Chapter 4

Example

Up to now, we have introduced the installation and concepts of artemis. This chapter will show you how to analyse with artemis through practical examples; if you want to know how to use artemis, it is no problem to start reading from here.

Subsections of Example

Subsections of Preparation

Basic

last modified: 2023-12-13 by Kodai Okawa

I would now like to introduce the actual analysis using the CRIB analysis server. There are two ways to enter the analysis server, directly or remotely via ssh. If you come to CRIB and operate the server directly, I think it is quicker to analyse using the server while asking the CRIB members directly as I think they are nearby.

1. SSH configuration

To enter the CRIB server, you need to enter the CNS network. To do this, you need to create an account on the CNS login server. Please contact Okawa (okawa@cns.s.u-tokyo.ac.jp) or the person responsible for CRIB (see here) and tell us that you want a login server account.

The CNS login server uses public key cryptography, so you need to send a shared key when you apply. This section describes how to create the key, especially on MacOS.

cd # move to /Users/yourname/ (home directory)
mkdir .ssh # if there is no .ssh directory
cd .ssh
ssh-keygen

You will be asked a number of interactive questions after this command, all of which are fine by default (Enter). Then you will see the pair of public-key and private-key.

ls 
id_rsa  id_rsa.pub

id_rsa is the private-key, and id_rsa.pub is the public-key. The private key is important for security reasons and should be kept on your own computer. Then, please send this public-key to the CNS member. in MacOS, open . command will open a finder for that directory, so it is easy to attach it to an email from here. In the email,

  • your fullname (affiliation)
  • username
  • attached public-key

are needed.

Next, let’s set up multi-stage ssh. As the login server is just a jump server, it is useful to be able to ssh to the CRIB analysis server at once! So create the following config file. The file placed in this directory is automatically read when you ssh.

cd ~/.ssh
vi config
 1Host login
 2    HostName CNS_loginserver_hostname
 3    User username
 4    IdentityFile ~/.ssh/id_rsa
 5    ForWardX11Timeout 24h
 6    ControlPersist 30m
 7    ForwardAgent yes
 8    ControlMaster auto
 9    ControlPath ~/.ssh/mux-%r@%h:%p
10
11# any name is okay
12Host cribana
13    HostName analysisPC_hostname
14    User crib
15    IdentityFile ~/.ssh/id_rsa
16    ProxyCommand ssh login nc %h %p
17    ForwardAgent yes
18    ControlMaster auto
19    ControlPath ~/.ssh/mux-%r@%h:%p
20    ControlPersist 30m

You will be informed of the second and third lines above that we highlighted, so please change this parts. And ask the IP address of the CRIB analysis PC to the CRIB member, and change the 13 line.

Then you can enter the CRIB analysis PC just by

ssh cribana

CRIB member will tell you the passward!

For the VNC server (local forwarding), please see this section.

2. your artemis configuration

When you enter the CRIB computer, please check this is zsh shell.

> echo $SHELL
/usr/local/bin/zsh
Info

Currently, zsh installed locally is used. It is planned to update the OS in the future, after which it will differ from this path in the future.

If it is not zsh (like bash), please command

> zsh

Then you can start to configure by

> artlogin yourname
# input your information...

> mkdir build
> cd build
> cmake ..
> make -j4
> make install
> acd

For the detail, please check here.

3. basic usage

  • start artemis
> acd # move to your artemis work directory
> a # start artemis!

> a macro/macro.C # run macro script
  • important command in the artemis console
# read steering file
artemis [*] add steering/hoge.yaml NAME=hoge NUM=0000

# start event loop
artemis [*] res
artemis [*] start # defined in CRIB artemis

# stop event loop
artemis [*] sus
artemis [*] stop # defined in CRIB artemis

# help
artemis [*] help

# quit from artemis
artemis [*] .q
  • commands for checking histograms
# check and move the directory
artemis [*] ls
artemis [*] cd 0 # cd ID

# move to home directory in artemis
artemis [*] cd # cd .. will work?

# draw the histograms
artemis [*] ht 0 colz # ht ID option
artemis [*] hn colz # draw the next histogram object
artemis [*] hb colz # draw the previous histogram object

# divide the canvas
artemis [*] zone 2 2 # 2 x 2 canvas

# save and print the canvas
artemis [*] sa
artemis [*] pri
  • analize using TTree
# check the files
artemis [*] fls

# move to the created ROOT file
artemis [*] fcd 0 # fcd fileID

# check the all branches
artemis [*] br

# check the data members or methods
artemis [*] br branchname # ex. artemis [1] br ppaca

# the name of TTree object is "tree" (actually TArtTree object)
artemis [*] tree->Draw("ppaca.fY:ppaca.fX>>ppaca(100,-20.,20., 100,-20.,20.)","","colz")

See here for an example using random numbers.

Tref for V1190

last modified: 2023-12-15 by Kodai Okawa

CRIB uses a multi-hit TDC called V1190 to take timing data (manual). When a trigger comes into this module, it opens a window with a set time width and records the timing of the data.

However, even if the signal is sent at exactly the same time to the trigger, due to the uncertainty in opening that window, the resulting channel will vary. Since absolute channel values will vary, but relative channel values for a given (especially trigger) timing will remain the same, it is necessary to subtract all data by some reference channel to achieve good timing resolution.

The signal that serves as the reference for that time is what we call Tref! (Time reference) Since it is essential that all events contain that data, we put the trigger signal in one of the channels and make it a Tref.

The “tref” settings are made in the following file:

Processor:
# J1 V1190A
  - name: proc_tref_v1190A_j1
    type: art::TTimeReferenceProcessor
    parameter:
      # [[device] [focus] [detector] [geo] [ch]]
      RefConfig: [12, 2,  7, 0, 15]
      SegConfig: [12, 2,  7, 0]

Parameters RefConfig and SegConfig are set using the same ID as in the map file.

The “RefConfig” represents the “Tref” signal and the “SegConfig” represents the V1190 module. Therefore, the role of the processor is to subtract the “Segconfig” V1190 all timing signal from the “RefConfig” tref signal.

To apply this processor, add the following line to the steering file. For example,

Anchor:
 - &input ridf/@NAME@@NUM@.ridf
 - &output output/chkf3@NAME@@NUM@.root
 - &histout output/chkf3@NAME@@NUM@.hist.root

Processor:
  - name: timer
    type: art::TTimerProcessor

  - name: ridf
    type: art::TRIDFEventStore
    parameter:
      OutputTransparency: 1
      InputFiles:
        - *input

  - name: mapper
    type: art::TMappingProcessor
    parameter:
      OutputTransparency: 1

  - include: tref.yaml
  - include: rf/rf.yaml
  - include: coin/coin.yaml
  - include: ppac/dlppac.yaml
  - include: ssd/f3ssd.yaml

  - name: outputtree
    type: art::TOutputTreeProcessor
    parameter:
      FileName:
        - *output
Note

The tref.yaml should be written before the main processor. In this example, it is written right after TMappingProcessor, and we recommend writing it in this position.

