[Solid_ec] 回复： Re: current estimation

Wed Apr 30 16:00:17 EDT 2014

I have updated the number for preshower  at high and low radiation area 
of PVDIS here
https://hallaweb.jlab.org/wiki/index.php/Solid_calorimeter_readout#preshower
The difference is not very large because the low energy gamma going a 
wide spread directions.

We will need to group the modules cleverly..
I see basically two ways
1. group modules from inner to outer radius into one MaPMT.
This way we can use one gain and have inner module output higher current 
and outer output lower current, as far as we keep overall current below 
10uA limit.
The gain required can be estimated by the average current, which is 5e3 
for PVDIS high or low area.
The complication is that different channels on one MaPMT will want 
different amplification. It's about 10-20 times difference from inner to 
outer radius
2. group modules from the same radius into one MaPMT.
This way module output similar current and we can keep similar 
amplification for one MaPMT.
The complication is that the most inner module at PVDIS high rate area 
may need gain as low as 1e3

I don't see any ideal way yet, maybe we need to combine 1 or 2 somehow.

Is there any other idea?

Thanks

Zhiwen

On 4/25/2014 2:32 PM, Xiaochao Zheng wrote:
> I wasn't very careful at the factor of 2-4 level. I will re-do all my calculation at some point. My last lecture will be next Wed and I will have much more time after that.
>
> Xiaochao
>
> ----- Original Message -----
> From: "Zhiwen Zhao" <zwzhao at jlab.org>
> To: "Xiaochao Zheng" <xiaochao at jlab.org>
> Cc: jinhuang at jlab.org
> Sent: Friday, April 25, 2014 2:27:54 PM
> Subject: Re: 回复： Re: current estimation
>
> By the way, if you were using 1e4/GeV comparing to 7.5e3/GeV(=30/4MeV) I
> used.
> Your should have higher current that mine, but now yours are lower.
> So there's something else?
>
> ZHiwen
>
> On 4/25/2014 1:19 PM, Xiaochao Zheng wrote:
>> Hi Zhiwen:
>>
>> I agree with your calculations now. For some reason the missing 0.01 did not affect my final result. I used 1E4 p.e./GeV which is very close to your 30/4e6.
>>
>> In other words, Jin, even though the email you sent me was missing the 0.01, the final result was not affected. I have to trace to the end of this and see how I made two mistakes even though they are now cancelling.
>>
>> So we are back to where we were, and there is no need to send JP the "news".
>>
>> Xiaochao
>>
>> ----- Original Message -----
>> From: "Zhiwen Zhao" <zwzhao at jlab.org>
>> To: "Xiaochao Zheng" <xiaochao at jlab.org>, jinhuang at jlab.org
>> Sent: Friday, April 25, 2014 10:40:32 AM
>> Subject: Re: 回复： Re: current estimation
>>
>> 1e4 rad/mon
>> 1e4/30/24/3600 rad/s
>> 1e4/30/24/3600*0.01 J/kg/s because 1rad=0.01J/kg
>> 1e4/30/24/3600*0.01*200e-3 is J/s
>> 1e4/30/24/3600*0.01*200e-3/1.6e-19 is eV/s
>> 1e4/30/24/3600*0.01*200e-3/1.6e-19*(30/4e6) is number of p.e/s
>> 1e4/30/24/3600*0.01*200e-3/1.6e-19*(30/4e6)*1.6e-19=5.8e-11 is C/s or A
>> I think this is correct.
>> not sure how you get 3.5e-11A, maybe you were using less p.e. per MIP?
>>
>> Also the ave PVDIS dose should be 2e4 rad/mon including gamma from both
>> beam and pi0
>>
>> I am working on updating PVDIS estimation with high and low rate area
>>
>> Zhiwen
>>
>> On 4/25/2014 9:03 AM, Xiaochao Zheng wrote:
>>> Zhiwen, can you confirm it should be 5.8e-13A, not e-11, from your calculation?
>>>
>>> This is embarrassing, but also a good news, since we can now comfortably use the 64-ch MAPMT.  I need to find a way to break the news to Jianping after Zhiwen confirms the result.
>>>
>>> Xiaochao
>>>
>>> ----- Original Message -----
>>> From: "Jin Huang" <jinhuang at jlab.org>
>>> To: "Xiaochao Zheng" <xiaochao at jlab.org>, "Zhiwen Zhao" <zwzhao at jlab.org>
>>> Sent: Friday, April 25, 2014 6:14:00 AM
>>> Subject: RE: 回复： Re: current estimation
>>>
>>>> 2) Should I use the 0.01 conversion, Jin?
>>>
>>> Yes. I missed ( 0.01 J/kg/rad ) in the email of March 1 " RE: PMT current " ... I am sorry about that.
>>>
>>> Jin
>>>
>>>
>>> -----Original Message-----
>>> From: Xiaochao Zheng [mailto:xiaochao at jlab.org]
>>> Sent: Friday, April 25, 2014 3:39 AM
>>> To: Zhiwen Zhao
>>> Cc: jinhuang at jlab.org
>>> Subject: Re: 回复： Re: current estimation
>>>
>>> Hi Zhiwen:
>>>
