE! :-)
>>>>
>>>> --
>>>>
>>>> --------------------------
>>>> | Octavian F Filoti |
>>>> | Nuclear Physics Group |
>>>> | Univ. of New Hampshire |
>>>> | 9 Library Way |
>>>> | Durham, NH 03824 |
>>>> | phone: (603)868-6882 |
>>>> | FAX: (603)862-2998 |
>>>> | email: ofiloti@unh.edu |
>>>> --------------------------
>>>>
>>>
>>>
>>> +-------------------------------------+--------------------------+
>>> | Office: | Home: |
>>> |-------------------------------------|--------------------------|
>>> | Dr. Michael Kohl | Michael Kohl |
>>> | Laboratory for Nuclear Science | 5 Ibbetson Street |
>>> | MIT-Bates Linear Accelerator Center | Somerville, MA 02143 |
>>> | Middleton, MA 01949 | U.S.A. |
>>> | U.S.A. | |
>>> | - - - - - - - - - - - - | - - - - - - - - -|
>>> | Email: kohlm@mit.edu | K.Michael.Kohl@gmx.de |
>>> | Work: +1-617-253-9207 | Home: +1-617-629-3147 |
>>> | Fax: +1-617-253-9599 | Mobile: +1-978-580-4190 |
>>> | http://blast.lns.mit.edu | |
>>> +-------------------------------------+--------------------------+
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>
>> --
>>
>> --------------------------
>> | Octavian F Filoti |
>> | Nuclear Physics Group |
>> | Univ. of New Hampshire |
>> | 9 Library Way |
>> | Durham, NH 03824 |
>> | phone: (603)868-6882 |
>> | FAX: (603)862-2998 |
>> | email: ofiloti@unh.edu |
>> --------------------------
>>
>
>
> +-------------------------------------+--------------------------+
> | Office: | Home: |
> |-------------------------------------|--------------------------|
> | Dr. Michael Kohl | Michael Kohl |
> | Laboratory for Nuclear Science | 5 Ibbetson Street |
> | MIT-Bates Linear Accelerator Center | Somerville, MA 02143 |
> | Middleton, MA 01949 | U.S.A. |
> | U.S.A. | |
> | - - - - - - - - - - - - | - - - - - - - - -|
> | Email: kohlm@mit.edu | K.Michael.Kohl@gmx.de |
> | Work: +1-617-253-9207 | Home: +1-617-629-3147 |
> | Fax: +1-617-253-9599 | Mobile: +1-978-580-4190 |
> | http://blast.lns.mit.edu | |
> +-------------------------------------+--------------------------+
>
>
>
>
>
>
>
>
>
>
>
>
>
>
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