PPAC calibration

last modified: 2023-12-18 by Kodai Okawa

CRIB use two kinds of PPAC (Parallel-Plate Avalanche Counter), charge division method or delay-readout method. The PPAC placed at the F1 focal plane is charge-devision type, and the parameters to be converted to position are fixed and do not need to be calibrated. Therefore we explain the calibration method for delay-line PPAC (dl-PPAC).

Principles

Here we briefly describe the principle of converting from the obtained signal to position, but for more details, see here1.

We will discuss the x-direction because x and y is exactly same. First, define the parameters as follows

  1. $k_x$ : convert from signal time difference to position [mm/ns]
  2. $T_{X1},~T_{X2}$ : time at both ends of delay-line, measured at TDC [ns]
  3. $T_{Xin-offset}$ : timing offset come from inside the chamber [ns]
  4. $T_{Xout-offset}$ : timing offset come from outside the chamber [ns] (like from cabling)
  5. $X_{offset}$ : geometry offset [mm]

The artemis codes calculate the X position like this formula (see TPPACProcessor.cc).

$$ X~\mathrm{[mm]} = k_x\left( \frac{T_{X1} - T_{X2} + T_{Xin-offset} - T_{Xout-offset}}{2} \right) - X_{offset}$$
Warning

Check the sign carefully! We often mistook the direction!!

Fixed parameters

The $T_{X1},~T_{X2}$ are measured value by TDC, and $k_x$ and $T_{Xin-offset}$ are specific value to PPAC, so we need to care only $T_{Xout-offset}$ and $X_{offset}$. $X_{offset}$ value depends on where we put the PPAC, so what we have to do is determine the line calibration parameter ( $T_{Xout-offset}$).

The following is a list of dl-PPAC parameters used in CRIB experiment.

PPAC ID $k_x$ [mm/ns] $k_y$ [mm/ns] $T_{Xin-offset}$ $T_{Yin-offset}$
#2 1.256 1.256 0.29 mm 0.18 mm
#3 1.264 1.253 0.22 mm 0.30 mm
#7 1.240 1.242 0.92 ns 1.58 ns
#8 1.241 1.233 0.17 ns 0.11 ns
#9 1.257 1.257 0.05 mm 0.04 mm
#10 1.257 1.257 0.05 mm 0.04 mm
Warning

Different units are used for the offset. However, since the effect of this offset is eventually absorbed to the other offset value, it is no problem to use the values if we calibrate it correctly.

Parameter setting

PPAC parameters are defined in the following files

For example, it is like this:

Type: art::TPPACParameter
Contents:
# #7 PPAC
  f3bppac: # this is the name of PPAC, should be the same name with the one in steering file!
    ns2mm:
    - 1.240
    - 1.242
    delayoffset:
    - 0.92
    - 1.58
    linecalib:
    - 1.31
    - -1.00
    # 0: no exchange, 1: X -> Y, Y -> X
    exchange: 0
    # 0: no reflect, 1: X -> -X
    reflectx: 1 
    geometry:
    - 0.0
    - 0.5
    - 322.0
    TXSumLimit:
    - -800.0
    - 2000.0
    TYSumLimit:
    - -800.0
    - 2000.0
  • ns2mm

    This is $k_x$ and $k_y$ parameters -> input the fixed value

  • delayoffset

    This is $T_{Xin-offset}$ and $T_{Yin-offset}$ parameters -> input the fixed value

  • linecalib

    This is explained next.

  • exchange, reflectx

    This parameter should be changed depending on the direction in which the PPAC is placed. The meanings of the parameters are given above as comments.

    Note

    CRIB takes a coordinate system such that when viewed from downstream of the beam, the x-axis is rightward and the y-axis is upward. In other words, it takes a right-handed coordinate system with the beam as the Z-axis. While looking at the actual data, change these parameters so that the coordinate system becomes this coordinate system.

  • geometry

    In the Line calibration, please set this value to (0,0). After Line calibration, if we put the PPAC with some geometry offset, we should change this parameters. Please be careful that the parameter will add minus this value for X and Y. Z offset will be used for TPPACTrackingProcessor.

  • TXSumLimit, TYSumLimit

    Used to determine if it is a good event or not. Currently not used.

Line calibration

Before starting line calibration, please make sure that map file and steering file is correctly set. Also we need parameter file of prm/ppac/ch2ns.dat to convert TDC channel to ns unit. (already prepared I think)

graph LR;
    A[TDC channel] -->|prm/ppac/ch2ns.dat| B[ns scale]
    B --> |prm/ppac/dlppac.yaml|C{PPAC object}

When you complete the setting except for linecalib parameters, let’s start calibration! We prepared two useful macros to calibrate dl-PPAC.

First, we have to prepare the data with masks on the PPAC like following picture. This mask has holes at 12.5 mm intervals.

The position of the alpha line through the central hole can be calculated and the offset adjusted to achieve that position. The geometry inside the PPAC is as follows. I think all PPAC geometries used by CRIB are the same.

The parameters required to calculate the coordinates of the position are as follows.

  • PPAC ID
  • PPAC direction (first layer is X or Y)
  • alpha source offset X
  • alpha source offset Y
  • distance between the mask and alpha source
  • reflectx in the dlppac.yaml

Using these parameters, the macro/PPACLineCalibration.C calculate the theoretical position and how much the parameters should be moved.

Example

Let’s calibrate PPACa as an example.

  • PPAC ID : #2
  • First layer is Y
  • alpha source offset X : 0.0 mm
  • alpha source offset Y : 2.2 mm
  • distance between the mask and alpha source : 92 mm
  • reflectx : 1 (have reflection)

When we set the parameter like this files, the XY figure can be obtained.

Type: art::TPPACParameter
Contents:
  # #2 PPAC
  f3appac:
    ns2mm:
      - 1.256
      - 1.256
    delayoffset:
      - 0.29
      - 0.18
    linecalib:
      - 0.0
      - 0.0
    exchange: 0
    reflectx: 1
    geometry:
      - 0.0
      - 0.0
      - -677.0 # user defined
    TXSumLimit:
      - -800.0
      - 2000.0
    TYSumLimit:
      - -800.0
      - 2000.0

Then we can run the macro.

> acd
> vi macro/run_PPACLineCalibraion.C
# please set the parameters.
# instruction is written in this file

> a
artemis [0] add steering/hoge.yaml NAME=hoge NUM=0000
artemis [1] res
artemis [2] .x macro/run_PPACLineCalibration.C
# -- snip --

===================================================
center position (cal)  : (-0, -0.51413)
center position (data) : (0.890109, -0.274066)
difference             : (0.890109, 0.240065)
move parameters        : (-1.41737, 0.382269)
===================================================

And please input this value to the dlppac.yaml.

