diff --git a/documentation/release_6.2.htm b/documentation/release_6.2.htm
index b8d738acb..ccab3e59e 100644
--- a/documentation/release_6.2.htm
+++ b/documentation/release_6.2.htm
@@ -8,7 +8,8 @@
Summary of changes in STIR release 6.2
- This version is 100% backwards compatible with STIR 6.1. However, C++-17 is now required.
+ This version is 100% backwards compatible with STIR 6.1, aside from the default of the
+ tail-fitting of the scatter estimator (see below). However, C++-17 is now required.
Overall summary
@@ -55,6 +56,15 @@ New functionality
Changed functionality
+ -
+ The default minimum scale factor for tail-fitting in the scatter estimation is now 0.05 (was 0.4).
+ This (temporarily) resolves a problem that for the Siemens mMR, the default factor was too large
+ (see issue #1280.
+ WARNING:This potentially changes your scatter estimates. (You can check log files
+ of the scatter estimation to see what the scaling factors are.) However,
+ the Siemens mMR example files already lowered the default scale factor to .1, so if you used
+ those, you will get identical results.
+
-
Array::sum()
(and hence images etc) now accumulates in a variable at higher precision to avoid loss of precision.
PR #1439
diff --git a/examples/samples/scatter_estimation_par_files/scatter_estimation.par b/examples/samples/scatter_estimation_par_files/scatter_estimation.par
index b6aebf8f0..e989fc8b2 100644
--- a/examples/samples/scatter_estimation_par_files/scatter_estimation.par
+++ b/examples/samples/scatter_estimation_par_files/scatter_estimation.par
@@ -75,8 +75,10 @@ export scatter estimates of each iteration := 1
output scatter estimate name prefix := ${scatter_prefix}
output additive estimate name prefix:= ${total_additive_prefix}
-maximum scatter scaling factor := 2 ;10
-minimum scatter scaling factor := 0.4 ;0.1
+; Optionally set thresholds for tail-fitting. For most scanners, the scale factors should be a
+; bit larger than 1, but this is not always the case.
+maximum scatter scaling factor := 2
+minimum scatter scaling factor := 0.1
;Upsample and fit
; defaults to 3.
diff --git a/src/scatter_buildblock/ScatterEstimation.cxx b/src/scatter_buildblock/ScatterEstimation.cxx
index 0356c2be5..6984a054c 100644
--- a/src/scatter_buildblock/ScatterEstimation.cxx
+++ b/src/scatter_buildblock/ScatterEstimation.cxx
@@ -85,7 +85,7 @@ ScatterEstimation::set_defaults()
this->output_scatter_estimate_prefix = "";
this->output_additive_estimate_prefix = "";
this->num_scatter_iterations = 5;
- this->min_scale_value = 0.4f;
+ this->min_scale_value = 0.05f;
this->max_scale_value = 100.f;
this->half_filter_width = 3;
}