>>> There is a typo in the table: The Preshower are 3.5E-11uA without gain. (My hand-written notes have 70uA with 2E6 gain, so must be 3.5E-11A, not E-12). This does not affect the rest of the table because the Shower shows 5E-11uA without gain, and all calculations of anode currents with gain are comparable between preshower and shower.
>>>
>>> Now I have a question for your formula: When I did my calculation I followed Jin's formula which did not have the 0.01 conversion from rad to J/kg. If I follow yours, I get about 0.58E-12, 100 times smaller than your 5.8E-11uA. So questions now are:
>>>
>>> 1) Can you check your calculation (just the one-line formula here);
>>> 2) Should I use the 0.01 conversion, Jin?
>>>
>>> Xiaochao
>>>
>>> ----- Original Message -----
>>> From: "Zhiwen Zhao" <zwzhao at jlab.org>
>>> To: "Xiaochao Zheng" <xiaochao at jlab.org>
>>> Cc: jinhuang at jlab.org
>>> Sent: Thursday, April 24, 2014 10:24:01 PM
>>> Subject: Re: 回复： Re: current estimation
>>>
>>> HI, Xiaochao
>>>
>>> In your table here, you have 1e4 rad/mon for 200g preshower and you get 3.5E-12A before any PMT gain
>>> http://hallaweb.jlab.org/experiment/PVDIS/SoLID/EC/meetings/SoLID_EC_Weekly_minutes.html#20140326
>>>
>>> Here I try to do the calculation
>>> 1e4/30/24/3600*0.01*200e-3*(30/4e6)=5.8e-11A
>>> which is an order larger than your result.
>>>
>>> The number I used are 1e4 rad/mon, 30*24*3600 second,0.01 covert rad to J/kg, 200e-3 kg,30 photonelectron every 4 MeV energy deposited in preshower scintillator.
>>>
>>> Zhiwen
>>>
>>> On 4/24/2014 7:56 PM, Xiaochao Zheng wrote:
>>>> Zhiwen I believe my calculation is correct. You can check mine and find the difference from yours. My notes are all in the minutes.
>>>>
>>>> Xiaochao
>>>>
>>>> ----------------------------------------------------------------------
>>>> ------ Associate Professor, Department of Physics, University of
>>>> Virginia
>>>> 382 McCormick Rd, Charlottesville, VA 22904
>>>> Telephone: (434) 243-4032 (during academic year); or (757) 810-2885
>>>> (summer)
>>>> Homepage: http://people.virginia.edu/~xz5y/Main.html
>>>> ----------------------------------------------------------------------
>>>> ------
>>>>
>>>>
>>>> ----- 原始邮件 -----
>>>> 发件人: Zhiwen Zhao <zwzhao at jlab.org>
>>>> 收件人: jinhuang at jlab.org
>>>> 抄送: 'Xiaochao Zheng' <xiaochao at jlab.org>
>>>> 已发送邮件: Thu, 24 Apr 2014 01:28:22 -0400 (EDT)
>>>> 主题: Re: current estimation
>>>>
>>>> You are right. That's the problem.
>>>> You only include dose by gamma from e- beam on target, so you get
>>>> 1e4rad/month, my result matches yours In addition, I have dose by
>>>> gamma from pi0 on target and baffle, so there is another 1e4rad/mon So
>>>> my result is actually 2e4rad/month in total.
>>>>
>>>> Xiaochao, I think Jin's and my results are ok, could you check your
>>>> previous current calculation?
>>>>
>>>> Zhiwen
>>>>
>>>> On 4/24/2014 1:13 AM, Jin Huang wrote:
>>>>> May I ask what is ...*0.01 ...? Are you sure it is not .../0.01... ?
>>>>>
>>>>> I would write the formula explicitly as:
>>>>> 100e3 GeV/s *1e9 eV/GeV *1.6e-19 J/eV / ( 0.01 J/kg/rad ) / (200e-3
>>>>> kg)
>>>>> *(3600*24*30 s/moth)
>>>>> = 2e4 rad/month
>>>>>
>>>>> Cheers,
>>>>>
>>>>> Jin
>>>>>
>>>>>
>>>>> -----Original Message-----
>>>>> From: Zhiwen Zhao [mailto:zwzhao at jlab.org]
>>>>> Sent: Wednesday, April 23, 2014 4:54 PM
>>>>> To: Jinhuang
>>>>> Cc: Xiaochao Zheng
>>>>> Subject: Re: current estimation
>>>>>
>>>>> hi, Jin
>>>>>
>>>>> Using my background files and your reponse function, I estimate the
>>>>> PVDIS average preshower energy deposition in scintillator is
>>>>> 100e3GeV/s referred to
>>>>> https://hallaweb.jlab.org/wiki/index.php/Solid_calorimeter_readout#en
>>>>> ergy_de po_and_number_of_photons.2C_per_unit_time
>>>>>
>>>>>
>>>>> assuming 200g scintillator material, I got the dose is
>>>>> 100e3*1e9*1.6e-19*0.01/200e-3*3600*24*30=2rad/mon
>>>>> while Xiaochao is using 1e4rad/mon from you.
>>>>>
>>>>> Do you know why the huge difference?
>>>>> Maybe your dose estimation is for the whole preshower including
>>>>> scintillator and lead?
>>>>>
>>>>> Zhiwen
>>>>>
>>>>> On 4/17/2014 4:53 PM, Zhiwen Zhao wrote:
>>>>>> Hi, Xiaochao
>>>>>>
>>>>>> Here is the updated current estimation for preshower
>>>>>>
>>>>>>
>>>>>> Please take a look and use the "ave" to compare to your current
>>>>>> result
>>>>>>
>>>>>> I am working on shower current now
>>>>>>
>>>>>> Zhiwen
>>>>>
>>>>
>>>