diff --git a/Trigger/TrigHypothesis/TrigMuonHypoMT/python/TrigMuonHypoMTConfig.py b/Trigger/TrigHypothesis/TrigMuonHypoMT/python/TrigMuonHypoMTConfig.py
index 135eb8f7611a43416320ec84aeadc2e68965348f..88b6cb96c27bdd3eb109f8cfe4c07470292781ae 100755
--- a/Trigger/TrigHypothesis/TrigMuonHypoMT/python/TrigMuonHypoMTConfig.py
+++ b/Trigger/TrigHypothesis/TrigMuonHypoMT/python/TrigMuonHypoMTConfig.py
@@ -262,55 +262,65 @@ class TrigMufastHypoConfig(object):
 
         tool = TrigMufastHypoTool( toolName )  
 
-        nt = len(thresholds)
-        log.debug('Set %d thresholds', nt)
-        tool.PtBins = [ [ 0, 2.5 ] ] * nt
-        tool.PtThresholds = [ [ 5.49 * GeV ] ] * nt
-        tool.PtThresholdForECWeakBRegionA = [ 3. * GeV ] * nt
-        tool.PtThresholdForECWeakBRegionB = [ 3. * GeV ] * nt
-
-        for th, thvalue in enumerate(thresholds):
-            if (thvalue == 'passthrough'):
-                tool.PtBins[th] = [-10000.,10000.]
-                tool.PtThresholds[th] = [ -1. * GeV ]
-                tool.AcceptAll = True
-            else:
-                if "idperf" in toolName or int(thvalue) < 5:
-                    thvaluename =  thvalue + 'GeV_v15a'
-                elif "0eta105" in toolName:
-                    thvaluename = thvalue+ "GeV_barrelOnly_v15a"
+        if "muoncalib" in toolName:
+            tool.DoCalib = True
+            nt = len(thresholds)
+            tool.PtBins = [ [ 0, 2.5 ] ] * nt
+            try:
+                tool.AcceptAll = False
+    
+            except LookupError:
+                raise Exception('MuFast Hypo for muoncalib chain  Misconfigured')
+        else:
+            nt = len(thresholds)
+            log.debug('Set %d thresholds', nt)
+            tool.PtBins = [ [ 0, 2.5 ] ] * nt
+            tool.PtThresholds = [ [ 5.49 * GeV ] ] * nt
+            tool.PtThresholdForECWeakBRegionA = [ 3. * GeV ] * nt
+            tool.PtThresholdForECWeakBRegionB = [ 3. * GeV ] * nt
+    
+            for th, thvalue in enumerate(thresholds):
+                if (thvalue == 'passthrough'):
+                    tool.PtBins[th] = [-10000.,10000.]
+                    tool.PtThresholds[th] = [ -1. * GeV ]
+                    tool.AcceptAll = True
                 else:
-                    thvaluename = '6GeV_v15a'
-
-
-
-                log.debug('Number of threshold = %d, Value of threshold = %s', th, thvaluename)
-
-                try:
-                    tool.AcceptAll = False
-                    values = muFastThresholds[thvaluename]
-                    tool.PtBins[th] = values[0]
-                    tool.PtThresholds[th] = [ x * GeV for x in values[1] ]
-                    log.debug('Configration of threshold[%d] %s', th, tool.PtThresholds[th])
-                    log.debug('Configration of PtBins[%d] %s', th, tool.PtBins[th])
-                    if thvaluename in muFastThresholdsForECWeakBRegion:
-                        spThres = muFastThresholdsForECWeakBRegion[thvaluename]
-                        tool.PtThresholdForECWeakBRegionA[th] = spThres[0] * GeV
-                        tool.PtThresholdForECWeakBRegionB[th] = spThres[1] * GeV
+                    if "idperf" in toolName or int(thvalue) < 5:
+                        thvaluename =  thvalue + 'GeV_v15a'
+                    elif "0eta105" in toolName:
+                        thvaluename = thvalue+ "GeV_barrelOnly_v15a"
                     else:
-                        log.debug('No special thresholds for EC weak Bfield regions for %s. Copy EC1 for region A, EC2 for region B.', thvaluename)
-                        spThres = values[0][1]
-                        if thvaluename == '2GeV' or thvaluename == '3GeV':
+                        thvaluename = '6GeV_v15a'
+    
+    
+    
+                    log.debug('Number of threshold = %d, Value of threshold = %s', th, thvaluename)
+    
+                    try:
+                        tool.AcceptAll = False
+                        values = muFastThresholds[thvaluename]
+                        tool.PtBins[th] = values[0]
+                        tool.PtThresholds[th] = [ x * GeV for x in values[1] ]
+                        log.debug('Configration of threshold[%d] %s', th, tool.PtThresholds[th])
+                        log.debug('Configration of PtBins[%d] %s', th, tool.PtBins[th])
+                        if thvaluename in muFastThresholdsForECWeakBRegion:
+                            spThres = muFastThresholdsForECWeakBRegion[thvaluename]
                             tool.PtThresholdForECWeakBRegionA[th] = spThres[0] * GeV
-                            tool.PtThresholdForECWeakBRegionB[th] = spThres[0] * GeV
+                            tool.PtThresholdForECWeakBRegionB[th] = spThres[1] * GeV
                         else:
-                            tool.PtThresholdForECWeakBRegionA[th] = spThres[1] * GeV
-                            tool.PtThresholdForECWeakBRegionB[th] = spThres[2] * GeV
-
-                        log.debug('Thresholds for A[%d]/B[%d] = %d/%d', th, th, tool.PtThresholdForECWeakBRegionA[th], tool.PtThresholdForECWeakBRegionB[th])
-
-                except LookupError:
-                    raise Exception('MuFast Hypo Misconfigured: threshold %r not supported' % thvaluename)
+                            log.debug('No special thresholds for EC weak Bfield regions for %s. Copy EC1 for region A, EC2 for region B.', thvaluename)
+                            spThres = values[0][1]
+                            if thvaluename == '2GeV' or thvaluename == '3GeV':
+                                tool.PtThresholdForECWeakBRegionA[th] = spThres[0] * GeV
+                                tool.PtThresholdForECWeakBRegionB[th] = spThres[0] * GeV
+                            else:
+                                tool.PtThresholdForECWeakBRegionA[th] = spThres[1] * GeV
+                                tool.PtThresholdForECWeakBRegionB[th] = spThres[2] * GeV
+    
+                            log.debug('Thresholds for A[%d]/B[%d] = %d/%d', th, th, tool.PtThresholdForECWeakBRegionA[th], tool.PtThresholdForECWeakBRegionB[th])
+    
+                    except LookupError:
+                        raise Exception('MuFast Hypo Misconfigured: threshold %r not supported' % thvaluename)
 