Type: art::TPPACParameter
Contents:
  # #2 PPAC
  f3appac:
    ns2mm:
      - 1.256
      - 1.256
    delayoffset:
      - 0.29
      - 0.18
    linecalib:
      - -1.417
      - 0.382
    exchange: 0
    reflectx: 1
    geometry:
      - 0.0
      - 0.0
      - -677.0 # user defined
    TXSumLimit:
      - -800.0
      - 2000.0
    TYSumLimit:
      - -800.0
      - 2000.0

Then you can complete the line calibration of the PPAC.

> a
artemis [0] add steering/hoge.yaml NAME=hoge NUM=0000
artemis [1] res
artemis [2] .x macro/run_PPACLineCalibration.C
# -- snip --

===================================================
center position (cal)  : (-0, -0.51413)
center position (data) : (-0.0191028, -0.571067)
difference             : (-0.0191028, -0.0569366) # <= almost zero!
move parameters        : (0.0304184, -0.0906633)
===================================================
Info

Because of the accuracy of the fitting, it does not make much sense to move the parameters any further.

The PPAC is then ready to be used by measuring how much offset the beamline axis has with respect to the delay-line axis at the position where the PPAC is actually placed, and putting this into the geometry parameters.


  1. H. Kumagai et al., Nucl. Inst. and Meth. A 470, 562 (2001) ↩︎

MWDC calibration

last modified: 2024-01-22 by Kodai Okawa

updating…

Alpha calibration

last modified: 2023-12-23 by Kodai Okawa

This is the CRIB alpha source information. (unit: MeV)

ID alpha-2 alpha-3
4.780 3.148
5.480 5.462
5.795 5.771

calibration files

SSD calibration files need to be set at prm/ssd/ directory. The directory structure is like this:

$ tree -L 2 prm/ssd
prm/ssd
├── ch2MeV.dat # test file
├── ch2ns.dat # test file
├── f2ch2MeV.dat
├── f2ch2MeV_raw.dat
├── f2ch2ns.dat
├── tel1
│   ├── ch2MeV_dEX.dat
│   ├── ch2MeV_dEX_raw.dat
│   ├── ch2MeV_dEY.dat
│   ├── ch2MeV_dEY_raw.dat
│   ├── ch2MeV_E.dat
│   ├── ch2MeV_E_raw.dat
│   ├── ch2ns_dEX.dat
│   ├── ch2ns_dEY.dat
│   ├── ch2ns_E.dat
│   └── tel_conf.yaml # telescope configuration, explain later

-- snip --

The prm/ssd/ch2MeV.dat and prm/ssd/ch2ns.dat are used for test, so in the beam time measurement, actually this files are not necessory. And prm/ssd/f2* files are used for F2SSD calibration, and files in prm/ssd/tel1/ directory are used for SSDs of a telescope.

The ch2ns.dat depends on TDC setting, so basically we don’t have to care so muc (Usually the setting (the value) is same with previous experiment.), so we have to prepare the ch2MeV.dat files!

Note

The file name need to be set like this example. The loaded parameter file name is defined SSD steering file, and we don’t want to change the SSD steering files so much, so please use such file names.

The “ch2MeV.dat” file format is like this:

# offset gain
1.7009  0.0173
0.0 1.0 # if there are some SSDs or strip SSD, you can add the line.
$$ E~\mathrm{[MeV]} = \mathrm{offset} + \mathrm{gain} \times \mathrm{ch} $$

Usage

We prepared useful macros to calibrate many SSDs. Please check these for more information.

It is sufficient to use the AlphaCalibration.C, but it is recommended to use the run_AlphaCalibration.C to keep a record of what arguments were used to calibrate.

After you prepared alpha calibration data and steering file (for example steering/calibration.yaml) to show raw data, you can use this macro.

$ acd
$ vi macro/run_AlphaCalibration.C
# please set the parameters.
# instraction is written in this file

$ a
artemis [0] add steering/hoge.yaml NAME=hoge NUM=0000
artemis [1] res
artemis [2] .x macro/run_AlphaCalibration.C

Then the parameter file that defined at the “run_AlphaCalibration.C” and calibration figures will be created automatically.

These are example of the figures;

  • raw fitting figure (figure/calib/tel*/ch2MeV_*/raw/)
  • calibration line and residual figure (figure/calib/tel*/ch2MeV_*/calibration/)
$ a
artemis [0] add steering/hoge.yaml NAME=hoge NUM=0000
artemis [1] res
artemis [2] fcd 0
artemis [3] zo
artemis [4] tree->Draw("...") # draw calibrated data
artemis [5] gStyle->SetOptStat(0)
artemis [6] sa

MUX calibration

last modified: 2024-01-22 by Kodai Okawa

updating…

Set parameters

last modified: 2024-01-22 by Kodai Okawa

updating…

Git

last modified: 2024-01-22 by Kodai Okawa

Analysis files for each experiment are managed using git. This is so that they can be quickly restored if they are all lost for some reason.

Git is a bit complicated and you can commit freely if you are knowledgeable, but if you are unfamiliar with it, you don’t have to worry too much. The main use is that if someone creates a useful file, it will be reflected for each user as well.

Here is a brief description of how to use it.

Directory structure

In the CRIB analysis PC, we used local repository. The files related the repository is stored here.

> cd ~
> tree -L 1 repos/exp
repos/exp
├── he6p2024.git
├── he6p.git
└── o14a.git

# 2023/12/18 current status
Warning

Note that if you delete the files in this directory, you will lose all backups.

basic commands

I will describe the most commonly used commands and how to resolve conflicts.

Subsections of Online analysis

F1

last modified: 2024-01-20 by Kodai Okawa

From here, we would like to explain in detail how to analyze the actual experiment. We assume that you have already prepared your the analysis environment. It is okay either your own directory or the default directory (see CRIB configuration). If you are not ready yet, please see here.

So let’s start to check the data. At the F1 focal plane, there is (charge-divition) PPAC. The steering file to analyze f1 data is chkf1.yaml.

We usually use “chk” (check) as a prefix of the steering files to analyze from raw binaly data.

$ artlogin (username)
$ a
artemis [0] add steering/chkf1.yaml NAME=hoge NUM=0000
artemis [1] res

The important data is “X position” at the F1PPAC. The histogram can be check by following step:

artemis [2] sus
artemis [3] ls

 artemis
>   0 art::TTreeProjGroup f1check         f1_check
    1 art::TAnalysisInfo analysisInfo

artemis [4] cd 0
artemis [5] ls

 f1check
>   0 art::TH1FTreeProj f1ppac_X        f1ppac X
    1 art::TH1FTreeProj f1ppac_Y        f1ppac Y
    2 art::TH1FTreeProj f1ppac_X1raw    f1ppac X1raw
    3 art::TH1FTreeProj f1ppac_X2raw    f1ppac X2raw
    4 art::TH1FTreeProj f1ppac_Y1raw    f1ppac Y1raw
    5 art::TH1FTreeProj f1ppac_Y2raw    f1ppac Y2raw
    6 art::TH2FTreeProj f1ppac_x_y      f1ppac X vs Y
    7 art::TH2FTreeProj f1ppac_x_rf     f1ppac X vs RF
    8 art::TH2FTreeProj f1ppac_x1_x2    f1ppac x1 vs x2
    9 art::TH2FTreeProj f1ppac_y1_y2    f1ppac y1 vs y2

Many histograms are defined, but in practice it’s enough to check the first X position. Sometimes we check other raw data histograms to see if the behavior of F1PPAC is correct or not.

artemis [6] ht 0

Usually a gaussian fit is performed to get center the position.

artemis [7] xf

For the commane “xf” (xfitg), please check here.

