GSI Forum: MVD » More no of Hits than Points

Home » PANDA » PandaRoot » MVD » More no of Hits than Points

Show: Today's Messages :: Polls :: Message Navigator

More no of Hits than Points [message #6343]

Thu, 10 April 2008 14:41

Vanniarajan Suyam Jothi
Messages: 35
Registered: October 2007
Location: Groningen

continuous participant

From: *KVI.nl

Hello Ralf,
Here I have attached the datas from the points, strip hits and pixel hits. Here as you see, there are 22060 points, and there are 26161 pixel digis and 72212 strip strip digis. During the discussion somebody said there are two side of a strip one gets two digis per point. In that case I would expect 44120 strip digis.

Or Can you tell me if I am missing some thing here?

Cheers,
Vanni

Attachment: out.ps
(Size: 213.49KB, Downloaded 816 times)

Report message to a moderator

Re: More no of Hits than Points [message #6348 is a reply to message #6343]

Thu, 10 April 2008 16:27

Ralf Kliemt
Messages: 508
Registered: May 2007
Location: GSI, Darmstadt

first-grade participant

From: 141.30.85*

Hello Vanni,

Let me explain how we produce our hits:
First is the simulation storing Points. Each point contains the entry and exit coordinates of the track through the sensor. From this we digitize to column/row information or to top.bottom strip numbers (according to the sensor type).
This results into clusters of several (usually 1-3) Pixel digis or strip digis which produce one Hit.
Maybe you should have a look to the slides from the Collaboration meetings :

To give you an impression I plotted the multiplicity of digis in one hit.

Toggle Spoiler

Attachment: stripclustmult.png
(Size: 12.67KB, Downloaded 1288 times)

Report message to a moderator

Re: More no of Hits than Points [message #6350 is a reply to message #6343]

Thu, 10 April 2008 16:35

Ralf Kliemt
Messages: 508
Registered: May 2007
Location: GSI, Darmstadt

first-grade participant

From: 141.30.85*

Toggle Spoiler

The multiplicities are 2.9 for strips and 2.3 for pixels (DPM@6GeV)

So playing with these numbers:(26000/2.2) + (72000/(2.9*2)) = 24200

So this looks OK from my point of view.

In the end you should have the same order in the numbers of Points and Hits.

Hopefully this helps,

Ralf.

Attachment: pixelclustmult.png
(Size: 11.83KB, Downloaded 1274 times)

Report message to a moderator

Re: More no of Hits than Points [message #6354 is a reply to message #6348]

Thu, 10 April 2008 17:07

Vanniarajan Suyam Jothi
Messages: 35
Registered: October 2007
Location: Groningen

continuous participant

From: *KVI.nl

Hello Ralf,
The Slides from the Collaboration meeting gives impression that a hit is constructed from 7 points at the first sight.

Now i understand it better. a monte- carlo point goes through several pixel sensors.

Thank you,
Vanni

Report message to a moderator

Re: More no of Hits than Points [message #6359 is a reply to message #6343]

Fri, 11 April 2008 01:27

Ralf Kliemt
Messages: 508
Registered: May 2007
Location: GSI, Darmstadt

first-grade participant

From: *z.pppool.de

Hi Vanni,

Please don't mix the names. We have Monte-carlo points geometrical motivated digis and reconstructed hits.
So one point leads to several digis and should be found and reconstructed into a hit.

Cheers, Ralf.

PS: I am aware of being too pedantic here, but I like to have it clear. - Ralf

Report message to a moderator

Previous Topic:	Problem with Mvd Reco
Next Topic:	Issues on the mvd root geometry 1.0

Goto Forum:

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Fri Feb 20 07:41:48 CET 2026

Total time taken to generate the page: 0.00734 seconds