         return tool
 
diff --git a/Trigger/TrigHypothesis/TrigMuonHypoMT/src/TrigMufastHypoTool.cxx b/Trigger/TrigHypothesis/TrigMuonHypoMT/src/TrigMufastHypoTool.cxx
index af4a2f308f5a6ab010fe0abad8992f8f87ef3fd0..95feafcc0d06435cb3287f9607ac07bd51ec6696 100644
--- a/Trigger/TrigHypothesis/TrigMuonHypoMT/src/TrigMufastHypoTool.cxx
+++ b/Trigger/TrigHypothesis/TrigMuonHypoMT/src/TrigMufastHypoTool.cxx
@@ -34,6 +34,9 @@ StatusCode TrigMufastHypoTool::initialize()
      ATH_MSG_DEBUG("AcceptAll = True");
      ATH_MSG_DEBUG("Accepting all the events!");
   }
+  else if(m_doCalib){
+     ATH_MSG_DEBUG("This is muon calibration chain.");
+  }
   else {
      ATH_MSG_DEBUG("AcceptAll = False");
      m_bins.resize (m_ptBins.size());
@@ -145,6 +148,12 @@ bool TrigMufastHypoTool::decideOnSingleObject(TrigMufastHypoTool::MuonClusterInf
       zatBeam = -9999.;
    }
 