When you think the signals from F1PPAC is okay, but position seems wrong (the X position is different from the setting of F1 slit), pleace modify the parameter files.

It is actually charge-divition PPAC, but the structure of parameter file is the same with dl-PPAC, so please also check PPAC preparation.

F2

last modified: 2024-01-20 by Kodai Okawa

The basic usage is the same.

We use this steering file to check F2 data.

$ artlogin (username)
$ a
artemis [0] add steering/chkf2.yaml NAME=hoge NUM=0000
artemis [1] res
artemis [2] sus
artemis [3] ls

 artemis
>   0 art::TTreeProjGroup f2check         f2_check
    1 art::TAnalysisInfo analysisInfo
artemis [4] cd 0
artemis [5] ls

 f2check
>   0 art::TH1FTreeProj f2PPAC X        f2ppac x
    1 art::TH1FTreeProj f2PPAC Y        f2ppac y
    2 art::TH1FTreeProj f2SSD raw       f2ssd raw
    3 art::TH1FTreeProj f2SSD raw (low) f2ssd raw (low)
    4 art::TH1FTreeProj f2SSD cal       f2ssd cal
    5 art::TH2FTreeProj f2PPAC X vs Y   f2ppac X vs Y
    6 art::TH2FTreeProj F2PPAC X vs RF0 f2ppac X vs rf0
    7 art::TH2FTreeProj F2PPAC Y vs RF0 f2ppac Y vs rf0
    8 art::TH2FTreeProj RF0 vs F2SSD raw rf0 vs f2ssd raw
    9 art::TH2FTreeProj RF0 vs F2SSD cal rf0 vs f2ssd cal
   10 art::TH2FTreeProj RF1 vs F2SSD cal rf1 vs f2ssd cal
   11 art::TH2FTreeProj F2PPAC X vs F2SSD raw f2ppac x vs f2ssd raw
   12 art::TH2FTreeProj F2PPAC X vs F2SSD cal f2ppac x vs f2ssd cal
   13 art::TH2FTreeProj F2PPAC Y vs F2SSD cal f2ppac y vs f2ssd cal
   14 art::TH1FTreeProj RF0             rf0

As you know, you can check the histograms

# for 1D histograms
artemis [*] ht [id]
artemis [*] hn # histogram next
artemis [*] hb # histogram before (back?)
# for 2D histograms
artemis [*] ht [id] colz # colz is option
artemis [*] hn colz
artemis [*] hb colz

If you want to save,

artemis [*] sa
artemis [*] pri

PPAC

last modified: 2024-01-22 by Kodai Okawa

updating…

MWDC

last modified: 2024-01-22 by Kodai Okawa

updating…

Telescope

last modified: 2024-01-22 by Kodai Okawa

In the CRIB experiment, we often use a “telescope” consisting of DSSSD (Double-Sided SSD) and SSD (Single-Pad SSD). The combination of these multiple Si detectors as a dE-E detector is called a telescope.

To analyze the data as telescope data rather than individual detectors, I created a data class called TTelescopeData. This section describes its data structure and usage.

Please assume that one of the name of TTelescopeData object is “tel1”

# after some process
artemis [*] br tel1

 art::TTelescopeData

 Data Members

                 TVector3   fPos                   detected position (X, Y, Z)
                      int   fXID                   X strip number
                      int   fYID                   Y strip number
                      int   fNE                    number of all SSDs
                   double   fdE                    energy at first layor
                   double   fdEX                   X side energy (=~ fdEY)
                   double   fdEY                   Y side energy (=~ fdEX)
                   double   fE                     added energy at thick SSDs
                   double   fEtotal                all energy deposit in the telescope
                   double   fTiming                timing information at the first layor (X side)
                   double   fYTiming               for case that X side have trouble (Y side)
                   double   fTheta_L               reaction angle in LAB system
           vector<double>   fEnergyArray           energy array for each SSD
           vector<double>   fTimingArray           timing array for each SSD
                ESortType   kID
                ESortType   kTiming
               ESortOrder   kASC
               ESortOrder   kDESC

# snip for Method as for now

These are the all data members of the “TTelescopeData”. The most commonly used variables are “fXID”, “fYID”, “fdE” and “fE”. Other variables are accessed by using methods (explain later). The meaning of these variables are written the upper code block.

We use them like,

artemis [*] tree->Draw("tel1.fYID:tel1.fXID>>strip(16,-0.5,15.5, 16,-0.5,15.5)","","colz")
artemis [*] tree->Draw("tel1.fdE:tel1.fE","","")

or we can use in histogram definition file of course.

The following are the methods of the TTelescopeData object:

# after some process
artemis [*] br tel1

# snip for Data Members

 Methods

          TTelescopeData&   operator=
                 TVector3   GetPosition
                 Double_t   X
                 Double_t   Y
                 Double_t   Z
                     void   SetPosition
                     void   SetPosition
                    Int_t   GetN
                     void   SetN
                    Int_t   GetXID
                     void   SetXID
                    Int_t   GetYID
                     void   SetYID
                 Double_t   GetdE
                     void   SetdE
                 Double_t   GetdEX
                     void   SetdEX
                 Double_t   GetdEY
                     void   SetdEY
                 Double_t   GetE
                     void   SetE
                 Double_t   GetEtotal
                     void   SetEtotal
                 Double_t   GetTelTiming
                     void   SetTelTiming
                 Double_t   GetTelYTiming
                     void   SetTelYTiming
                 Double_t   GetTheta_L
                     void   SetTheta_L
                 Double_t   A
              DoubleVec_t   GetEnergyArray
                 Double_t   GetEnergyArray
                     void   PushEnergyArray
              DoubleVec_t   GetTimingArray
                 Double_t   GetTimingArray
                     void   PushTimingArray
                 Double_t   E
                 Double_t   T
                     void   Copy
                     void   Clear
                   Bool_t   CheckTObjectHashConsistency

 See also

     art::TDataObject       base class for data object

The most commonly used methods are “X()”, “Y()”, “Z()”, “E()”, “T()” and “A()”. There are also longer name methods, but it is troublesome to write long methods, so I prepared short name methods. The longer name methods are mainly used in the source processor to make it more readable.

