diff --git a/wimprates/bremsstrahlung.py b/wimprates/bremsstrahlung.py
index 18f5769..a9de57c 100644
--- a/wimprates/bremsstrahlung.py
+++ b/wimprates/bremsstrahlung.py
@@ -103,7 +103,7 @@ def integrand(erec):
 @wr.vectorize_first
 def rate_bremsstrahlung(w, mw, sigma_nucleon, interaction='SI',
                         m_med=float('inf'), t=None, 
-                        halo_model = wr.standard_halo_model(),**kwargs):
+                        halo_model = None,**kwargs):
     """Differential rate per unit detector mass and recoil energy of
     Bremsstrahlung elastic WIMP-nucleus scattering.
 
@@ -122,6 +122,7 @@ def rate_bremsstrahlung(w, mw, sigma_nucleon, interaction='SI',
     Further kwargs are passed to scipy.integrate.quad numeric integrator
     (e.g. error tolerance).
     """
+    halo_model = wr.standard_halo_model() if halo_model is None else halo_model
     vmin = vmin_w(w, mw)
 
     if vmin >= wr.v_max(t, halo_model.v_esc):
diff --git a/wimprates/elastic_nr.py b/wimprates/elastic_nr.py
index 9f8a1e5..7a736ac 100644
--- a/wimprates/elastic_nr.py
+++ b/wimprates/elastic_nr.py
@@ -179,7 +179,7 @@ def vmin_elastic(erec, mw):
 @wr.vectorize_first
 def rate_elastic(erec, mw, sigma_nucleon, interaction='SI',
         m_med=float('inf'), t=None, 
-        halo_model = wr.standard_halo_model(), **kwargs):
+        halo_model = None, **kwargs):
     """Differential rate per unit detector mass and recoil energy of
     elastic WIMP scattering
 
@@ -200,6 +200,7 @@ def rate_elastic(erec, mw, sigma_nucleon, interaction='SI',
 
     Analytic expressions are known for this rate, but they are not used here.
     """
+    halo_model = wr.standard_halo_model() if halo_model is None else halo_model
     v_min = vmin_elastic(erec, mw)
 
     if v_min >= wr.v_max(t, halo_model.v_esc):
diff --git a/wimprates/electron.py b/wimprates/electron.py
index 8aef834..3aefc53 100644
--- a/wimprates/electron.py
+++ b/wimprates/electron.py
@@ -146,7 +146,7 @@ def diff_xsec(q):
         # Note dblquad expects the function to be f(y, x), not f(x, y)...
         def diff_xsec(v, q):
             result = q * dme_ionization_ff(shell, erec, q)
-            result *= 1 / v * halo_model.valocity_dist(v, t)
+            result *= 1 / v * halo_model.velocity_dist(v, t)
             return result
 
         r = dblquad(
diff --git a/wimprates/migdal.py b/wimprates/migdal.py
index ff0fa52..5645131 100644
--- a/wimprates/migdal.py
+++ b/wimprates/migdal.py
@@ -41,7 +41,7 @@ def vmin_migdal(w, erec, mw):
 @wr.vectorize_first
 def rate_migdal(w, mw, sigma_nucleon, interaction='SI', m_med=float('inf'),
                 include_approx_nr=False,
-                t=None, halo_model = wr.standard_halo_model(), **kwargs):
+                t=None, halo_model = None, **kwargs):
     """Differential rate per unit detector mass and deposited ER energy of
     Migdal effect WIMP-nucleus scattering
 
@@ -65,6 +65,7 @@ def rate_migdal(w, mw, sigma_nucleon, interaction='SI', m_med=float('inf'),
     Further kwargs are passed to scipy.integrate.quad numeric integrator
     (e.g. error tolerance).
     """
+    halo_model = wr.standard_halo_model() if halo_model is None else halo_model
     include_approx_nr = 1 if include_approx_nr else 0
 
     result = 0