+   if(m_doCalib){
+      result = false;
+      ATH_MSG_DEBUG("This muoncalib chain is only monitored.");
+      return result;
+   }
+
    //Get the Pt cut for that eta bin
    double threshold = 0;
    float absEta = fabs(fexEta);
@@ -258,7 +267,7 @@ StatusCode TrigMufastHypoTool::decide(std::vector<MuonClusterInfo>& toolInput) c
    size_t numTrigger = m_ptBins.size(); 
    size_t numMuon = toolInput.size();
    ATH_MSG_DEBUG("Retrieved from TrigMufastHypoAlg and Running TrigMufastHypoTool for selections.");
-
+   
    if ( numTrigger == 1 ) {	// in case of HLT_mu4, HLT_mu6 and so on.
       ATH_MSG_DEBUG("Number of muon event = " << numMuon );
       ATH_MSG_DEBUG("Applying selection of single << " << m_decisionId );
diff --git a/Trigger/TrigHypothesis/TrigMuonHypoMT/src/TrigMufastHypoTool.h b/Trigger/TrigHypothesis/TrigMuonHypoMT/src/TrigMufastHypoTool.h
index 8a7a9ea0c389de2d026a304712efcc28b8fcd2da..ac8e1d0d585045ef98ef37a58afc3a67b4ec245c 100644
--- a/Trigger/TrigHypothesis/TrigMuonHypoMT/src/TrigMufastHypoTool.h
+++ b/Trigger/TrigHypothesis/TrigMuonHypoMT/src/TrigMufastHypoTool.h
@@ -100,6 +100,10 @@ class TrigMufastHypoTool: public ::AthAlgTool {
     Gaudi::Property<bool>  m_decisionPerCluster { 
 	this, "DecisionPerCluster", true, "Is multiplicity requirement refering to muons ( false ) or RoIs/clusters with muons ( false ), relevant only in when multiplicity > 1" };
 
+    Gaudi::Property< bool > m_doCalib {
+        this, "DoCalib", false, "muoncalib chain" };
+
+
     // Other members:   
     std::vector<size_t> m_bins = {0};
 