  • X(): return fPos.X(), detected X position
  • Y(): return fPos.Y(), detected Y position
  • Z(): return fPos.Z(), detected Z position
  • E(): return fEtotal, total energy deposit in the telescope
  • E(id: int): return fEnergyArray[id], energy deposit of each Si layer, id=0 means dE, id=1 means second layer
  • T(): return fTiming, detected timing at first layer
  • T(id: int): return fTimingArray[id], timing at the “id” th Si detector
  • A(): return fTheta_L, the angle of the event, deg unit

We use them like:

artemis [*] tree->Draw("tel1.Y():tel1.X()","","colz")
artemis [*] tree->Draw("tel1.E(0):tel1.E()","","colz")
artemis [*] tree->Draw("tel1.E():tel1.A()","","colz")

F3

last modified: 2024-01-22 by Kodai Okawa

In the physics run (production run or physics measurement), we check all the detector data like tracking detector (PPAC, MWDC), TOF (RF) and Telescope data. In order to analyse them, we prepared steering/chkf3.yaml steering file. This file includes all the information of F3 analysis.

$ artlogin (username)
$ a
artemis [0] add steering/chkf3.yaml NAME=hoge NUM=0000
artemis [1] res
artemis [2] sus
artemis [3] ls

 artemis
>   0 art::TTreeProjGroup f3check         f3check
    1 art::TAnalysisInfo analysisInfo
    2 art::TTreeProjGroup mwdca           mwdca
    3 art::TTreeProjGroup mwdcb           mwdcb
    4 art::TTreeProjGroup tel1            tel1
    5 art::TTreeProjGroup tel2            tel2
    6 art::TTreeProjGroup tel3            tel3
    7 art::TTreeProjGroup tel4            tel4
    8 art::TTreeProjGroup tel5            tel5
    9 art::TTreeProjGroup tel6            tel6
   10 art::TTreeProjGroup MUX             MUX
   11 TDirectory MWDCCalibHists  MWDC calibration

# this is the situation at 2024/01/22

There are many histogram definition, and you can freely update the histogram files.

Because this file contains most of the knowledge about the steering file, so you can test your own histogram or something based on this file.

$ cd steering
$ cp chkf3.yaml chkYourOwnName.yaml
$ vi (emacs) chkYourOwnName.yaml
# change or test something

$ acd
$ a
artemis [0] add steering/chkYourOwnName.yaml NAME=hoge NUM=0000
artemis [1] res
artmeis [2] sus

# some analysis

Gate

last modified: 2024-01-17 by Kodai Okawa

It is very important to select events for online analysis as well. There are several options to do so, and I will cover all of them. If you know other useful way, please let me know.

  • Histogram definition
  • TCutG object
  • TGateStopProcessor

For clearer understanding, we will use this figure, and we call this as default figure:

Histogram definition

We explained in the Histograms page, but again we describe about histogram definition focus on the cut part.

The default figure defined like this:

anchor:
  - &f2ppacx ["f2ppac.fX",200,-50.,50.]
  - &f2ppacy ["f2ppac.fY",200,-50.,50.]
alias:
group:
  - name: f2check
    title: f2_check
    contents:
      - name: f2PPAC X vs Y
        title: f2ppac X vs Y
        x: *f2ppacx
        y: *f2ppacy

For example, let’s add the gate to select only “-10.0 < X < 10.0”. We can use alias node to define that.

anchor:
  - &f2ppacx ["f2ppac.fX",200,-50.,50.]
  - &f2ppacy ["f2ppac.fY",200,-50.,50.]
alias:
  centerx: abs(f2ppac.fX) < 10.0;
group:
  - name: f2check
    title: f2_check
    contents:
      - name: f2PPAC X vs Y{centerx}
        title: f2ppac X vs Y{centerx}
        x: *f2ppacx
        y: *f2ppacy
        cut: centerx

Then the following histogram is created.

Also, multiple conditions can be specified at the same time.

anchor:
  - &f2ppacx ["f2ppac.fX",200,-50.,50.]
  - &f2ppacy ["f2ppac.fY",200,-50.,50.]
alias:
  centerx: abs(f2ppac.fX) < 10.0;
  centery: abs(f2ppac.fY) < 10.0;
group:
  - name: f2check
    title: f2_check
    contents:
      - name: f2PPAC X vs Y{centerx && centery}
        title: f2ppac X vs Y{centerx && centery}
        x: *f2ppacx
        y: *f2ppacy
        cut: centerx && centery

TCutG object

We can also use TCutG object to select the event. As in new commands page, let’s assume we create this TCutG ROOT file by tcutg command. And the ROOT file and TCutG object name is f2star.

If you want to use this object to select event, just add this line is fine, as long as you use userlogon.C.

anchor:
  - &f2ppacx ["f2ppac.fX",200,-50.,50.]
  - &f2ppacy ["f2ppac.fY",200,-50.,50.]
alias:
group:
  - name: f2check
    title: f2_check
    contents:
      - name: f2PPAC X vs Y{f2star}
        title: f2ppac X vs Y{f2star}
        x: *f2ppacx
        y: *f2ppacy
        cut: f2star

Of course we can use in “tree->Draw()” because this TCutG objects are automatically loaded. The following sentence generate the same figure.

artemis [] fcd 0
artemis [] zo
artemis [] tree->Draw("f2ppac.fY:f2ppac.fX>>(200,-50.,50., 200,-50.,50.)","f2star","colz")

TGateStopProcessor

The method used until now was to process just histograms and analyze them for all events in the event loop. If you know which events you don’t want, there are processors that allow you to skip the event loop under certain conditions. This may speed up the event loop.

For example. when we want to analyze only beam single event (it means the events are not coincident with SSD, and let’s suppose that condition is given by single.fID==0), let’s prepare the steering file.

Processor:
  - name: proc_gateinit
    type: art::TGateArrayInitializer
    parameter:
      OutputTransparency: 1

  - name: proc_gate
    type: art::TTreeFormulaGateProcessor
    parameter:
      Definitions:
        - "beam_single; single.fID==0"
      OutputTransparency: 1
      Verbose: 1

  - name: beam_single_gate
    type: art::TGateStopProcessor
    parameter:
      GateName: beam_single
      OutputTransparency: 1
      StopIf: 0
      Verbose: 1

To use TGateStopProcessor, we need to initialize the “gate” array object, so the first art::TGateArrayInitializer is needed. In the second processor, art::TTreeFormulaGateProcessor, we define the gate condition.

Then the art::TGateStopProcessor judges the event is skipped or not. In the case of StopIf: 0, artemis ignore the event that the condition become false. In other words, StopIf: 0 means artemis will analyze the event only when the condition is true.

Then, including this yaml file to the main steering file, you can check only the selected events.

