Spatial resolution and temporal resolution problem

[Dileshwar_Netam]

Hi everyone , I am a newbie to GARFIELD++ and I need to calculate both the spatial resolution and the time resolution but I cannot find any direct class to calculate them,
how can i calculate them. Can i calculate spatial resolution through this
aval.GetElectronEndpoint(j, x1, y1, z1, t1, e1, x2, y2, z2, t2, e2, status) at X spread for x2 & Y Spread for Y2 and also time resolution for t2
Is I’m calculating correct way or wrong , Plz correct me!
Give some suggestions , examples

Thanks!

[Danilo]

Hi Dileshwar,

Welcome to the ROOT Community. I am adding in the loop @hschindl .

Cheers,
D

[Dk_ntm]

Hi @Dileshwar_Netam ,

@Piet might be able to help you with this.

[Piet]

Dear @Dileshwar_Netam

First of all few questions:
(1) what is the detector / geometry you are working in?
(2) in which particles are you interested? A track / Single Photon / Single Electron?
(3) what is the level of detail you would like to implement in your simulation?

Depending on the answer on the above questions there are different strategies. I can briefly illustrate one of the options, but we would need more details about what you would like to do exactly.

E.g. for the simulation of the spatial resolution of a simplied MPGD (e.g. the single-gem example) you can:
Loop over let’s say 5000 tracks, where you vary both the starting point (x0,y0) and your angle (dx0, dy0) within reasonable settings. You simulate the primary ionization of this track and you start an avalanche for each of the electrons. Then depending on the readout of your detector (strips / pads / pixels) and your front-end electronics (digital or analog) you can save your endpoints in a 1D or 2D histogram where the bins correspond to your readout. If your readout is digital, you are forced to take the center of all bins that above some threshold set by you. If your readout is analog, you can fit a function (e.g. a gaussian) to all bins that are above some threshold set by you.

If instead you want to go in more detail, and you have a geometry that includes also the readout strips and pads, and you have weighting fields calculated for them, you simulate the same tracks and lauch an avalanche for each of the primary electrons created. This time you can register the signal pulses on each of your strips/pads and discriminate them: determine the time they go above threshold and ask the charge of the signal. Again you can fill histograms with this, fit with a gaussian and extract the mean and standard deviation.

Kind regards
Piet

[Dileshwar_Netam]

Dear @Piet, thank you for your response! Here are the details of my work:

1. Detector / Geometry: I am working on a single-layer GEM detector. The geometry includes a drift region, the GEM foil, and a collection region. I have defined these using GMSH and imported the field maps into Garfield++.
2. Particles of Interest: I am primarily interested in simulating single-electron avalanches resulting from ionization events. In the future, I might extend this to study tracks from charged particles.
3. I would like to include sufficient detail to calculate the spatial resolution (spread of the avalanche endpoints) and the Temporal resolution (time spread of collected electrons at the anode). At this stage, I am focusing on using the avalanche endpoint positions (x2, y2) for spatial resolution and the arrival times (t2) for time resolution. According to me the temporal resolution and spatial resolution this is the way to calculate, if my approach is wrong for wrong plz correct me. If needed, I can refine the gas properties or add more detailed physics interactions for better accuracy.

As i know Temporal distribution, The temporal distribution can be split
into two parameters.
The first parameter is the time between the initial ionization by the muon and the
arrival of the electrons on the readout plane and 2nd The second parameter is the time interval over which the electrons are spread out at the readout plane. The spacial distribution (Spatial resolution is the detector’s ability to determine the positions where electrons from the avalanche process arrive on the readout plane). spread of the electrons on the readout board belonging to the same
avalanche is also important.
Could you kindly confirm if this approach is suitable for calculating spatial and time resolution, or suggest any improvements or additional details I should include? Can you plz correct me if i’m wrong .

Thank you!

[Piet]

Dear @Dileshwar_Netam

I was not able to fully follow your reasoning on how you can split the temporal distribution into parameters. Since you are interested in the single GEM case, I made an example how you can create your own toy-experiments by modifying the single-gem example that comes with the garfield installation [1], and I attached it, such that you can have a look. I smeared the x0,y0,z0 point for the starting position of your single electron. I made some theoretical (best possible resolution) and some realistic (based on detector readout granularity) spatial resolution plots.
This example works with the ANSYS FEM solution provided in [1].

In this example there is a drift region of 1mm with a field of 1kV/cm, a 50um single GEM with 300V voltage difference between top and bottom and an induction region of 1mm with a field of 2kV/cm. If you do not smear the position of your single electron in the z-direction (height), then your time resolution is (slightly) better.

Hope this can serve for some inspiration.
Kind regards
Piet

gemResolution.C (5.7 KB)

[1] Examples/Gem · master · garfield / garfieldpp · GitLab

[Dileshwar_Netam]

I want a plot like this, I know the one given for triple GEM.

Thanks Sir for your time and understanding.

[Piet]

Hi @Dileshwar_Netam

I guess here the single electron is put at fixed distance in z. Could you provide a reference to this thesis?

[Dileshwar_Netam]

Yes, the single electron is placed at a fixed distance in the z-direction. The reference for this approach is taken from this
thesis4.pdf (3.0 MB)

[Piet]

I think you can use the code I provided you and fix (x,y,z) coordinates of your electron that you launch. You will be able to reproduce these plots. Please keep in mind that these plots are for a Triple-GEM configuration, therefore the spatial distribution and temporal distribution are wider than what you will obtain for a Single-GEM configuration.
greets
Piet