diff --git a/Trigger/TrigValidation/TrigAnalysisTest/share/q221_RDOtoRDOTrig_mt1_build.ref b/Trigger/TrigValidation/TrigAnalysisTest/share/q221_RDOtoRDOTrig_mt1_build.ref
index 78ad2ae88dcc4c4c118801069bbb3c4eebe961c5..496bb1a35d929d653fd8f9b1b4164559f514cd11 100644
--- a/Trigger/TrigValidation/TrigAnalysisTest/share/q221_RDOtoRDOTrig_mt1_build.ref
+++ b/Trigger/TrigValidation/TrigAnalysisTest/share/q221_RDOtoRDOTrig_mt1_build.ref
@@ -226,6 +226,12 @@ TrigSignatureMoniMT                                INFO -- #877042532 Features
 TrigSignatureMoniMT                                INFO HLT_j85_ftf_pf_L1J20 #1538535401
 TrigSignatureMoniMT                                INFO -- #1538535401 Events         19         19         9          -          -          -          -          9
 TrigSignatureMoniMT                                INFO -- #1538535401 Features                             15         -          -          -          -
+TrigSignatureMoniMT                                INFO HLT_mu0_muoncalib_L1MU20 #997163309
+TrigSignatureMoniMT                                INFO -- #997163309 Events          8          8          0          -          -          -          -          0
+TrigSignatureMoniMT                                INFO -- #997163309 Features                              0          -          -          -          -
+TrigSignatureMoniMT                                INFO HLT_mu0_muoncalib_L1MU4_EMPTY #782182242
+TrigSignatureMoniMT                                INFO -- #782182242 Events          0          0          0          -          -          -          -          0
+TrigSignatureMoniMT                                INFO -- #782182242 Features                              0          -          -          -          -
 TrigSignatureMoniMT                                INFO HLT_mu10_lateMu_L1MU10 #48780310
 TrigSignatureMoniMT                                INFO -- #48780310 Events           10         10         0          0          -          -          -          0
 TrigSignatureMoniMT                                INFO -- #48780310 Features                               0          0          -          -          -
diff --git a/Trigger/TrigValidation/TrigAnalysisTest/share/ref_RDOtoRDOTrig_mt1_build.ref b/Trigger/TrigValidation/TrigAnalysisTest/share/ref_RDOtoRDOTrig_mt1_build.ref
index 823a9af771838d61ce57313b4401171718bbad03..71cdadac1e701cbe603dc41f7a67f12044bcc7fe 100644
--- a/Trigger/TrigValidation/TrigAnalysisTest/share/ref_RDOtoRDOTrig_mt1_build.ref
+++ b/Trigger/TrigValidation/TrigAnalysisTest/share/ref_RDOtoRDOTrig_mt1_build.ref
@@ -226,6 +226,12 @@ TrigSignatureMoniMT                                INFO -- #877042532 Features
 TrigSignatureMoniMT                                INFO HLT_j85_ftf_pf_L1J20 #1538535401
 TrigSignatureMoniMT                                INFO -- #1538535401 Events         19         19         9          -          -          -          -          9
 TrigSignatureMoniMT                                INFO -- #1538535401 Features                             15         -          -          -          -
+TrigSignatureMoniMT                                INFO HLT_mu0_muoncalib_L1MU20 #997163309
+TrigSignatureMoniMT                                INFO -- #997163309 Events          8          8          0          -          -          -          -          0
+TrigSignatureMoniMT                                INFO -- #997163309 Features                              0          -          -          -          -
+TrigSignatureMoniMT                                INFO HLT_mu0_muoncalib_L1MU4_EMPTY #782182242
+TrigSignatureMoniMT                                INFO -- #782182242 Events          0          0          0          -          -          -          -          0
+TrigSignatureMoniMT                                INFO -- #782182242 Features                              0          -          -          -          -
 TrigSignatureMoniMT                                INFO HLT_mu10_lateMu_L1MU10 #48780310
 TrigSignatureMoniMT                                INFO -- #48780310 Events           10         10         0          0          -          -          -          0
 TrigSignatureMoniMT                                INFO -- #48780310 Features                               0          0          -          -          -
diff --git a/Trigger/TrigValidation/TrigUpgradeTest/share/full_menu_build.ref b/Trigger/TrigValidation/TrigUpgradeTest/share/full_menu_build.ref
index a9c40f9d240c676518713253f6d3ded3d7ca5b59..8b7219128677a35f401fddbee3fad96b1354ed00 100644
--- a/Trigger/TrigValidation/TrigUpgradeTest/share/full_menu_build.ref
+++ b/Trigger/TrigValidation/TrigUpgradeTest/share/full_menu_build.ref
@@ -235,6 +235,12 @@ TrigSignatureMoniMT                                 INFO -- #1538535401 Features
 TrigSignatureMoniMT                                 INFO HLT_mb_sptrk_L1RD0_FILLED #4097312640
 TrigSignatureMoniMT                                 INFO -- #4097312640 Events         20         20         -          -          -          -          -          20         
 TrigSignatureMoniMT                                 INFO -- #4097312640 Features                             -          -          -          -          -          
+TrigSignatureMoniMT                                 INFO HLT_mu0_muoncalib_L1MU20 #997163309
+TrigSignatureMoniMT                                 INFO -- #997163309 Events          20         20         0          -          -          -          -          0          
+TrigSignatureMoniMT                                 INFO -- #997163309 Features                              0          -          -          -          -          
+TrigSignatureMoniMT                                 INFO HLT_mu0_muoncalib_L1MU4_EMPTY #782182242
+TrigSignatureMoniMT                                 INFO -- #782182242 Events          20         20         0          -          -          -          -          0          
+TrigSignatureMoniMT                                 INFO -- #782182242 Features                              0          -          -          -          -   
 TrigSignatureMoniMT                                 INFO HLT_mu10_lateMu_L1MU10 #48780310
 TrigSignatureMoniMT                                 INFO -- #48780310 Events           20         20         0          0          -          -          -          0          
 TrigSignatureMoniMT                                 INFO -- #48780310 Features                               0          0          -          -          -          
diff --git a/Trigger/TrigValidation/TriggerTest/share/ref_data_v1Dev_build.ref b/Trigger/TrigValidation/TriggerTest/share/ref_data_v1Dev_build.ref
index a9c40f9d240c676518713253f6d3ded3d7ca5b59..bc4d42ea44412adf35c304db50c4b3175234432a 100644
--- a/Trigger/TrigValidation/TriggerTest/share/ref_data_v1Dev_build.ref
+++ b/Trigger/TrigValidation/TriggerTest/share/ref_data_v1Dev_build.ref
@@ -235,6 +235,12 @@ TrigSignatureMoniMT                                 INFO -- #1538535401 Features
 TrigSignatureMoniMT                                 INFO HLT_mb_sptrk_L1RD0_FILLED #4097312640
 TrigSignatureMoniMT                                 INFO -- #4097312640 Events         20         20         -          -          -          -          -          20         
 TrigSignatureMoniMT                                 INFO -- #4097312640 Features                             -          -          -          -          -          
+TrigSignatureMoniMT                                 INFO HLT_mu0_muoncalib_L1MU20 #997163309
+TrigSignatureMoniMT                                 INFO -- #997163309 Events          20         20         0          -          -          -          -          0          
+TrigSignatureMoniMT                                 INFO -- #997163309 Features                              0          -          -          -          -          
+TrigSignatureMoniMT                                 INFO HLT_mu0_muoncalib_L1MU4_EMPTY #782182242
+TrigSignatureMoniMT                                 INFO -- #782182242 Events          20         20         0          -          -          -          -          0          
+TrigSignatureMoniMT                                 INFO -- #782182242 Features                              0          -          -          -          -    
 TrigSignatureMoniMT                                 INFO HLT_mu10_lateMu_L1MU10 #48780310
 TrigSignatureMoniMT                                 INFO -- #48780310 Events           20         20         0          0          -          -          -          0          
 TrigSignatureMoniMT                                 INFO -- #48780310 Features                               0          0          -          -          -          
diff --git a/Trigger/TriggerCommon/TriggerMenuMT/python/HLTMenuConfig/Menu/LS2_v1.py b/Trigger/TriggerCommon/TriggerMenuMT/python/HLTMenuConfig/Menu/LS2_v1.py
index e9be877863f600879c7bd472805d9286faac97b6..fb67019da0f226b34b834343f457e2c21690d570 100644
--- a/Trigger/TriggerCommon/TriggerMenuMT/python/HLTMenuConfig/Menu/LS2_v1.py
+++ b/Trigger/TriggerCommon/TriggerMenuMT/python/HLTMenuConfig/Menu/LS2_v1.py
@@ -66,6 +66,9 @@ def setupMenu():
         ChainProp(name='HLT_2mu4_muonqual_L12MU4',  groups=MultiMuonGroup),
         ChainProp(name='HLT_2mu6_muonqual_L12MU6',  groups=MultiMuonGroup),
 