Anchor:
  - &input ridf/@NAME@@NUM@.ridf
  - &output output/@NAME@/@NUM@/hoge@NAME@@NUM@.root
  - &histout output/@NAME@/@NUM@/hoge@NAME@@NUM@.hist.root

Processor:
  - name: timer
    type: art::TTimerProcessor

  - name: ridf
    type: art::TRIDFEventStore
    parameter:
      OutputTransparency: 1
      InputFiles:
        - *input
      SHMID: 0

  - name: mapper
    type: art::TMappingProcessor
    parameter:
      OutputTransparency: 1

# include some other steering files

  - include: gate/coin.yaml

  - name: outputtree
    type: art::TOutputTreeProcessor
    parameter:
      FileName:
        - *output
Info

We didn’t check if we can use the TCutG object in this process…

Shifter task

last modified: 2023-12-20 by Kodai Okawa

Scaler

last modified: 2023-12-20 by Kodai Okawa

Timestamp

last modified: 2023-12-15 by Kodai Okawa

Raw data checker

last modified: 2024-01-22 by Kodai Okawa

Artemis produces mainly TArtTree and the branches are TClonesArray(art::hoge). It means that all objects rely on the artemis library, and we cannot open and check the data by using normal ROOT.

Also, sometimes it is necessary top check the raw data obtained by ADC and TDC as it is. Of course, the real raw data is binary and therefore difficult to read, so we will check the raw data after the decoders.

Related processors;

How to check the raw data

1. prepare conf files

We already prepared conf/map files, but in this case, we need to prepare conf/seg files. There are two files. This is an example, so please change it according to the experimental conditions.

#modulename:
#  id: module id (it is module-specific)
#  ch: channel number
#  values:
#    - name1: [Nbin: int, min: double, max: double] it is for 2D histogram (these values vs. ch)
#    - name2: [Nbin: int, min: double, max: double] <= somehow two line needed...?

MADC32:
  id: 32
  ch: 32
  values:
    - adc: [4000, 0., 4000.]
    - tdc: [4000, 0., 4000.] # no use, but seems it needed...

V1190A:
  id: 24
  ch: 128
  values:
    - tdcL: [300, -5000., 300000.]
    - tdcT: [300, -5000., 300000.]

The module id list is here.

#segment_name:
# segid: [[dev], [fp], [det]] <= same as a map file
# type: V7XX <= defined type in modulelist.yaml
# modules:
#   - id: geo1
#   - id: geo2

V1190:
  segid: [12, 0, 7]
  type: V1190A
  modules:
    - id: 0
    - id: 1

MADC:
  segid: [12, 1, 6]
  type: MADC32
  modules:
    - id: 0
    - id: 1
    - id: 2

2. use “steering/chkseg.yaml”

Based on these two conf file, the steering/chkseg.yaml file produce rawdata histograms and TTree object. We can use steering/chkseg.yaml without any change I think.

This is an example from one CRIB experiment.

$ a
artemis [0] add steering/chkseg.yaml NAME=hoge NUM=0000
artemis [1] res
artemis [2] sus
artemis [3] ls

 artemis
>   0 TDirectory SegmentHistogram art::TSegmentCheckProcessor

artemis [4] cd 0
artemis [5] ls

 SegmentHistogram
>   0 TDirectory E7_V1190        E7_V1190
    1 TDirectory J1_V785         J1_V785
    2 TDirectory J1_MADC         J1_MADC
    3 TDirectory J1_V1190        J1_V1190

artemis [6] cd 0
artemis [7] ls


 E7_V1190
>   0 TH2F E7_V1190_0_tdcL E7_V1190_0_tdcL
    1 TH2F E7_V1190_0_tdcT E7_V1190_0_tdcT
    2 TH2F E7_V1190_1_tdcL E7_V1190_1_tdcL
    3 TH2F E7_V1190_1_tdcT E7_V1190_1_tdcT

# we can check these histograms by ht command

artemis [8] fcd 0
artemis [9] br
E7_V1190_0           vector<vector<int> >
E7_V1190_1           vector<vector<int> >
J1_V785_0            vector<int>
J1_V785_1            vector<int>
J1_V785_2            vector<int>
J1_MADC_3            vector<int>
J1_MADC_4            vector<int>
J1_MADC_5            vector<int>
J1_V1190_0           vector<vector<int> >
Info

If the module ID = 24 or 25, it is multihit TDC, so the branch become 2D vector. When you want to use std::vector method, you can use by “@” like

artemis [*] tree->Draw("J1_V785_0@.size()")

Of course we can open this output ROOT file from normal ROOT.

Subsections of Offline analysis

New processors

last modified: 2023-12-15 by

Merge files

last modified: 2023-12-15 by Kodai Okawa

Python environment

last modified: 2023-12-15 by Kodai Okawa

pyROOT

last modified: 2023-12-15 by Kodai Okawa

Analysis example

last modified: 2024-08-14 by Kodai Okawa

A brief example of an analysis flow using artemis_crib is given below. This is just the method recommended by okawak, so you can proceed with the analysis as you like.

I hope this page will give you some ideas.


  1. Get calibration paramters
  2. Concentrate on one RUN (one or two hours data) for analysis.
  3. Briefly check other RUNs to see if the trend is the same.
  4. Determine the appropriate gate (like remove noise, not precisely).
  5. Create ROOT files for all RUNs with appropriate Gate.
  6. Merging the ROOT files to one file.
  7. Determine further detailed gates (essensial gate like selecting proton).
  8. Create a ROOT file with only selected events from the original ROOT file.
  9. Repeat steps 6 and 7.
  10. Create a histogram that gives the physical quantity you want.
  11. If necessary, create a simulation and produce a histogram you want.
  12. Manipulate the histograms using macros (.C file) or pyROOT to produce the final result.

1. Concentrate on one RUN (one or two hours data) for analysis

The acquired data contains a lot of noise and other data that is not absolutely necessary for analysis, and if you use artemis to do an event loop for all events, it will take a long time. Therefore, a root file should only be created for a specific RUN (data file) to save time. (It is tempting to look at the data using with a lot of statistics, but we believe that this is done by online-analysis and concentrate on reducing useless data.)

$ artlogin (user)
$ a

artemis [] a steering/hoge.yaml NAME=run NUM=0000
artemis [] .q

As you want to look at a variety of data I think, it is convenient to create a canvas each time with ‘tree->Draw()’, instead of defining a histogram. Not defining a histogram also has the advantage that the event loop is faster.

Once the root file has been created, it can be read directly from that file, eliminating the waiting time.

$ a output/created_rootfile_path.root

artemis [] tree->Draw("hoge")

It is good idea to make a “.C” macro file to record and reproduce the analysis process.

Here are some points I think would be good to check:

  • reproduce the online-analysis
  • check if the calibration parameter is correct
  • check multiplicity of the beam tracking detector (PPAC or MWDC)
  • proper timing of PPACa/b or MWDCa/b (because we may be using multihit TDC, V1190)
  • check the beam properties difference between “beam_single” trigger and “SSD_coin” trigger
  • RF timing with “beam_single” and “SSD_coin” trigger should be different, so need to check the offset value.
  • check RF timing and contamination of the beam with “beam_single” trigger

If there are problems during the experiment, there may be many other things to check.

