Different Crystals

Scintillation crystals, PMTs, voltage dividers etc...
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gerhard
Posts: 9
Joined: 05 Jul 2016, 04:57
Location: Burgwedel, Germany
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Different Crystals

Post by gerhard » 04 Nov 2016, 06:38

Good evening dear members,
I have a problem showing one of my crystals. It is a 2,5 x2,5 inch NaI crystal. It shows some distortion on the base in PRA 15 but not in Theremino MCA.
C137_2,5_021116.png
C137 with 2,5 inch NAI
C137_2,5_021116.png (55.19 KiB) Viewed 1276 times

C137_2,5.png
C137 with 2,5 inch NAI
C137_2,5.png (53.35 KiB) Viewed 1276 times
than with a selfbuilt 18x40mm NAI Detector
C137_CA_011116.jpg
C137 with 18x40mm NAI
C137_CA_011116.jpg (65.44 KiB) Viewed 1276 times
C137_CA.png
C137 with 18x40mm NAI
C137_CA.png (93.58 KiB) Viewed 1276 times
than with the factory built GS 1,5x1,5 inch System
C137_GS_021116.jpg
C137 with 1,5x1,5 inch NAI
C137_GS_021116.jpg (69.27 KiB) Viewed 1276 times
C137_GSa.png
C137 with 1,5x1,5 inch NAI
C137_GSa.png (50.33 KiB) Viewed 1276 times
and at last with my new RAP47 1mm CsI detector
C137_Rap47a_031116.png
C 137 with RAP47 1mm CsI
C137_Rap47a_031116.png (44.63 KiB) Viewed 1276 times
So, i am new, please can You make any comments,what You see thats wrong ?
Esp. on the 2,5 inch System
Resolution about +- 8 %

thank You
Attachments
C137_RAP47_031116.png
C 137 with RAP47 1mm CsI
C137_RAP47_031116.png (92.25 KiB) Viewed 1276 times

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Steven Sesselmann
Posts: 599
Joined: 27 Apr 2015, 11:40
Location: Sydney
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Re: Different Crystals

Post by Steven Sesselmann » 04 Nov 2016, 16:28

Not exactly sure what distortion you are referring to, is it the sharp edge on the right shoulder?

If so can you check if your Tolerance correction is set to Zero in Data Acquisition and Analysis?


C137_2%2C5_021116.png
CS137
C137_2%2C5_021116.png (42.16 KiB) Viewed 1266 times
Steven Sesselmann | Sydney | Australia | gammaspectacular.com | groundpotential.org | rephopper.com | beejewel.com.au |

gerhard
Posts: 9
Joined: 05 Jul 2016, 04:57
Location: Burgwedel, Germany
Contact:

Re: Different Crystals

Post by gerhard » 05 Nov 2016, 02:47

Thank You, Mr. Sesselmann, for help.
I use PRA 15 and Tolerance Threshold is 5, Correction is 0 and Boost gain 1.
No shielding at all. I dont have one.
Yes, the right, but also the left shoulder. This peak seems on the base not symmetrical and especially on the left shoulder. It deviates to the left.
I have read in Your Forum,that maybe, the crystal is a little wet, than the left schoulder ist going more to the left. I think it was luuk ?
But, maybe, i am wrong and missunderstood something.
I use for C137 this old spark gap, 4 together in a housing of plastik.
But, if You think, this spectrums are more or less ok, so please,tell me.

With best regards
gerhard

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