+       # ATR-20650
+        ChainProp(name='HLT_mu0_muoncalib_L1MU4_EMPTY', groups=SingleMuonGroup),
+        ChainProp(name='HLT_mu0_muoncalib_L1MU20',      groups=SingleMuonGroup),
      ]
 
     TriggerFlags.EgammaSlice.signatures = TriggerFlags.EgammaSlice.signatures() + [
diff --git a/Trigger/TriggerCommon/TriggerMenuMT/python/HLTMenuConfig/Menu/SignatureDicts.py b/Trigger/TriggerCommon/TriggerMenuMT/python/HLTMenuConfig/Menu/SignatureDicts.py
index a23e5cef356799be889027b88bdb9689b17c905a..0bc8ac71ea7c3118e0a506d22c8fb85991fc81f2 100644
--- a/Trigger/TriggerCommon/TriggerMenuMT/python/HLTMenuConfig/Menu/SignatureDicts.py
+++ b/Trigger/TriggerCommon/TriggerMenuMT/python/HLTMenuConfig/Menu/SignatureDicts.py
@@ -184,7 +184,7 @@ MuonChainParts = {
     'trigType'       : ['mu'],
     'etaRange'       : ['0eta2550','0eta105'],
     'threshold'      : '',
-    'extra'          : ['noL1', 'Comb', 'fast', 'msonly','lateMu', "Dr"],
+    'extra'          : ['noL1', 'Comb', 'fast', 'msonly','lateMu', "Dr", "muoncalib"],
     'IDinfo'         : [],
     'isoInfo'        : ['ivar','ivarmedium'],
     'invMassInfo'    : ['10invm70'],
diff --git a/Trigger/TriggerCommon/TriggerMenuMT/python/HLTMenuConfig/Muon/MuonDef.py b/Trigger/TriggerCommon/TriggerMenuMT/python/HLTMenuConfig/Muon/MuonDef.py
index 078d2f797c6eb6188639677849bbfbc72519759e..be2f895ecba2b9ba97564c3e0fc56cf3e1069f26 100755
--- a/Trigger/TriggerCommon/TriggerMenuMT/python/HLTMenuConfig/Muon/MuonDef.py
+++ b/Trigger/TriggerCommon/TriggerMenuMT/python/HLTMenuConfig/Muon/MuonDef.py
@@ -127,7 +127,8 @@ class MuonChainConfiguration(ChainConfigurationBase):
             "ivarmedium":[['getmuFast', 'getmuComb'], ['getmuEFSA', 'getmuEFCB', 'getmuEFIso']],
             "invM":[[],['getmuInvM']],
             "lateMu":[[],['getLateMuRoI','getLateMu']],
-            "Dr": [['getmuFastDr', 'getmuCombDr']]
+            "Dr": [['getmuFastDr', 'getmuCombDr']],
+            "muoncalib":[['getmuFast']]
         }
 
         return stepDictionary