2. Briefly check other RUNs to see if the trend is the same

It is possible that some parameter is different for each RUN. There are many possibilities, for example, a trouble may have occurred and the conditions of the detector have changed. In such cases, it is necessary to take action, for example, to prepare several calibration parameters.

While some of these changes in parameters can be predicted in advance, unforeseen changes can also occur.

  • RF timing sometime change (relatie value)
    • -> need to modify the PID parameters
  • MUX position parameter sometimes shift
    • -> need to modify position calibration parameter

These are the problems I have encountered, but others with different tendencies may exist.

If you can anticipate it, it is good to have a plan for dealing with it at this point and move on to the next step. However, there is no need to waste time here as it can be noticed after merging the overall measurements in the following step.

3. Determine the appropriate gate (like remove noise, not precisely)
4. Create ROOT files for all RUNs with appropriate Gate
5. Merging the ROOT files to one file
6. Determine further detailed gates (essensial gate like selecting proton)
7. Create a ROOT file with only selected events from the original ROOT file
8. Repeat steps 6 and 7
9. Create a histogram that gives the physical quantity you want
10. If necessary, create a simulation and produce a histogram you want
11. Manipulate the histograms using macros (.C file) or pyROOT to produce the final result

Subsections of MC Simulation

Beam Generator

last modified: 2024-07-16 by Kodai Okawa

It is very useful to use Monte Carlo (MC) simulation to obtain various calculated values. From this section, we will show the simple example how to perform MC simulation using artemis.

First, we will set the generator of the beam that will bombard on the target. We have two kinds of generator:

  • Random parameter beam (using Random number)
  • Get beam parameter from ROOT file

After you get beam information from a measurement, second option might be useful.

Random Beam Generator

This is an example of a steering file.

Processor:
  - name: random_eventstore
    type: art::TRandomNumberEventStore
    parameter:
      OutputTransparency: 1
      MaxLoop: *loopnum

  - name: beam_generator
    type: art::TRandomBeamGenerator
    parameter:
      OutputCollection: *beam_name
      OutputTrackCollection: *track_name
      #beam particle information
      MassNum: *beam_A
      AtomicNum: *beam_Z
      ChargeNum: *beam_Z
      IniEnergy: *beam_E
      #beam tracking information
      Xsigma: 1.0 # mm
      Ysigma: 1.0 # mm
      Asigma: 1.0 # deg
      Bsigma: 1.0 # deg
      Esigma: *beam_Esigma

This produces two branch, “beam” and “track”.

  • beam: contain all information about beam ion
  • track: used for reconstract simulation

Actually “track” information is contained in “beam” branch.

Here is the detail of the type of “beam”.

artemis [] classinfo art::TParticleInfo

 art::TParticleInfo

 Data Members

                      int   fMassNumber                                
                      int   fAtomicNumber                              
                      int   fCharge                                    
                   double   fEnergy                kinetic energy in LAB system
                   double   fCurrentZ              current Z position  
                   double   fTime                  Duration time (ns)  
                   TTrack   fTrack                 tracking information in LAB system
           TLorentzVector   fVec                   lorentz vector (px, py, pz, E) of this particle
                   double   fTheta_cm              theta angle (deg) in CM system
                   double   fPhi_cm                phi angle (deg) in CM system

-- snip --

fCurrentZ is the current Z position and at the beam generation, this value will be set as 0 after this processor.

For example, the beam angle distribution will be like this.

Tree Beam Generator

The tracking information obtained from the experiment can also be used to generate the beam. In the current version, the position and angle of the beam are read from a ROOT file and the energy is given randomly.

This is an example of a steering file.

Processor:

  - name: periodic_tree
    type: art::TTreePeriodicEventStore
    parameter:
      OutputTransparency: 1
      FileName: *input
      TreeName: tree
      MaxEventNum: *loopnum

  - name: proc_copy_processor
    type: art::TBranchCopyProcessor
    parameter:
      InputCollection: f3ppac # need to inherit from TTrack
      OutputCollection: *track_name

  - name: beam_generator
    type: art::TTreeBeamGenerator
    parameter:
      InputCollection: *track_name
      OutputCollection: *beam_name
      # beam particle information
      MassNum: *beam_A
      AtomicNum: *beam_Z
      ChargeNum: *beam_Z
      IniEnergy: *beam_E
      Esigma: *beam_Esigma

It reads an object named “f3ppac”, which inherits from TTrack, from a TTree named “tree” in a file named “*input”, and creates an object of the same type as before named TParticleInfo.

Nbody Reaction

last modified: 2024-07-19 by Kodai Okawa

make a reaction considering phase space.

  • steering file example
  - name: reaction_proc
    type: art::TNBodyReactionProcessor
    parameter:
      InputCollection: *beam_name
      OutputCollection: products # size is DecayParticleNum
      OutputReactionCollection: reaction
      # beam information (for initialize TSrim)
      BeamNucleus: [*beam_Z, *beam_A] # (Z, A)
      BeamEnergy: *beam_E
      # target information
      TargetIsGas: true # false-> solid, true-> gas target
      TargetName: he # from TSrim energy loss
      TargetMassNum: 4 # hit ion
      TargetAtomicNum: 2 # hit ion
      TargetThickness: 1000 # mm (for gas target, allow up to this value)
      TargetPressure: 250 # Torr (used for gas target)
      # reaction particles information
      DecayParticleNum: 2
      ReactionMassNum: [29, 1] # will be [id=0, id=1]
      ReactionAtomicNum: [15, 1]
      ExciteLevel: [0.0, 0.0] # MeV
      # cross section file, if not, it use constant cross section for energy
      # require: "energy cross-section" format, deliminator should be a space ' '
      CrossSectionPath: path/to/cs/file
      CrossSectionType: 0 # 0-> LAB, kinematics is different, 1-> LAB, kinematics is same, 2-> CM

NOTE

  • using TSrim library, so need to set TargetName that registered this library
  • if cross section file is not found, it use constant dsigma/dE
  • cross section file format should be
# comment
# energy cross_section
0.0 0.0
0.1 1.0 # comment

# 0.2, 2.0 camma is not allowed...
  • output products is size two array, like products[0] -> id=0 particle
  • output reaction contain reaction information, like Ecm, Thetacm
artemis [] classinfo art::TReactionInfo

 art::TReactionInfo

 Data Members

                   double   fEnergy                / Ecm of the reaction
                   double   fTheta                 / Thetacm of the reaction
                   double   fX                     / reaction position at LAB system, x
                   double   fY                     / reaction position at LAB system, y
                   double   fZ                     / reaction position at LAB system, z
                   double   fExEnergy              / excited energy of residual nucleus
                ESortType   kID                                        
                ESortType   kTiming                                    
               ESortOrder   kASC                                       
               ESortOrder   kDESC   

Example of the output

We will show an example of a simulation performed for a gas target case like the steering file above. (of course we can use it also for solid target case!) Details of the reactions that took place are shown in these figures. The reaction cross section files are appropriately specified.

