Issue with coherent scattering

[mcolomermolla]

Trying to simulate the DS20k detector I encountered the following problems:

• Material is not defined for ds20 detector (that's not a real problem because one can give it directly to rate calculator), but maybe for the user it is not obvious).
• The coherent scattering channels are dropped as they have a different binning compared to other Ar channels: # drop coherent scattering channels, which have different binning df = df[df["name"].str.startswith('coh_') == False] Even though, the code is now written to deal with that case (all channels with same fixed binning (starts with %) VS channels with different defined binning (starts with SNnu))
• When I modify the channels_argon_coh.dat file (where there are no other channels with different binning) removing the start SNnu, the channels are not dropped but the rates obtained are still zero.
• The snowglobes_data for DS20k contains efficiency files only for coherent scattering, not for the other Ar-CC interactions, while smearing matrices do exist for all of them.

[JostMigenda]

Thanks for writing these up!

I’ll start with your last two points:

• It looks like the efficiency files (e.g. effic_coh_helm_nue_Ar_ds20.dat give an efficiency of 0.0 independent of energy; I suspect that’s why your rates are zero even after the modifications.
• Yes—snowglobes_data only contains the efficiency files present in the SNOwGLoBES repo. In practice, I don’t think these missing files matter much, though: Since the visible energy in neutrino-electron scattering is O(MeV)—i.e. several orders of magnitude higher than typical signals these DM detectors are built for—I’d expect that the efficiency is close to 1, which is also the default value used by snewpy if no efficiency file is provided.

Once those two points are fixed (which are outside the scope of snewpy, really; probably something we should discuss with DS20k folks in SNEWS first, and then discuss/track in an issue on the SNOwGLoBES repo), I agree the first two points are things we should improve in snewpy.

[Storreslara]

I can provide you guys with the effic file, which is dependent on nu_E [MeV])
ds20k_sn_nu_eff.csv

Let me know there is other DS related stuff I can help with

[mcolomermolla]

Thanks for writing these up!

I’ll start with your last two points:

• It looks like the efficiency files (e.g. effic_coh_helm_nue_Ar_ds20.dat give an efficiency of 0.0 independent of energy; I suspect that’s why your rates are zero even after the modifications.
• Yes—snowglobes_data only contains the efficiency files present in the SNOwGLoBES repo. In practice, I don’t think these missing files matter much, though: Since the visible energy in neutrino-electron scattering is O(MeV)—i.e. several orders of magnitude higher than typical signals these DM detectors are built for—I’d expect that the efficiency is close to 1, which is also the default value used by snewpy if no efficiency file is provided.

Once those two points are fixed (which are outside the scope of snewpy, really; probably something we should discuss with DS20k folks in SNEWS first, and then discuss/track in an issue on the SNOwGLoBES repo), I agree the first two points are things we should improve in snewpy.

Yes, I realised after that efficiencies are zero... so basically, deleting those files so that it uses by default eff=1 should be fine for the moment to get a reasonable output for the coherent channels. However, it still won't run all the channels together because of the different binning, I will have a look at that.

[OliverMacfadyen]

Hi I am a PhD student on DarkSide and I have just started working on snewpy and snews with a group at Oxford university. I was just wondering if anyone would be available to get me up to speed on this issue, where it is currently up to and if there is anything I can do to help.

[mcolomermolla]

Hi Oliver, Sorry for the late reply. At the moment, there have been no updates. If you want, I can write you an email and we set a zoom meeting so that I can explain to you the issues and where to start as we originally planned.

[Sheshuk]

Fixed in #319