[Eg2] Target densities

[Will Brooks]

On 1/11/11 6:52 PM, Steven L. Manly wrote:
> Interesting.  Will, you mentioned in today's meeting that someone has a
> file with the original measurements?  I didn't catch the name.  Who came
> up with the carbon number for the NIM article?
>
> -Steve
>
>
>> Hi everybody,
>>
>> After this afternoon meeting I have some concern about the values for the
>> target thickness especially Carbon.
>>
>> In the NIM paper there is a table indicating areal densities as: C = .38 ;
>> Fe = 0.31 ; Pb = 0.16 g/cm2
>> Simple calculation with Hyupwoo numbers gives 2H = .325 g/cm2
>>
>> Then ratios of electrons from the targets in data should give something
>> around: C = 1.17 ; Fe = .95 ; Pb = .49
>> I found with my cuts: C = .91 ; Fe = .96 ; Pb = .46 It is a good agreement
>> except for Carbon!
>>
>> If I use Hyupwoo numbers for the Carbon areal density, I find the same
>> than
>> in the NIM paper, but I am concerned with the value of 2.267 g/cm3 because
>> graphite seem to have variable density depending on the web site you
>> consult, what I could grab was that raw mineral graphite is between 2.09
>> and
>> 2.3 g/cm3 but that once treated it can get much lighter (I seen 1.57, 1.7
>> and 1.8 in various places). On the NIST web site they use density of 1.7
>> g/cm3 for graphite and that would lead to an areal density of .29 g/cm2
>> which give a ratio in data of .90 in agreement with what I observe in
>> data.
>>
>> --
>> Raphaël Dupré
>>
>>
>> Argonne National Laboratory
>>
>> Université Claude Bernard Lyon 1
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