This figure is the reaction energy at CM system.

This distribution was created from a file of reaction cross section. The effect of beam energy spread is included, so the edge of the peak is not sharp.

According to this energy distribution, the distribution of the positions of the reactions is as follows.

The angular distribution at CM system of reactions is assumed to be uniform. This figure shows the direction of one particle that is produced from this reaction.

Also the relationship between the kinematics of the reactions will be like this.

Geometry

last modified: 2024-07-19 by Kodai Okawa

Configure detector geometry to judge if the reaction particle hit the detector or not.

material:
  - name: Vaccum # id=0
    atomic_mass: 0.0
    atomic_num: 0.0
    density: 0.0 # g/cm3

  - name: Si # id=1
    atomic_mass: 28.084
    atomic_num: 14.0
    density: 2.321

# Note: beam axis -> z, upper direction -> y
conposition:
  detector:
    - name: tel1
      strip: [16, 16]
      center_rotation: [0., 0., 322.0] # mm
      offset: [0., 0., 0.]
      distance: 244.0 
      angle: -4.0 # deg
      thickness: [0.02, 0.301, 1.494, 1.486]
      pedestal: [0., 0., 0., 0.] # MeV, below this energy, assume 0 MeV
      material: [Si]

    - name: tel2
      strip: [16, 16]
      center_rotation: [0., 0., 322.0]
      offset: [0., 0., 0.]
      distance: 154.5
      angle: 27.0
      thickness: [0.02, 0.300, 1.494, 1.485]
      pedestal: [0., 0., 0., 0.] # MeV, below this energy, assume 0 MeV
      material: [Si]

volume:
  top: # detector world
    name: TOP
    type: box # now only box is available
    material: 0 
    size: [400.0, 200.0, 1288.0] # mm

  detector:
    - name: tel1
      type: box
      material: 1 
      size: [50.0, 50.0, 1.0] # mm

    - name: tel2
      type: box
      material: 1 
      size: [50.0, 50.0, 1.0] # mm

The geometry information is used only for the judgement, so any material is actually okay.

The material node is used to define TGeoMaterial and TGeoMedium classes. From name to density node are used to make a instance of this object. This values are not used in the current processors.

The next conposition node define the detector configuration. General telescopes of the CRIB experiment consist of DSSSD and SSD (single-pad), and the node below defines the SSD of the telescope.

  • name: Name of the telescope. For example tel1, tel2, and so on.
  • strip: X x Y strip number. It is defined as an array like [16, 32], this means X:16 strips and Y:32 strips
  • thickness: Thickness of the each layer. If there are two layer, the size of the array become two. You can add to any size. The unit is mm.
  • material: material of the each layer. The string is used in SRIMlib calculation. This node is defined as a array for each layer, but if it is one, the same material is applied. For example, in example.yaml, [Si] means [Si, Si, Si, Si]. (You need to prepare SRIMlib setting beforehand!)

As for the node is center_rotation, offset, distance and angle, please see this figure.

Please note that the center_rotation and offset are defined in (x, y, z) coordinate, and distance and angle are scalar value. The unit of length is mm, angle is deg.

Info

The sign of the angle is defined as positive at this figure (right-hand system). And generally, we set z=0 at target position. (For the gas target, we set 0 at window position.)

The last part volume node, the shape of the detector will be defined by using TGeoVolume class. The TGeoVolume needs name, type, material and size. For the type, I only prepared “box”. (It means the code use only vol->MakeBox method.)

The first top node must be set because it defined “detector world”. Generally, the material is okay to set vaccum. And the material is defined in the material node, and the id (the order) can be used. So the format is like material: 0. And the size is generally set to the size of the scattering chamber, but for the safety, it is okay to set larger number. Also the unit is mm and format is (x, y, z).

Next, at the volume/detector node, we can define the detector size.

Warning

NOTE: the volume/detector/name should be the same with conposition/detector/name node.


Then, let’s check if the parameter file can be correctly used.

Anchor:

Processor:
- name: detector_initialize
  type: art::TUserGeoInitializer
  parameter:
    FileName: prm/geo/example.yaml
    Visible: true
    OutputTransparency: 1

This steering file doesn’t use event loop. Just we want to check the parameter file works well or not.

Then let’s see in the artemis!

$ acd
$ a

-- snip --

artemis [0] add steering/geo_example.yaml

-- snip --

artemis [1] ls

 artemis
>   0 TGeoVolume TOP             Top volume

artemis [2]

The detector geometry object is successfully generated! In order to check the object, please use draw command for example. (It is defined only in CRIB artemis, to draw not only histogram object. This is under development.)

Or you can get the object with some methods and obj->Draw() will work.

artemis [2] draw 0

The red box is the TOP, and the black boxes are detectors. If the detector is placed where you expect it to be, the parameters have been successfully set!

Detect particles

last modified: 2024-07-22 by Kodai Okawa

Using the defined reactions (TNBodyReactionProcessor) and geometry (TUserGeoInitialiser) so far, it is possible to determine whether the particles enter the detector after the reaction and to simulate the parameters obtained.

  - name: detector_proc
    type: art::TDetectParticleProcessor
    parameter:
      InputCollection: products
      InputTrackCollection: track
      OutputCollection: detects
      # target information (use if gas target)
      TargetIsGas: *target_is_gas # true -> gas target
      TargetName: *target_name
      TargetPressure: *target_pressure # Torr (used for gas target)
      EnergyResolution: [0.0] # x 100 = %, det id = 0, 1, ..
  • products is an array object of produced ions [id=0 ion, id=1 ion…]
  • detects is an array object of detected ions [id=0 ion, id=1 ion…]

Example of the output

We will show an example of a simulation performed for a gas target case, and resolution = 0.0.

First, this is a figure of the detected position of light particle. We defined five telescopes in this example, and we can clearly see the position of the detectors. If we focus on heavy particle, we cannot see the position distribution because all ions are stopped in the gas target.

As an example, we will show you figures of a telescope with the largest angle. Here is dE-E plots.

The relationship between energy and timing is like this.

Also, here is the angular distribution of the LAB system.

Summary

The processor created by okawak allows simple simulations to be performed without creating new sources, if the following conditions are met.

  • use latest version of artemis_crib
  • properly install and link TSrim library
  • the target is registered the TSrim library
  • relatively low energy (some parts use classical kinematics)
  • the shape of the detectors is square (may update?)

There are only two files that need to be prepared for the simulation.

Solidangle

last modified: 2023-09-29 by KodaiOkawa
  • Beam_generator
  • Nbodyreaction
  • Geometry
  • Detect_particle

As an application of the above four sections, I would like to explain how to calculate solid angles using Monte Carlo methods!